hub motor random shut off

jatgm1

10 W
Joined
Mar 7, 2014
Messages
78
Location
mahopac, new york, united states of america
to get right to the point, i have a 1000w 48v cheap hub motor kit with a battery from "sunthing28" (i belive the battery is fine) and recently have run into a problem. i am riding my bike, just like everyday, and while i am riding the motor simply stops propelling me forward. the lights that indicate the battery life, located on the throttle, are still lit. then it starts propelling me forward again. it has been getting progressively worse. i have made sure all the connections i made, (wireing the battery to the motor controller, the plugs to the wires) are properly connected. the plug from the motor controller to the throttle is a plug, and is plugged in. the three colored wires going from the motor controller to the motor are enclosed in a small yellow plastic box thing which i have not yet checked (that is my next task which i will do in a few minutes) the other connector going from the motor controller to the motor was plugged in, however after i had the problem i thought maybe that was what was causing it so i shut the bike off, unplugged said white connector, and turned it on, for the problem to persist. i tried unplugging the plugs that went to the throttle, thinking maybe it thought i was hitting the brakes. after turning it off, unplugging the brake wires, and turning it back on, the problem persisted. does anyone have any suggestions? comments or concerns? i would greatly appreciate them. how would i find out what is wrong and fix it? p.s. i have a cheap voltimeter at my disposal. i think it may be broken though. i know the battery is dead, other than that, no idea.
 
get yourself a reliable multimeter along with an ebike tester...both must have tools for any ebiker.

It sounds to me like a battery problem, and you need to verify the voltage of each series cell level with a multimeter, both a full charge and when the cutoff occurs. It could be something as simple as you never allowing your battery to properly balance during charging, but it could be more serious. Without voltage measurement you can't know.
 
It's always a poor connection on a plug someplace. Could be halls or phases on the motor, or even just a throttle wire.

Apparently not the battery wire.
 
Kiriakos GR said:
John in CR said:
get yourself a reliable multimeter along with an ebike tester...both must have tools for any ebiker.

Please inform of what exactly you describe as ebike tester?
Thanks.

http://em3ev.com/store/index.php?route=product/product&path=41&product_id=87 I am sure this is what he means. Searching ebay yields similar results.
 
If it cuts out under high load, it's probably a battery problem. If it cuts out when you hit a bump, it's a connection problem. If you have an LCD and no speed sensor, it'll go to sleep after a fixed time. I have seen over-sensitive brake switches, where the wind was enough to activate, so completely disconnect your brake switches and leave them disconnected until the problem is sorted to eliminate them as a possibility.
 
jatgm1 said:
john, why do you believe it is the battery?

ESP. :lol:

Actually my clue was that it got progressively worse. That could have been cause by an initial out of balance condition that was never brought into balance. After manufacture the pack probably sat around for months or longer, so a higher rate of self-discharge in one cell put the pack out of whack. Then not knowing any better or how to check for balance, or how to run the charger for a very long time to balance, it got worse and worse.

When you get a new battery of any kind, whip your multimeter out and check it for balance before use or charging. Note any cells out of whack and by how much. Then fully charge it and check for balance again. If it's still out of whack check back on the forum for advice before using it.
 
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