Anybody know about battery load testers

[Industrial Toys]

I have a princess Auto Digital Style Load Tester. A friend of mine who deals in a lot of batteries keeps giving me used batteries that are "supposed" to be good. A got about eight different ones lately, and after charging them to around 13 volts for days on a small Schumaker charger ,my tester shows all of them FAIL, even at very low CCA settings.

Is my tester lying to me? All batteries pretty much read ten point something volts almost immediately when the device applies load, then shows fail.

So I did several things. Firstly let me say that the device does not change load resistance, only changes the time the load is applied to the battery based on CCA ratings. Is this a poor way of measuring different size batteries?

I checked the voltage measured my the tester with a fluke meter and believe the tester is accurate.

I measured, the current going through the tester with a Fluke clamp on DC meter and got a reading of 100 amps at the ten point something volts.

So my question is. If one puts a load of 100 amps on a good battery, is it normal for the voltage to drop to ten point something volts or is that too low?

 

[firemanmike69]

I have a big one at work, we test batteries that are fully charged to half the CCA rating for 15 seconds. It has a chart on it for pass/fail I'll look at it tomorrow but I'd think that dropping instantly to 10 volts with a 100 amp load isn't good

 

[davesl708]

I have a princess Auto Digital Style Load Tester. A friend of mine who deals in a lot of batteries keeps giving me used batteries that are "supposed" to be good. A got about eight different ones lately, and after charging them to around 13 volts for days on a small Schumaker charger ,my tester shows all of them FAIL, even at very low CCA settings.

Is my tester lying to me? All batteries pretty much read ten point something volts almost immediately when the device applies load, then shows fail.

So I did several things. Firstly let me say that the device does not change load resistance, only changes the time the load is applied to the battery based on CCA ratings. Is this a poor way of measuring different size batteries?

I checked the voltage measured my the tester with a fluke meter and believe the tester is accurate.

I measured, the current going through the tester with a Fluke clamp on DC meter and got a reading of 100 amps at the ten point something volts.

So my question is. If one puts a load of 100 amps on a good battery, is it normal for the voltage to drop to ten point something volts or is that too low?[/QUOTE]

First the test unit is probably right. They are getting rid of the batteries for a reason.
A 100 amp load is about what a starter would draw.
Most likely the tester is detecting an internal short between the plates.

 

[SPYDERLK]

I have a princess Auto Digital Style Load Tester. A friend of mine who deals in a lot of batteries keeps giving me used batteries that are "supposed" to be good. A got about eight different ones lately, and after charging them to around 13 volts for days on a small Schumaker charger ,my tester shows all of them FAIL, even at very low CCA settings.

Is my tester lying to me? All batteries pretty much read ten point something volts almost immediately when the device applies load, then shows fail.

So I did several things. Firstly let me say that the device does not change load resistance, only changes the time the load is applied to the battery based on CCA ratings. Is this a poor way of measuring different size batteries?

I checked the voltage measured my the tester with a fluke meter and believe the tester is accurate.

I measured, the current going through the tester with a Fluke clamp on DC meter and got a reading of 100 amps at the ten point something volts.

So my question is. If one puts a load of 100 amps on a good battery, is it normal for the voltage to drop to ten point something volts or is that too low?

You are measuring the V directly on the battery terminals right -- NOT from the clamp on the terminal? ... I agree 10V @ 100A is too low. I would expect 11.5 or better with the probes directly on the terminals.
larry

 

[Industrial Toys]

My gut feeling is that the batteries are no good. I know, I should just try to test some known good batteries. I wonder at what voltage the tester is passes the battery.

The other thing is that my charger only seems to charge to 13 volts, not 13.8. This can't help the situation. Maybe if the battery was .8 volt higher in charge the tester would OK it.

If the batteries are no good, I just don't understand how a guy who works with batteries day in and day out, and maybe handles a couple thousand a year could be so wrong! Some of the batteries looked as if they had clearly been in service for a while but the latest two looked brand new!

I don't have too much good to say about Princess Auto stuff, much like HF, but I always liked that Digital tester. Maybe I would have been farther ahead with the old dial type. Get a better feel for battery voltage under load. The one I bought before that, I just remembered it now, was a carbon pile tester. It went snap, crackle and pop the second time I used it! (Typical).

 

[tcartwri]

A good battery will make one of those testers smoke if you hold it for 15 seconds.

 

[2458n]

I just went through the battery testing routine today. Took my bad battery to Autozone to be charged and tested. Well they skipped the charging part and put a hand held load tester on it. Battery tested bad was only at 80%. How could they test it if they did not fully charge it? Manager was showing trainee how to sell a battery. Took mine and went home. Back to the junk yard where I had bought the group 65 battery for 20.00 dollars. They charged it for 3 hours and it really did fail. Autozone wanted 137.00 with exchange for a two year battery. Or I could have 0ne from behind the wall for 45.99, this was supposed to be one where someone bought a battery and then found out that they really needed a new alternator. The store took the battery back ,but could now not sell it as "new". Kubota now has a new junk 20 dollar battery from the yard. Back to your supply of free battery- at least the guy is trying to set you up.

 

[k0ua]

Lets discuss "bad" and "badder" batteries. A battery that holds 10.5 volts at 100 amp load is Not bad for some applications, but might not be all that good for cranking over a diesel tractor for instance in the middle of winter. I think some starters would draw more than 100 amps. But the battery could be used for other things like a smaller engines starting battery or to run radios or other things with a trickle charger on it to recharge it. So a battery with a high internal resistance that these batteries seem to have, could still be used for many other things.

 

[Industrial Toys]

On the bright side, I did get a nice big HD one, that has worked well since, a couple of years back that came out of a Police Cruiser. They were doing some "Green" project for anti idling and somehow the battery became surplus. I needed it because I had not bolted my battery down in my Kubota Loader, was working on soime wild inclines and the battery fell against the exhaust manifold! Not a good day!

I really only need one lesser battery to run my 12 volt fuel pumps. I just got rid of a couple of undoubtedly very expensive glas-mat batteries that were also "supposed" to be good. I had a special charger/conditioner but could not bring them back up to be starting batteries. Again, they showed full charge and would instantly go down to (again) ten point something volts.

I wonder what makes a Huge battery that has full voltage, lack any capacity at all. Is it simply sulfation? Most of these batteries I get have been used in commercial mobile Inverter service, so have usually seen a lot of charge/discharge cycles and maybe even discharged completely!

 

[skyhook]

IT, check out this test, pay close attention to question 11.
Once you put in an answer, it will tell you if your right or not.
I think you'll find this useful.

Online Practice Questions - Batteries