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Help a beginner make some decisions, please!

Keezle

New Member
Joined
Mar 15, 2021
Messages
6
Hi everyone!

Short intro - i'm rebuilding my very small fourwheelcamper (FWC) pop-up truck camper (on my 2012 Tacoma). The FWC came with some legacy solar equipment that i'm upgrading, except for one 100W Renogy panel. I'm adding a panel and was hoping they would be similar enough to wire in series (my roof cannot support more then 2 panels due to weight and space (surfboards, etc). I've done a few power audits and i'm right on the cusp of the minimalist system (https://www.mobile-solarpower.com/the-minimalist-great-for-small-vans-and-cars.html) to basically run a few lights, a dometic cooler, and charge phones etc. It may prove that I possibly need to add another battery or increase my panel size (but i've already got one panel, so it's a real small investment to just add one). To supplement being on the cusp, I would love to hook up to my alternator via DC / DC. I was all decided on what I need, but then came across the Renogy DC / DC 50a MPPT.

Scenario 1:
1x SOK 100 AH 12v
1000w Renogy PSW inverter
100/30 Victron Smart Controller
DC / DC Charger (undecided on which)

2x 100W Renogy panels

Scenario 2:
1x SOK 100AH 12v
1000 Renogy PSW Inverter
Renogy 50A DC-DC W/MPPT
2x 100W Renogy panels

Questions:

Scenario 2 downside is that apparently I can't wire in my panels in series, is that correct? Does the downside of wiring in parallel outweigh the benefit of the combined DC / DC and MPPT from Renogy? Scenario 2 would save me a good amount of space, and possibly give me enough room to add another battery in the very near future. Our camping style is camp one day, drive, camp2 days, drive etc etc - so we think the DC system would be a great addition.

Also, would like some input on whether these panels can actually be wired in series.

Panel 1 :
RNG -100D 100W
Open-Circuit Voltage: 22.5v
Optimum Operating Voltage: 18.9V
Optimum Operating Current: 5.29A
Short-Circuit Current 5.75A
Max System Voltage: 15A
Dimensions: 47x21.3/1.4in

Panel 2:
RNG 100W
Open Circuit Voltage: 21.6V
Optimum Operating Voltage: 17.9V
Optimum Operating Current: 5.72A
Short Circuit Current: 6.24A
Max System Voltage: 600V DC (?)
Dimensions: 42.2x19.6x1.38

If these panels are going to be a compatibility problem, I may just bite the small cost and upgrade to 2 bigger panels.

Appreciate the feedback, looking forward to my first install and the mistakes that i'll inevitably make along the way :)

Thank you very much!
 
Welcome to the forum.

In parallel, you might see a 5% performance hit due to the slight deviation in optimal operating voltages. In series, panel #2 would be limited to the lower current of panel 1. You might see up to 10% total performance hit in series.

MPPT controllers will still work with panels in parallel. You just might lose some of the benefit in low-light (sunrise/sunset) performance the higher series PV voltage can yield.

Panels in parallel also suffer less of a performance hit due to full or partial shading on one panel.

I wouldn't hesitate to use them in either configuration as the scenario dictated.
 
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