Mobile Setup

[LeoLopez]

Hello all, I'm a newbie so please take it easy on me as I learn. I was watching one of Will's videos over the 24v set up. I believe that that is what I will be going with. My reason for this is because I have a larger than usual set of solar panels. I have 4 405W Panels. I was planning on using two smaller solar charge controllers (Victron 100/50) per two solar panels into my battery bank. This is because I did not want to pay as much for the bigger size controller but is now proving to be more of a headache as I am overthinking everything I plan to do. I will then have an inverter and a converter (for DC appliances). Does this super simplified explanation work?

My second question is can I not charge my batteries with the alternator? I know Will mentioned it in his video, but I will be driving around a lot and was really banking on that.

TIA

 

[cdevidal]

So each 100V/50A controller has two 405W panels, and these are paralleled into a 24V bank, did I understand that correctly? What is the Voc of your panels? Should be listed on the rear or in the spec sheet.

Yes in theory the alternator can charge as well, though I believe you’re going to need a DC-DC converter to reach charging voltage. Someone more experienced than I will have to chime in on that.

 

[LeoLopez]

So each 100V/50A controller has two 405W panels, and these are paralleled into a 24V bank, did I understand that correctly? What is the Voc of your panels? Should be listed on the rear or in the spec sheet.

Yes in theory the alternator can charge as well, though I believe you’re going to need a DC-DC converter to reach charging voltage. Someone more experienced than I will have to chime in on that.

Yes, you understood that correctly! The VoC is 49.86 at 24v in parallel each pair of solar panels.

 

[rmaddy]

With two 405W panels you have 810W. With a 24V battery that is 810W / 24V = 33.75A. So you need a SCC with a output battery current of 30A, not 50A. With a Voc of 49.86V you could use a Victron 100/30 if you put the two panels in parallel. You can't put the two panels in series since the Voc would easily get over 100V. Voc goes up as the temperature goes down and the Voc of 49.86V is at 25ºC (77ºF).

Another option would be to use one SCC and put the panels in 2S2P. Then you would need the Victron 150/60.

The 100/30 is $226. Since you need two it's $452.
The 150/60 is $540.

While the single larger SCC is about $90 more than the two smaller ones there are several advantages. Easier install. Less wiring. Better performance since having the 4 panels in 2S2P will give you better low light charging power compared to an effective 4P setup.