Electric Bikes - power interruption question
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I have a Skyhawk 48V 500W front hub kit. I installed this system a couple of weeks ago and have driven it moderately without any problems. Just recently the power has repeatedly cut out while riding it.
I have ensured the batteries are charged (green light on the chargers); assuming the chargers are working correctly.
I have checked that all connections are tight.
Lights on the throttle indicate power, full and empty.
When operating correctly the 'power' and 'full' lights are lit.
When cutting out the 'empty' light will turn on, cut the power and then the light will turn to 'full'.
The duration between cutting in and out varies.
Any suggests and/or troubleshooting instructions would be greatly appreciated.
that's a difficult problem to diagnose over the internet. It could be something as simple as making sure a wire stays in contact with whatever it is attached to. It could also be a problem with your controller, your throttle, or (if you have them) the battery management electronics.
I doubt that this problem is caused by your battery charger or your batteries, because the throttle shouldn't ever indicate "full" unless the batteries and charger are ok.
06-02-08, 06:36 AM
This is a common problem. It is called "controller stall" . It will happen from time to time. Sometimes it happens after a long braking period. Not much you can do about it other than reset the controller by turning the power on & off. No real fix for it as far as I am aware. Just a combination of events confuses the controller.
06-02-08, 07:27 AM
I have this problem whenever I am trying to really work the motor. For example: going up a steep hill without peddling, holding the brakes and activating the throttle. I think it's a cutoff feature in either the battery management or the controller. It will cut out a couple times and then completely shut down.
It is probably a good thing because going up a hill without peddling heats everything up a lot. Using a 48 volt battery may trigger the same at starts on flat ground.
06-02-08, 07:55 AM
I wonder if your controller has an overcurrent protection circuit.
Please describe in more detail the conditions when this "shutoff" occurs.
cerewa, I agree that it is unlikely that it is the batteries and/or chargers since both the chargers and throttle indicator indicate that the batteries are fully charged.
I do not have any additional battery management electronics other than the feature that the system will automatically shut down when there isn't enough current and the hand brake shut-off switch (I forced this switch to stay connected because I couldn't use the hand brake lever that it was built into).
Oshawaebiker, I rode the bike for two or three weeks in a similar manner and under the same conditions without this stalling. This condition may be "controller stall" as you say but it is happening too frequently for the electric motor assist to be of any value to me. I drive approx. 800 or 900 feet and the stalling starts. If I keep the throttle engaged the motor will engage for a couple of seconds and then stall again. Once the controller (if this is the problem) is confused it never recovers. Stopping the bike and turning off and then on the key switch doesn't work either. The bike has to be shut off for a significant amount of time (hours?) before I can get 900 feet and then the endless stalls.
06-03-08, 09:09 AM
In that case I would be suspect of the controller. Sounds like thermal shutdown, the fact that it takes such a long time to self correct. Suspect that one of the FETs in the controller are breaking down under load.
reptilian, my Skyhawk hub motor is the 48V model; I have not over-watted a 24V or 36V motor and it has the corresponding 48V controller. This system does not require pedalling from a stop as the others do. Typically I do pedal assist because I agree that loading the motor will cause heat. If my stalling is caused by a cutoff feature when under excessive load then it has stopped functioning properly because it is happening on level ground with or without pedalling.
WJChris, my Skyhawk system has a brake lever cut-off switch, a controller feature to protect the motor if the current is too low and an inline 20A fuse. I don't know if it has any other type of overcurrent protection circuit.
I can ride the bike for about 900 feet and then the motor stalls. If I continue to give it throttle the motor will intermitantly engage for a couple of seconds and the light on the throttle will change from 'Full' to 'Empty' and back to 'Full' when the motor stalls. Turning off and then on the key will not reset the controller. It appears a significant amount of time (hours) is needed for the reset. After the reset I will be able to go approx. 900 feet and the stalling will start again.
Oshawaebiker, thanks for your reply. Is it possible for me to replace the FETs in the controller? If so is there any detailed instruction on how to do this? I am not an electrical techie but I am pretty handy.
If this isn't advisable can you or another forum member recommend a controller and where to purchase it? Is it possible to get a 'direct fit'? It is 48V 500W with brake shut-off and low current protection; the throttle indicates 'Power', 'Full' and 'Empty'. I cannot contact the person from which I purchased the Skyhawk kit. I know these are Grubee kits but I prefer to purchase from a dealer in Canada so I don't have to worry about the import taxes and hopefully delivery will be quicker.
06-04-08, 05:12 PM
If you have or can acquire a temperature controlled soldering iron , they are not that hard to replace. If you open your controller there will be several power tab semiconductors. read the numbers and you could google them to find which are the FETs . Then you could order or pick them up at Active or Electro-Sonic. Carefully desolder them and replace pin for pin and solder in place. Not that difficult but could be time consuming.
Oshawaebiker, another development. The bike has sat for about a week because of the aforementioned problem. Today I attached the chargers to ensure the batteries don't discharge to too low of a level while the bike sits waiting for repair. When I now turn on the key the throttle indicator says the batteries are empty. With this now happening do you suggest any other troubleshooting or should I proceed with replacing the controller or trying to replace the FETs. Thanks again knurn
06-07-08, 09:30 PM
With this new issue I think you have more issues with the controller than just the FETs. At this point with out more expertise it would probably be more effective for you to replace the controller. Is the unit still under warranty if so have your dealer replace it.
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