Need info on some type of battery load/checker for ( 12volt 34 type U1 Ah
SLA Battery ) These are generally used in electric wheelchairs/scooters.
Have been told not to load check these batteries by a couple of local
battery stores, but know for a fact the places that sell them do use some
sort of load checker for checking on them for warranty puposes. Anyone know
for sure & what might be available in a not to expensive checker. Thanks
Gimpy.

Gimpy wrote:
Need info on some type of battery load/checker for ( 12volt 34 type U1 Ah
SLA Battery ) These are generally used in electric wheelchairs/scooters.
Have been told not to load check these batteries by a couple of local
battery stores, but know for a fact the places that sell them do use some
sort of load checker for checking on them for warranty puposes. Anyone know
for sure & what might be available in a not to expensive checker. Thanks
Gimpy.

http://www.vard.org/jour/83/20/1/pdf/kauzlarich.pdf

AFAIK the use a standard lead-acid battery but the wheelchairs are
driven by a PWM control system rather than as an essentially DC load
for starting an automobile, for example. The above link is a paper on
some testing procedures/results.

Seems as though would use the chair itself as a test load and check for
loaded voltage as the first approximation.

Is there a problem w/ the chair supplier not being able to test or
simply wanting something independent?

I don't believe a standard load test is really applicable rather than
there being a reason it can't be done, though, in response to initial
question.

So, nothing specific, but a few ideas and one reference that might
prove educational on the subject.

HTH....

Thanks HTH, but that article I believe was written for an engineer ? The
info I did get from it was stuff I already knew.. I am in a wheelchair & do
use an electric scooter outside the house & the scooter does like a
wheelchair use 2 U1 batteries in series for 24v. These things are pretty
expensive & last year I bought 2 new ones & they petered out in about 4
mo's. My son took them into the store where he bought them & they used some
type load tester to determine one OK & one dropped off after a min. or so.
Yr's warrt. so they gave me one new battery. What I was looking for was a
tester I could use here at the house as I now have a couple of spare
batteries & generally trade in 2 for 2 & just could be one of those I'm
trading in is still usable ?? This is why I was wondering about a
load/tester that would work & not damage anyrthing. Have been told car/truck
load testers are a no-no & could damage these batteries?? In anycase thanks
for your help. Gimpy



"dpb" wrote in message
oups.com...

Gimpy wrote:
Need info on some type of battery load/checker for ( 12volt 34 type U1
Ah
SLA Battery ) These are generally used in electric wheelchairs/scooters.
Have been told not to load check these batteries by a couple of local
battery stores, but know for a fact the places that sell them do use some
sort of load checker for checking on them for warranty puposes. Anyone
know
for sure & what might be available in a not to expensive checker. Thanks
Gimpy.

http://www.vard.org/jour/83/20/1/pdf/kauzlarich.pdf

AFAIK the use a standard lead-acid battery but the wheelchairs are
driven by a PWM control system rather than as an essentially DC load
for starting an automobile, for example. The above link is a paper on
some testing procedures/results.

Seems as though would use the chair itself as a test load and check for
loaded voltage as the first approximation.

Is there a problem w/ the chair supplier not being able to test or
simply wanting something independent?

I don't believe a standard load test is really applicable rather than
there being a reason it can't be done, though, in response to initial
question.

So, nothing specific, but a few ideas and one reference that might
prove educational on the subject.

HTH....

"dpb" wrote in
oups.com:


Gimpy wrote:
Need info on some type of battery load/checker for ( 12volt 34 type
U1 Ah SLA Battery ) These are generally used in electric
wheelchairs/scooters. Have been told not to load check these
batteries by a couple of local battery stores, but know for a fact
the places that sell them do use some sort of load checker for
checking on them for warranty puposes. Anyone know for sure & what
might be available in a not to expensive checker. Thanks Gimpy.

http://www.vard.org/jour/83/20/1/pdf/kauzlarich.pdf

AFAIK the use a standard lead-acid battery but the wheelchairs are
driven by a PWM control system rather than as an essentially DC load
for starting an automobile, for example. The above link is a paper on
some testing procedures/results.

