Hey everyone, I've got a layout for my solar setup that includes three 100W panels wired in series to an MPPT charge controller, and then it goes to a battery and inverter for AC output. I'm looking to make sure everything's set up correctly and would love help with a few specific questions:
1. For the connection from the panels to the MPPT, since it's in series and I want to be able to service it safely, I'm thinking about using a disconnect switch rated for at least 8A. But I can't find a switch that small. Is it okay to just use a breaker instead?
2. Regarding the MPPT to the battery, I plan to add another 100W panel later on. Should I go for a 40A breaker now, or should I play it safer with a 30A and upgrade later when I add that panel?
3. Finally, for the battery to the inverter line, I'm using a 100Ah LiFePO4 battery connected to a 1100W pure sine inverter. I'm not sure about the breaker size here. Would a 125A or 150A breaker be appropriate? Also, I'd like to include an in-line power analyzer rated for 150A; will that affect my setup in any way?
After everything, the system will run to my camp using 10AWG wire to an inside panel.
3 Answers
Good questions!
1. Yeah, a breaker can work well instead of a disconnect switch. It's important that it can handle the amps. A breaker just makes it easier to reset if you need to.
2. I'd suggest going with the 40A breaker now. It can give you room for that future panel without hassle.
3. For your battery to inverter, going with a 150A breaker is a safe bet given your inverter's rating. Just be cautious with the in-line power analyzer since cheaper models can sometimes be unreliable at higher currents.
Hey there! For your first question, it's totally fine to use a breaker instead of a disconnect switch for your panel-to-MPPT connection, especially since you're only dealing with a single string of panels. Just make sure the breaker is rated for the current you expect.
As for the MPPT to battery connection, if you're adding a panel later, it might be better to go with the 40A breaker from the start. It gives you the flexibility without having to switch it out later.
Lastly, regarding the breaker size between the battery and inverter, yes, a 125A or 150A breaker seems appropriate, based on your inverter's specs. Also, use a good quality in-line power analyzer that can handle the amperage. Just make sure it’s designed to operate safely with that load.
For your setup, I recommend considering a combiner box for the panels as it simplifies connections and adds fuses for safety. You don't really need a disconnect switch in your case; just sticking with a breaker should be fine.
About sizing the breakers: you should calculate using what the continuous load will be for the system to ensure safety without tripping. And lastly, I’d steer clear from cheaper in-line analyzers; they tend to fail and can introduce inaccuracies in measurements.