MP5 no longer moves but throttle does light up after reverse polarity.

[JayDee]

Hi All,

New to the forum but had MP's since 2011, I guess. 

After accidentally hooking up a new battery pack to my MP5 the motor will no longer turn.   I upgraded to a 48v batt instead of 36v but while soldering connectors I mistakenly revered pos and neg and got a large spark on the connector to the MP5 when I tried to connect it.  It was then I realized the mistake and re-soldered the battery connector but now the motor does not move when the throttle is opened.   What damage have I caused ?

Thanks for any advise!

[Bikemad]

Hi JayDee andto the forum.

If you are very lucky, the controller may have survived the reverse polarity if the Battery's BMS prevented excessive current from damaging it. 

If you temporarily reconnect the old 36V battery and the motor still runs, then the controller should be OK, but you will then need to adjust the Nominal Battery Voltage (V) setting in the controller to 48V using the USB programming lead and PI-800 programming software (or Bluetooth dongle and smart phone App.) before the controller will work with the new 48V battery.

The actual voltage of a 48V pack is typically higher than the 52V overprotection value setting that is set by default with the 36V nominal battery voltage settings:



However, if it doesn't run on the old 36V battery (or on the new 48V battery after being reprogrammed for the correct battery voltage) then the controller may have suffered damage from the reverse polarity. 

I'm keeping my fingers crossed and hoping that the controller still works.



Alan
 

[JayDee]

Hi Alan,

Thanks so much for this info.  Im hoping that it might be ok indeed since it stil lights up and when I connect the Bluetooth adapter I still see the GM showing up in a bluetooth list and can see it flashing.  Two more questions for you:

1) Do you know if there is a working IOS app to program the controller yet?  The one called 'golden motor UI" in the app store (apple) just crashes when you try to enumerate bluetooth devices to connect to. 

2) Can this even be programmed with the App even if it worked or will I need to get the USB lead in any case ?

[Bikemad]

1) The original iOS App I tested on my wife's iPhone 4S only worked as a display device and was not able to set the program parameters.
I am not a big fan of Apple products so I have not tried any subsequent versions of the iOS App.

2) The Android App is definitely able to program the controller (check out this video for more details) but I don't know about recent iOS versions.
Perhaps you can obtain or even borrow an old Android phone with Android version 4.4 (KitKat) or newer and use the GM Android App to adjust the voltage?

Alan
 

[JayDee]

Hi Alan,

I see now that I ordered the 36volt version of the twist throttle.  Could it be also that I need the 48v of that throttle and thats why no throttle response?  I havent had a chance to test yet with the original battery since its actually broken but my 48v pack is LiPo so at full charge its still not over 51 volts.

[Bikemad]

Hi JayDee,

The voltage rating of the throttle only affects the operation on the LED battery gauge and would not prevent the throttle from working on 24V, 36V or 48V.
The LEDs of the 36V gauge will remain on constantly with a 48V pack as the pack voltage would need to be below 36.2V before the green light would even start to go off.
Check out this post for further information on the battery gauge.

48V LiPo, LiMnO₂ and LiFePO₄ packs are typically well over 51V when fully charged:

• 13S LiPo/LiMnO₂ = 48.1V nominal (3.7V x 13) and 54.6V fully charged (4.2V x 13).
• 14S LiPo/LiMnO₂ = 51.8V nominal (3.7V x 14) and 58.8V fully charged (4.2V x 14).
• 16S LiFePO₄ = 51.2~52.8V nominal (3.2~3.3V x 16) and 57.6~58.4V fully charged (3.60~3.65V x 16).

However, if you actually have a 12S LiPo pack which would be 44.4V nominal (3.7V x 12) and 50.4V fully charged (4.2V x 12), and your battery voltage is less than 52V (the default set maximum voltage protection level for a controller configured for 36V ) then a damaged controller is the most likely cause if the motor still refuses to run. 

Alan