Lead acetate batteries rechargeable?

[W. eWatson]

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
<http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

 

[Phil Allison]

"W. eWatson"

Are such 12v batteries rechargeable?

** Yes.

And the name is " Sealed Lead Acid" or SLA

What type of small (alarm,

motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

** Ever hear of Google ??

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

** It helps.....

.... Phil

 

[fungus]

On Tuesday, August 21, 2012 6:05:19 AM UTC+2, W. eWatson wrote:

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Yep. The charge/discharge cycle is bad for
lead batteries. The lead atoms move around
with every cycle and never reform into the
nice neat plates of a new battery. Every
cycle damages them. The deeper the cycle,
the more damage.

Car batteries are usually the worst for
this, it's perfectly possible to wreck
one in 12 cycles.

You can get "deep cycle batteries" which
are better.

http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery#Cycles

 

[Tim Wescott]

On Mon, 20 Aug 2012 21:05:19 -0700, W. eWatson wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/
B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the
battery?

I can't speak to lead acetate specifically, but Google is Your Friend.

Gel-cell batteries are sealed cells that use some additive to the
electrolyte to make it into a goo -- and no, I haven't tried opening one
up, so I couldn't tell you just how gooey. Google is Your Friend.

Improper use of any rechargeable battery will trash it. Letting them go
all the way flat either through use or self-discharge is a pretty good
way to seriously shorten battery life.

And yes, specific battery chemistries need specific charging strategies.
Google is Your Friend.

The "Battery University" has some pretty good articles, although like
anything on the web you should read them with a grain of salt.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

On Mon, 20 Aug 2012 21:05:19 -0700, "W. eWatson"
<wolftracks@invalid.com> wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

Haven't researched lead acetate abtteries, but have used a variety of
lead-acid batteries, both flooded (removable caps to add water) and
sealed (gel, AGM, etc).

The key to long life is proper charging and careful discharging, and
ensuring the battery is kept charged.

Careful discharge means never discharging the battery below 50%, even
if that means getting a higher capacity battery than the orignal.

I got PowerWheels cars for the grandkids several years ago (free on
Freecycle and Craig's List when the battery dies) and replaced the
orignal (%90) battery with a slightly higher capacity gel cell ad a
smart charger (the original PowerWheels charger will overcharge the
battery). I charged the batteries quarterly even if they were not
used. The batteries I installed 3 or 4 years ago are still good.

 

[W. eWatson]

On 8/20/2012 9:40 PM, Phil Allison wrote:

"W. eWatson"

Are such 12v batteries rechargeable?

** Yes.

And the name is " Sealed Lead Acid" or SLA

What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

** Ever hear of Google ??
It wasn't that friendly.


Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

** It helps.....

... Phil

 

[W. eWatson]

On 8/21/2012 9:27 AM, news@jecarter.us wrote:

On Mon, 20 Aug 2012 21:05:19 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

Haven't researched lead acetate abtteries, but have used a variety of
lead-acid batteries, both flooded (removable caps to add water) and
sealed (gel, AGM, etc).

The key to long life is proper charging and careful discharging, and
ensuring the battery is kept charged.

Careful discharge means never discharging the battery below 50%, even
if that means getting a higher capacity battery than the orignal.

I got PowerWheels cars for the grandkids several years ago (free on
Freecycle and Craig's List when the battery dies) and replaced the
orignal (%90) battery with a slightly higher capacity gel cell ad a
smart charger (the original PowerWheels charger will overcharge the
battery). I charged the batteries quarterly even if they were not
used. The batteries I installed 3 or 4 years ago are still good.

How is the % measured? With what instrument?

 

[Tim Wescott]

On Tue, 21 Aug 2012 10:20:57 -0700, W. eWatson wrote:

On 8/20/2012 9:40 PM, Phil Allison wrote:
"W. eWatson"

Are such 12v batteries rechargeable?

** Yes.

And the name is " Sealed Lead Acid" or SLA

What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge
them with? Is a gel battery preferable? What is gel?

