Li-ion UPS battery substitution in UPS...

[Fred Bloggs]

On Wednesday, October 19, 2022 at 5:03:37 AM UTC-4, Robert Roland wrote:

On Tue, 18 Oct 2022 10:43:25 -0500, Bert Hickman
be...@capturedlightning.com> wrote:

Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?
Why would you want to? There are several parameters to consider.

Li batteries age quite fast if kept at full charge. Lead-Acid
batteries last the longest when kept at full charge.

LA\'s biggest disadvantages, compared to Li, is that they are heavy and
large. For a UPS, those disadvantages are normally not important.

LA is simply the best choice for standby applications such as UPS,
emergency ligting and similar.

Looks like a lot of people never got the memo because lithium is about all you see in standby applications these days. That doesn\'t mean it\'s right, it just means that\'s what just about everybody is doing.

--
RoRo

 

[Fred Bloggs]

On Wednesday, October 19, 2022 at 5:52:37 AM UTC-4, a a wrote:

On Wednesday, 19 October 2022 at 11:03:37 UTC+2, Robert Roland wrote:
On Tue, 18 Oct 2022 10:43:25 -0500, Bert Hickman
be...@capturedlightning.com> wrote:

Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?
Why would you want to? There are several parameters to consider.

Li batteries age quite fast if kept at full charge. Lead-Acid
batteries last the longest when kept at full charge.

LA\'s biggest disadvantages, compared to Li, is that they are heavy and
large. For a UPS, those disadvantages are normally not important.

LA is simply the best choice for standby applications such as UPS,
emergency ligting and similar.
--
RoRo
wrong
in your car you use exactly: lead-acid batteries
but you don\'t use car lead-acid batteries in UPS
since in UPS you use Gel batteries

You could most certainly use wet cell lead acid in the UPS if you\'re not afraid of spillage and explosion hazards.

The ultimate lead acid batteries are the AGM. You see them used a lot in solar backup applications, the reason being they can withstand very deep discharge that would destroy a lesser battery. There are automotive versions available too, and they cost top dollar, as in ???x ( changes all the time, price is coming down though) the ordinary battery, last time I checked. In addition to surviving deep discharge, they pack a helluva wallop peak current. That\'s why they\'re the battery of choice in all those compact car starter accessories you see for sale.

 

[Don Y]

On 10/21/2022 5:51 PM, Fred Bloggs wrote:

On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem to
be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them (and
dubious, even then).

If you are having problems with battery life in UPS, look to see how it is
being charged. Many \"cook\" their batteries (poor circuit tolerances).
Also, they seem intent on recharging QUICKLY (in case another outage??)
instead of trying to prolong the batteries\' service life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not much
money there (~$0.20/pound). OTOH, if you have a bigger UPS, you can get a
fair bit back (I got over $100 for the dead batteries in my biggest UPS)

Do you really think the modern lithium battery is just a dumb collection of
cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging current
when fully charged. And that BMS is probably made by Analog Devices. Last
time I looked the charge management cuts off the float mode charge current
when it has fallen to 25% or so of the initial Ipk delivered to the
uncharged battery. And there\'s a sensitivity of 100:1 state of charge to the
temperature dependent open terminal voltage, so the process requires great
precision. Nonetheless, it\'s simple to very reliably put the lithium into
the SLA charge circuit- within reason.

Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate
a replacement battery chemistry? That the charger isn\'t actively
monitoring charge current? And determining state of charge by
noticing its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design
and drop in a \"lead-acid emulator\" for the incremental cost of the
\"emulator battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

 

[John Walliker]

On Saturday, 22 October 2022 at 02:15:25 UTC+1, Fred Bloggs wrote:

On Wednesday, October 19, 2022 at 5:52:37 AM UTC-4, a a wrote:
On Wednesday, 19 October 2022 at 11:03:37 UTC+2, Robert Roland wrote:
On Tue, 18 Oct 2022 10:43:25 -0500, Bert Hickman
be...@capturedlightning.com> wrote:

Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?
Why would you want to? There are several parameters to consider.

Li batteries age quite fast if kept at full charge. Lead-Acid
batteries last the longest when kept at full charge.

LA\'s biggest disadvantages, compared to Li, is that they are heavy and
large. For a UPS, those disadvantages are normally not important.

LA is simply the best choice for standby applications such as UPS,
emergency ligting and similar.
--
RoRo
wrong
in your car you use exactly: lead-acid batteries
but you don\'t use car lead-acid batteries in UPS
since in UPS you use Gel batteries
You could most certainly use wet cell lead acid in the UPS if you\'re not afraid of spillage and explosion hazards.

The ultimate lead acid batteries are the AGM. You see them used a lot in solar backup applications, the reason being they can withstand very deep discharge that would destroy a lesser battery. There are automotive versions available too, and they cost top dollar, as in ???x ( changes all the time, price is coming down though) the ordinary battery, last time I checked. In addition to surviving deep discharge, they pack a helluva wallop peak current. That\'s why they\'re the battery of choice in all those compact car starter accessories you see for sale.

Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then \"just work\". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.

John

 

[Don Y]

On 10/22/2022 12:52 AM, John Walliker wrote:

Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then \"just work\". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.

But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones?

