No power on Magic Pie 5

[Kim]

Hi I'd like to post a question. I just got a used golden motor Magic Pie 5 and it cut out. I replaced the battery with a new one and when I turn the battery on (in the cradle) the blue light cuts off on the battery and it makes a short beep sound. Where should I start when looking for faults? Thanks.

[Sam.Vanratt]

Hi Kim
did the MP5 ever worked at your site before? How much maximum voltage is the battery? Did you program the MP5?
It may be the Undervoltage security or maybe the overvoltage "I'm now dead". I tend to the first one
Cheers
Sam

[Kim]

Hi. Yes it was working for one long ride (15 miles). Then the battery was charged with a faulty charger (found out later it was faulty), then battery was erratic, going from green to amber and red irregularly. Then when battery was low the whole thing cut out and wouldn't switch on. I since got a new battery and charger but still won't power on the bike. Battery has a green light when switched on (off the bike), but when you plug it in the bike the green light goes off and the battery makes 1 beep. The battery has panasonic cells at (2900mAh) and is 48v.

[Kim]

How much maximum voltage is the battery?
I think it's 54.6v

Did you program the MP5? No, I got it second hand and haven't changed any of the program.


It may be the Undervoltage security or maybe the overvoltage "I'm now dead". I tend to the first one

Can you explain what Undervoltage security is? Is there a way to reinstate it? I'm pretty sure the faulty battery was running under voltage. What should I do if that was the case?

And over voltage? Does it mean something is blown?

Cheers

[Sam.Vanratt]

Hi Kim
with 54,6V you mean a 13S battery at full charge? The MP5 should work good with it as long as you don't do a regen brake (which could hype the voltage engaged quite over 60V).
The mP5 has an overvoltage protection to save the battery from deadly overcharging (Lithium likes to burn...) and an undervoltage protection, again to save the battery from deep discharge.
When a 36V battery was defined then your behavior sounds exactly like your situation. Was the battery before a 48V block as well? Same chemistry? A LiFePO4 has a much smaller fully charged/fully discharged windows than LiMn/LiPo blocks. GoldenMotor normally uses LiFePO4 (for their much longher durability for years), so a "48V Block" is 16S with a overvoltage of 57,6V and undervoltage of about 48V. A 36V block is according about 43,2V overvoltage and 33,6V in undervoltage. With a different chemistry the real values changes of course.
Do you have the BT dongle as well to program the MP5? As I'm only familiar with the MP3 (which is years beyond) I'd only guess.
Alan or Gary are the "up to date" guys here :-)

To test I'd try to discharge your pack for a while (a voltmeter and a big resistor helps here) so the voltage drops maybe below the overvoltage mark. It'd help to know the former battery pack (chemistry = voltage levels + xS wiring) to define what's the problem with the new pack+MP5
Cheers
Sam

[Kim]

The previous battery was a 48v 11.6ah lithium pack.

 If I plug the USB cable in to the mp5 (hooked up to pc software) could I check the voltage settings there? The previous owner is going to send me the USB cable next week.

The new battery is 54.6v at full charge yes. Regen breaking is currently enabled. If I can access it with the software then I can turn off the regeneration breaking right?

[Tommycat]

The previous battery was a 48v 11.6ah lithium pack.

13s4p configuration.  54.6 v full charge.

 If I plug the USB cable in to the mp5 (hooked up to pc software) could I check the voltage settings there? The previous owner is going to send me the USB cable next week.

Yes, you can see the voltage set-points and modify if needed. You'll need the software program and driver of course.

The new battery is 54.6v at full charge yes. Regen breaking is currently enabled. If I can access it with the software then I can turn off the regeneration breaking right?

Yes, you can turn it off. Reducing its force is also available.

I've been running a 52 volt nominal pack at 30 percent regeneration for over a year and have had no issues. No big hills tho.

I'd double check your new battery connections verifying correct polarity. Something shorting?

[Kim]

 Once I get the USB cable I can try adjusting the voltage settings etc but I suspect there may be a short somewhere. I'm having someone check for shorts. Is it possible to buy individual components if necessary?

[Tommycat]

These may help to check the continuity of the harness...







Controllers are available and come with the lower harness. Upper harnesses are available, as well as the individual components that attach to it.

See Gary at...

https://www.goldenmotor.bike/

[Bikemad]

Hi Kim and a belatedto the forum.

It is possible for the controller to sometimes fail in a short circuit state, but usually when this occurs, the wheel is noticeably difficult to turn.
Does your wheel spin easily, or is it impossible to spin it quickly?

Check out this post for a simple way of checking whether the controller's battery leads are internally short circuited.

If the wheel is very difficult to spin (making the bike hard to push) then it is likely to be the controller that has failed.

When the motor decided to cut out, was it by any chance while you were braking at high speed?

Alan
 

[Kim]

Hi Alan,
Happy to be here,

The motor is very hard to turn. It's a real mission to move the bike anywhere at all just now.

As far as I remember the throttle was pretty full on when it cut out and the battery was low. I'm not sure whether I was breaking at the time though.

If it is the controller do you think it would be repairable or would I need a new one? Thanks

[Bikemad]

Hi Kim, unfortunately it sounds like the controller has definitely died. 

I think it will be at least two of the six MOSFETs (possibly more) that have failed in a short circuit state, but it is difficult to say whether more electronic components may have also sustained damage within the controller. 

If you remove the controller and disconnect the three thick Phase wires going to the motor, you should find that the wheel will turn easily again, as the resistance is purely due to the Electromagnetic Dynamic Braking effect caused by the shorted MOSFETs.

Unfortunately, the controller's circuit boards are potted in a silicone gel type compound which makes it very difficult to dismantle the controller to allow failed components to be replaced:



The MOSFETs are the six black square objects mounted on the underside of the outermost circuit board:



Unfortunately, I don't think that you will be able to successfully access and replace the damaged components, so you will probably need to replace the complete controller assembly.

Alan
 

[Kim]

Thanks for the info Alan. Is there a UK distributor that could sell me a controller?

[Bikemad]

There are 7 UK dealers listed on GM's Dealer list but I don't know if any of them stock replacement controllers.

As they all have phone numbers, you should be able to give them a quick call to find out.

If you can't find one locally in the UK, Gary (GM Cananda) usually keeps them in stock.

Alan
 

[Kim]

I've ordered an MP5 controller and hopefully get it swapped over tomorrow. Do you have any installation tips?


Thanks