** Ever hear of Google ??
It wasn't that friendly.

Phil defines "friendly". Of course, he defines it in a way no one else
in the universe does.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[ehsjr]

On 8/21/2012 1:23 PM, W. eWatson wrote:

On 8/21/2012 9:27 AM, news@jecarter.us wrote:
On Mon, 20 Aug 2012 21:05:19 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.

It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the
battery?

Haven't researched lead acetate abtteries, but have used a variety of
lead-acid batteries, both flooded (removable caps to add water) and
sealed (gel, AGM, etc).

The key to long life is proper charging and careful discharging, and
ensuring the battery is kept charged.

Careful discharge means never discharging the battery below 50%, even
if that means getting a higher capacity battery than the orignal.

I got PowerWheels cars for the grandkids several years ago (free on
Freecycle and Craig's List when the battery dies) and replaced the
orignal (%90) battery with a slightly higher capacity gel cell ad a
smart charger (the original PowerWheels charger will overcharge the
battery). I charged the batteries quarterly even if they were not
used. The batteries I installed 3 or 4 years ago are still good.

How is the % measured? With what instrument?

A 12V lead acid battery is considered 100% discharged when
the voltage at its terminals measures 10.5 volts. Discharging
it that far causes damage. I don't know what the poster has in
mind by his 50% figure, but if you figure it as 12V-10.5V * 50%
it's 11.25V, which is a sensible cut off voltage. The cut off
voltage is the level you set at which the circuit will disconnect
the battery from the load so that no further discharge occurs.

Ed

 

[John G]

W. eWatson laid this down on his screen :

On 8/20/2012 9:40 PM, Phil Allison wrote:
"W. eWatson"

Are such 12v batteries rechargeable?

** Yes.

And the name is " Sealed Lead Acid" or SLA

What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

** Ever hear of Google ??
It wasn't that friendly.
ACID instead of Acetate may have given Googo a chance. :-Z
Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.
It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the battery?

** It helps.....

... Phil

--
John G

 

On Wed, 22 Aug 2012 01:51:18 -0400, ehsjr <ehsjr@nospamverizon.net>
wrote:

On 8/21/2012 1:23 PM, W. eWatson wrote:
On 8/21/2012 9:27 AM, news@jecarter.us wrote:
On Mon, 20 Aug 2012 21:05:19 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.

It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the
battery?

Haven't researched lead acetate abtteries, but have used a variety of
lead-acid batteries, both flooded (removable caps to add water) and
sealed (gel, AGM, etc).

The key to long life is proper charging and careful discharging, and
ensuring the battery is kept charged.

Careful discharge means never discharging the battery below 50%, even
if that means getting a higher capacity battery than the orignal.

I got PowerWheels cars for the grandkids several years ago (free on
Freecycle and Craig's List when the battery dies) and replaced the
orignal (%90) battery with a slightly higher capacity gel cell ad a
smart charger (the original PowerWheels charger will overcharge the
battery). I charged the batteries quarterly even if they were not
used. The batteries I installed 3 or 4 years ago are still good.

How is the % measured? With what instrument?

A 12V lead acid battery is considered 100% discharged when
the voltage at its terminals measures 10.5 volts. Discharging
it that far causes damage. I don't know what the poster has in
mind by his 50% figure, but if you figure it as 12V-10.5V * 50%
it's 11.25V, which is a sensible cut off voltage. The cut off
voltage is the level you set at which the circuit will disconnect
the battery from the load so that no further discharge occurs.

Ed

Voltage is the easiest way to guess the state of charge, but the
battery needs to be idle for some hours to get an accurate voltage.

The ultimate method is to use a "smart" meter that measures power in
and power out and thus knows how much of the AH capacity has been
used.

The simple method is to measure the current drain of the device being
powered and multiply that by the time: 1.5 amps times 4 hours = 6 AH.
If you started with a fully charged 12AH bettery, you're at the 50%
point. If the battery is 10AH, then you shoukd have stopped at 3
hours, 20 minutes (5AH).

 

[Tim Wescott]

On Wed, 22 Aug 2012 16:05:34 +1000, John G wrote:

W. eWatson laid this down on his screen :
On 8/20/2012 9:40 PM, Phil Allison wrote:
"W. eWatson"

Are such 12v batteries rechargeable?