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to
carry the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car,
would you expect to be able to turn it over?

 

[John Walliker]

On Saturday, 22 October 2022 at 09:06:33 UTC+1, Don Y wrote:

On 10/22/2022 12:52 AM, John Walliker wrote:
Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then \"just work\". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.
But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones?

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to
carry the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car,
would you expect to be able to turn it over?

I think it varied according to which vehicle. A couple of weeks ago I used it
every time I started the engine (1.8l petrol) of my car because the car battery had
developed a very high internal resistance and probably also had a shorted cell.
The voltage dropped to 6V on trying (and failing) to crank the engine. The
charging voltage was only about 12.5V. With the Li starter pack the engine would
start immediately. I have now replaced the battery.
In the case of the Ferrari FF (not mine, sadly) the battery was completely dead and
it took many attempts to get it started with the Li starter pack, so the Li battery
really was doing all the work. However, this was a 6.3 litre, 650HP V12 engine.
It did start in the end. Its battery accepted no charge whatsoever - it would not
even run its lights after a 20 minute drive.
In the case of the diesel van, it may well have added just enough charge to make
a difference in the 20 seconds or so between connecting it and starting the engine.
My unit has very short, very thick (6AWG) cables:

no.co/gb70

Usefully, it also has a regulated 12Vdc output.

John

 

[Don Y]

On 10/22/2022 3:41 AM, John Walliker wrote:

On Saturday, 22 October 2022 at 09:06:33 UTC+1, Don Y wrote:
On 10/22/2022 12:52 AM, John Walliker wrote:
Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then \"just work\". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.
But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones?

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to
carry the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car,
would you expect to be able to turn it over?

I think it varied according to which vehicle. A couple of weeks ago I used it
every time I started the engine (1.8l petrol) of my car because the car battery had
developed a very high internal resistance and probably also had a shorted cell.
The voltage dropped to 6V on trying (and failing) to crank the engine. The
charging voltage was only about 12.5V. With the Li starter pack the engine would
start immediately. I have now replaced the battery.
In the case of the Ferrari FF (not mine, sadly) the battery was completely dead and
it took many attempts to get it started with the Li starter pack, so the Li battery
really was doing all the work. However, this was a 6.3 litre, 650HP V12 engine.
It did start in the end. Its battery accepted no charge whatsoever - it would not
even run its lights after a 20 minute drive.
In the case of the diesel van, it may well have added just enough charge to make
a difference in the 20 seconds or so between connecting it and starting the engine.
My unit has very short, very thick (6AWG) cables:

no.co/gb70

Usefully, it also has a regulated 12Vdc output.

That\'s considerably beefier than the units I\'ve seen -- which looked more
like DMMs with dinky little (thin) leads (shirt-pocket sized)! Hence my
suspicion that they were just (rapidly) topping off a depleted battery.

 

[Fred Bloggs]

On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:

On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem to
be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them (and
dubious, even then).

If you are having problems with battery life in UPS, look to see how it is
being charged. Many \"cook\" their batteries (poor circuit tolerances).
Also, they seem intent on recharging QUICKLY (in case another outage??)
instead of trying to prolong the batteries\' service life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not much
money there (~$0.20/pound). OTOH, if you have a bigger UPS, you can get a
fair bit back (I got over $100 for the dead batteries in my biggest UPS)

Do you really think the modern lithium battery is just a dumb collection of
cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging current
when fully charged. And that BMS is probably made by Analog Devices. Last
time I looked the charge management cuts off the float mode charge current
when it has fallen to 25% or so of the initial Ipk delivered to the
uncharged battery. And there\'s a sensitivity of 100:1 state of charge to the
temperature dependent open terminal voltage, so the process requires great
precision. Nonetheless, it\'s simple to very reliably put the lithium into
the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate
a replacement battery chemistry? That the charger isn\'t actively
monitoring charge current? And determining state of charge by
noticing its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design
and drop in a \"lead-acid emulator\" for the incremental cost of the
\"emulator battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has, the replacement battery can be made to look identical to the original. Cutting off the charge current in float mode does not mean opening a relay switch or something crude like that. The replacement battery can present enough of a self-discharge current loading to make itself look real enough.

 

[Ed Lee]

On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:

On 10/22/2022 12:52 AM, John Walliker wrote:
Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then \"just work\". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.
But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones? .

My Leaf won\'t wakeup after 2 or 3 days sleeping. It\'s mostly because of the 100W power relay. I could just jumper short the relay output, when i open up the battery next time. For now, i just added a 200Wh (3S9P) Li power brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when charging. It\'s fine in this case. The Li battery mostly keep the LA battery from dropping too low.

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to
carry the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car,
would you expect to be able to turn it over?

Yes it does. But better to keep the LA when close to fully charge, and less cycling on the Li.

 

[Don Y]

On 10/22/2022 6:34 AM, Fred Bloggs wrote:

On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries
for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem
to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them
(and dubious, even then).

