Expected voltage sag?
I've got two 6 volt GC batteries. I have an inverter just powering a laptop. It's pulling under 100 watts AC. What kind of voltage sag would you expect that to put on these batteries if they were full...
Forum Discussion
ewarnerusa wrote:DrewE wrote:
Does the battery voltage recover immediately when the inverter is turned off? If so, it may be a relatively high resistance spot in the circuit and not a battery problem. This may be a poor connection at a battery terminal, for instance, caused by corrosion or crud on the wire terminal, or a poor ground, or.....
Yes it does recover immediately. Wouldn't taking my voltage readings directly from the battery posts essentially bypass any wiring issues? I get that I would be measuring voltage drop due to resistance in the wiring if I took measurements anywhere near the inverter. I did clean up my connections after getting the camper back home in the fall, there was corrosion present when there never was before. Wiring is quite fat and relatively short, so I don't suspect a problem there. I'll see what the other inverter does which shares the same wiring to the battery (2 gauge, 5').
If there's a poor connection for whatever reason in the jumper between the two 6V batteries, that would still be reflected in a voltage reading taken at the extreme battery terminals.
I'm not suggesting that the connections are necessarily bad, only that it is a possibility to consider and rule out. Taking a voltage reading between, for instance, the terminals of the batteries that the inter-battery jumper connects to would easily show whether you're getting an unacceptable voltage drop there or not. (Basically, any voltage drop would be unacceptable at 10A, or at least any drop above a very few millivolts.)
