I recently bought a rural property that has a Tesla Powerwall 2 along with about 10KW of solar panels installed (Fronius inverter). The panels are mostly shaded until after 10am in winter and don't face the equator very well. The system is from the last 5 years. Now, I'm considering adding a standalone solar system with batteries (not a Powerwall) and want to set up a ground-mounted array about 100 meters away from the house. I plan to have the panels, inverter, and batteries in the field while running a 240v supply back to the Powerwall like a generator. I feel it would be a waste to decommission the Tesla system or to cut down the trees for better sun exposure. I'd love to hear thoughts on this, especially if anyone has experience with similar setups. Also, has anyone dealt with a long 100m 240v run? Did you run into voltage drop issues? Thanks!
1 Answer
Absolutely, you definitely need to think about voltage drop in your design. It's usually better to keep the inverter and balance of system (BOS) closer to where the power is being used and run the longer 100m wire with higher voltage DC from the panels instead. That way, you minimize energy loss over distance.
Yeah, I was thinking of running at 240v too since it's a higher voltage. I'm considering using either 16 or 25mm copper for that 100m run to manage the voltage drop properly, depending on the final distance.
That makes sense! Since you'll have two battery systems, just be cautious with the setup. If you aren't careful, one battery bank might discharge to charge the other, which could waste energy.