Theoretical solar build check

Hi guys. Still loving this forum! The immense amount of info is overwhelming but helpful.

So here’s what I have so far on paper. Curious of any advice or things I’ll need to add. I’m not including smaller components yet for the list. It’ll be 12v dc with 120v ac for wall plug ins and mini split a/c

4x Renogy 450w rigid panels
42v VOC , 14a isc

Victron SmartSolar 100a/250v mppt cc

8x Litime 230ah lifepo4 batteries in parallel

Victron Multiplus 3000va 12v inverter charger

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On the panels I’m assuming 2s2p will be my best bet with using the one charge controller? As far as my research showed this should be a completely compatible system. Thanks for info!

1800W/14.4V = 125A

Flat panels on the roof aren't likely to perform much past 80% of spec, and that's only in the middle of the day. Doubt you're losing much of anything using 100A on a theoretical 125A.

Everything seems to line up. 4S or 4P would also be fine. If there's any chance of roof protrusions shading panels, go 4P.

A 150/100 is cheaper than a 250/100 and would work for 4P or 2S2P.

1800W of solar should be good for about 7.2kWh/day usage.

23.6kWh of battery is likely overkill based on the available solar, but there's no harm in that if it's what you want.

Is the vehicle electrical system custom, or is it an RV with a 30A or 50A shore power design?

sunshine_eggo said:

1800W/14.4V = 125A

Flat panels on the roof aren't likely to perform much past 80% of spec, and that's only in the middle of the day. Doubt you're losing much of anything using 100A on a theoretical 125A.

Everything seems to line up. 4S or 4P would also be fine. If there's any chance of roof protrusions shading panels, go 4P.

A 150/100 is cheaper than a 250/100 and would work for 4P or 2S2P.

1800W of solar should be good for about 7.2kWh/day usage.

23.6kWh of battery is likely overkill based on the available solar, but there's no harm in that if it's what you want.

Is the vehicle electrical system custom, or is it an RV with a 30A or 50A shore power design?

Click to expand...

Thanks for the reply! So the vehicle is a e350 cutaway van shuttle bus. So the only electrical currently installed, aside from the ford van wiring, is the exterior lights and a motorized bus door. Which I’m going to relocate and run new wiring for alot of it. Shuttle bus builders aren’t exactly the most elegant with wiring. Other than that it’ll be completely DIY.

The large battery bank is essentially overkill but a safety net in case of breakdowns, charging concerns, panel failure, etc on the road. I want to ensure a/c or heat for our pets no matter what happens. We may end up downsizing it to 6 batteries if we can’t make them all fit.


Now for the charge controller, the 150v should work? I can’t remember now off the top of my head, but for some reason I convinced myself it wouldn’t lol. I can’t recall exactly why. But I see it could definitely work now. I will say though that charge controllers are rated at 30a per mc4 connector pair, and 3 pairs total. Is running 28a, or 2 panels per mc4 pair a bad idea?

midwestsolarnoob said:

Thanks for the reply! So the vehicle is a e350 cutaway van shuttle bus. So the only electrical currently installed, aside from the ford van wiring, is the exterior lights and a motorized bus door. Which I’m going to relocate and run new wiring for alot of it. Shuttle bus builders aren’t exactly the most elegant with wiring. Other than that it’ll be completely DIY.

The large battery bank is essentially overkill but a safety net in case of breakdowns, charging concerns, panel failure, etc on the road. I want to ensure a/c or heat for our pets no matter what happens. We may end up downsizing it to 6 batteries if we can’t make them all fit.


Now for the charge controller, the 150v should work?

Click to expand...

Good for 150Voc. 2S would only be 84Voc.

midwestsolarnoob said:

I can’t remember now off the top of my head, but for some reason I convinced myself it wouldn’t lol. I can’t recall exactly why. But I see it could definitely work now. I will say though that charge controllers are rated at 30a per mc4 connector pair, and 3 pairs total. Is running 28a, or 2 panels per mc4 pair a bad idea?

Click to expand...

28A will be a very rare event, and the MC4 rating seems pretty solid.

Depending how everything fits together running the panels as 2 separate strings of 2S to 2 SCC might be easier. Dual 50amp can be wired with 6 awg vs the 2 awg needed for a single 100a