doubravsky wrote:
What's the best way to determine if the battery is full? I'm not well versed on electrical stuff and know I need to learn it. I looked at the number on the inverter switch, which starts to beep in the mid 11's. When I'm charging with generator the number goes up to 13.7, but then once I turn off gen it goes down to about 12.7 .... but seems to start lowering pretty quickly. I'm wondering if this is from the "surface charge" that you mentioned.
The 13.7v would be the voltage that the converter is putting out. That would seem to indicate that you have an older Parallax converter. The 12.7v is the battery voltage and may include some surface charge. If you have some lights on or using some battery current, the surface charge should dissipate within a short time and the battery voltage should stabilize at the voltage you could use to calculate what the state of charge (SOC) is.
If I am right about the Parallax converter, it will take many hours to recharge the battery from 50% SOC.
Another thought: A fully charged battery should have a no load voltage of 12.6+v and ~12.1v would indicate 50% SOC.