If you are having problems with battery life in UPS, look to see how
it is being charged. Many \"cook\" their batteries (poor circuit
tolerances). Also, they seem intent on recharging QUICKLY (in case
another outage??) instead of trying to prolong the batteries\' service
life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not
much money there (~$0.20/pound). OTOH, if you have a bigger UPS, you
can get a fair bit back (I got over $100 for the dead batteries in my
biggest UPS)

Do you really think the modern lithium battery is just a dumb collection
of cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging
current when fully charged. And that BMS is probably made by Analog
Devices. Last time I looked the charge management cuts off the float
mode charge current when it has fallen to 25% or so of the initial Ipk
delivered to the uncharged battery. And there\'s a sensitivity of 100:1
state of charge to the temperature dependent open terminal voltage, so
the process requires great precision. Nonetheless, it\'s simple to very
reliably put the lithium into the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively monitoring
charge current? And determining state of charge by noticing its
relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design and
drop in a \"lead-acid emulator\" for the incremental cost of the \"emulator
battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has,
the replacement battery can be made to look identical to the original.
Cutting off the charge current in float mode does not mean opening a relay
switch or something crude like that. The replacement battery can present
enough of a self-discharge current loading to make itself look real enough.

And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W>
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX>

$1000 premium for lithium battery pack. Same exact run-times,
same load capacity, same networking capability, same display
(literally the same module). Ah, but the more expensive one has
a shiny front panel (and isn\'t intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter;
doubtful a SOHO user would bother with it as he\'d likely not have
many such devices, many batteries to replace, etc. Note the number
of lead-acid offerings vs. lithium -- why is that?]

 

[Ed Lee]

On Saturday, October 22, 2022 at 8:16:46 AM UTC-7, Don Y wrote:

On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries
for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem
to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them
(and dubious, even then).

If you are having problems with battery life in UPS, look to see how
it is being charged. Many \"cook\" their batteries (poor circuit
tolerances). Also, they seem intent on recharging QUICKLY (in case
another outage??) instead of trying to prolong the batteries\' service
life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not
much money there (~$0.20/pound). OTOH, if you have a bigger UPS, you
can get a fair bit back (I got over $100 for the dead batteries in my
biggest UPS)

Do you really think the modern lithium battery is just a dumb collection
of cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging
current when fully charged. And that BMS is probably made by Analog
Devices. Last time I looked the charge management cuts off the float
mode charge current when it has fallen to 25% or so of the initial Ipk
delivered to the uncharged battery. And there\'s a sensitivity of 100:1
state of charge to the temperature dependent open terminal voltage, so
the process requires great precision. Nonetheless, it\'s simple to very
reliably put the lithium into the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively monitoring
charge current? And determining state of charge by noticing its
relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design and
drop in a \"lead-acid emulator\" for the incremental cost of the \"emulator
battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has,
the replacement battery can be made to look identical to the original.
Cutting off the charge current in float mode does not mean opening a relay
switch or something crude like that. The replacement battery can present
enough of a self-discharge current loading to make itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX

1500VA or 100Wh? See first comment. That\'s certainly expensive. I can get 100Wh for $28.9999

 

[Fred Bloggs]

On Saturday, October 22, 2022 at 11:16:46 AM UTC-4, Don Y wrote:

On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries
for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem
to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them
(and dubious, even then).

If you are having problems with battery life in UPS, look to see how
it is being charged. Many \"cook\" their batteries (poor circuit
tolerances). Also, they seem intent on recharging QUICKLY (in case
another outage??) instead of trying to prolong the batteries\' service
life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not
much money there (~$0.20/pound). OTOH, if you have a bigger UPS, you
can get a fair bit back (I got over $100 for the dead batteries in my
biggest UPS)

Do you really think the modern lithium battery is just a dumb collection
of cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging
current when fully charged. And that BMS is probably made by Analog
Devices. Last time I looked the charge management cuts off the float
mode charge current when it has fallen to 25% or so of the initial Ipk
delivered to the uncharged battery. And there\'s a sensitivity of 100:1
state of charge to the temperature dependent open terminal voltage, so
the process requires great precision. Nonetheless, it\'s simple to very
reliably put the lithium into the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively monitoring
charge current? And determining state of charge by noticing its
relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design and
drop in a \"lead-acid emulator\" for the incremental cost of the \"emulator
battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has,
the replacement battery can be made to look identical to the original.
Cutting off the charge current in float mode does not mean opening a relay
switch or something crude like that. The replacement battery can present
enough of a self-discharge current loading to make itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX

$1000 premium for lithium battery pack. Same exact run-times,
same load capacity, same networking capability, same display
(literally the same module). Ah, but the more expensive one has
a shiny front panel (and isn\'t intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter;
doubtful a SOHO user would bother with it as he\'d likely not have
many such devices, many batteries to replace, etc. Note the number
of lead-acid offerings vs. lithium -- why is that?]

You\'re becoming hysterical. Batteries are not precision components. Any design that\'s looking at voltage time drift or charge rates to make any decisions is deluding itself. All you end up doing is set up the user for quirky indications they\'ll just learn to ignore.

 

[Ed Lee]

On Saturday, October 22, 2022 at 2:05:28 PM UTC-7, Fred Bloggs wrote:

On Saturday, October 22, 2022 at 11:16:46 AM UTC-4, Don Y wrote:
On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid batteries
for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m concerned
about their safety in this application. New Li-ion UPS systems seem
to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed them
(and dubious, even then).

