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
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').
Our weather has been pleasantly warm these past couple weeks (approaching 60F during the day) and the batteries behave the same. It just happened to be a bit below freezing this morning.
Another thought... I wouldn't doubt that they batteries are compromised and should be replaced if I want the full benefits of 2x6V GC batteries. But wouldn't damage also result in decreased capacity? I mean it seems like they recover back to an acceptable voltage after drawing ~90 Ah from them last night (came back up to 12.3V at -1C temp). So capacity seems unaffected but they experience much higher voltage sag under load than they should.
