Simplest (and cheapest) way to charge 3s li-ion pack using a 12v solar panel

YuvalS · 2019-08-22T13:43:47.000Z

I have a 12v solar panel and want to use it for charging a 3s(4p) 18650s pack to use in camping.

I already know that I need a 3s protection board but have some questions:
1. Are the cheap protection boards (this for example) are also cc/cv balance chargers? I.e. can I simply connect it to a 12V DC source and it will charge it safely?
2. Is it ok to keep it connected to the solar panel also after fully charged?
3. Is it ok to keep it connected to the solar panel while load (lamp for example) is connected to the pack?
4. If the solar panel is only 12V, will the pack ever be fully charged (3*4.2=12.6V)?

5. Am I stupid and it will not work (or burn my car) ?

Rusty4x4 · 2019-08-22T15:51:38.000Z

As to #4, “12v” solar panels often go up to 20-22v with no load and make the most power when run at 15-18v depending on the intensity of the sunlight so fully charging a battery to 12.6v is no problem. Look at the “Voc” and “Vmp” ratings of the panel you are using to confirm this. Voc= voltage with an open circuit, Vmp= voltage at maximum power point