18650 battery capacity range.

[Ian Field]

Having discovered that recycling bins in various shops are a good source of
lithium battery packs that can be put to various uses, I notice quite a
spread in claimed Ah capacities on the information labels.

The first aquisition was labelled "5.2Ah" - there weren't any parallel
combinations as it contained an uneven number of cells.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel pairs -
so I assume the individual cell capacity is 2.1Ah.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so I'm
wondering if I'm missing something?!

Thanks for any help.

 

[Brian Gregory]

On 21/12/2014 17:49, Ian Field wrote:

Having discovered that recycling bins in various shops are a good source
of lithium battery packs that can be put to various uses, I notice quite
a spread in claimed Ah capacities on the information labels.

The first aquisition was labelled "5.2Ah" - there weren't any parallel
combinations as it contained an uneven number of cells.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so I'm
wondering if I'm missing something?!

Thanks for any help.

Maybe it's like with Nickel metal hydride cells where they have slowly
leaned to make higher and higher capacity cells of the same size?

Also I believe 18650 sometimes include protection ICs, sometimes not.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

 

[Ian Field]

"Brian Gregory" <bvdvgvrvevgvovrvy@gmail.com> wrote in message
news:m77nm6$gr9$1@dont-email.me...

On 21/12/2014 17:49, Ian Field wrote:
Having discovered that recycling bins in various shops are a good source
of lithium battery packs that can be put to various uses, I notice quite
a spread in claimed Ah capacities on the information labels.

The first aquisition was labelled "5.2Ah" - there weren't any parallel
combinations as it contained an uneven number of cells.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so I'm
wondering if I'm missing something?!

Thanks for any help.

Maybe it's like with Nickel metal hydride cells where they have slowly
leaned to make higher and higher capacity cells of the same size?

Also I believe 18650 sometimes include protection ICs, sometimes not.

One of the packs I stripped for cells said "5.2Ah" in the info label - a
quick search didn't find any 18650 cells higher than about 3.4Ah.

One of the packs had parallel pairs, the 5.2Ah pack had an odd number of
cells, so parallel pairs isn't likely. The pack with parallel pairs was
marked "4.2Ah", so I assume the individual cells are 2.1Ah.

 

[Robert Roland]

On Mon, 22 Dec 2014 18:40:12 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

One of the packs had parallel pairs, the 5.2Ah pack had an odd number of
cells, so parallel pairs isn't likely.

I have seen laptop batteries with three cells in parallel. I think it
was 3x3, or 3S3P.
--
RoRo

 

[Ian Field]

"Robert Roland" <fake@ddress.no> wrote in message
news:cq5j9adrk5l6rhj5lrclb09gjmej9vf35u@4ax.com...

On Mon, 22 Dec 2014 18:40:12 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

One of the packs had parallel pairs, the 5.2Ah pack had an odd number of
cells, so parallel pairs isn't likely.

I have seen laptop batteries with three cells in parallel. I think it
was 3x3, or 3S3P.

Is there a derating curve for parallels, or do you actually get the sum of
all the capacities?

 

[Charlie+]

On Tue, 23 Dec 2014 17:26:11 +0100, Robert Roland <fake@ddress.no> wrote
as underneath :

On Mon, 22 Dec 2014 18:40:12 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

One of the packs had parallel pairs, the 5.2Ah pack had an odd number of
cells, so parallel pairs isn't likely.

I have seen laptop batteries with three cells in parallel. I think it
was 3x3, or 3S3P.

Yes Ive seen 3S3P as well, each 3P set of cells having separated control
and monitoring circuitry. C+

 

[Robert Roland]

On Tue, 23 Dec 2014 17:43:19 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

Is there a derating curve for parallels, or do you actually get the sum of
all the capacities?

You do get the sum of the capacity of all the cells.

Also, since the internal remittances are also paralleled, you get a
battery that has less internal resistance and therefore is capable of
delivering more current.

The disadvantage of paralleling versus a single, bigger cell is size
and weight. You will hardly ever see a model airplane with a parallel
setup, since weight is so important in a plane.

Lithium cells are well suited for parallel operation, since they are
charged to a specific voltage.
--
RoRo

 

[Ian Field]

"Robert Roland" <fake@ddress.no> wrote in message
news:tl9l9adm819q403c1uebd7eevovkstjecq@4ax.com...

On Tue, 23 Dec 2014 17:43:19 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

Is there a derating curve for parallels, or do you actually get the sum of
all the capacities?

