MP1 failure problems

[Ryan]

I bought my Magic Pie in May, 2010, so I think that predates even the MP2.  It has been working fine until recently.  When I am on a flat street or going up a hill, if I engage the thumb throttle, the motor starts for about a second, then suddenly stops.  I am unable to restart the motor unless I stop riding, disconnect the power cord from the battery, reconnect it, then try again.  I have noticed that if I engage the throttle ever so slowly, I can get the motor to work to full throttle and complete a ride up hill or on a flat surface.  Bear in mind that I am pedaling the entire time I am engaging the throttle and the motor does respond from slow to fast speeds.  The motor has plenty of power (no power loss).  Also, I noticed that recently the LED lights on the thumb throttle no longer illuminate.  I have already replaced the thumb throttle with a new one and the problems prevail.

I am wondering if I am having internal controller problems and if so, can I replace the internal controller with a new one? Thanks for your help!

[Eriknoort]

sounds like a bad battery to me.
When you accelerate the voltage drop and the bms shutting down the battery.

[Ryan]

What is the bms?  Can it be replaced?  The battery holds a charge just fine.

[Eriknoort]

The BMS is the battery management system. It checks the voltage of each cell. If the voltage of one cell is to low or to high it switch of the whole battery.

[Ryan]

Can individual cells be replaced in the battery?  How would I test them?

[Eriknoort]

You can open the battery and measure the individual cells. They all should read the same voltage.
you can also measure while charging.
If it is a 36V battery you can have a 10 cell or a 12 cell battery.
The 10 cell battery, each cell should charge to 4.2V.
The 12 cell battery, each cell should charge to 3.6V.
You can charge the individual cell to the max value. (Balancing the battery).
If you have a 10 cell battery it is probable the end of life of the battery.
If you have a 12 cell battery it should last longer.
If there is one or some bad cells it is posible to replace.
Be carefull if you make a short circuit the cell can explode or start burning.

[Ryan]

My battery is 48V.  Where do I apply the probes of the multimeter to test voltages?
Where can I obtain replacement cells?  What are the specs of the individual cells (so I know what to order)?

[Eriknoort]

You have to open the battery and measure each cell.
Maybe there is a type number on the cells.