Sudden electrical fault Magic Pie 3 - please advice :-)

[JohhnyD123]

Hi,

I just assembled my new e-bike w/Golden Motor MP3 and their 48V 10Ah battery (the bike is a new cheap 14kg 26" MTB.
Alu frame and front dampers with torque arms and disc. Motor is in front and the battery on is on the rear rack).

It all worked like a charm yesterday, today it's dead. Thumb throttle does not work and it's light for battery indication does
not go on. Checked all connections and battery is fine (reading 50,1V). What to check next - the internal motor controller ?..
I have the USB cable and win7/64. What software do I need need and how can I do the checking ? Is there another way to check the
controller or do I have to dissassemble to find out if It's OK ?

:?
Second;
From what I have read on misc. forums the internal controller is not so good on MP3, and I can get a lot more out of the motor with an
external controller & LiPo batteries. The motor can handle 1500W right ? - or can it do even more ? I would like to get max power out of
my e-bike. I would need top speed of approx 45km/h, min. 20km range - then max power for the rest. Anyone have a good
recommendation for upgrades and options ?..


Any good advices would be highly apreciated!

Thanks,
JD

 

[JohhnyD123]

BTW; is there a way to add a "boost" function by adding a extra LiPo battery to the one I have ? - And what
which parts to I need ? ..

 

[Icewrench]

Triple check that the battery is fully charged and all connections are making good contact.
If all connectios are good then it might be time to think about the controller.
Is the wheel hard to turn by hand?. If it is then that could be a bad fet in the conttroller.
But be sure to re check that all connectors have the pins and sockets fully seated in the connector housing.

Good Luck

 

[JohhnyD123]

Thanks. I cannot find any connection errors / bad contacts.

I wonder if I got the wrong charger ?

The charger has a lable which says "Li-Ion battery charger" - model HP8204L4.

But my 48V 10Ah battery should be LiFePo4 - Isn't thad a different battery type than Li-Ion ?
(the battery is marked LFP-4810S-LT which i think indicatis it's LiFePo4)


Best regards,
JD

 

[JohhnyD123]

BTW; the wheel is just like before when it comes to turning it - giving the same sound / low resistance. If controller is defect,
would i feel difference by turning the wheel ?..

However, I didn't hear any "peep" sounds and horn did not work when I was using the bike yesterday. Else
the cruise controler worked fine and the bike had plenty of power.

I built a similar bike from GM before, using 48V 1000W motor (before magic pie) and a 48V 20Ah Ping LiFePo4.

This one felt approx similar in strength ....

Thanks,
JD

 

[Icewrench]

Try checking for voltage to the throttle, and any other external bits the pie may have.
Still nothing?? Might be time to look inside it.
Maybe a pie user will have some good clues for you.

If a motor is hard to turn by hand when the controller is connected and easy when the controller is disconnected then that points to a fet problem in the controller. That is not the only thing that can blow up in a controller.

Li ion is a name that covers several different flavors of lithium mixtures.

 

[dnmun]

.

 

[JohhnyD123]

Yes, it's the battery is from Goldenmotor as well. It's 48V 10Ah and labled LFP-4810S-LT. According to Goldenmotor it should have 30A (3C)
continous drain rate, and I was thinking this would be a good battery. Is it not ? I have charged it for quite a while, but still measure only 50,2V
with my voltmeter.

It could happen i left the ignition on overnight... could this be bad ?

Thanks a lot for all replies,

JD

 

[JohhnyD123]

Charger is marked 3A output. See picture.

 

[dnmun]

.

 

[JohhnyD123]

Ok thanks. The charter gives 58,1 V reading, the battery 50,2V - 50,3V.

How can I find out if it is the LiFePo4 battery I got and not the 12S LiMn2O ?

The LiFePo4 is newer and better, right ?

Did not get any answers from Goldenmotor forum yet....


Thanks,
JD

 

[JohhnyD123]

I have now put 5 charge cycles to my new 48V 10Ah LiFePo4 battery from Goldenmotor. It has reached 53,5-54 V when fully charged the last 3 times. Charger output is 58,5V.
Checked with two different voltmeters. I carefully opened the aluminum casing to look inside, and I'm quite sure it is LiFePo4 and not the older LiMn cells.

Does this indicate something is wrong with the battery ? Could it be that one of the cells is defect or not connected ?

Thanks,
JD

 

[dnmun]

.

 

[JohhnyD123]

I checked the battery again today after charging, and it measured 53,4V like before (and charger 58,5V). Then I opened the battery (see picture) and
measured each of the 16 cells. Each cell measured exactly 3,32V, except for cell nr. 11 (from left ref. picture) which measured 3,56V.

If I'm supposed to get close to 58V after charging, can there be something wrong with the BMS ? ...


Thanks,
JD

 

[dnmun]

.

 

[JohhnyD123]

Thank you very much for helping!

I don't know how I can measure voltage directly on the BMS - there seems to be little space for this - see pictures. I tried to dissassemble the 10 small screws
you can see on the metal plate to remove the plate from the circuit board, but the metal plate is glued on and I don't feel comfortable trying to break it off.
By removing the screws I could remove the thin carton plate on the backside and take a photo of the circuit board as you can see.

I measured voltages of the cells again the same way but with the charger connected, and got the following results :
3.35, 3.34, 3.35, 3.35, 3.34, 3.34, 3.35, 3.34, 3.35, 3.35, 3.69, 3.35, 3.35, 3.34, 3.36, 3.34

As you can see, again the cell nr. 11 from left measured considerably higher voltage than the rest.

So what do you suggest i should do?..

Thanks,
JD