You do get the sum of the capacity of all the cells.

Also, since the internal remittances are also paralleled, you get a
battery that has less internal resistance and therefore is capable of
delivering more current.

The disadvantage of paralleling versus a single, bigger cell is size
and weight. You will hardly ever see a model airplane with a parallel
setup, since weight is so important in a plane.

Lithium cells are well suited for parallel operation, since they are
charged to a specific voltage.

There was an article on paralleling lithium in a past issue of Elektor, they
focussed on the equalising current of joining 2 cells with dissimilar charge
and making sure charge/discharge ratings weren't exceeded.

The article didn't answer any of my questions - some of the packs I
harvested contained parallel cells that were like that since manufacture.

 

[~misfit~]

Once upon a time on usenet Ian Field wrote:

Having discovered that recycling bins in various shops are a good
source of lithium battery packs that can be put to various uses, I
notice quite a spread in claimed Ah capacities on the information
labels.

Claimed and actual aren't the same.

The first aquisition was labelled "5.2Ah" - there weren't any parallel
combinations as it contained an uneven number of cells.

Odd. <g> Either outrageous claim or some awesome electronic trickery going
on.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

That's a reasonable capacity for an 18650.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so I'm
wondering if I'm missing something?!

IME 18650 capacity varies from abpout 1.2Ah to 3.2Ah depending on age of
cell (newer ones are improved), price of cell and source. Also often claimed
capacity and actual are very different. Again IME Japanese cells have a much
higher capacity than most Chinese cells. I've found that laptop cells in the
last couple of years average around 2.6Ah whilst (DIY-level) powertool
battery packs from the same period tend to average 1.5Ah. The difference is
likely down to the cost of the devices they're powering.

Trade powertools often have 2.5 - 3.0Ah cells fitted but cost 3x what the
DIY versions cost. Likely a goodly chunk of that increased cost is down to
the price of the cells.

I wish I could find (and access) recycling bins such as you mention. The
only time I found one it had a slot to drop the battery pack in - I couldn't
get anything out. When I asked the store manager if I could have a look with
the view of re-using a pack or two I was told it wasn't possible as they
take over responsibilty for proper recycling of the batteries when their
customers put them in there and he has no control over what I would then go
on to do with them. In short it was a legal thing. Damn red tape!
--
Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)

 

[~misfit~]

Once upon a time on usenet Robert Roland wrote:

On Tue, 23 Dec 2014 17:43:19 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

Is there a derating curve for parallels, or do you actually get the
sum of all the capacities?

You do get the sum of the capacity of all the cells.

Also, since the internal remittances are also paralleled, you get a
battery that has less internal resistance and therefore is capable of
delivering more current.

The disadvantage of paralleling versus a single, bigger cell is size
and weight. You will hardly ever see a model airplane with a parallel
setup, since weight is so important in a plane.

Lithium cells are well suited for parallel operation, since they are
charged to a specific voltage.

Question for you;

I've pulled a couple of laptop battery packs apart for the cells. I have an
LED headlamp that I use quite a bit which takes two 18650s in parallel (but
will of course run off one). I have no elegant way of checking the remaining
capacity of the cells I'm using. Just today I decided to charge the two
(Sony) cells that I have in it and, in my 'dumb' charger that switches off
at 4.2v for each cell one only charged for 30 minutes while the other is
still charging three hours later. (It charges at 500mA.)

What can I deduce from this? Is the cell that took little charge better than
the one that took a lot or vice-versa? Is it fine to continue using this
pair together? Is using 18650s in parallel like (the ideal of) communism -
'from each according to it's ability and to each according to it's needs'?
Oh, the headlamp wasn't dimming so the pack wasn't 'flat'. It's just it'd
been used for a few hours so I wanted to top it up.

Cheers,
--
Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)

 

[Ian Field]

"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:majsac$fpn$1@dont-email.me...

Once upon a time on usenet Robert Roland wrote:
On Tue, 23 Dec 2014 17:43:19 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

Is there a derating curve for parallels, or do you actually get the
sum of all the capacities?

You do get the sum of the capacity of all the cells.

Also, since the internal remittances are also paralleled, you get a
battery that has less internal resistance and therefore is capable of
delivering more current.

The disadvantage of paralleling versus a single, bigger cell is size
and weight. You will hardly ever see a model airplane with a parallel
setup, since weight is so important in a plane.

Lithium cells are well suited for parallel operation, since they are
charged to a specific voltage.

