Magic Pie 5 Bike looses power

[Bikewrangler]

Hi everyone. I have now (finally) put my bike together (see pic).
Magic Pie 5 with bluetooth  option and EM3ev jumbo shark 48v & 17 amp battery.
However ,when I ride, out of the blue I loose power. It mostly happens when I use full throttle (but also when just half or so).
If I engage cruise control, it goes along fine for a while, then it "kicks me off" or out of cruise mode and I have to engage it again.
The power lights on the throttle disappear for about 3-4 sec and then it is back again.
Also it "arrests" the drive wheel (this happens very rarely) but it`s like a crunching noise for 2 sec and the wheel "brakes".

So I need some help figuring out what the problem is.
Is it a connection problem? (I have checked and can not find any loose wires or such).
I did not solder the main battery feed to the controller, but they are securely together with shrink tube over.

Is it maybe the BMS on the battery that cuts out? (battery is up to spec and should deliver the power the bike demands, 25 draw).

Or is there maybe something wrong with my controller? (I ordered a new one from Gary Solo, but now he is MIA & not answering my e-mails and the controller is still not here, ordered a month ago, is this "normal"?

Any help or insight is very helpful - Regards from Jim in Norway

[Bikewrangler]

Hmm, trying to add pic, oops got one twice now.

[Bikemad]

So I need some help figuring out what the problem is.
Is it a connection problem? (I have checked and can not find any loose wires or such).
I did not solder the main battery feed to the controller, but they are securely together with shrink tube over.

Sounds like a poor connection or BMS problem, but I suggest that you either crimp, solder, or use a terminal block on the two battery wires to form a decent connection that will handle the current.

If that doesn't cure the problem, it could be the battery's BMS cutting out prematurely or a poor contact where the battery clips into the mounting bracket.

Or is there maybe something wrong with my controller? (I ordered a new one from Gary Solo, but now he is MIA & not answering my e-mails and the controller is still not here, ordered a month ago, is this "normal"?

Unlikely to be a controller problem if the power lights on the throttle are disappearing.

Gary is not MIA, he is currently extremely busy trying to catch up with everything following a recent bereavement.

I'm sure he will respond to emails etc. as soon as he is able to do so.

Alan
 

[Bikewrangler]

Thank you very much (again) for your insight and my condolences to Gary.
This is the same problem I had with a cheap 36v battery with only 15 amp draw, then it seemed very obvious that it was the battery BMS cutting out when I asked "too much" of the battery. With this old battery I used terminal blocks.

I figured it would go away with the upgraded EM3ev jumbo shark 48v & 17 amp battery. It has Samsung 35E: 46.8V nominal, 17.0Ah, ~796Whrs - with 25A Continuous, 34A Max Burst Current. As I understand my MP5 should work fine with that?
Does anyone else here have any experience with this battery?

The battery to slider connection is very sturdy and I never loose power on bumps in the road (I have many and big bumps here). This also leads me to believe it is not the connection to/from slider to controller (there are long strands on both ends and I braided them together very tight (like with hair) and used 2 shrink tubes in 2 sizes (the latter one is industrial extra strong with glue). It made for a much cleaner look as I hate the homemade look of wires, crimps and terminal blocks everywhere.

Worst part is I did not have any issues with the previous bike with GM back rack battery (other than weight distribution and the look of it), but not a single hiccup. Oh well, I guess I soon will have a new MP5 controller for sale. Really wish GM would offer a battery for the motor that does not flip me over because of the weight in the back, (not to mention the much improved handling/riding with a low center bottle battery). I did buy the GM bottle battery (which was dead on arrival here, when I complained they said (and I quote) "This is not a very good battery, you should buy the back rack battery" ...

Can anyone recommend a battery? (that ships to Norway)? - Jim

[Bikemad]

Hi Jim,

Although the Samsung 35E pack has a recommended Max Discharge Current of 25A continuous and 34A burst, the maximum recommended current for the BMS is 50A, and its trip current is set just above 60A.  Therefore the current drawn by the Magic Pie should not be enough to trip the BMS as your controller has a possible maximum current setting of 30A (although it is typically set to 25A from the factory)..

