House battery voltage under draw?
I have a new (to me motor home) and an upgrade from my old one. In my old RV, I had to check the house battery voltage manually. With the new rv, I have a switch on the wall. However, when I check t...
Forum Discussion
tommymsw wrote:
1. When I say the batteries when NOT under load go back to low 12 again, that is BEFORE they charge back up. They do charge back up to full again.
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However, if the volts do appear lower when under load, how then do you know when to stop using them? I assumed you could check them in use and know when you need to stop.
How do you know they are charged fully when you charge them?
Voltage accurately corresponds to State of Charge only after battery has rested for (at least) 12 hours since charging, and in absence of loads. Get a multimeter and measure directly on battery contacts, not through the wires several feet long.
Solar charger reading 14V (or is it a remote voltmeter again?) - this doesn't tell much, either. Only after it had STAYED at 14.4-14.6 for an hour or two, you can be sure that it's charged more than 75-80%, though it won't be full yet.
In use voltage readings are all over, you can't rely on them. If you need to know when to stop (whether you meant to stop using energy or to stop charging) - you need to install inline amper-hour meter. When being charged with solar panel, there is no need to stop charging, good solar controller will stop by itself. Not all of them are equally good, though.