Question for you;

I've pulled a couple of laptop battery packs apart for the cells. I have
an LED headlamp that I use quite a bit which takes two 18650s in parallel
(but will of course run off one). I have no elegant way of checking the
remaining capacity of the cells I'm using. Just today I decided to charge
the two (Sony) cells that I have in it and, in my 'dumb' charger that
switches off at 4.2v for each cell one only charged for 30 minutes while
the other is still charging three hours later. (It charges at 500mA.)

What can I deduce from this? Is the cell that took little charge better
than the one that took a lot or vice-versa? Is it fine to continue using
this pair together? Is using 18650s in parallel like (the ideal of)
communism - 'from each according to it's ability and to each according to
it's needs'? Oh, the headlamp wasn't dimming so the pack wasn't 'flat'.
It's just it'd been used for a few hours so I wanted to top it up.

The current tails off as charging progresses, I'd assume the one that
doesn't take much current for long has lost a chunk of its capacity.

There are hazards in recharging an over discharged cell - some datasheets
and appnotes show a constant power charging phase on the control chip for
this situation.

In any event; you should avoid exceeding the 4.2V on the terminals - they
tend to vent with flaming gas if overcharged!!!

 

[Ian Field]

"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:majrsg$e7s$1@dont-email.me...

Once upon a time on usenet Ian Field wrote:
Having discovered that recycling bins in various shops are a good
source of lithium battery packs that can be put to various uses, I
notice quite a spread in claimed Ah capacities on the information
labels.

Claimed and actual aren't the same.

The first aquisition was labelled "5.2Ah" - there weren't any parallel
combinations as it contained an uneven number of cells.

Odd. <g> Either outrageous claim or some awesome electronic trickery going
on.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

That's a reasonable capacity for an 18650.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so I'm
wondering if I'm missing something?!

IME 18650 capacity varies from abpout 1.2Ah to 3.2Ah depending on age of
cell (newer ones are improved), price of cell and source. Also often
claimed capacity and actual are very different. Again IME Japanese cells
have a much higher capacity than most Chinese cells. I've found that
laptop cells in the last couple of years average around 2.6Ah whilst
(DIY-level) powertool battery packs from the same period tend to average
1.5Ah. The difference is likely down to the cost of the devices they're
powering.

Trade powertools often have 2.5 - 3.0Ah cells fitted but cost 3x what the
DIY versions cost. Likely a goodly chunk of that increased cost is down to
the price of the cells.

I wish I could find (and access) recycling bins such as you mention. The
only time I found one it had a slot to drop the battery pack in - I
couldn't get anything out.

In a certain supermarket; the battery recycling is a bit smaller than an oil
drum and has a sort of plastic chimney with a slot to drop the cells in.

On one occasion it seemed fixed on so I couldn't figure how to shift it - I
thought they'd got wise to me.

More recently it was just dropped in place - but it had recently been
emptied, so I wouldn't have been able to reach anything interesting.

Also the security guard usually lurks within yards of the recycling - so I
have to pick my moment when he wanders off.

Building supplies/DIY/tool shops is a potential resource I keep meaning to
check out - it would probably help if I went in there to spend some money
and asked on the offchance.

 

[~misfit~]

Once upon a time on usenet Ian Field wrote:

"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:majsac$fpn$1@dont-email.me...
Once upon a time on usenet Robert Roland wrote:
On Tue, 23 Dec 2014 17:43:19 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:

Is there a derating curve for parallels, or do you actually get the
sum of all the capacities?

You do get the sum of the capacity of all the cells.

Also, since the internal remittances are also paralleled, you get a
battery that has less internal resistance and therefore is capable
of delivering more current.

The disadvantage of paralleling versus a single, bigger cell is size
and weight. You will hardly ever see a model airplane with a
parallel setup, since weight is so important in a plane.

Lithium cells are well suited for parallel operation, since they are
charged to a specific voltage.

Question for you;

I've pulled a couple of laptop battery packs apart for the cells. I
have an LED headlamp that I use quite a bit which takes two 18650s
in parallel (but will of course run off one). I have no elegant way
of checking the remaining capacity of the cells I'm using. Just
today I decided to charge the two (Sony) cells that I have in it
and, in my 'dumb' charger that switches off at 4.2v for each cell
one only charged for 30 minutes while the other is still charging
three hours later. (It charges at 500mA.) What can I deduce from this? Is
the cell that took little charge
better than the one that took a lot or vice-versa? Is it fine to
continue using this pair together? Is using 18650s in parallel like
(the ideal of) communism - 'from each according to it's ability and
to each according to it's needs'? Oh, the headlamp wasn't dimming so
the pack wasn't 'flat'. It's just it'd been used for a few hours so
I wanted to top it up.