If you are having problems with battery life in UPS, look to see how
it is being charged. Many \"cook\" their batteries (poor circuit
tolerances). Also, they seem intent on recharging QUICKLY (in case
another outage??) instead of trying to prolong the batteries\' service
life.

Finally, note that many places will pay you for the lead in your old
batteries. If you\'re just using 12V7.2AHr batteries, then there\'s not
much money there (~$0.20/pound). OTOH, if you have a bigger UPS, you
can get a fair bit back (I got over $100 for the dead batteries in my
biggest UPS)

Do you really think the modern lithium battery is just a dumb collection
of cells. The products going after the SLA market almost certainly have
built-in BMS ( battery management system) that cuts off the charging
current when fully charged. And that BMS is probably made by Analog
Devices. Last time I looked the charge management cuts off the float
mode charge current when it has fallen to 25% or so of the initial Ipk
delivered to the uncharged battery. And there\'s a sensitivity of 100:1
state of charge to the temperature dependent open terminal voltage, so
the process requires great precision. Nonetheless, it\'s simple to very
reliably put the lithium into the SLA charge circuit- within reason..
Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively monitoring
charge current? And determining state of charge by noticing its
relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design and
drop in a \"lead-acid emulator\" for the incremental cost of the \"emulator
battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has,
the replacement battery can be made to look identical to the original..
Cutting off the charge current in float mode does not mean opening a relay
switch or something crude like that. The replacement battery can present
enough of a self-discharge current loading to make itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX

$1000 premium for lithium battery pack. Same exact run-times,
same load capacity, same networking capability, same display
(literally the same module). Ah, but the more expensive one has
a shiny front panel (and isn\'t intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter;
doubtful a SOHO user would bother with it as he\'d likely not have
many such devices, many batteries to replace, etc. Note the number
of lead-acid offerings vs. lithium -- why is that?]
You\'re becoming hysterical. Batteries are not precision components. Any design that\'s looking at voltage time drift or charge rates to make any decisions is deluding itself. All you end up doing is set up the user for quirky indications they\'ll just learn to ignore.

Charge rate is no big deal. A small 18650 can take up to 3A to 5A charging.. Voltage is more important. My eTank #2 is 34x 3S batteries without BMS. Typical EV equivalence is 32x, which run the cells between 3.5V to 4.2V. I run mine at 34x with cells between 3V and 4V. I check and balance them manually. No pillows and/or firecrackers yet.

My eTank #3 will have EMS.

 

[Don Y]

On 10/22/2022 2:05 PM, Fred Bloggs wrote:

On Saturday, October 22, 2022 at 11:16:46 AM UTC-4, Don Y wrote:
On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid
batteries for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m
concerned about their safety in this application. New Li-ion UPS
systems seem to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed
them (and dubious, even then).

If you are having problems with battery life in UPS, look to see
how it is being charged. Many \"cook\" their batteries (poor
circuit tolerances). Also, they seem intent on recharging QUICKLY
(in case another outage??) instead of trying to prolong the
batteries\' service life.

Finally, note that many places will pay you for the lead in your
old batteries. If you\'re just using 12V7.2AHr batteries, then
there\'s not much money there (~$0.20/pound). OTOH, if you have a
bigger UPS, you can get a fair bit back (I got over $100 for the
dead batteries in my biggest UPS)

Do you really think the modern lithium battery is just a dumb
collection of cells. The products going after the SLA market almost
certainly have built-in BMS ( battery management system) that cuts
off the charging current when fully charged. And that BMS is
probably made by Analog Devices. Last time I looked the charge
management cuts off the float mode charge current when it has fallen
to 25% or so of the initial Ipk delivered to the uncharged battery.
And there\'s a sensitivity of 100:1 state of charge to the
temperature dependent open terminal voltage, so the process requires
great precision. Nonetheless, it\'s simple to very reliably put the
lithium into the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage
source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively
monitoring charge current? And determining state of charge by noticing
its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become
disconnected? Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design
and drop in a \"lead-acid emulator\" for the incremental cost of the
\"emulator battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS
has, the replacement battery can be made to look identical to the
original. Cutting off the charge current in float mode does not mean
opening a relay switch or something crude like that. The replacement
battery can present enough of a self-discharge current loading to make
itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put a
lithium battery in them and they\'ll throw a fault -- because the battery
isn\'t discharging at the expected rate; or is charging at the wrong rate
(dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more for
those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W> MSRP $2,899.99
https://www.amazon.com/dp/B09JR6ZCQX

$1000 premium for lithium battery pack. Same exact run-times, same load
capacity, same networking capability, same display (literally the same
module). Ah, but the more expensive one has a shiny front panel (and isn\'t
intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter; doubtful
a SOHO user would bother with it as he\'d likely not have many such
devices, many batteries to replace, etc. Note the number of lead-acid
offerings vs. lithium -- why is that?]

You\'re becoming hysterical.

Hysterical? Wow, you\'ve sure got a perverse sense of reality!

Batteries are not precision components. Any
design that\'s looking at voltage time drift or charge rates to make any
decisions is deluding itself. All you end up doing is set up the user for
quirky indications they\'ll just learn to ignore.

I guess products that have done so and are in the field, WITHOUT COMPLAINT,
must not exist in your perverse reality!

