i really need some help with my custom ebike

[callum]

battery i bought worked straight out the box so unplugged it charged then tried to plug it in again and now it does not work when the battery is not plugged into the bike it reads 49v but when its plugged into the bike now it then reads 0.03v unplug it again back to 49v can someone please help me with this ?

 

[rich c]

What do you mean, "worked straight out of the box". Does that mean you had it in the bike and you rode it? Where are you measuring the battery voltage when it's in the bike? My guess is that the battery management system is seeing a short and is shutting down to protect the battery pack. Is there a fuse in the pack to protect it from a short? Like I said, just a guess. Try checking continuity of the wiring harness.