** Yes.

And the name is " Sealed Lead Acid" or SLA

What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge
them with? Is a gel battery preferable? What is gel?

** Ever hear of Google ??
It wasn't that friendly.
ACID instead of Acetate may have given Googo a chance. :-Z

Man, I saw the acetate and assumed that the Battery Gurus had cooked up a
new twist on the old chemistry.

If the OP just means lead acid -- well duh, of course they're
rechargeable!

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

 

[W. eWatson]

....

battery). I charged the batteries quarterly even if they were not

used. The batteries I installed 3 or 4 years ago are still good.

How is the % measured? With what instrument?

A 12V lead acid battery is considered 100% discharged when
the voltage at its terminals measures 10.5 volts. Discharging
it that far causes damage. I don't know what the poster has in
mind by his 50% figure, but if you figure it as 12V-10.5V * 50%
it's 11.25V, which is a sensible cut off voltage. The cut off
voltage is the level you set at which the circuit will disconnect
the battery from the load so that no further discharge occurs.

Ed
A poster slightly above my post mentioned %. Not me. Anyway thanks for

the clarification.

 

[krw@att.bizzzzzzzzzzzz]

On Wed, 22 Aug 2012 10:51:57 -0400, news@jecarter.us wrote:

On Wed, 22 Aug 2012 01:51:18 -0400, ehsjr <ehsjr@nospamverizon.net
wrote:

On 8/21/2012 1:23 PM, W. eWatson wrote:
On 8/21/2012 9:27 AM, news@jecarter.us wrote:
On Mon, 20 Aug 2012 21:05:19 -0700, "W. eWatson"
wolftracks@invalid.com> wrote:

Are such 12v batteries rechargeable? What type of small (alarm,
motorcycle) batteries are rechargeable? What do I need to recharge them
with? Is a gel battery preferable? What is gel?

I need it for a Celestron telescope, 6" mirror. I had a lead acetate
for the scope, and it seemed like it could be charged with a jumper
battery I have. In any case, it seems unusable now--after two years of
occasional use. Maybe 12 uses for 2-3 hours each in that period.

Maybe this is the ticket.
http://www.amazon.com/Rechargeable-Sealed-Lead-Battery-Electronics/dp/B000BPCUXO>.

It's lead acetate, so that answers one question. Maybe the one about a
recharger too. Does a recharger service have to match up with the
battery?

Haven't researched lead acetate abtteries, but have used a variety of
lead-acid batteries, both flooded (removable caps to add water) and
sealed (gel, AGM, etc).

The key to long life is proper charging and careful discharging, and
ensuring the battery is kept charged.

Careful discharge means never discharging the battery below 50%, even
if that means getting a higher capacity battery than the orignal.

I got PowerWheels cars for the grandkids several years ago (free on
Freecycle and Craig's List when the battery dies) and replaced the
orignal (%90) battery with a slightly higher capacity gel cell ad a
smart charger (the original PowerWheels charger will overcharge the
battery). I charged the batteries quarterly even if they were not
used. The batteries I installed 3 or 4 years ago are still good.

How is the % measured? With what instrument?

A 12V lead acid battery is considered 100% discharged when
the voltage at its terminals measures 10.5 volts. Discharging
it that far causes damage. I don't know what the poster has in
mind by his 50% figure, but if you figure it as 12V-10.5V * 50%
it's 11.25V, which is a sensible cut off voltage. The cut off
voltage is the level you set at which the circuit will disconnect
the battery from the load so that no further discharge occurs.

Ed

Voltage is the easiest way to guess the state of charge, but the
battery needs to be idle for some hours to get an accurate voltage.

The ultimate method is to use a "smart" meter that measures power in
and power out and thus knows how much of the AH capacity has been
used.

That presumes you know what the actual capacity is. With Nickle or Lithium
chemistries this can easily be measured but finding the bottom of the pool
with a lead battery will damage it.

The simple method is to measure the current drain of the device being
powered and multiply that by the time: 1.5 amps times 4 hours = 6 AH.

1/4C will give a different number than 1/10C.

