EVG E Bike Hub Motor problems

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sbaussie   1 µW

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EVG E Bike Hub Motor problems

Post by sbaussie » Feb 20 2021 1:30am

Have just acquired an EVG (or EV Global ) E bike 24V . It was sitting at a friends barn getting trashed so she gave it to me . Dont know much of its history but love dickering on things like this so I dove in . Swapped out rotting tires for some slightly used mtn bike tires I had , cleaned it all up , took it all to pieces , recycled old sla batteries and ordered 2 new ones put it all back together. It did all the beeping with new battery installed , scrolled thru the colored lights to show full charge . Lights worked though little light on switch doesnt show them as being on. Tail light works, brake lights and sensors behave as they should after a little convincing. Alas no motor response when throttle applied.
What I have checked/ done.
Checked throttle with multimeter according to downloaded manual and resistance changes or doesnt as it should across red/black...brown/ black .
24 V at positive lead from controller to ground when throttle opened. as it should .
0-24V at quick connect that goes to rear hub/ motor as I give it throttle (actually up to 25.8V)
no response if small wires from thermistor (think that's what its called) are disconnected. Once connected responds as before.
Took off rear wheel and removed motor.
Definitely had suffered from some weather not too bad but some corrosion .
Connected jumpers from battery to leads to motor and Voila it turns over . Put it in vice and reconnected and it hummed (well maybe not hummed) but ran fine . Thought maybe I loosened up some crud or something .
I then reconnected leads from controller to motor ,(just the motor no wheel hub/rim etc) connected leads for thermistor and tried throttle ..Nothing ?? Tested ends of leads from controller and still get 0-25.8 V with actuation of throttle
So I'm out of ideas . new batteries, full charge, 24V motor and controller (I believe). Not the brake sensors as I tried with them disconnected from controller also .

Love any ideas , comments

Mike

powrtrip   1 mW

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Re: EVG E Bike Hub Motor problems

Post by powrtrip » Feb 21 2021 9:04am

Did you try to pedal and go

The old bikes do not have throttle start

Once pedal assist kicks in, then you can use throttle...

I had same problem/non problem... LOL

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amberwolf   100 GW

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Re: EVG E Bike Hub Motor problems

Post by amberwolf » Feb 22 2021 12:21am

sbaussie wrote:
Feb 20 2021 1:30am

24 V at positive lead from controller to ground when throttle opened. as it should .
Is that just 24v? At full charge? It should be closer to 28-29v for the typical SLA "24v" pack (empty is down around 20-24v, depending on the system).
0-24V at quick connect that goes to rear hub/ motor as I give it throttle (actually up to 25.8V)
no response if small wires from thermistor (think that's what its called) are disconnected. Once connected responds as before.
Took off rear wheel and removed motor.
Definitely had suffered from some weather not too bad but some corrosion .
Connected jumpers from battery to leads to motor and Voila it turns over . Put it in vice and reconnected and it hummed (well maybe not hummed) but ran fine . Thought maybe I loosened up some crud or something .
If the motor works direclty from the battery, and the controller gives the right output to the motor but the motor doesn't turn, it means there is a connection problme between the two. That's usually corroded contacts or crimps at the motor-controller connector, or pins that are backing out as you push them together. Makes *a* connection, so you can read it without a load on a meter, but not a good enough connection for a motor to run from.
I then reconnected leads from controller to motor ,(just the motor no wheel hub/rim etc) connected leads for thermistor and tried throttle ..Nothing ?? Tested ends of leads from controller and still get 0-25.8 V with actuation of throttle
This is a good sign, as it means the controller and the rest of it is all working. Do you get that same voltage at that same point when the motor is attached?


So I'm out of ideas . new batteries, full charge, 24V motor and controller (I believe).
What's the actual voltage you get on the batteries when full? It should be around 28-29v.
Not the brake sensors as I tried with them disconnected from controller also .
Some brake switches are Normally Open, meaning they are open circuit when pulled, and some are Normally Closed, meaning they are shorted when pulled. The most common are the latter type. But some use the former, NO type, and those then must make a connnection (short) in order for the bike to work. It sounds from your other tests that these are the normal NC type, and are likely working fine. But if you want to test, you can measure the wires from the levers (not connected to the bike) with your multimeter on 2ohms or continuity, and see if you get OL on the screen when they are pulled, or when they are not pulled.

If they are OL (or low ohms) both ways, the switches are probably damaged, and this test won't help us figure out anything beyond that.

If they are OL when pulled, but low ohms when not pulled, then these are the rarer NO type, whcih means to test the controller you have to have a short between brake wires to make the motor run (opposite of most bikes), so unplugging them actually makes the motor not work.

If they are low ohms when pulled, and OL when not, they're typical brake levers and unplugging them guarantees no ebrake signal from them to shutoff the motor for testing.
powrtrip wrote:
Feb 21 2021 9:04am
Did you try to pedal and go

The old bikes do not have throttle start

Once pedal assist kicks in, then you can use throttle...

I had same problem/non problem... LOL
EVG is a throttle only bike. No PAS.

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