PinkLeopard wrote:
Replaced 2-6 volt house batteries because they weren't holding a charge. Immediately afterwards voltage dropped rapidly to about 12.8. Checked water - it's ok. Charged with generator and shore power to 13.6 but they're not holding a charge.
Seems normal to me.
12.8 is the highest voltage that flooded lead acid battery will sit at when it is full of power.
You might be expecting something else, but the rest of us are not.
13.6 volts is the normal charge battery (power flowing slowly into the battery). Say up to 5% of the battery capacity per hour - thus 220 amp hour golf cart battery might charge up to 11 amps per hour when the battery is between 90 and 99% full, while at 13.6 volts charging.
13.2 is a normal "Float" charge, say if the charger is well designed, and the battery will not overcharge, and will not be discharging, or charging rapidly. It might be charging very slowly, like less than 5 amp hours per hour.
12.8 volts is the normal "Full" battery resting voltage, say when it is between 90 and 100% full. 12.7 or 12.6 would indicate 80 - 85% full.
11.5 would be the lowest I would allow my battery to go without recharging, and normally I would not let them get that low. Kinda like running your car until it is well below the E on the gas gauge. Better to refill at 1/4 full. Much better to refill at 50% discharged, the battery life will last much longer if you recharge the battery before it is less than 50% full.
The RV will use about 35 amp hours per day if the CO and propane detectors are left on all the time and the RV is not plugged in. If you only have a 15 watt solar panel, then that will not keep up with normal usage, even if all the lights are left off and the furnace is not run.
One of my 120 watt solar panels can make about 35 amp hours daily, and keep the battery full.
Fred.
