Fusing solar panel cables

[steve yates]

I have a 50w panel feeding two batteries via a 10a pwm dual controller. The cable from the controller is 3mm rated for 20a.
I presume that the pos cable between each battery and the controller will need its own fuse, but should that be over 20a to match the cable or say 15a for the controller?
Ive seen often enough here that the fuse protects the cable not the eqpt, but I just want to check and whether the fuse should be 20a or bigger.
Thanks

 

[adamlang]

50w doesn't seem much for two batteries, unless it's a typo, 5 or 10 amp fuse would be fine I expect. I'd probably match the controller at 15 amp as you may add more solar eventually.

 

[LadyInBed]

I would fuse for the max o/p of the controller.

 

[VicS]

I have a 50w panel feeding two batteries via a 10a pwm dual controller. The cable from the controller is 3mm rated for 20a.
I presume that the pos cable between each battery and the controller will need its own fuse, but should that be over 20a to match the cable or say 15a for the controller?
Ive seen often enough here that the fuse protects the cable not the eqpt, but I just want to check and whether the fuse should be 20a or bigger.
Thanks

There should be a fuse in each battery positive connection, located as close as practical to the batteries.

The fuses must not be of greater rating than the maximum rating of the cable, or they won't protect it .

There is no reason for them to be significantly higher than the max charge current they might carry..

 

[steve yates]

Thx guys

 

[coopec]

I am asking exactly exactly the same questions myself. I've downloaded this article which you may find helpful.

How to Fuse your Solar System