Quote:
Originally Posted by Boilermaker57201
I have a 36 volt ezgo txt. I have tested my pack with a load tester i borrowed from work. I tested each one and they read ok on the 6 volt section. It seemed near the end of last golf season i didn't have as much power or time on batteries. Is there a better way to test them? If they are getting weak, will it help to buy one or two as i can to spread out the cost of new ones, or will that not help me or do any damage to new batteries?
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Accurate load testing of deep-cycle lead-acid batteries take an expensive piece of specialized test equipment that discharges the battery(ies) at a constant amp flow over a measured period of time and automatically stops the discharge and timer when 1.75VPC (Volts per Cell) is reached. The results are typically Minutes @ 75A for 6V batteries or Minutes @ 56A for 8V and 12V batteries and compared to the rated runtime given by the battery manufacturer.
For example: A Trojan T-105 6V-225AH battery has a rating of 115 Minutes @ 75A and is the the runtime is half of that or less, the battery is at the end of its usable lifespan.
The battery load testers found in auto parts stores are designed to test SLI (Starter/Lights/Ignition) batteries and do not accurately test deep-cycle batteries.
While it doesn't measure runtime, you can attach a DVM to the battery pack and measure the pack voltage while going up hill to see how low it goes under load. If it drops below about 30V for a 36V pack, connect the DVM to individual batteries and find out if one or more is dropping significantly more than the others.
Putting new batteries into a battery pack that is over 6 months old should be avoided. The new batteries will soon acquire the same aging as the old batteries. If you find some batteries whose voltage drops significantly more than others, they can be replaced with good batteries approximately the same AH and age, or if new ones have to be used, the must be considered sacrificial batteries and will need to be replaced at the same time the rest of the pack is replaced.
In other words, replacing the batteries piecemeal doesn't work very well and will cost more money in the long run.