Fuses needed?

[ShedPower]

Hi

i am new on here, and new to solar. My goal is to get our small freezer on solar. I so, I have had my first go at a system using

3 x 120w solar panels in paralell
3 x 130w leisure batteries, sealed led acid in paralell
1 x automatic transfer switch
1 x Victron 100/20 charge controller
1 x. 1000w inverter

freezer uses 800w a day. This seems to be doing the job.

my biggest head scratch at the moment is fuses. I have a 100 amp between the battery and inverter, and 50 amp fuse between the charge controller and batteries. I am not sure if I need a:

* fuse between panels and controller
* fuses between inverter and transfer switch
* fuse between transfer switch and load, although the plug does have a 13 amp fuse in it.

also the cables on the batteries are car battery cables from Amazon but they are not the thickest ones (seems to be two sizes.

And to combine the 3 panels I’m using a 30amp junction box used in normal AC house electrics. Not sure if that’s correct or would give too much resistance etc.

So that’s where I’m upto!

Trevor

[Mike90250]

so, fuses are to protect the wires from heating up and causing a fire. To size the fuses or circuit breakers, you need to KNOW what size ( gauge, ga ) the wires are.
Your inverter should have information on the input fuse size, and then you buy wire that the fuse will protect.

[chrisski]

For fuses between the panels and controller, chec the max series fuse rating and that is probably exceeded. Almost always three or more panels need to be fused. On three of four setups i have, i use circuit breakers to shut off and assist in trouble shooting. In the fourth its fuses.

in general, i fuse everything before and after my 8 stud busbar. I don’t know about the transfer switch. Everything needs to be fused so that if there was a short a fuse would blow and not the wire melt.