Low voltage indicated with full charge

Springer55

10 µW
Joined
Nov 23, 2017
Messages
5
My ebike won't run. Battery indicator on display shows battery empty. Battery volts on display show 41v.
I have a 36v dolphin battery, kt-lcd3 display and a kt-36s controller anx a 350w mxus hub motor. Battery voltage on display shows 41v. Battery voltage with a meter shows 41v. The little battery indicator at the top of the display shows empty.i checked to make sure all my connectors were tight.
Put bike on my rack. Motor will run slowly at about 2mph and chatters. No visual problems inside controller.
This showed up after I finished charging my battery.
Could this be a bms problem, or something else?
I appreciate any suggestions.
 
Can you measure the voltage with the motor running? Seems odd the voltmeters show 41v, but the display indicator shows empty.
 
When I turned the motor, the voltage on the display drop to around 40v and cycles about .1 or .2 volts, which would be normal
 
It seems like the battery itself is OK then. The controller would be the next likely problem. Take apart the connectors and carefully inspect the pins/sockets. Look for out of position parts or signs of heat. If all the connectors check out OK, then it might be worth trying to open the controller for a visual inspection. Could be a loose connection inside.

The display unit is also possible, but I don't think it sounds like a display issue.
 
Inside the controller looks good. No obvious physical problems. I wish I had a schematic of that controller. Google search shows up nothing.
 
I am having the very same problem with my 36v e-bike. My battery is fine as it works well on other bikes. I suspect the co troller. Did you ever solve this problem? Thanks!
 
I realize your last post was 3 months, but, I had the same problem. So, I searched "Hub motor chatter" and found this excellent post:

Sunder   1 GW: "I'm going to take a wild stab that it's a badly tuned sensorless start. If it is, it will judder and hum a bit...went to the Lishui site, but can't find your exact model, but all their eBike controllers support both modes, so it's possible that it was designed for a sensored start, and hence the sensorless settings were never set up, but the hall sensors aren't working so it's falling back."

So, I pulled my bike's 5-wire Hall sensor plug....voila: hub motor turns normally! Now to investigate sensored vs sensorless start.
My controller is a new "refurbished" 500W controller from ebikeling I got on sale just yesterday.

Ref: Sunder's post:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=107515&hilit=Chatter+sunder#p1573996
 
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