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Zero Motorcycles Forum | 2013+ / Re: anyone really know how the Low Power B+ circuit fuse works? I need help
« on: February 08, 2022, 01:36:47 AM »
When the contactor is open (key is switched off) and the low power fuse removed, there schould not be any power on the bike ,the battery is then completely isolated from the rest of the bike. On the 2013 models there where two fuses on the original batteries, but on most bikes the original battery has been replaced by a 2015 one ( with only one fuse)
The MBB and the dc-dc converter are hot wired via this fuse, and it protects the bms in the event of a short in the hot wired parts and cables.
If you still have voltage with contact off and low power fuse removed, you have to find out where it comes from. Make sure the contactor is open (could be welded) Check if the high voltage pins on the dc-dc also receive 110v. You could unplug the battery (very hard to reach, especially on a 2013 )
I wouln d install a new MBB before you know where this voltage comes from and this is corrected.
Good luck
The MBB and the dc-dc converter are hot wired via this fuse, and it protects the bms in the event of a short in the hot wired parts and cables.
If you still have voltage with contact off and low power fuse removed, you have to find out where it comes from. Make sure the contactor is open (could be welded) Check if the high voltage pins on the dc-dc also receive 110v. You could unplug the battery (very hard to reach, especially on a 2013 )
I wouln d install a new MBB before you know where this voltage comes from and this is corrected.
Good luck
