I have a 5.6 kw Voltronic inverter with one 4.8 kwh Dyness battery and 125A battery fuse.

If I wish to add another battery, do I need another set of battery fuses, to be compliant. Or can I skip the 2nd battery fuse if the batteries are in parallel?

 

Edited September 24, 20232 yr by Boomer

I'm not sure about SANS regulations (mechanic by trade) but I would say yes. If you think logically, you need to be able to safely isolate all components in a system in case of failure. For example, one of the two batteries fail and you need to remove it and send it for repairs. It's not safe to have any "hot" cables hanging around but if you have an isolator/fuse on both batteries you can isolate the faulty one by removing the fuse and still keep a safe enviroment. That was just the way I was thinking when I installed mine. After all, in the end it's all about safety right?

 

Very good explanation above...Gets down to the exact reason of why the SANS says why it does. 

Many thanks for the explanations above. Could anyone share where in SANS it says we need a battery fuse for each battery. 

Sorry for the newbie questions but isn't the purpose of the fuse to prevent surges either way (input/output)?

There are only 2 cables (+/-) going into the inverter so where would the 2 fuses be installed? One on each cable? Also, shouldn't it matter if it's connected in series/parallel?

The calculation for the required fuse that I found online is

(rated power / voltage) × 1.25

Would those 2 suggested fuses be half of the total size each?

In my head, 1 fuse makes more sense but I'm sure somebody will correct me if i'm wrong...my 2c

So with 2 batteries in parallel where a busbar is not being used then a single fuse would be fine I imagine as you would only have 2 cables coming from the batteries (Positive & Negative).

 

 

If you were to connect batteries to a busbar, then each battery would require a fuse between the battery & busbar.

This is exactly what the manual says. But I'm told that SANS requires 1 fuse per battery.

 

 

Many thanks for the explanations above. Could anyone share where in SANS it says we need a battery fuse for each battery. 

Interpret below as all pos and negs needs to be disconnected.