Overcurrent protection on battery, nothing works now

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butters149

100 mW
Joined
Mar 4, 2019
Messages
49
Hi everyone,

I just recently modified my super 73 with a leafbike 2000 watt rear hub motor with their controller and using it a EM3EV 14.8 battery at 52volts LG HG2 cells. My bike WAS running but now is not running anymore due to overcurrent protection on my battery, according to what their warning lights mena (1 red and 1 green bar). Below are the events that led to this but I am not sure what happened.

1.) Initially my bike would not run when I first plugged in everything, the LCD would turn on when I press power, but once I switched the controller plug to the other hall sensor (I have two for some reason) then everything worked.
2.) Riding around was ok, after a bit the throttle would cut out during initial acceleration, but if I backed off and rolled on slower it would be fine.
3.) Was riding in my apt, short bursts when did a little wheelie, popped down and the bike shut off, now it says overcurrent whenever I turn on the battery and I hear a little click. Help!
 
Yes, I plugged and re-plugged it. I tried opening the controller but the screws are kinda tight heh.
 
butters149 said:
but once I switched the controller plug to the other hall sensor (I have two for some reason) then everything worked.
Click to expand...

Do you mean you have two sets of hall sensor plugs coming from your controller or from your motor? Can you post a picture?
 
Sounds like either the controller shorted or the BMS has a problem. If you disconnect the controller from the battery, see if the lights clear. If you have an ohmmeter, try measuring across the battery wires going to the controller when it's unplugged. If the controller is shorted, it will look like zero ohms. A good controller will show some kind of reading other than zero and slowly change as the caps charge up.
 
i have a volt meter but not sure how to measure it. Also when the controller is on the bracket but NOT connected to the controller system the lights clear.
 
Disconnect the battery first, then put your meter in Ohms mode. Test the meter by touching the probes together and see that it goes to zero or near zero. Then try measuring ohms across the main black and red wires going to the controller. You can measure it where they attach to the board if you still have it apart. Otherwise anywhere you can make a connection. If the controller is shorted, this will look the same as just touching the probes to each other. If the controller is not shorted, you should see some kind of reading that increases with time and stops at something much greater than zero.

If the controller doesn't look shorted, then the problem is most likely in the BMS.
 
If you're using leafbike's controller, you've got a 60 amp controller.
What's the cutoff amps on the em3ev battery? my guess is 50A or lower.

I have no experience with leafbike's controller because it looks like junk and is not programmable.
However, you can shave the shunt to drop the maximum amps drawn..
 
For the price they sell the leafbike controller at, its good to know its a 60A controller, but its still a trapezoid waveform. That price comes in at half the price of the kit w/display.
 
One or more blown MOSFETs in the controller willdo that. Disconnect the controller and measure the resistance between the black battery wire and each of the three motor phase wires, then repeat for the red battery wire to get 6 readings. Each group of three should be the same as each other.
 
Still curious about the two hall sensor plugs. Your pics didn't show them. I don't see anything that resembles two hall sensors plugs in the pics on their website. Maybe you fried something plugging into the other connector?
 
d8veh said:
One or more blown MOSFETs in the controller willdo that. Disconnect the controller and measure the resistance between the black battery wire and each of the three motor phase wires, then repeat for the red battery wire to get 6 readings. Each group of three should be the same as each other.
Click to expand...

What would cause it to blow? It’s not because of bad bms? These companies are in China so their responses are not good and em3ev has very slow response times. Makes me regret going down this path.
 
Just go ahead and buy another controller off of ebay.
Look at the seller hksunwin to see if you can find a good deal on a controller.
Otherwise his are a little on the high side now, just buy any ole controller that suits your battery.

Greentime has good controllers at reasonable prices, even sensorless controllers!
No more hall sensor wires to hook up!
 
butters149 said:
What would cause it to blow? It’s not because of bad bms? These companies are in China so their responses are not good and em3ev has very slow response times. Makes me regret going down this path.
Click to expand...
The BMS would not cause a controller to blow. Lots of other things can make a controller blow, if that is the problem.
Without more testing, you really don't know if it is the BMS or the controller causing the problem.

It may also be possible that the sudden inrush current when first connecting the controller could trip the BMS. Normally this doesn't happen, but there are a lot if different BMS designs. If this was the case, both the BMS and controller may be "good" but just have a problem with the initial surge.
 
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