## Answer

Apr 26, 2024 - 08:07 AM

Yes, solar panels are self regulating and for small arrays you can probably get away without circuit protection on the input side of the MPPT. In this case though because your 48 volt lithium bank is immensely powerful you need circuit protection at this end of the system as well as at the destination battery. At the lithium (input) end you need to use a fuse rated for the system voltage. Since the max current the MPPT can pass is 30 amps and the expected max output voltage is 14.4 volts we can use the formula Watts = Volts x Amps to determine that the expected max power will be 14.4 volts x 30 amps = 432 Watts. Then on the input side we can do the same equation but now at 48 volts to see that the expected current, when the battery is at 48 volts, would be 432 Watts / 48 volts = 9 Amps. It would be common practice to make the fuse size 25% more than the expected current. You are going to have a hard time sourcing such a small fuse rated for 48 volts so you might end up having to go a bit bigger. The only one I can think of that we sell is a terminal fuse, the smallest we sell is 30 amps.