My MP4 is set to the maximum battery current (30A) but my wattmeter has never recorded more than 34.5A of current being drawn.
Therefore, if you set the battery current on the controller below 25A (i.e. 22A @ 48V, which is still over a kW) then the cells should never be overloaded. 

However, if the cutting out still continues with a 22A current setting, then it may be due to weak battery cells or possibly the BMS could be faulty.

If the new battery is not yet balanced properly, a low group of cells could cause the BMS to cut the power prematurely.
I suggest that you lower your current settings and then cycle the battery (use it and recharge it) a few times to see what happens.

If it doesn't cut out at the lower current setting, you may find that after a few discharge/recharge cycles, the controller current setting could be increased back up to 25A without the cutting out reoccurring.

Alan
 

[Bikewrangler]

I did go into the app settings and set it to 22 (did not help) and then 18 (did not help) but I did not cycle the battery, I will try that now. With the battery I got the charger with a 90% or Full charge switch, I have used the 90% position for charging (EM3 claims it should balance the battery several times during charging, including at 90%. I will try 22 and drain the battery and then charge it up again to full (a few times). Will report back on the progress. Thank you so much yet again (will soon owe you my firstborn)

[Bikemad]

EM3 claims it should balance the battery several times during charging, including at 90%.

I would be very surprised if the BMS can balance the battery at 90%, as most will only balance the individual cell groups once the battery is nearing 100% charge (4.2V per cell).

If the cell groups are only being charged to 90% (presumably the charger voltage is reduced to ~53.3V instead of 54.6V, or ~4.1V per cell instead of 4.2V) they will probably never reach the BMS's preset 4.2V balance voltage where it would typically begin bleeding off the excess voltage by switching a small resistive load across each fully charged cell group as required, in order to prevent the higher voltage cell groups from exceeding 4.2V.
This would then allow the lower voltage cell groups to slowly catch up until all the cell groups eventually stabilise at the same 4.2V level.

It's probably easier to visualise what is happening if you think of top end balance charging as being a race between the 13 different runners (cell groups), where the fastest runners reach the finish line first, but are then physically restrained and prevented from crossing the finish line until all of the other (slower) runners have been allowed to catch up.
This ensures that all of the runners will cross the finish line at exactly the same time. 

Alan
 

[Adamsavage79]

 Bikewrangler where you able to solve your problem ? It does sound like a bad connection somewhere, but I recall my old ebike kit would sometimes arrest the wheel and I would get a loud grinding sound. If I let go of the throttle for 1-2 seconds and then reapplied it. The motor would chug along just fine.

[Bikewrangler]

Hi everyone. Winter in Norway has put a hold on my biking and updates. I do have the arrest and after 3-5 sek the bike is fine again. I got a tip on not using a 90% / 100% switch on my battery charger. I depleted the battery and recharged it again up to 100%... Not a a 100% sure but it seemed to do the trick, the thing is that I at the same time managed to go into settings via blutooth and change the regen brake setting from :closed to :open, then the bike halted a lot (was very hard to go forward when I used the brakes, not like before the change where there was a bit of resistance but not like this, this is before the pads even touched the disk). Then the battery went haywire and the bike shut off completely. Now I can not reconnect to change the setting back to open.

Anyone knows how to remedy this? Is there a way to reset the controller to factory default? or am I out of luck and have to swap controllers (with the drop out "strengtheners" on both sides it is a PAIN to do that job).

Thnx for any help - Jim Norway

[Bikemad]

Hi Jim.

If you accessed it via Bluetooth to enable the regen, you should be able to disable it by doing exactly the same thing again, but selecting :closed instead of :open.

If you have the USB programming cable, you should also be able to change it back using that.

As far as I am aware, the main way to reset the controller is by using the Bluetooth dongle or USB cable.
However, some controllers had an unused four pin connector on the PCB which I suspect is probably used for programming it at the factory.

Unfortunately there is no documentation on how to use this connector, and I don't even know if the later controllers even have this connector.

Alan