Seems as though would use the chair itself as a test load and check
for loaded voltage as the first approximation.

Is there a problem w/ the chair supplier not being able to test or
simply wanting something independent?

I don't believe a standard load test is really applicable rather than
there being a reason it can't be done, though, in response to initial
question.

So, nothing specific, but a few ideas and one reference that might
prove educational on the subject.

HTH....



I suspect a electric wheelchair/mobility chair would use a deep-discharge
type of lead acid battery,like a boat trolling motor would use.
Auto LA batteries are designed for short,very heavy current draws,then a
fast recharge.

--
Jim Yanik
jyanik
at
kua.net

Gimpy wrote:
Thanks HTH, but that article I believe was written for an engineer ? The
info I did get from it was stuff I already knew.. I am in a wheelchair & do
use an electric scooter outside the house & the scooter does like a
wheelchair use 2 U1 batteries in series for 24v. These things are pretty
expensive & last year I bought 2 new ones & they petered out in about 4
mo's. My son took them into the store where he bought them & they used some
type load tester to determine one OK & one dropped off after a min. or so.
Yr's warrt. so they gave me one new battery. What I was looking for was a
tester I could use here at the house as I now have a couple of spare
batteries & generally trade in 2 for 2 & just could be one of those I'm
trading in is still usable ?? This is why I was wondering about a
load/tester that would work & not damage anyrthing. Have been told car/truck
load testers are a no-no & could damage these batteries?? In anycase thanks
for your help. Gimpy


One important item about any battery is to limit the depth of discharge.
A good voltmeter is a fairly good indication of the condition. I
would think that hooking a digital voltmeter to both batteries would
provide information on how they are discharging. The problem is that
the voltage varies just a small amount from full charge to 75% or 50%
state of charge.
100%: 12.65 volts
75%: 12.45
50%: 12.24
25%: 12.06
0%: 11.89

And how you charge is also very important. The goal is to avoid
sulfation of the battery. For your purpose a good four stage charger is
almost a necessity. Perhaps you already have that.

Section 9:

http://www.batteryfaq.org

You could rig up an automobile headlight with some test leads. Connect to
the battery, if it is good, the bulb should be bright and not dim for many
minutes. Probably need to test for only a few minutes to spot a bad
battery. You could also connect a voltmeter in parallel if you want to.


"Gimpy" wrote in message
...
Need info on some type of battery load/checker for ( 12volt 34 type U1 Ah
SLA Battery ) These are generally used in electric wheelchairs/scooters.
Have been told not to load check these batteries by a couple of local
battery stores, but know for a fact the places that sell them do use some
sort of load checker for checking on them for warranty puposes. Anyone
know for sure & what might be available in a not to expensive checker.
Thanks Gimpy.

Rich256 wrote:


One important item about any battery is to limit the depth of discharge.
A good voltmeter is a fairly good indication of the condition. I
would think that hooking a digital voltmeter to both batteries would
provide information on how they are discharging. The problem is that
the voltage varies just a small amount from full charge to 75% or 50%
state of charge.
100%: 12.65 volts
75%: 12.45
50%: 12.24
25%: 12.06
0%: 11.89

But a battery can measure correct voltage without supplying useable
current. The best way to check would be to solder a pair of leads on a
12v automotive backup bulb, and place the bulb leads & voltmeter leads
across the battery terminals at the same time. Or an alternative is to
use the bulb by itself - the brightness of the bulb is a good indicator
of battery charge under a small load.
Bob

Bob wrote:
Rich256 wrote:

One important item about any battery is to limit the depth of discharge.
A good voltmeter is a fairly good indication of the condition. I
would think that hooking a digital voltmeter to both batteries would
provide information on how they are discharging. The problem is that
the voltage varies just a small amount from full charge to 75% or 50%
state of charge.
100%: 12.65 volts
75%: 12.45
50%: 12.24
25%: 12.06
0%: 11.89

But a battery can measure correct voltage without supplying useable
current. The best way to check would be to solder a pair of leads on a
12v automotive backup bulb, and place the bulb leads & voltmeter leads
across the battery terminals at the same time. Or an alternative is to
use the bulb by itself - the brightness of the bulb is a good indicator
of battery charge under a small load.
Bob


Those voltages I give are unloaded and are correct. If you loaded them
you will get something completely different. Measuring the unloaded
voltage of of a totally discharged battery would produce what you call
"correct voltage" but it would be less than 12 volts. Put a load on it
and it will drop to near zero.

So if he wants to get a measurement of the state of charge it is
possible with the voltmeter. The better alternative is using a
hydrometer but that is difficult with with his system.

He needs to know what the state of charge is. Putting a bulb on a 75%
discharged battery like his will still produce about the same brightness.

If you have a good calibrated voltmeter such as a Fluke you can get a
good idea of what the state of charge is by measuring the unloaded
voltage. I neglected to say that those voltages are at a temperature of
80F. They will be slightly higher or lower (perhaps .02v or so) at
higher or lower temperatures.

"Jeff" wrote in
:

You could rig up an automobile headlight with some test leads.
Connect to the battery, if it is good, the bulb should be bright and
not dim for many minutes. Probably need to test for only a few
minutes to spot a bad battery. You could also connect a voltmeter in
parallel if you want to.

Definitely use a meter to monitor battery voltage -under load-;that's
what's important.That's how you spot a bad/marginal cell.

A typical auto headlight is around 55 watts at 12V,so that's only about a 4
amp load.Enough to check voltage,and not as heavy a load as an automotive
load tester that draws 100's of amps.



"Gimpy" wrote in message
...
Need info on some type of battery load/checker for ( 12volt 34 type
U1 Ah SLA Battery ) These are generally used in electric
wheelchairs/scooters. Have been told not to load check these
batteries by a couple of local battery stores, but know for a fact
the places that sell them do use some sort of load checker for
checking on them for warranty puposes. Anyone know for sure & what
might be available in a not to expensive checker. Thanks Gimpy.




--
Jim Yanik
jyanik
at
kua.net

Jim Yanik wrote:
"Jeff" wrote in
:

You could rig up an automobile headlight with some test leads.
Connect to the battery, if it is good, the bulb should be bright and
not dim for many minutes. Probably need to test for only a few
minutes to spot a bad battery. You could also connect a voltmeter in
parallel if you want to.

Definitely use a meter to monitor battery voltage -under load-;that's
what's important.That's how you spot a bad/marginal cell.

A typical auto headlight is around 55 watts at 12V,so that's only about a 4
amp load.Enough to check voltage,and not as heavy a load as an automotive
load tester that draws 100's of amps.


Agree on the meter. For his application I would be tempted to mount two
meters and so that the voltage for both batteries could be monitored
all the time. A significant difference would indicate a possible
problem. They would not have to be a top brand such as a Fluke. Just
two similar digital meters that would give a relative reading. A state
of charge reading needs to be done when the batteries have set for quite
a while after being recharged. Soon he would know what that reading
should be.

To minimize sulfation and to obtain long battery life they should be
recharged as soon as possible after use especially when they have been
deeply discharged.



"Gimpy" wrote in message
...
Need info on some type of battery load/checker for ( 12volt 34 type
U1 Ah SLA Battery ) These are generally used in electric
wheelchairs/scooters. Have been told not to load check these
batteries by a couple of local battery stores, but know for a fact
the places that sell them do use some sort of load checker for
checking on them for warranty puposes. Anyone know for sure & what
might be available in a not to expensive checker. Thanks Gimpy.

