I'm setting up a small solar system for my cabin with one 325W panel and two sets of golf cart batteries. I've found that the panel's position works great in winter and spring, but isn't ideal during the summer months due to the house's configuration. I plan to add a second panel in a spot that gets more sun in the summer. However, since these two panels will produce different amounts of power, I'm unsure how to connect them. Should I wire them in parallel to avoid issues, or is it safe to use them in series if I add bypass diodes? If I go with parallel, can they go directly into the same Victron MPPT charge controller, or do I need to combine them before the controller?
1 Answer
For the best performance, I recommend wiring the two panels in parallel, as long as their voltage and amperage ratings match (like both being 18V and 7A, for example). This setup allows you to utilize the full power from each panel, even if one is shaded while the other gets direct sunlight. If one panel is obstructed, it won’t affect the other one’s output.
If you do end up with panels that don't match, consider using separate charge controllers for each panel, which you can then wire into the same battery bank.
Using diodes is a great way to manage the power flow, acting like one-way streets to prevent backflow from a stronger panel to a weaker one. And remember, in parallel, you'll be combining the amperages while keeping the voltage the same.
Wiring panels in series can lead to problems if one panel is less illuminated, effectively bottlenecking the higher-output panel. So, go parallel if you want flexibility in managing different sunlight conditions!
Thanks for the insight! I'm no electrician either, but I'm curious: the panel I have now outputs 9.64A at Pmax—do you think my 20A controller is sufficient, or should I go for one with a bigger buffer? Also, when connecting the outputs, do I need some special junctions or just standard wiring? Any advice would help!