The current tails off as charging progresses, I'd assume the one that
doesn't take much current for long has lost a chunk of its capacity.

Or the other ones internal resistance has gone high? It took six hours to
charge and was fairly warm by the end. 2.5w going in to charge them and I'd
say from halfway through it was radiating 2w of that as heat. For now I've
just put the one that was charged in 30 minutes into the headlamp and will
see how long it lasts. However it's been wet here for a while so in a day or
two....

There are hazards in recharging an over discharged cell - some
datasheets and appnotes show a constant power charging phase on the
control chip for this situation.

I know nothing about this charger other than
http://www.mrpositive.co.nz/camelion-usb-18650-battery-charger/
http://www.camelionbattery.com/index.php?option=com_sobi2&sobi2Task=sobi2Details&catid=104&sobi2Id=963&Itemid=115&lang=en

In any event; you should avoid exceeding the 4.2V on the terminals -
they tend to vent with flaming gas if overcharged!!!

Indeed. This charger stops charging at 4.2v (apparently).

Cheers,
--
Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)

 

[~misfit~]

Once upon a time on usenet Ian Field wrote:

"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:majrsg$e7s$1@dont-email.me...
Once upon a time on usenet Ian Field wrote:
Having discovered that recycling bins in various shops are a good
source of lithium battery packs that can be put to various uses, I
notice quite a spread in claimed Ah capacities on the information
labels.

Claimed and actual aren't the same.

The first aquisition was labelled "5.2Ah" - there weren't any
parallel combinations as it contained an uneven number of cells.

Odd. <g> Either outrageous claim or some awesome electronic trickery
going on.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

That's a reasonable capacity for an 18650.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so
I'm wondering if I'm missing something?!

IME 18650 capacity varies from abpout 1.2Ah to 3.2Ah depending on
age of cell (newer ones are improved), price of cell and source.
Also often claimed capacity and actual are very different. Again IME
Japanese cells have a much higher capacity than most Chinese cells.
I've found that laptop cells in the last couple of years average
around 2.6Ah whilst (DIY-level) powertool battery packs from the
same period tend to average 1.5Ah. The difference is likely down to the
cost of the devices
they're powering.

Trade powertools often have 2.5 - 3.0Ah cells fitted but cost 3x
what the DIY versions cost. Likely a goodly chunk of that increased
cost is down to the price of the cells.

I wish I could find (and access) recycling bins such as you mention.
The only time I found one it had a slot to drop the battery pack in
- I couldn't get anything out.

In a certain supermarket; the battery recycling is a bit smaller than
an oil drum and has a sort of plastic chimney with a slot to drop the
cells in.
On one occasion it seemed fixed on so I couldn't figure how to shift
it - I thought they'd got wise to me.

More recently it was just dropped in place - but it had recently been
emptied, so I wouldn't have been able to reach anything interesting.

Also the security guard usually lurks within yards of the recycling -
so I have to pick my moment when he wanders off.

Building supplies/DIY/tool shops is a potential resource I keep
meaning to check out - it would probably help if I went in there to
spend some money and asked on the offchance.

Thanks for the reply. I'm an invalid with limited mobility so 'shopping' for
a battery recycle drop-off isn't really an option.

Last year I had a rare windfall just as my cordless drill and (corded)
jigsaw both started playing up terminally. I used the money to buy myself
some new tools, Bosch DIY range. "Power4ALL" 18v Li-Ion;
http://www.bosch-do-it.co.nz/nz/en/diy/power-tools/c203621/p116076/18-volt-lithium-ion-cordless-system/psr-18-li-2.html
http://www.bosch-do-it.co.nz/nz/en/diy/power-tools/c203668/p116172/18-volt-lithium-ion-cordless-system/pst-18-li.html
and, just for good measure;
http://www.bosch-do-it.co.nz/nz/en/diy/power-tools/c203668/p116616/18-volt-lithium-ion-cordless-system/pks-18-li.html

The first two came with two battery packs each and, as I don't use three
tools at once I sorted out the two with the newest date stamp, charged them
fully then discharged about half-way (the first two tools have 'battery
gauges'). Then I put them in zip-lock bags and in the fridge. From using the
tools quite a bit in the first couple of months I think the 1.2Ah battery
claim is *very* conservative. Maybe so tradesmen don't use these for light /
medium duty rather than trade tools?

