Fuse before or after on/off switch?

tampano

Finding my (electric) wheels
Aug 18, 2017
24
0
55
London
Hi everyone,
as I'm trying to put my new 10s4p pack of 18650 in the same solid box of my bike, I'm adapting the connections to the previous ones.

You'll find the attachment picture where I outlined all the connections (batteries, bms, etc.)

My only double at the moment is about where to have the fuse (it's a 30A) in the discharge path (bottom right in the picture)

In my opinion it makes perfect sense AFTER the on/off switch I have with a key.

Does it make sense to you as well or there could be a reason to have it before the switch? Unfortunately I didn't take enough pictures when I dismantled the old battery.

Thanks
 

Attachments

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,914
8,529
61
West Sx RH
Usually a battery fuse goes between source and switch, it place early in the wiring is to protect other parts from damage.
The charge fuse isn't generally needed as the mains plug is fused.
 

tampano

Finding my (electric) wheels
Aug 18, 2017
24
0
55
London
Usually a battery fuse goes between source and switch, it place early in the wiring is to protect other parts from damage.
The charge fuse isn't generally needed as the mains plug is fused.
Just to be sure...you suggest to have the "discharge" fuse between the battery and the switch?
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
It makes no difference where the fuse is, likewise the switch. Just put it somewhere where you can get to it.

Is that an original key switch or some other type? If you want a switch on a battery, it's much better to switch off the discharge MOSFETs rather than the main power because you can use any switch you want. Switches on the main power wires need to be very robust because they get burnt by the inrush into the controller's capacitors.
 
D

Deleted member 25121

Guest
It would be best to have the "discharge" fuse as close as possible to the battery ie between the battery and the switch. In that way the battery is protected from short circuits around the switch caused by a faulty switch or damaged wiring.
 

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