I have a couple of questions about a solar electric project I'm working on.
I wasn't sure if I should post this in the "Electrical" or "Green" section but this made the most sense. Sorry if it's a lot of questions. I mostly understand what I'm doing except for some of the finer details below.
To light my shed I use a small solar panel that produces 6 Watts at about 18V in full sun. This is wired to an inexpensive charge controller (from eBay) which charges a 12V deep cycle battery (SLA) and cuts off the load if battery voltage drops below a certain point. I wired 2 12V receptacles to the "load" screws. One has a 12V hand held spotlight (rarely used) and the other has an AC power inverter. This feeds a string of LED xmas bulbs for a total of 25 Watts.
- Everything worked fine until I added the charge controller into the mix and also added a new inverter into the mix. The old one was... well OLD and I killed it on a road trip, unrelated to the solar stuff (and it's not just the fuse... it's dead and it eats fuses now). But as soon as I plug in the new inverter (by itself with nothing plugged in) the battery voltage drops significantly and the controller kills the load. I think it's because the new inverter has a cooling fan and the old one did not. I assume I need to get an inverter without a fan. Does this sound right?
- Does it matter that the Inverter is rated for 20Amps but the controller is only rated for 12Amps?
- My multimeter reads 18V +/- in full sun at the panel, but only 12-14V on the charge controller's solar panel connection screws. It seems like it increases slowly as the battery charges but I've never seen it above 13.6V even though the panel reading is consistently over 18V. Is that a normal aspect of "controlling" the charge?
- I put my battery in an old metal toolbox with the lid ajar. Is this safer than no container? Do I need to worry about fire on a system like this? The panel is obviously outside but everything else is protected inside.
- Is there anything I overlooked in this setup? It was mostly an experiment but I like having free light in my shed at night.