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General Category => Magic Pie & Smart Pie Discussions => Topic started by: stump on May 16, 2012, 10:01:39 PM

Title: 48 volt Magic Pie internal shutting off under moderate loads
Post by: stump on May 16, 2012, 10:01:39 PM
hi my Magic Pie 48 volt is shutting off at moderate loads its about 2 years oldstarted happening about a year after I owned it the plug in battery broke and replaced the plug it was falling out all the time n shuting off. ever since this happened never really worked like it use 2 but after sittin for the winter it seems worse shutting off alot checked all my connections and it doesnt seem to make a difference with battery charge I can make it shut off just as easy on a fresh charge as I can after a 10 km drive any ideas?
Title: Re: 48 volt Magic Pie internal shutting off under moderate loads
Post by: Bikemad on May 17, 2012, 01:35:44 AM

It sounds like you may have some weak cells in the battery causing the BMS to shut off the power.

If you are able to check the voltage, try and see what the battery voltage is immediately before it cuts out under load.

Alan
 
Title: Re: 48 volt Magic Pie internal shutting off under moderate loads
Post by: csm on May 18, 2012, 04:04:56 AM
Quote from: Bikemad on May 17, 2012, 01:35:44 AM

It sounds like you may have some weak cells in the battery causing the BMS to shut off the power.

If you are able to check the voltage, try and see what the battery voltage is immediately before it cuts out under load.

Alan

Alan, what voltage does the BMS cut off power at?
Title: Re: 48 volt Magic Pie internal shutting off under moderate loads
Post by: Bikemad on May 18, 2012, 03:41:48 PM

I don't have one to test, but I'm guessing it would be:
If it cuts out at a much higher voltage than expected, it could be due to a faulty group of cells falling below the cells pre-set low voltage limit, which I'm also guessing will be <=3V per cell on the Li4Mn2 packs.

If anyone has some more exact results, please let us know.

Alan
   
Title: Re: 48 volt Magic Pie internal shutting off under moderate loads
Post by: csm on May 18, 2012, 07:25:23 PM
Quote from: Bikemad on May 18, 2012, 03:41:48 PM
I don't have one to test, but I'm guessing it would be:
  • <21V for the 24V pack
  • <30V for the 36V pack
  • <39V for the 48V pack

Alan, testing would not solve this problem. Seems like you don't know what Golden Motor designed the circuits to cutoff the voltage on thier BMS products. Where are the people from Golden Motor? Have they abandoned this forum with answers to these specific technical questions on their products? This is absolutely necessary to get answered to know that the BMS is or is not functioning properly.