Load testing 8V with load tester

gsf35099

Hello gang,

I have a load tester to test my batteries, pretty sure I have a battery giving me some problems. Probably going to replace the entire pack (sucks as the batteries are only 3 1/2 years old & going to be hard to find a used battery in similar shape as my pack), but my pack is not holding the charge after sitting for a week or driving uphill. It just does not have the torque or speed I used to have. I'm also going to have my motor rebuilt and want to make sure the pack is in the best condition as possible..

Anyway, I have T-875's and I have been reading all the threads and spec sheets and thinking that providing 100 amp load for 15 sec's should be enough of a load to show good or bad?? Will this work??

I'm going to load each with the 100 amps and read the volts with my DVM as well as the analog on the loader and record the values. Pretty sure this should point me at the bad battery.

thanks,

BGW

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scottyb

ANother method would be to connect your handheld DMM to each battery individually and go for a ride. A quick acceleration (uphill if one's available) will give good load comparisons - write the starting voltage & low number down for each battery, then compare

gsf35099

Thanks, Scotty.

I may have to do that. I've got 4 batteries load tested with 100 amps for ~15secs and the are 6.89 to 7.3. Would that 6.89v battery be a problem?

I was hoping I would see one drop really hard say 5-6 volts..
Two more still to check.

scooterman

Could i use my Fluke clamp on meter to do a current test or this no good for these batteries?

gsf35099

Scooterman, Yes, that is what Scottyb is saying. Clamp the meter to each back and check them as you ride.

Scottyb,
Question for you. What kind of pack voltage do you see going up a hill on any of your 48 volt carts?
I'm seeing 46.5 heading a pretty steep hill here in my yard.

I'm thinking my problem is now my motor has just run about to the end of its life.. :) It is the original 91 36v motor and probably time to be rebuilt.
As for the batt's, when I think about it, the temp has been fluctuating here from 80 to below freezing for several weeks now and I'm now thinking I don't have a battery issue.

scooterman

I'm, taking Ammeter not DMM

You may just need brushes on that motor, bearings and brushes aren't that difficult to replace.

gsf35099

scooterman,
is the Ammeter a digital volt meter? Pretty sure what scottyb ment by DMM is (Digital Multi Meter) they are also known as DVM (Digital Volt Meter) but the DMM can measure both digital and analog.
If your meter will measure DC volts your good to go.

As for my motor, I have wanted to have Plum Quick rebuild it when it was time to pull it and now seems like the perfect time.. I still run about 18 MPH on flat ground but just don't have the torque like I did.

scooterman

Actually it can read voltage but no it is an Ammeter It reads amps. I forgot it doesn't read DC amps, just Ac so never mind the question.

allenb12

Under a load test 6 volts would indicate a 8 volt battery was bad. A shorted battery will go to 0 under a load test.