Portable system panel/controller configuration

[Benjamin Nead]

Hi everyone . . .

I got here the last week after watching a few of Will Prowse's YouTube videos and following the links from there. Immediate help to ironing out some of my basic ideas came from snoobler (it turns out we've actual have met in person,) Steve_S (we've talked to each for years on the CleanTechnica blog) and JoeHam . . .

https://diysolarforum.com/threads/new-member-from-tucson-az.14881/

Basically, I want to build a portable system that moves beyond the ready-to-go ones (Bluetti, Goal Zero, EcoFlow, etc.) but still not so large that I can't carry it around in the back on my Mitsubishi i-MiEV electric car. I'm posting this under the forum's Vehicle Mounted Systems subheading. But what I'm going to be doing is carrying the system within the vehicle, setting it up for a day or so at a time and then packing it up to drive away.

The typical demanding load would be running things like an 1800W induction hotplate a few times a day for short periods and plugging in my car's EVSE in independently (ie: not at the same time,) which I would set at a low 8A/~1kWh draw, but for a few hours continuously. I'm not living off grid, nor do I intend to rely on my potable to system for all of my cooking and/or vehicle charging needs.

I'm now focused on building a 24V/8S 2560Wh LiFePO4 battery around the 100Ah Fortune cells, a 3000W inverter of some sort (exact one TBD) and the Overkill Solar BMS . . . all of which is pretty mainstream stuff from what I've seen people here talk about and build.

Where I diverge for my particular application is that I have to choose panels that are small enough to transport in my (surprisingly spacious inside at around 50 cubic feet with the rear seats down) subcompact EV and deploy conveniently. 50W panels, measuring roughly 2' X 2' each, are the ideal solution.

So, mapping out something that will allow me to charge the 2560W battery over the period of a typically 6 hour sunny Arizona day means I'll probably need around 600W of these 50W panels (12 panels total.) All of that is actually quite doable, as I've got ideas about storage/deployment issues that I'll talk more freely about at some future date. What I really need to know sooner than later is how, exactly, I should hook up 12 such panels.

These 50W panels are basically going to be 18Voc and 8A (Imp) each . . .

1) 2 panels in parallel @ 100W ea., with 6 controllers? (I'm guessing not.)

2) 3 panels in parallel @ 150W ea., with 4 controllers? (maybe?)

3) 4 panels in parallel @ 200W ea., with 3 controllers? (perhaps the best option?)

4) 6 panels in parallel @ 300W ea., with 2 controllers? (another good way to do it?)

or . . .

5) 12 panels parallel @ 600W with 1 controller? (I'm also guessing not likely.)

Once that's figured out, this will help choose which controller(s) to use. I'm going to guess that the Victron or Genasun lines will have something I'll like.

Thanks in advance . . .

 

[HRTKD]

The more panels you can put in series and the fewer solar charge controllers used, the less wiring you need to cart around.

Portable panels implies a tilt mechanism (manual). The more panels you have, the more tilt mechanisms you'll need. Have you looked to maximize the panel size given your interior dimensions?

 

[Benjamin Nead]

I guess what I'm looking is for the most efficient way to do it, electronically, and not have to buy a single controller that's physically as large as the assembled battery. I don't mind a multiple controller setup, if that's what it takes. Also, a few extra wires to hook up doesn't scare me. I used to assemble medium sized concert sound systems and the amount of mic and speaker cables I used to wrap up at the end of the night would pale in comparison to what I would be dealing with on my proposed portable PV system.

Without giving to much away just yet, I think I've come up with a very efficient way to deal with reasonably quick setup and repeatable angling of multiple panels. The mechanical crafting of such a system is within my skill set and budget. I've ordered a single 50W test panel that, in terms of physical dimensions, is absolutely ideal (21.3" X 21.3".) It should be arriving within the next couple of days and I'll test out electrical specs. If it passes that test and looks to be built well, I'll order more.

I know I'm probably going to get a lot of suggestions here to go with 100W panels or bigger. Size wise, that simply won't work. I've spent numerous years with tape measure in hand inside my vehicle mapping out that part. Also . . . no flex panels.