How to test auxiliary batteries for amperage?

I have an amp meter on my system, to test capacity I use my inverter and a small crock pot to load battery. Current X time = Amp Hours. Not perfect, but good enough for me.

Doug

I dread having to lug these monsters anywhere.
The doctor says not to lift or carry anything heavier than a roll of paper towels.

Regardless, if I get the batteries close to the now grounded truck camper then I can substitute them for the camper batteries (via jumper cables).
If the bats are still good then they should lift the camper a few times no problem.

Thanks for keeping me mentally engaged with this project.
The camper is bagged and tarped at the moment so it might be a few days but I'll report back when this is done.

Raften wrote:
Get a load tester.

Yep. Are they even thirty bucks?

Something like this will work fine.

If you need new batteries, what's the plan for logistics?

MEXICOWANDERER wrote:
If you need new batteries, what's the plan for logistics?

The batteries are in a box. I use a roller cart. And I have a small garden tractor with a front end bucket.
So it's a matter of shuffling them place to place. Lift with the tractor.
I will sell them if they are any good.

BigHat,

Don't work so hard.
You don't even want to do the test at started load, so don't.
Get a good volt meter, an ammeter (even cheap will work), either a refractometer (what I use) or a hydrometer and a pair of headlight bulbs. Charge the bank to full density (12.60). Measure the bank voltage. Connect the ammeter and the headlights to the banks and look at the clock and the ammeter. After a time, I like to use one hour, disconnect things. Let the bank settles (15 minutes is good) and measure the both the bank voltage and the electrolyte density.

You now know the state of charge from two benchmarks and how many Ampere-Hours were drawn from the bank. The amount of discharge should be close the distance between 12.60V and 12.00V that is the 50% discharge mark. You can make a quick guess, or you can do a short search on the web for the tables that list this data. If the density readings don't agree with the voltage, there is something wrong that could matter.

I used to carry the pair of old sealed beams and cables in a box as I did this test for boat owners more than a dozen times a year. I could still do it, I have the box but the business that requires discretionary income is dead in my area. Killed by the recession that has not nearly ended here(I don't care what they say), but I will be ready if and when it does ever end.

Matt

Matt is right.

Full load testing means achieving 50% of CCA for 15-seconds while monitoring voltage. A capacity test will tell you if the battery is damaged. But it takes a lot longer and I deal with an OP's inquiry if it is valid. You wanted to know about carbon pile load testing.

Handheld CHEESE GRATER load testers are great for lawn and garden tractor size batteries. Try to test and regular RV battery and it would be tantamount to giving an Olympic weightlifter a 25-pound barbell and seeing if he could lift it.

Foolish me. If I was selling batteries like those, I would reveal to potential buyers exactly what happened and that the batteries were tested and proven good. But that's me.

Slap a STRONG 12-volt muffin fan onto the Harbor Freight 500-amp variable load tester and it turns mediocre into decent.