Designs that just look at voltage trip points are the ones that
annoy users with erroneous data.

If I dump C/10 into a battery pack FOR TWELVE HOURS and see no change in
pack voltage, is that just a quirk? What about three hours? One hour?
Maybe I should just wait a week and, at the end of the week, the cell
voltage will spontaneously indicate a full charge?

Despite the fact that, HISTORICALLY (remember, I can watch the battery
FOREVER; it\'s built into the circuit!) it has registered a specific change
in each of those intervals?

If I\'m a constant load and, today, see the pack voltage dropping at rate R1
and, historically, it has always dropped at ~R0 (R0 << R1), should I just
assume that\'s a quirk and NOT act on it? Has my implementation ACTUALLY
changed so that the components are dissipating more power -- yet NOTHING
IS WRONG?

We EXPECT components to behave in largely predictable ways. Otherwise,
we couldn\'t design with them.

 

[Fred Bloggs]

On Saturday, October 22, 2022 at 5:29:19 PM UTC-4, Don Y wrote:

On 10/22/2022 2:05 PM, Fred Bloggs wrote:
On Saturday, October 22, 2022 at 11:16:46 AM UTC-4, Don Y wrote:
On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid
batteries for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m
concerned about their safety in this application. New Li-ion UPS
systems seem to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had blessed
them (and dubious, even then).

If you are having problems with battery life in UPS, look to see
how it is being charged. Many \"cook\" their batteries (poor
circuit tolerances). Also, they seem intent on recharging QUICKLY
(in case another outage??) instead of trying to prolong the
batteries\' service life.

Finally, note that many places will pay you for the lead in your
old batteries. If you\'re just using 12V7.2AHr batteries, then
there\'s not much money there (~$0.20/pound). OTOH, if you have a
bigger UPS, you can get a fair bit back (I got over $100 for the
dead batteries in my biggest UPS)

Do you really think the modern lithium battery is just a dumb
collection of cells. The products going after the SLA market almost
certainly have built-in BMS ( battery management system) that cuts
off the charging current when fully charged. And that BMS is
probably made by Analog Devices. Last time I looked the charge
management cuts off the float mode charge current when it has fallen
to 25% or so of the initial Ipk delivered to the uncharged battery.
And there\'s a sensitivity of 100:1 state of charge to the
temperature dependent open terminal voltage, so the process requires
great precision. Nonetheless, it\'s simple to very reliably put the
lithium into the SLA charge circuit- within reason.
Do you really think a UPS treats a battery as an ideal voltage
source?

Do you really think a product designed years ago can just tolerate a
replacement battery chemistry? That the charger isn\'t actively
monitoring charge current? And determining state of charge by noticing
its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

\"Gee, battery stopped taking charge current. Has it become
disconnected? Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design
and drop in a \"lead-acid emulator\" for the incremental cost of the
\"emulator battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS
has, the replacement battery can be made to look identical to the
original. Cutting off the charge current in float mode does not mean
opening a relay switch or something crude like that. The replacement
battery can present enough of a self-discharge current loading to make
itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put a
lithium battery in them and they\'ll throw a fault -- because the battery
isn\'t discharging at the expected rate; or is charging at the wrong rate
(dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more for
those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W> MSRP $2,899.99
https://www.amazon.com/dp/B09JR6ZCQX

$1000 premium for lithium battery pack. Same exact run-times, same load
capacity, same networking capability, same display (literally the same
module). Ah, but the more expensive one has a shiny front panel (and isn\'t
intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter; doubtful
a SOHO user would bother with it as he\'d likely not have many such
devices, many batteries to replace, etc. Note the number of lead-acid
offerings vs. lithium -- why is that?]

You\'re becoming hysterical.
Hysterical? Wow, you\'ve sure got a perverse sense of reality!
Batteries are not precision components. Any
design that\'s looking at voltage time drift or charge rates to make any
decisions is deluding itself. All you end up doing is set up the user for
quirky indications they\'ll just learn to ignore.
I guess products that have done so and are in the field, WITHOUT COMPLAINT,
must not exist in your perverse reality!

Designs that just look at voltage trip points are the ones that
annoy users with erroneous data.

If I dump C/10 into a battery pack FOR TWELVE HOURS and see no change in
pack voltage, is that just a quirk? What about three hours? One hour?
Maybe I should just wait a week and, at the end of the week, the cell
voltage will spontaneously indicate a full charge?

Despite the fact that, HISTORICALLY (remember, I can watch the battery
FOREVER; it\'s built into the circuit!) it has registered a specific change
in each of those intervals?

If I\'m a constant load and, today, see the pack voltage dropping at rate R1
and, historically, it has always dropped at ~R0 (R0 << R1), should I just
assume that\'s a quirk and NOT act on it? Has my implementation ACTUALLY
changed so that the components are dissipating more power -- yet NOTHING
IS WRONG?

We EXPECT components to behave in largely predictable ways. Otherwise,
we couldn\'t design with them.

Sounds like you\'re confusing predictability with eternality. Talk about oversimplification. The measurements you touched on are largely a big unknown, not only in principle but in practice. Any instance of a particular battery is more than just the battery itself but also it\'s entire life history of charge and discharge cycles, storage temperature, maybe a bunch of other stuff known to have significant impact on battery life. Did you do any pulsed impedance measurements with varying test loading while you were at it. IIRC the terminal impedance tells some people a lot about the battery condition.