If you started with a fully charged 12AH bettery, you're at the 50%
point. If the battery is 10AH, then you shoukd have stopped at 3
hours, 20 minutes (5AH).

This assumes that your 12AH battery is good/new (and the supplier isn't
lying).

 

[W. eWatson]

I have a 12v Xantrex 600HD that has a meter on it. Maybe there are
rechargers for less hefty batteries that have a meter?

 

[ehsjr]

On 8/22/2012 1:10 PM, W. eWatson wrote:

I have a 12v Xantrex 600HD that has a meter on it. Maybe there are
rechargers for less hefty batteries that have a meter?

A recharger with a built in meter doesn't fit in with what was being
discussed, which was the level to which a battery was _discharged_.
If you have to monitor a recharger with a meter, throw it away
and get one that _automatically_ provides a proper charge to the
battery, regardless of whether you're watching a meter or not.

With regard to the discharge cycle, you want an _automatic_ circuit
to protect the battery - a meter provides only monitoring and measuring,
not automatic disconnect. If all you have is a built
in meter and you're not paying attention to it, you can easily
discharge the battery too far.

A cheap VOM will likely be at least as accurate as a meter built
into a power pack.

With regard to your Xantrex: the owner's manual states that the
charge % indicator is accurate only when the unit has been
disconnected from all loads and charging sources for at least
15 minutes. The manual also states that the unit will sound
an alarm when the voltage drops to 11 volts, and automatically
disconnect from the load when the voltage drops to 10.5, provided
the AC outlet on/off switch is turned on. That's the right idea,
but the wrong implementation. The voltage levels should be
higher - 11.5 volts for the alarm, and 11.0 volts for the
disconnect. In addition, the alarm and disconnect functions
should not depend on the position of the AC outlet switch, they
should operate any time current is being drawn from the battery.
It is obvious that the Xantrex was not engineered for maximum
battery life, nor the more or less permanent usage in your
dome/telescope. That doesn't mean you can't use it for that - you
can. But the questions you have asked over a long period of
time have been more detailed in nature than something like:
"What is the easiest way for me to power the dome?"
If you want the easiest way, just use the Xantrex or equivalent
to bring power out there each time. It still means you need to
do some research to find out if your controller(s) and motors
will work properly for long enough on the 12V DC that the
Xantrex/equivalent can provide, and how often you need to
recharge.

Ed

 

[W. eWatson]

On 8/22/2012 8:09 PM, ehsjr wrote:

On 8/22/2012 1:10 PM, W. eWatson wrote:
I have a 12v Xantrex 600HD that has a meter on it. Maybe there are
rechargers for less hefty batteries that have a meter?

A recharger with a built in meter doesn't fit in with what was being
discussed, which was the level to which a battery was _discharged_.
If you have to monitor a recharger with a meter, throw it away
and get one that _automatically_ provides a proper charge to the
battery, regardless of whether you're watching a meter or not.
Per Google, I see they are probably called float (or automatic) float.

Some are pretty pricey. I think I'll pass in favor of using my VOM, as
necessary. For the 6" scope, I do not think this poses a problem. More
below.

With regard to the discharge cycle, you want an _automatic_ circuit
to protect the battery - a meter provides only monitoring and measuring,
not automatic disconnect. If all you have is a built
in meter and you're not paying attention to it, you can easily
discharge the battery too far.


A cheap VOM will likely be at least as accurate as a meter built
into a power pack.


With regard to your Xantrex: the owner's manual states that the
charge % indicator is accurate only when the unit has been
disconnected from all loads and charging sources for at least
15 minutes. The manual also states that the unit will sound
an alarm when the voltage drops to 11 volts, and automatically
disconnect from the load when the voltage drops to 10.5, provided
the AC outlet on/off switch is turned on. That's the right idea,
but the wrong implementation. The voltage levels should be
higher - 11.5 volts for the alarm, and 11.0 volts for the
disconnect. In addition, the alarm and disconnect functions
should not depend on the position of the AC outlet switch, they
should operate any time current is being drawn from the battery.
It is obvious that the Xantrex was not engineered for maximum
battery life, nor the more or less permanent usage in your
My (second) Xantrex turned out to be a stinker in that despite charging

it every 3 months, it is barely in the game anymore.

