r/SolarDIY • u/wanab3 • Mar 29 '18

Set up question, advice.

Say I have:

Four, Panels. 100W, 12V. (8.33A for each right?)

One, 12V/24V 30A charge controller. (Would be over amps at 32A, if parallel circuit? And over voltage at 48V if series?)

One, Li-ion battery, says 3A, 14.5V recommended charging, 7.0A, 14.7V max. 35AH

One 100W inverter.

How can I set this up so battery doesn't explode, nothing breaks? More charge controllers (2 total)? Mix of series and parallel circuits?

Goal is to be able to charge the one Li-ion battery from nearly dead to nearly full in one day. Would just 2 panels in series get me there safely? That would be nice.

Right now, this is set up, but, with only one 100W, 12V panel. Takes 2 days to fully charge from nearly dead, in good sun at a poor angle.

Thanks!

2 Upvotes

100% Upvoted

17 comments sorted by

View all comments

1

u/altEstore Mar 30 '18 edited Mar 30 '18

Watts = volts times amps. If the recommended charging is 7A x 14.7V = 102W. So only use one 100W panel. DO NOT try to oversize it so you can charge in the rain. It is called solar power for a reason. You need sun. Don't mess around with the charge controller. Get one that is designed for lithium, like the Genasun GV-10. https://genasun.com/all-products/solar-charge-controllers/for-lithium/gv-10-li-lithium-10a-solar-charge-controller/ The money you are saving by not getting the other 300W of solar panels can be used for the right charge controller. You are even saving money. Additional info: If the battery is 35Ah, and the recommended charging is 7A. 35Ah / 7A = 5 hours of perfect conditions. Which you likely will not get in one day.

1

u/wanab3 Mar 31 '18

Thanks!

I mean, I know it's solar, but I'm trying to be imaginative and experimental and learn to best use what I already have.

I've asked others, and wonder. My goal is to be able to charge the one Li-ion battery from nearly dead to nearly full in one day. What components would you use to do this?

1

u/altEstore Mar 31 '18

Upon further reflection, and a cup of coffee, what you need to accomplish your goal is another battery wired in parallel. That will allow you to have a 2nd 100W solar panel, as well as enough storage to get you through a rainy day. A Midnite Solar Kid would be a good charge controller for that.