 

[Don Y]

On 10/22/2022 11:19 AM, Ed Lee wrote:

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the UPS has,
the replacement battery can be made to look identical to the original.
Cutting off the charge current in float mode does not mean opening a relay
switch or something crude like that. The replacement battery can present
enough of a self-discharge current loading to make itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it doesn\'t
see a battery; on another, it won\'t run it\'s self checks; etc. You don\'t
know what \"firmware A\" expects of it\'s battery that \"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX

1500VA or 100Wh? See first comment. That\'s certainly expensive. I can get 100Wh for $28.9999

1500VA load capacity. Run time (for each) is 5 minutes at full load
(about 13 minutes at half load -- though the lead acid unit will go
almost 15 minutes). I have several of the first unit that I use
to power my \"bench tops\" (anything located *on* my bench vs. UNDER).

My point is, they could have taken the existing LA design and just
put lithium batteries in it, if there was no other consequence to
changing the battery chemistry. After all, they allegedly \"look
just like lead acid\", right? :> And, other than longevity and
power density, they offer no better *performance* in this example
(in practical terms: run time!)

My experience (processing LITERALLY *thousands* of discarded UPSs
that are still operational -- except for their batteries) has been
that folks think they need a UPS. And, later, decide they aren\'t
worth the trouble. Mains power, in most places, is pretty
reliable. Outages infrequent. And, systems (except life support)
tend to be reasonably robust in limiting loss due to abrupt
outages.

[Think about it; do you really do any work during an outage?
This machine -- and the modem -- have an oversized backup
that will keep them operational for a couple of hours. But,
every other machine just needs to stay \"up\" until I can get
around to noting what they were doing, at the time of the outage,
and cleanly shutting them down -- before the UPS daemon does
that unilaterally]

Most of the 12 (15?) UPSs that I have here were rescued NIB;
many with functional battery packs (some happened to have been
warehoused too long before being discarded). Anything with bad
batteries has a (recycle) value of about $5 -- largely for the
weight of the switching transformer (plastic has NO value and
the tin/steel case is $0.01/pound; circuit boards have very little
precious metals so pennies, there).

[An unattended workstation is typically idle and the disk cache has
already been written out so you\'re only concerned with outages
WHILE you are actively working on something.]

Hence my points to the OP. Think about WHY you are looking at lithium
pack replacements (they are roughly double the price of lead acid;
is the inconvenience of replacing them every three or four years
really worth the price? Are you sure you won\'t be replacing (or
discarding!) the UPS in that same interval??

[I see a market for oversized \"super caps\"; temporary energy reservoirs
to let UPSs ride out very short outages -- a second or two -- without
the need for replacement]

 

[Don Y]

On 10/22/2022 7:18 AM, Ed Lee wrote:

On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:
On 10/22/2022 12:52 AM, John Walliker wrote:
Not in mine. It uses lithium cells, is easy to hold in one hand and has
started a variety of large engines including diesel vans and a Ferrari
FF. One of the nice things about Li cells is that the starter pack can
sit on the shelf for a year without any attention and then \"just work\".
(I do leave it slightly discharged to help preserve battery life.) It
was very reasonably priced about 3 years ago, mostly because I bought it
on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40%
discount, valid for 1 hour, popped up and I took it.
But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones? .

My Leaf won\'t wakeup after 2 or 3 days sleeping. It\'s mostly because of the
100W power relay.

Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?
Why isn\'t the resting state of the relay the one that doesn\'t draw
power? Does an additional 100W \"driving load\" hurt your efficiency
that much that it has to be moved to the \"charging\" state?

I could just jumper short the relay output, when i open
up the battery next time. For now, i just added a 200Wh (3S9P) Li power
brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when
charging. It\'s fine in this case. The Li battery mostly keep the LA
battery from dropping too low.

So, you\'re just using the lithium battery to keep the leaky lead acid
battery \"topped off\". Could that brick achieve the same purpose if
connected to the battery via a pushbutton that you momentarily activate
prior to starting the vehicle? (Or, is the LA battery your main propulsion
battery pack)

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to carry
the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car, would
you expect to be able to turn it over?

Yes it does. But better to keep the LA when close to fully charge, and less
cycling on the Li.

 

[Don Y]

On 10/22/2022 2:46 PM, Fred Bloggs wrote:

On Saturday, October 22, 2022 at 5:29:19 PM UTC-4, Don Y wrote:
On 10/22/2022 2:05 PM, Fred Bloggs wrote:
On Saturday, October 22, 2022 at 11:16:46 AM UTC-4, Don Y wrote:
On 10/22/2022 6:34 AM, Fred Bloggs wrote:
On Friday, October 21, 2022 at 9:39:16 PM UTC-4, Don Y wrote:
On 10/21/2022 5:51 PM, Fred Bloggs wrote:
On Tuesday, October 18, 2022 at 5:10:35 PM UTC-4, Don Y wrote:
On 10/18/2022 8:43 AM, Bert Hickman wrote:
Does anyone have any experience swapping out old lead-acid
batteries for Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I\'m
concerned about their safety in this application. New Li-ion
UPS systems seem to be extremely expensive.
I wouldn\'t trust them -- unless the UPS manufacturer had
blessed them (and dubious, even then).