Ah, you remembered my dome/obs. There is where I would need a (float)
automatic recharger. It will easily run the 6" scope, but it sure is bulky.

I've run into a blank wall with regard to providing control of the dome
shutter and rotation to keep the shutter open where the large scope is
pointing. First though, I bought a hefty 12v Kirkland deep cycle battery
from CostCo back around Feb or March. It has not been used, but I do not
think has significantly discharged. The charger (float) need I mentioned
in the last paragraph would probably be helpful there until and when I
get the battery in use.

Regarding the dome control project, I think there may be one guy in the
50 states who knows how to do this, and he lives in Hawaii. He does it
for a living. In the last 6 months, I've managed to purchase the
Kirkland battery, soft start device, power inverter, aluminum sheets for
shelves on the dome walls, relays, NEMA box, and a few other parts. In
that time, I've had five people here who could likely do the job.
Eventually, all but one showed up to do it. I've offered attractive
money. The one who did show up got a real job and disappeared. My last
resort now seems to be the fellow who built the obs. He tells me his son
may have the skills to install the circuit cards, and wire up matters.
I'll know in early Sept. If I knew more about relays, I could probably
do it myself. If you or anyone lives near Sacramento, CA I have a job
for you.

dome/telescope. That doesn't mean you can't use it for that - you
can. But the questions you have asked over a long period of
time have been more detailed in nature than something like:
"What is the easiest way for me to power the dome?"
If you want the easiest way, just use the Xantrex or equivalent
to bring power out there each time. It still means you need to
do some research to find out if your controller(s) and motors
will work properly for long enough on the 12V DC that the
Xantrex/equivalent can provide, and how often you need to
recharge.

Ed

 

[ehsjr]

On 8/23/2012 7:39 PM, W. eWatson wrote:

On 8/22/2012 8:09 PM, ehsjr wrote:
On 8/22/2012 1:10 PM, W. eWatson wrote:
I have a 12v Xantrex 600HD that has a meter on it. Maybe there are
rechargers for less hefty batteries that have a meter?

A recharger with a built in meter doesn't fit in with what was being
discussed, which was the level to which a battery was _discharged_.
If you have to monitor a recharger with a meter, throw it away
and get one that _automatically_ provides a proper charge to the
battery, regardless of whether you're watching a meter or not.
Per Google, I see they are probably called float (or automatic) float.
Some are pretty pricey. I think I'll pass in favor of using my VOM, as
necessary. For the 6" scope, I do not think this poses a problem. More
below.

With regard to the discharge cycle, you want an _automatic_ circuit
to protect the battery - a meter provides only monitoring and measuring,
not automatic disconnect. If all you have is a built
in meter and you're not paying attention to it, you can easily
discharge the battery too far.


A cheap VOM will likely be at least as accurate as a meter built
into a power pack.


With regard to your Xantrex: the owner's manual states that the
charge % indicator is accurate only when the unit has been
disconnected from all loads and charging sources for at least
15 minutes. The manual also states that the unit will sound
an alarm when the voltage drops to 11 volts, and automatically
disconnect from the load when the voltage drops to 10.5, provided
the AC outlet on/off switch is turned on. That's the right idea,
but the wrong implementation. The voltage levels should be
higher - 11.5 volts for the alarm, and 11.0 volts for the
disconnect. In addition, the alarm and disconnect functions
should not depend on the position of the AC outlet switch, they
should operate any time current is being drawn from the battery.
It is obvious that the Xantrex was not engineered for maximum
battery life, nor the more or less permanent usage in your
My (second) Xantrex turned out to be a stinker in that despite charging
it every 3 months, it is barely in the game anymore.

Ah, you remembered my dome/obs. There is where I would need a (float)
automatic recharger. It will easily run the 6" scope, but it sure is bulky.

I've run into a blank wall with regard to providing control of the dome
shutter and rotation to keep the shutter open where the large scope is
pointing. First though, I bought a hefty 12v Kirkland deep cycle battery
from CostCo back around Feb or March. It has not been used, but I do not
think has significantly discharged. The charger (float) need I mentioned
in the last paragraph would probably be helpful there until and when I
get the battery in use.

