Battery testing

[Colwyn D]

I have 4 group 31 agm's as a house bank and would like to test them as I believe one may be failing. Is there a way to test battery capacity/health when the specific gravity of the acid cannot be taken?

[oscarvan]

https://www.amazon.com/Calculated-Industries-8715-AccuMaster-Resistance/dp/B07CL8RPDS/ref=sr_1_21?ie=UTF8&qid=1548816768&sr=8-21&keywords=battery+tester

A (https://www.amazon.com/Calculated-Industries-8715-AccuMaster-Resistance/dp/B07CL8RPDS/ref=sr_1_21?ie=UTF8&qid=1548816768&sr=8-21&keywords=battery+tester)side from that, you can charge them completely, and then fully disconnect them and simply measure voltage over time.... Should stabilize at 12.6 after about an hour. If one starts dropping faster than the others, there's your problem. Does not guarantee the others are 100% though, but if they fail this test they ARE bad.

[Boatsb]

Pulse tech makes a nice unit for about $250.00

[Reefgeorge]

You fully charge the batteries. Knock off the surface charge with a light load, then isolate each battery and apply a known high load, monitor the voltage and compare the result to the battery spec:

https://www.amazon.com/OTC-3180-Battery-Load-Tester/dp/B000F5HU6C/ref=sr_1_6?ie=UTF8&qid=1549265498&sr=8-6&keywords=battery+load+tester

Many battery issues are the result of charging issues so make sure that your system is capable of getting all of the batteries to 100% charge level.

George

[oscarvan]

And.....when was the last time they were equalized?