If you are having problems with battery life in UPS, look to
see how it is being charged. Many \"cook\" their batteries
(poor circuit tolerances). Also, they seem intent on
recharging QUICKLY (in case another outage??) instead of
trying to prolong the batteries\' service life.

Finally, note that many places will pay you for the lead in
your old batteries. If you\'re just using 12V7.2AHr batteries,
then there\'s not much money there (~$0.20/pound). OTOH, if you
have a bigger UPS, you can get a fair bit back (I got over
$100 for the dead batteries in my biggest UPS)

Do you really think the modern lithium battery is just a dumb
collection of cells. The products going after the SLA market
almost certainly have built-in BMS ( battery management system)
that cuts off the charging current when fully charged. And that
BMS is probably made by Analog Devices. Last time I looked the
charge management cuts off the float mode charge current when it
has fallen to 25% or so of the initial Ipk delivered to the
uncharged battery. And there\'s a sensitivity of 100:1 state of
charge to the temperature dependent open terminal voltage, so
the process requires great precision. Nonetheless, it\'s simple
to very reliably put the lithium into the SLA charge circuit-
within reason.
Do you really think a UPS treats a battery as an ideal voltage
source?

Do you really think a product designed years ago can just tolerate
a replacement battery chemistry? That the charger isn\'t actively
monitoring charge current? And determining state of charge by
noticing its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs
replacing?

\"Gee, battery stopped taking charge current. Has it become
disconnected? Has it failed?\"

Why are lithium based solutions MULTIPLES of the price of
lead-acid solutions? Surely they could just take an EXISTING lead
acid design and drop in a \"lead-acid emulator\" for the incremental
cost of the \"emulator battery\" over the lead-acid original.

Maybe there\'s more to the technology than you think!

Not really. I don\'t care what kind of battery charge management the
UPS has, the replacement battery can be made to look identical to
the original. Cutting off the charge current in float mode does not
mean opening a relay switch or something crude like that. The
replacement battery can present enough of a self-discharge current
loading to make itself look real enough.
And, you\'ll discover on one UPS the UPS won\'t turn on because it
doesn\'t see a battery; on another, it won\'t run it\'s self checks; etc.
You don\'t know what \"firmware A\" expects of it\'s battery that
\"firmware B\" doesn\'t.

All of the battery-backed products I\'ve designed predated lithium. Put
a lithium battery in them and they\'ll throw a fault -- because the
battery isn\'t discharging at the expected rate; or is charging at the
wrong rate (dv/dt); or, the monitoring circuitry appears defective;
etc.

\"Hey, let\'s make this lithium battery look EXACTLY like a lead acid --
so it HAS NO ADVANTAGES over a lead acid battery! But, we can charge
more for those non-differences!\"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W> MSRP $2,899.99
https://www.amazon.com/dp/B09JR6ZCQX

$1000 premium for lithium battery pack. Same exact run-times, same
load capacity, same networking capability, same display (literally the
same module). Ah, but the more expensive one has a shiny front panel
(and isn\'t intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the
cost of an additional rack unit. *Might* be important in a datacenter;
doubtful a SOHO user would bother with it as he\'d likely not have many
such devices, many batteries to replace, etc. Note the number of
lead-acid offerings vs. lithium -- why is that?]

You\'re becoming hysterical.
Hysterical? Wow, you\'ve sure got a perverse sense of reality!
Batteries are not precision components. Any design that\'s looking at
voltage time drift or charge rates to make any decisions is deluding
itself. All you end up doing is set up the user for quirky indications
they\'ll just learn to ignore.
I guess products that have done so and are in the field, WITHOUT
COMPLAINT, must not exist in your perverse reality!

Designs that just look at voltage trip points are the ones that annoy
users with erroneous data.

If I dump C/10 into a battery pack FOR TWELVE HOURS and see no change in
pack voltage, is that just a quirk? What about three hours? One hour?
Maybe I should just wait a week and, at the end of the week, the cell
voltage will spontaneously indicate a full charge?

Despite the fact that, HISTORICALLY (remember, I can watch the battery
FOREVER; it\'s built into the circuit!) it has registered a specific
change in each of those intervals?

If I\'m a constant load and, today, see the pack voltage dropping at rate
R1 and, historically, it has always dropped at ~R0 (R0 << R1), should I
just assume that\'s a quirk and NOT act on it? Has my implementation
ACTUALLY changed so that the components are dissipating more power -- yet
NOTHING IS WRONG?

We EXPECT components to behave in largely predictable ways. Otherwise, we
couldn\'t design with them.

Sounds like you\'re confusing predictability with eternality. Talk about
oversimplification. The measurements you touched on are largely a big
unknown, not only in principle but in practice. Any instance of a particular
battery is more than just the battery itself but also it\'s entire life
history of charge and discharge cycles, storage temperature, maybe a bunch
of other stuff known to have significant impact on battery life. Did you do
any pulsed impedance measurements with varying test loading while you were
at it. IIRC the terminal impedance tells some people a lot about the battery
condition.

