The week my solar setup almost killed my bacon

Last month I had a string of three overcast days in a row up here in the Ozarks. My little 200 watt panel couldn't keep up and my battery bank dropped to 11.8 volts by Thursday morning. I had to run the generator just to keep my fridge from going warm and losing a month's worth of venison. Has anyone else had to guess when to fire up the generator based on weather radar?

3 comments

3 Comments

jakeb811mo ago

Get a little hydrometer and check your cells like @morgan_king36 said, because 11.8 volts is flirting with permanent damage. I've been there with my own bank down here in the Ozarks and sulfation sets in fast once you dip below 12.0 under load. What works for me is watching the 7 day forecast and if I see three days of clouds coming, I run the genny for an hour at noon each day just to keep the batteries above 12.2. That way I'm not guessing and I don't lose my deer meat. Also helps to set a low voltage alarm on your charge controller so it beeps at you before things get critical.

morgan_king361mo ago

11.8 volts is already deep into battery damage territory for most lead acid banks. You're talking permanent sulfation at that point. Did you check the specific gravity on your cells after that happened or just let it ride?

juliarodriguez1mo ago

Bought a cheap hydrometer after the first time I killed a bank that way and yeah it's eye opening how fast those numbers drop when cells start going bad. I ended up rigging a timer on my genny to kick on automatically whenever voltage hits 12.1 just to save myself the hassle of checking it every day.