question

There's a Victron MPPT calculator, check using that. Be careful, you've mixed up series and parallel in your question.

Assuming the Victron calculator says OK, I'd go with the 150/45 and wire the panels in series. But up to you. And I'd get the bigger battery. But that's me. Not a recommendation.

Just to gather more detail. Is this your first solar based system? Do you have experience with 100+V electrics before? Assuming that you are using a 12V system and 1-3m long runs for cables since you said it was a camper van?

Also assume that you dont have the batteries yet? Since still "debating".

I also assume that you noticed that the 100/50 does come in 2 varieties, with Bluetooth and without it. For a Camper, please do yourself a favor and dont skimp on BT connectivity.

Also it DOES NOT support 48V. The 150/45 does.

I have installed the 100/50 and a 100/20 at my cabin with 5kWh of LiFePo4 batteries. 2 systems at 2 cabins. 3kWh with battery heater and 2kWh without. Finnish winter usage for the larger one.

BUT, as I have later installed 20kWh of LFP at my house, the 48V advantages have indeed won me over. From now on everything will be 48V for me. Efficiency per watt goes up by a factor of 4 in financials.

Also there are so many happy campers in Youtube who have left the ways of 12V in the past with the march of the ever cheaper 48V LFP for campers. Or a dual system with both.

Back to your system plans.

With 2 panels and short runs the efficiency differences wont matter, so mostly this will be a question between safety, cost and futureproofing.

If this is your first build and you are sure that you wont be needing 48 volt support in the future, using that cheaper option in parallel with double the amperage is a safe bet. I would use 6mm2 cable with the PV. Double insulated with a light flexible duct, since in a car, things rattle and scrape. A LOT. You dont want the car to peel the PV insulation.

BUT, the above 12V choice also restricts you to the 12V curse, which is the higher amperage with every part of your system going forward. The wires, the MPPTs, the inverters, the lot. Lots of weight needed to handle the higher amperage = More and more costs. It all adds up fast.

Last and most important. DO NOT underestimate the power of over 100V DC electricity when doing things in series. 50V is so much safer. Especially when you dont really need the high voltage for long runs or high battery bank voltage(PV need to be 5V above the system bat voltage to recharge).

One 5:30AM "brain fart" while doings some modifications with the PV wires with bare wet hands(from hand to hand, through your heart), and you are DEAD.

Here is a handy table of DC wire gauge needs.

https://www.altestore.com/diy-solar-resources/wire-sizing-tool-for-12-24-and-48-volt-dc-systems/

PV wire is quite easy in your case even in parallel with only 2 panels. 6mm is good for max 30Amps total.

Mostly the heavier cables are related to the 12V load circuits(this is mostly where people skimp in the wire size and make mistakes with overloading the system). Depending on your load needs.

Just make sure to use proper wire sizes and fuses with proper torque on the connections(manual). Fire hazard is a bitch when not taken seriously.

Thanks again for your reply. I am using bus bars which I made from 30mm x 6mm copper, along with 60mm2 cable for the connections to the battery, inverter etc, running through ANL fuses. I have a main shut off for the battery to the positive bus bar, the solar input will go around this so I can still charge the battery with all the circuits off. None of the cable runs are longer than 50cm.