No. You\'re overcomplicating things! You want dimensioned values for
observations; I just want *trends*.

I don\'t care what the rate of current flow out of the battery is FOR
THIS DEVICE. I know the nominal design rate and have selected the battery
with that in mind. Nor do I care how \"robust\" this particular battery
happens to be -- it may have been sitting on a shelf in the stockroom
a few months longer than some other battery. Or, the specific gravity
of the electrolyte may be at the other end of the manufacturer\'s tolerance.

The *user* only cares about:
- how long will the unit remain operational in the absence of power
(will I be able to finish the uninterruptible process that I have
begun before it unilaterally shuts down?)
- how long will the battery continue to provide this level of
performance before requiring replacement

As the battery is continuously observable, I can make those predictions
FOR THIS BATTERY IN THIS DEVICE.

You WATCH THE BATTERY. FOREVER. You TAKE NOTES. You don\'t care if it
performs identically to every other battery. Rather, you notice how THIS
battery performs in THIS circuit with THESE tolerances in THESE
environmental conditions. You expect it to perform roughly the same,
tomorrow. And, you expect its performance to gradually degrade up to
a point where it fails to meet the design goals.

BEFORE it gets to that point (and pisses off the user), you alert the user
to that fact.

When the battery is replaced, you restart the observation process anew.

And, you didn\'t have to incur additional manufacturing test or calibration
steps to provide this information!

 

[Ed Lee]

On Saturday, October 22, 2022 at 2:53:30 PM UTC-7, Don Y wrote:

On 10/22/2022 7:18 AM, Ed Lee wrote:
On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:
On 10/22/2022 12:52 AM, John Walliker wrote:
Not in mine. It uses lithium cells, is easy to hold in one hand and has
started a variety of large engines including diesel vans and a Ferrari
FF. One of the nice things about Li cells is that the starter pack can
sit on the shelf for a year without any attention and then \"just work\".
(I do leave it slightly discharged to help preserve battery life.) It
was very reasonably priced about 3 years ago, mostly because I bought it
on an Amazon \"flash\" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40%
discount, valid for 1 hour, popped up and I took it.
But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting \"unusable\" coulombs to useful ones? .

My Leaf won\'t wakeup after 2 or 3 days sleeping. It\'s mostly because of the
100W power relay.
Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?

No, 100W when the car is on. After a few days, the 12V battery is too weak to pull the 100W power relay (switching 400V on).

Why isn\'t the resting state of the relay the one that doesn\'t draw
power? Does an additional 100W \"driving load\" hurt your efficiency
that much that it has to be moved to the \"charging\" state?
I could just jumper short the relay output, when i open
up the battery next time. For now, i just added a 200Wh (3S9P) Li power
brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when
charging. It\'s fine in this case. The Li battery mostly keep the LA
battery from dropping too low.
So, you\'re just using the lithium battery to keep the leaky lead acid
battery \"topped off\". Could that brick achieve the same purpose if
connected to the battery via a pushbutton that you momentarily activate
prior to starting the vehicle? (Or, is the LA battery your main propulsion
battery pack)

Yes, i also did an emergency jump charging from 400V to 12V with 5S5P 200K resistor. Not very efficient, but works and i happened to have the resistors in the car, and 400V tap in the backseat. The traction/propulsion battery is 24kWh 96S Li.

Most of the units I\'ve seen have ~16AWG leads -- hardly enough to carry
the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car, would
you expect to be able to turn it over?

Yes it does. But better to keep the LA when close to fully charge, and less
cycling on the Li.

 

[Don Y]

On 10/22/2022 3:05 PM, Ed Lee wrote:

My Leaf won\'t wakeup after 2 or 3 days sleeping. It\'s mostly because of
the 100W power relay.
Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?

No, 100W when the car is on. After a few days, the 12V battery is too weak
to pull the 100W power relay (switching 400V on).

Is there a parasitic drain on that battery? Or, is it just undersized
for the task? (one would expect a car sitting for 2 or 3 days to be
somewhat \"normal use\")

Why isn\'t the resting state of the relay the one that doesn\'t draw power?
Does an additional 100W \"driving load\" hurt your efficiency that much that
it has to be moved to the \"charging\" state?
I could just jumper short the relay output, when i open up the battery
next time. For now, i just added a 200Wh (3S9P) Li power brick (around 5
pounds) to the LA battery. The Li BMS cutoff at 11.5V when charging.
It\'s fine in this case. The Li battery mostly keep the LA battery from
dropping too low.
So, you\'re just using the lithium battery to keep the leaky lead acid
battery \"topped off\". Could that brick achieve the same purpose if
connected to the battery via a pushbutton that you momentarily activate
prior to starting the vehicle? (Or, is the LA battery your main
propulsion battery pack)

Yes, i also did an emergency jump charging from 400V to 12V with 5S5P 200K
resistor. Not very efficient, but works and i happened to have the
resistors in the car, and 400V tap in the backseat. The traction/propulsion
battery is 24kWh 96S Li.

This suggests either replacing the battery with something with less
leakage/more reserve (assuming there is no unintentional leak)
or just installing the lithium battery as a built-in jump starter.

Though your approach suggests you don\'t have to worry about
keeping the lithium charged if permanently installed (?)