They charge *so* much for replacement batteries that if I'd just bought the
four batteries it would have cost me nearly 70% of what the three tools, two
chargers and four batteries cost. So I'm going to get every last bit of use
out of the batteries I have - On my income I'll really need to baby these
puppies as I doubt I'll ever be able to replace them again. That said
they're excellent tools. I used to work as a cabinetmaker and used
trade-quaility Makita tools and, after having these ~9 months and using them
a lot as they were 'new toys' they feel better made than the Makitas ever
did.

LOL. The drill has something like 5x the torque of my old cheapie cordless
and, when I was testing it out after I bought it I sprained my wrist driving
huge screws into and out of some waste pine! Heh, I even removed the
galvanising off the screws.
--
Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)

 

[Ian Field]

"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:mammcl$850$1@dont-email.me...

Once upon a time on usenet Ian Field wrote:
"~misfit~" <shaun.at.pukekohe@gmail.com> wrote in message
news:majrsg$e7s$1@dont-email.me...
Once upon a time on usenet Ian Field wrote:
Having discovered that recycling bins in various shops are a good
source of lithium battery packs that can be put to various uses, I
notice quite a spread in claimed Ah capacities on the information
labels.

Claimed and actual aren't the same.

The first aquisition was labelled "5.2Ah" - there weren't any
parallel combinations as it contained an uneven number of cells.

Odd. <g> Either outrageous claim or some awesome electronic trickery
going on.

The next rescue was marked "4.2Ah", and contained 3 sets of parallel
pairs - so I assume the individual cell capacity is 2.1Ah.

That's a reasonable capacity for an 18650.

The next was lowest yet at 2.0Ah.

This seems to be quite a spread for apparently identical cells, so
I'm wondering if I'm missing something?!

IME 18650 capacity varies from abpout 1.2Ah to 3.2Ah depending on
age of cell (newer ones are improved), price of cell and source.
Also often claimed capacity and actual are very different. Again IME
Japanese cells have a much higher capacity than most Chinese cells.
I've found that laptop cells in the last couple of years average
around 2.6Ah whilst (DIY-level) powertool battery packs from the
same period tend to average 1.5Ah. The difference is likely down to the
cost of the devices
they're powering.

Trade powertools often have 2.5 - 3.0Ah cells fitted but cost 3x
what the DIY versions cost. Likely a goodly chunk of that increased
cost is down to the price of the cells.

I wish I could find (and access) recycling bins such as you mention.
The only time I found one it had a slot to drop the battery pack in
- I couldn't get anything out.

In a certain supermarket; the battery recycling is a bit smaller than
an oil drum and has a sort of plastic chimney with a slot to drop the
cells in.
On one occasion it seemed fixed on so I couldn't figure how to shift
it - I thought they'd got wise to me.

More recently it was just dropped in place - but it had recently been
emptied, so I wouldn't have been able to reach anything interesting.

Also the security guard usually lurks within yards of the recycling -
so I have to pick my moment when he wanders off.

Building supplies/DIY/tool shops is a potential resource I keep
meaning to check out - it would probably help if I went in there to
spend some money and asked on the offchance.

Thanks for the reply. I'm an invalid with limited mobility so 'shopping'
for a battery recycle drop-off isn't really an option.

Technically I could get done for stealing - you'd probably have a card or
two in your favour to just ask.

If they're not very helpful - shop somewhere else.

 

[~misfit~]

Once upon a time on usenet ~misfit~ wrote:
[snipped]

I know nothing about this charger other than
http://www.mrpositive.co.nz/camelion-usb-18650-battery-charger/
http://www.camelionbattery.com/index.php?option=com_sobi2&sobi2Task=sobi2Details&catid=104&sobi2Id=963&Itemid=115&lang=en

In any event; you should avoid exceeding the 4.2V on the terminals -
they tend to vent with flaming gas if overcharged!!!

Indeed. This charger stops charging at 4.2v (apparently).

Ehhh! I just bit the bullet and ordered a Nitecore D2 charger for not much
more than I paid for the charger above - I have some body fat, I don't need
to eat this week. They weren't this cheap when I was looking last year
dammit or I would have bought one then. Oh well, with the LCD and available
data when charging I should be able to get a better idea of which of my
cells are best.
--
Shaun.

"Humans will have advanced a long, long, way when religious belief has a
cozy little classification in the DSM."
David Melville (in r.a.s.f1)