We have a 45 watt system–3 panels/2 batteries that output 12 volts. We have a charge controller in place and a 400 watt inverter. We started with running 2 LED lights off of it, not using the inverter. (The LEDs plug directly into the charge controller (cc)-and run off of DC power. Everyday we’d come home and the batteries were showing 12.5-13.4 volt charge. Excellent.
Then we turned on the inverter and plugged in a small radio and our two cell phones. Our daily charge dropped to 12.7. The we added a small fan…and started leaving the radio on for the furry crew during the day. Our daily charge dropped to 12.1.
Then we added a small fan upstairs because it’s starting to get hot at night. Daily charge remained at 12-12.1. Then I added a larger more powerful fan for a couple of nights (man, was that nice!) and our daily charge started dipping down into the low 11s.
During this time I came home and a when I tried to use the inverter a red light would come on and it wouldn’t power anything. But if I kept messing with it-eventually it would work.
Here’s where the problems began. We noticed that sometimes if the inverter was running-the cc wouldn’t power the lights-but it was inconsistent so I figured it was a glitch.
Then one night I plugged in the awesome fan directly into the inverter and fell asleep enjoying the breeze. I woke up sweating to no fan running. I could hear the inverter running. I tried to turn on my trusty LEDs-nothing.
Aw man. I reluctantly pulled out my head lamp–I had gotten used to a light switch–and went downstairs. Inverter was outputting no power and the little red light was on. I turned it off and trudged back upstairs to sweat and try to sleep. The cc showed 10.7.
Well-it was time to read the instructions. ;-)…
I found out that both the inverter and the cc have low charge limits called faults. If the charge drops below 11.1 on the cc it won’t work. If the charge drops below 10.8 on the inverter it won’t work. The purpose, as the manuals state, is to “prevent battery damage.”
So we may have damaged our batteries. Whaaaat? Much to our dismay–both of us thought you could pull them down at least to 40%! We have not run anything off of them for 2 nights and we are back up to 12.1.
My big, fat plan now is to talk to the people at Battery Joe’s. I need guidance…do we buy more batteries, another panel—both?!
I need my head lamp to go back to gathering dust.