So You Own An AGM Battery...
AGM batteries can sulfate just like any other lead acid battery. Other than by Ouija Board how would YOU determine if a battery has become sulfated and how severe is the sulfation, and if desulfation ...
Forum Discussion
Some tips: A 50 watt 12 volt trouble light bulb from a hardware or auto parts store is the cheapest reliable load I am aware of. 4 amperes more or less (connect it and see with your meter)
I would use time rather than voltage. A decent 100 amp battery should discharge to around 50% in 12 hours, right? So I set the alarm clock, then when it goes off I go and see where the voltage is.
Use your manufacturer's voltage charge percentage guide to calibrate the test.
Want to test two or three batteries at the same time?
Buy two or three lights and bases. Connect them in series. Series connect two or three batteries accordingly. Same test done by hours. Carefully note the word SERIES. You are making a 24 or 36 volt circuit. Connect the light bulbs IN SERIES just like you do with golf car 6 volt batteries.
BUT when using multiple batteries, check the voltage of EACH 12 volt battery independently WHILE the batteries are under test near the end, say at 10 hours.
Have one with a half volt sag in it? Cull that battery. Or maybe 2 or all three batteries are not up to snuff.
All for the price of two or three light bulbs, wire big enough to run 4 amperes through, some handy boxes and ingenuity. Most any Digital multimeter will do fine.
You DO need to measure amperage to get a baseline. And you DO need the manufacturer's percentage state of charge voltage chart.
All this without using an amp hour meter. Perfectionist insist on a kWh meter but when the "magic light bulb" goes off over a person's head, the results can be impressive.
I would use time rather than voltage. A decent 100 amp battery should discharge to around 50% in 12 hours, right? So I set the alarm clock, then when it goes off I go and see where the voltage is.
Use your manufacturer's voltage charge percentage guide to calibrate the test.
Want to test two or three batteries at the same time?
Buy two or three lights and bases. Connect them in series. Series connect two or three batteries accordingly. Same test done by hours. Carefully note the word SERIES. You are making a 24 or 36 volt circuit. Connect the light bulbs IN SERIES just like you do with golf car 6 volt batteries.
BUT when using multiple batteries, check the voltage of EACH 12 volt battery independently WHILE the batteries are under test near the end, say at 10 hours.
Have one with a half volt sag in it? Cull that battery. Or maybe 2 or all three batteries are not up to snuff.
All for the price of two or three light bulbs, wire big enough to run 4 amperes through, some handy boxes and ingenuity. Most any Digital multimeter will do fine.
You DO need to measure amperage to get a baseline. And you DO need the manufacturer's percentage state of charge voltage chart.
All this without using an amp hour meter. Perfectionist insist on a kWh meter but when the "magic light bulb" goes off over a person's head, the results can be impressive.
