I'm setting up a backup system for a fridge and deep freezer using 2 12.8V 280Ah batteries, a 3000W 12V inverter, and a Victron 150/100 solar charge controller, along with 4 100W panels. I went with the Victron because I plan to expand later on, but I'm worried about underpaneling it and whether it's safe. My inverter is limited to 12V, which means I need to connect my batteries in parallel. Should I consider getting a 24V inverter instead? Also, is it necessary to downgrade my charge controller, or will my current setup work fine?
3 Answers
Your Victron 150/100 will handle under or over paneling well, but do check the VOC for your panels. Ideally, it shouldn't exceed 150V, especially in colder conditions. Your current setup should be sufficient, but going for 24V can give you a better performance as you add more panels in the future.
You're fine underpaneling a Victron MPPT; it can still work efficiently. Your solar input won't be drastically affected—it just becomes a bit more wasteful. But you need to consider how your inverter works, too. If it's a basic inverter and not a Multiplus, idle draw could be problematic when running directly off solar. It's usually better to go with a higher voltage setup beyond 2kW, but your Victron 3000W is good. Just to be safe, you might want to assess the idle power consumption based on your specific inverter model.
Definitely swap for a 24V inverter; it's more efficient than sticking with 12V. Wiring your batteries in series will boost your system. As for your charge controller, the Victron is suitable. Just keep an eye on your panels' voltage—make sure their combined open-circuit voltage stays below the controller's limit. Moving to larger panels could enhance your setup too!