Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Breakers, Fuses and Shunt Trips
Those of us using fuses don't (I think) use the fast ones as need to allow for short "normal" surges, eg a fridge motor start. You don't want nuisance blows, especially with fuses.
While you're building your system breakers make more sense for flexibility & can be reset.

i actually have "fuse disconnects" on my 4x battery banks but probably should have gone with breakers....

Yes you need a shunt trip to properly protect the packs from over/under voltage on cells & other faults.
Running off solar, DIY & electronics fan :-)
I have fuse wire (30awg) on each cell.  The overall battery bank goes thru a 400a ABB shunt-trip (controlled by Batrium) to the control box.  So the ABB is the master battery disconnect and the individual fuse wires are the 'battery fuses'.     A while back HBPowerwall accidentally shorted a 80-100p pack and it blew most of the fuse wires - so I was convinced that in a catastrophic short the fuse wires would act. 

If you look to the left, you can see the 'red wire' connecting each battery in parallel - going up to the ABB.

Now keep in mind that my battery bank is 'one monolithic battery' and not designed for the disonnect of individual batteries, so there was no need for circuit breakers at the battery level from that standpoint. 

But hey, that's just what I'm doing.
The fuse cant be tripped via the bms. Thats why you use a breaker with shunt trip. The electrician that say otherwise dont know what a bms is and what the external breaker is for.

Its better to have the breaker with shunt trip than a fuse IF you bms dont have any other means to disconnect.with a proper shunt trip breaker and bms it can even Sense if it tripped and take action like alert you Smile

If you want install a fuse and. Abreaker. The fuse is rather cheap in comparative.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 100kWh LiFePo4 | 20kWh 14s 18650 |  66*260W Poly | ABB S3 and S5 Trip breakers
Upcoming: 14S 18650~30kWh
I see comments implying fuses and breakers can be used interchangeably... It is important to note they really have different applications.

Where a breaker could fail, a fuse would not.

I use an ABB shunt trip with contactor on the main battery bank. External systems to control.
I use HRC fuse on the battery mains to protect the wiring
I use fuses off the distribution point to protect the wiring to the loads
I use DC breakers at the load, sized for the load to protect the appliance from overload.

Forum Jump:

Users browsing this thread: 1 Guest(s)