I have a trolling motor and a large lithium battery on my sailboat. The two are good enough to get me home from about 3 miles out if the wind dies, though it will take a while. I got a small solar panel from HF. https://www.harborfreight.com/15-wat...ger-62449.html.
I hooked it up to my battery and my ammeter showed a half amp going into the battery, but after two days the voltage on the battery hadn't gone up. I know it isn't big enough to fully charge it, but I expected to see something. Or maybe the solar panel is simply too small to have any effect.
Perhaps at night the battery loses power to the solar cell? My EE courses were way before any of this stuff existed, so I have no idea.
But if it is, HF sell a solar panel controller; https://www.harborfreight.com/7-amp-...tor-96728.html. Is that like to help? A more expensive one says it prevents current lose through the panel, but this one doesn't.
Anyone know?
You can't go by their descriptions anyhow... I got a great deal on 100' of 3/8" polyester rope for $8. Got it home and found it was PP.