Battery charge level, how low is too low?

[oldpa]

We plan to go down to Everglades NP. and dry camp at Flamingo campground. The Dimensions 130 watt inverter that's in our M/H will turn off when the batteries run down to 10.5 volts. Is it OK to let the batteries get this low and not be recharged unit the next day?
Greg

[oldpa]

We plan to go down to Everglades NP. and dry camp at Flamingo campground. The Dimensions 130 watt inverter that's in our M/H will turn off when the batteries run down to 10.5 volts. Is it OK to let the batteries get this low and not be recharged unit the next day?
Greg

[Pusherman]

Greg, I would suggest that is too low to let your batteries voltage level get to. You may have problems starting your generator at that low voltage.

Batteries are about 50% discharged at approx. 12.0 volts. If they go below 12V I would start the gennie to recharge.

P.S. Turn off the inverter before going to bed so as to not run down the batteries.

[Navy Flier]

I agree with pusherman and will state that at 10.5 volts your batteries will be too low to start your generator. I might ask what item is so necessary to use that you risk damaging your batteries and why not just use the generator?

[oldpa]

We don't do much dry camping, so I was not sure how low I could go on the battery voltage. After I posted my question, I looked around more and it seems 11.9 to 11.7 is as low as you should ever go. We wanted to see the Super Ball game. It will be on here in the east after dark and I did not want to make generator noise for the other campers. There are a lot of tenters and pop up's at Flamingo.
As a test, I ran the satellite receiver and the TV using the inverter in our back yard tonight. After 4 1/2 hours the voltage only went down to 12.1 volts so I guess we are good to go. We will run the generator in the morning to recharge the batteries.
Thanks, Greg

[John_Canfield]

12.3V measured with the battery at rest for 24 hours is generally considered to be 50% discharged. 12.9V is generally considered to be 100% charged. (You might find disagreements of a tenth of a volt here and there as to the charge state.)

Since it isn't easy/practical to measure the voltage with the battery at rest, you need to make an educated guess about your battery state unless you check the charge state with a hydrometer.

We have our Auto Gen Start programmed to start the genny when it detects battery voltage at 11.5 volts for one minute (or whatever the time is - I forgot.)

Like the other have suggested, I also think 10.5V is too low a cut-off voltage. Try 11.5V or a little higher until you gain some "feel" for your batteries.

For best battery life, try not to ever discharge your batteries below 50%.