Regarding the dome control project, I think there may be one guy in the
50 states who knows how to do this, and he lives in Hawaii. He does it
for a living. In the last 6 months, I've managed to purchase the
Kirkland battery, soft start device, power inverter, aluminum sheets for
shelves on the dome walls, relays, NEMA box, and a few other parts. In
that time, I've had five people here who could likely do the job.
Eventually, all but one showed up to do it. I've offered attractive
money. The one who did show up got a real job and disappeared. My last
resort now seems to be the fellow who built the obs. He tells me his son
may have the skills to install the circuit cards, and wire up matters.
I'll know in early Sept. If I knew more about relays, I could probably
do it myself. If you or anyone lives near Sacramento, CA I have a job
for you.

Wish I could, because it is an interesting project, but I'm in NY.

Regarding the charger: if all you want is a float charger,you can build
that cheaply and easily. Note that a float charger will not
charge your battery properly, where properly means a 3 stage
charge cycle. But it will work to keep a battery at full charge,
and will charge a partly discharged battery to full charge,
given enough time. If your battery usage is such that a float
charger has enough time to recharge the battery between uses,
then you can get away with that, and it doesn't need to
be automatic. The float charger provides a fixed voltage at
a low current, and won't overcharge your battery when it is
properly designed. It's not as good as a 3 stage charger, but
it may be perfect for your needs, and it costs way less.

To build a float charger, get Item Number 18724 PS from MPJA
and Catalog #: 276-1141 from Radio Shack. Wire the two
diodes contained in the package from Radio Shack in series
with the + lead from the 15 volt regulated supply from MPJA.
Like this:

------ D1 D2
| +|--->|--->|----to batt +
| PS |
| 15V |--------------to batt -
------

Note that the banded end of the diodes must be as shown.

That will provide ~13.8 volts to the battery. It is not
a *perfect* float charger, but is darn close. It's just
3 parts and is really simple to put together.

The diodes cost $1.59 for 2, the MPJA supply is $5.95. See:
http://www.mpja.com/15VDC-16A-Regulated-Plug-Supply-GME/productinfo/18724+PS/

(watch out for line wrap above)

By the way leaving your Kirkland battery alone - that is,
not giving it a charge every so often - will eventually kill
it. Give it a proper charge once a month or so, or put it on
float charge.

Ed

 

[W. eWatson]

....

Wish I could, because it is an interesting project, but I'm in NY.

Regarding the charger: if all you want is a float charger,you can build
that cheaply and easily. Note that a float charger will not
charge your battery properly, where properly means a 3 stage
charge cycle. But it will work to keep a battery at full charge,
and will charge a partly discharged battery to full charge,
given enough time. If your battery usage is such that a float
charger has enough time to recharge the battery between uses,
then you can get away with that, and it doesn't need to
be automatic. The float charger provides a fixed voltage at
a low current, and won't overcharge your battery when it is
properly designed. It's not as good as a 3 stage charger, but
it may be perfect for your needs, and it costs way less.

To build a float charger, get Item Number 18724 PS from MPJA
and Catalog #: 276-1141 from Radio Shack. Wire the two
diodes contained in the package from Radio Shack in series
with the + lead from the 15 volt regulated supply from MPJA.
Like this:

------ D1 D2
| +|--->|--->|----to batt +
| PS |
| 15V |--------------to batt -
------

Note that the banded end of the diodes must be as shown.

That will provide ~13.8 volts to the battery. It is not
a *perfect* float charger, but is darn close. It's just
3 parts and is really simple to put together.

The diodes cost $1.59 for 2, the MPJA supply is $5.95. See:
http://www.mpja.com/15VDC-16A-Regulated-Plug-Supply-GME/productinfo/18724+PS/


(watch out for line wrap above)

By the way leaving your Kirkland battery alone - that is,
not giving it a charge every so often - will eventually kill
it. Give it a proper charge once a month or so, or put it on
float charge.

Ed

Thanks for the tips. I bought a Schumacher 1.6 A Speed Charter

Maintainer for the Costco battery.