Fuse Size


New Member
Jun 22, 2021
I know you fuse wires not x.... So please don't comment that. I'm trying to determine what size fuses to use with my 24V system. How much larger then the load should fuses be. I read a number of different answers given online ranging from 20-50% larger?
My DC fuse panel is rate for 100a continuous. I'll probably only be using half of that at first. The wire size is 2awg from main distribution bar to a 100 amp battery protect (used to allow BMS to disconnect loads) the the wire size from battery protect to panel is 2x 4awg. The reason being I couldn't find 2awg lugs for #10 stud. I'm planning on having two negative buses (one on each side of box) for elegance and simplicity. Each bus will have it's own main 4awg return negative. Is this safe? The inverter/motor loads on the fuse box are a 300w inverter (12.5 DC amps) and a 2.2 max amp water pump. Should I fuse the positive circuit with a 150 or 125 mega fuse be?

The main battery cable will be 2/0 (00). At the lynx distributor I have the main DC load cable fused, Multiples 24/3000/70-50 fused with a 300 amp fuse as manual calls for, DC DC charger and one unused fuse spot. The solar is connected directly to battery positive with the solar circuts fused with small t fuses in a triple holder. (T Fuses only $10!). There was an amazing deal on a 3 pole 600V Littlefuse holder on Ebay for 26.43 cheaper then comparable 300V holders everywhere else. In the smallest sizes the 600V T fuses are actually cheaper. Maybe because they are more commonly used in industry. Is there anything wrong with using a 600V T fuse over 300V. I know the fuses are slightly longer and aren't interchangeable with the other type. What size of T-fuse should I use for the main battery cable 300 or 350? Something else?

I'm going to ground the negative side at the bus bar? Should I so it at the battery instead?
Would it be ok to ground the solar panels directly to the DSR20 charge controller directly to the negative battery terminal? or should I put it on the main bus bar?

Thanks in advance for all your help!