Gimpy writes:

Anyone know for sure & what might be available in a not to
expensive checker.

You want a carbon pile tester:

http://www.harborfreight.com/cpi/cta...emnumber=90636

Walmart and auto parts stores also test batteries, if you can find someone
sympathetic enough to thumb in your specs to the automated tester.

In article , "Gimpy"
wrote:

Thanks HTH, but that article I believe was written for an engineer ? The
info I did get from it was stuff I already knew.. I am in a wheelchair & do
use an electric scooter outside the house & the scooter does like a
wheelchair use 2 U1 batteries in series for 24v. These things are pretty
expensive & last year I bought 2 new ones & they petered out in about 4
mo's. My son took them into the store where he bought them & they used some
type load tester to determine one OK & one dropped off after a min. or so.
Yr's warrt. so they gave me one new battery. What I was looking for was a
tester I could use here at the house as I now have a couple of spare
batteries & generally trade in 2 for 2 & just could be one of those I'm
trading in is still usable ?? This is why I was wondering about a
load/tester that would work & not damage anyrthing. Have been told car/truck
load testers are a no-no & could damage these batteries?? In anycase thanks
for your help. Gimpy

What you want is a meter to read the difference between the batteries
WHILE YOU ARE USING THEM. This is easily done with a small cheap
voltmeter (preferably center reading) and two equal resisters. Put the
resisters in series from +24v to (-) and connect the voltmeter from the
center of the pair of resisters to the center joining strap of the
batteries (+12 v nominal). The meter should read zero if the batteries
have the same voltage under load, and will deflect one way or the other
if one battery gets weaker than the other. You could use a cheap
digital and read + and - or a center zero analog of about +/- 4 volts or
so.

--
Free men own guns - www.geocities/CapitolHill/5357/ (add .com after geocities)

Nick Hull wrote:
In article , "Gimpy"
wrote:

Thanks HTH, but that article I believe was written for an engineer ? The
info I did get from it was stuff I already knew.. I am in a wheelchair & do
use an electric scooter outside the house & the scooter does like a
wheelchair use 2 U1 batteries in series for 24v. These things are pretty
expensive & last year I bought 2 new ones & they petered out in about 4
mo's. My son took them into the store where he bought them & they used some
type load tester to determine one OK & one dropped off after a min. or so.
Yr's warrt. so they gave me one new battery. What I was looking for was a
tester I could use here at the house as I now have a couple of spare
batteries & generally trade in 2 for 2 & just could be one of those I'm
trading in is still usable ?? This is why I was wondering about a
load/tester that would work & not damage anyrthing. Have been told car/truck
load testers are a no-no & could damage these batteries?? In anycase thanks
for your help. Gimpy

What you want is a meter to read the difference between the batteries
WHILE YOU ARE USING THEM. This is easily done with a small cheap
voltmeter (preferably center reading) and two equal resisters. Put the
resisters in series from +24v to (-) and connect the voltmeter from the
center of the pair of resisters to the center joining strap of the
batteries (+12 v nominal). The meter should read zero if the batteries
have the same voltage under load, and will deflect one way or the other
if one battery gets weaker than the other. You could use a cheap
digital and read + and - or a center zero analog of about +/- 4 volts or
so.

Or what I was thinking of was using two of those cheap meters. One
across each battery. Harbor Freight has some that would be good enough.
If during use one of the batteries drops more than the other some
corrective action might be needed such as a desulfation charge on that
battery.

"Richard J Kinch" wrote in message
. ..
Gimpy writes:

Anyone know for sure & what might be available in a not to
expensive checker.

You want a carbon pile tester:

http://www.harborfreight.com/cpi/cta...emnumber=90636

Walmart and auto parts stores also test batteries, if you can find someone
sympathetic enough to thumb in your specs to the automated tester.

Thanks for all the info guys. A lot of stuff to look over & try