Can I use my 36v 10ah LiFePo4 battery with this bike??

[StudEbiker]

Hey, I just wanted to check with the board before I do something stupid. The question regarding the battery is in my last post in this thread. Thanks!

http://endless-sphere.com/forums/viewtopic.php?f=3&t=14302

 

[dogman dan]

If that bike ran on that dinky little sla battery, it should run just fine on 10 ah of lifepo4. The voltage of the 36v lifepo4 will not be more than about 2v higher hot off the charger, but it should hav a LOT less voltage sag when you twist the throttle.

 

[StudEbiker]

Thanks Dogman. I set it up to run of the battery and I was able to get the motor to run when it was turned up side down (no drag), but then when I tried to take it for a real ride the motor wouldn't ever catch all the way. Is this maybe bad halls?? I noticed it is labeled three permanent magnet motor, and it has four wires coming out of it. Four wires seems strange to me. Any ideas?

 

[Icewrench]

http://endless-sphere.com/forums/viewtopic.php?f=14&t=8976

Maybe mr electric has some info on that stylish ride.

 

[StudEbiker]

Awesome, thanks for the link Icewrench!!

 

[dogman dan]

for wires could be a brushed motor, two power wires and a pair of temp sensors like a heinzmann. In that case, two of the wires would be substantially smaller than the power wires.

If it's a sensorless brushless controller, three wires would be for power, but the 4th one? Theres one I've never heard of. A temp sensor would need two wires. A ground wire?

The only other possibility I can think of is a brushed motor with two sets of wires and brushes, so it still runs if a set of brushes fails.

I'd look at the controller to see if anything is written on it that might explain. Like brushed controller vs brushless.

The problem can't be halls, if there were hall sensors in the motor, you'c have 5 sensor wires, and three power wires. I'd look for poor connections somewhere.
It's possible the motor got overheated and has damage inside from climbing too steep a hill.

 

[StudEbiker]

In the other thread on this bike gmouchawar confirmed that this is a brushless and sensorless motor. I may go over the connections and check that everything is hooked up well. On the plus side, it doesn't look like this bike has ever seen a drop of rain. The overheating issue is something I hadn't considered though. The guy did say he got this out of a buy he did in a storage facility in Las Vegas, so that might be something worth checking in to. I would need to open it up and it would be the epoxy softening that has caused a magnet or more to loosen correct?? When I have the bike turned up side down the motor seems to run pretty strong once it gets going, but it does seem to have a hard time getting started. Do you know if there might be an easy way to bypass the european pedal sensor and put a thumb throttle on the bike?

 

[dogman dan]

I have no experience with pas, so I'm not too sure about how those are wired, but I belive they use hall sensors, so mabye a bad hall or bad connection there could affect the controllers power. What you describe sounds like bad hall connections on a regular hubmotor. If there is no plug on the controller for a throttle, then it would be hard to add one. But any sensorless, or pedal first type controller should run the motor fine with a throttle. Since there is no throttle, that explains why no halls on the motor. They would not be needed since you have to pedal first to activate pas. So it would naturally come with a pedal first controller.

The more I think about it, I bet the motor is ok, but a melted motor is a possibilty. But more likely the small battery would run down before than could happen.