That's what I've always been told. I've even seen it happen in golf carts. I know that even with my 1G, the voltmeter will read over 13 volts (can't remember how much) right after I shut the truck off. It will drop back to 12.7 after a time. I do know that batteries can show fine on volts, but still not have much in the way of amps. Since you just shut your truck off and only have a total of 900 CCA, I'd say that it's that time. If your 3G is working good, it should not overcharge your batteries. It has a regulator for a reason. At least it's summer time and you should be fine running on one battery for a little while. Don't have any extra electrical things (like A/C blower) on until it's running and, of course, get another battery in there before it cools off very much just in case.
Well he was measuring voltage at the batteries, I don't have any real gauges yet
I'm going to run the voltage sense wire to the output stud to be sure, it's running somwhere else now, I don't remember. Starter solenoid maybe? Idk it's been a few years.
Check all your cables. Maybe have your starter tested. It’s one of those things that flat batteries will speed the decline of your starter because it has to draw more current to make the same wattage. It just spirals. Same with the starter, if it’s getting weak, it takes longer to start so it’s harder on the batteries.
I'm afraid they would just tell me "yup it spins" I don't think they can load test it. I'll be honest, there have been a few times of impatience and over cranking on my part which I'm sure hasn't helped. I'm considering pulling it apart and looking at it, it is just a parts store reman.
I might be considering a powermaster as one and done to check it off the list though.
Cables look good but can't hurt to clean the grounds up again.