Battery Fusing

[PaulF007]

I have been looking at the amount of Amps moving in and out of my batts for that last few weeks and one thing I noticed is that on Charge the peak I got was 50a (I assume that was on a cloudy day) and on the draw side 30a max . 

The question is , if you peak charge is 50 a then should your fuse not be about 60a (+20%) ? and if you use 60a fuse will that put a resistance on the line? I currently have a 150a fuse and it seems a bit big for my consumption.

Any thoughts?

 

Regards

Paul

[Chris Hobson]

56 minutes ago, PaulF007 said:

The question is , if you peak charge is 50 a then should your fuse not be about 60a (+20%) ? and if you use 60a fuse will that put a resistance on the line? I currently have a 150a fuse and it seems a bit big for my consumption.

Any thoughts?

Hi Paul a 5kVA Axpert's maximum draw should be 83A. DC fuses should be derated by 25% for temperatures over 25^oC. So 83A times 1.25 equals 104 A. I would say 100A fuse should be sufficient. Whilst you busy ensure that your cabling is correct.

The large DC fuses have two blades which is more than sufficient to carry the current. In fact those blades could carry double the rated current of the fuse. Inside the fuse is a parallel pathway which takes part of the current. This pathway is sensitive and if the total current exceeds the rating of the fuse this parallel pathway blows allowing a spring loaded mechanism to disconnect the main current carrying portion of the fuse. Quite clever in my opinion. So one is hardly introducing a resistance on the line.