I just inherited an XB-500 Electric bike from my father in law that pass away.
My question is I have charged the batterys and I have 52 volts to the batterys. I battery gauge shows that it is fully charged. When I give it some throttle the back tire where the motor is turn very slow with a little noise. Not any power to ride it.
Where do I go from here and would it be wise for me to take the back tire off and take a look at the motor? What is my next step for being a electric bicycle tech.
xb-500 First Time Tech at this
Tue, 01/11/2011 - 17:30
#1
xb-500 First Time Tech at this
Who's online
There are currently 0 users online.
Who's new
- eric01
- Norberto
- sarim
- Edd
- OlaOst
Support V is for Voltage
Welcome to the adventure!
You had one good observation, the 52V. I hope that was with a voltmeter (if not, get one - they're cheap and incredible accurate these days).
A couple of questions:
Does the wheel turn freely when unpowered? The brake should absolutely not drag. (Tire pressure and head bearings are also good to check.)
What is the voltage when you are opening the throttle? Dead batteries may charge to 52 volts, but drop below 45V when asked to put out current. If this is true, get a reading UNDER LOAD of each individual battery. It may just be one dead one.
What do the connectors between the controller and the motor look like? What about the wires? (heated, broken, chafed)
On a brushless motor, the controller will have two heavy lines from the pack, a few control wires, three individual phase wires that deliver the power to the motor, and five phase wires in a common connector that tell the controller where in the revolution the motor is.
Mark
Hello Mark,
Thanks for responding. I only have a volt meter. I located the voltage wires from the controller back to the motor. Where do you want me to read the voltage when I open the throttle? If you are refering to the two voltage wires running back to the motor from the controller I only have about 1 volt. I am assuming that my batteries have dead cells but still read voltage.How would I do I get a reading under load?
Thanks
Rick
I just got some new batteries so I could test it and also have some spare batteries. Still having the same problem. Back tire spins very slow. Not enough power to ride. The back tire spins great so I know the brake is not sticking. How do I determine if it is the controller or the motor?
Well, your batteries were probably all right then. The battery voltage I wanted you to check under load is the total pack voltage. The voltmeter mounted on the instrument cluster would show you that; here's a pix of what it looks like at 45V:
You can also get to that in the seat-front charging port. With clips instead of the normal probes, you could even get the reading while moving forward.
To see individual battery voltages, you will need to pop the top off the battery box. You will have to pull the box before you can get to the top panel's screws. The battery box lock may be frozen.
Given that the batteries are all right, I would think about the electronics. The principle of a brushless motor is that the controller sends a pulse of power to the correct phase of the motor based on the reported position of the armature based on the info from the Hall effect transducers.
First I would check all connections. You should have TWO heavy lines from the battery to the controller, THREE fine lines with individual connectors for the motor phase wires, and FIVE fine lines into a single 6 contact connector for the Hall effect position sensors. All connectors should be clean and bright. In addition, the Hall effect leads can be mis-connected to get the same "gutless" behavior. In my circuit diagram, I show:
#1 is at top left when looking at the face of the socket side with the catch to the left.
I would also suggest replacing the three phase connectors with Grubb screw terminals.
Assuming the connectors are tight, clean, and secure. I suspect it might be either the motor or the controller. I don't know what tests to do to confirm the operation of the motor itself. There's more expertise on offer over at Endless-Sphere on this. Personally, I would probably have to get a second controller and try replacing it: an A-B test. There is probably some more elegant and cheap way to figure it out, but I don't know it.
Mark