General Category > Magic Pie & Smart Pie Discussions
.. MP5 ..conking out ...from the heat ???
diverdon:
Hello , Today my bike conked out ...again ..for the 2nd day in a row .. Thought I fixed it yesterday but looks like maybe not .. 30 minutes into a 40 minute easy slow 7-8 mph ride I do most every day ... Felt like the bike just turned off ... I could turn the battery off and back on and it would allow the thumb throttle to just work for a second before it would shut off again .. I petaled the mile or so home ...not as much fun .. The problem showed every time I tried to use the throttle and I had an extra one from an old build ..Put it on and it works fine ...
Today I went on the same ride and it conked out in about the same place ... Thinking now it might have something to do with the battery ... I put a voltmeter on the output and sure enough it shuts off power as soon as I hit the Thumb Throttle ....
Anyone else had this problem ? Battery is 2-3 years old 52 volts 17 amp hours ..I'm pretty sure I have ridden when it was this Hot Before .. Kinda stumped ... Perhaps I will put the Battery in the Freezer for a few minutes and see if that "fixes" it ..
Sorry this is so Long ..Just wanted to try and explain the problem .... First time in nearly 4 years I've had a problem and I think it's the Battery and not the MP5 ...
diverdon:
Tried the freezer for 29 minutes to cool down the battery .. No Change .. I have a "smart" battery charger it can charge to 80 , 90 or 100 % ... I most always charge to %80 at 1 amp ..got it sitting on 1 amp now and I'm going to 100 % ... I have heard you need to "balance" your cells this way every now and then ... Maybe? ... I will report back ..The controller cannot turn off the battery ??? can it ? as that's what it seems like is happening ..shutting off when it gets a load on it ..
Bikemad:
--- Quote from: diverdon on August 28, 2023, 05:30:21 PM ---The controller cannot turn off the battery ??? can it ? as that's what it seems like is happening ..shutting off when it gets a load on it ..
--- End quote ---
Hi Don,
The controller cannot turn off the battery power, only the battery's BMS is able to do that.
It definitely sounds like a battery problem, but I don't think it is heat related, as it is more likely to be a weak cell or low voltage (unbalanced) cell that is causing the BMS to cut the power from the battery.
Charge it to 100% each time it is used over the next couple of weeks and see if it improves. If you have only been charging it to 80% each time, it could be that the cells are just very imbalanced.
I also suggest that you charge it for as long as possible and don't turn it off as soon as the green light comes on.
I have been using the same Hailong 48V 10Ah battery for over 3 years now and I typically have to charge it for at least 18 hours before the cells are fully balanced.
My charger is plugged into a mains power meter so that I can monitor the power being drawn as the battery charges:
The red LED indicator on the charger usually turns green after just 2~3 hours of charging (at which point the charger's cooling fan also stops) but the battery's voltage is only ~54.40V and the charger is still drawing ~13 Watts from the mains.
Over the next 15~16 hours the Battery's BMS slowly balances the cells and the power being drawn from the mains will gradually drop all the way down to ~1.0 Watt and the battery voltage will increase to ~54.54V.
Ideally, my battery's fully charged voltage should be 54.60V, but the charger's regulated output seems to be ~0.1% lower than it should be. ::)
When the power meter reads 1.0~1.1 Watts, I know that my battery is fully charged and the cells properly balanced, and then I can then turn off and disconnect the charger.
If your battery has only been 80% charged for several weeks (or even months) then the BMS would not have been able to balance the cells at all over this time, therefore it will probably take several weeks (or even several months) of long 100% charging to fully equalize the voltages of all of the cells.
However, if you have faulty or weak cells instead of low voltage imbalanced "good" cells that are causing the BMS to cut the power, then even with 100% charging, the battery is unlikely regain a large percentage of its original capacity. :(
Alan
diverdon:
Thanks for your help Alan ... You gave me some good points .. My charger is this thing from luna cycle ..it will charge automatically to 80-90 or 100 % and I can choose from between 1-5 amps ... I have been charging this pack to 80% a lot ..I try to not let it go below 49 volts ..It's the Haloing 52 volt 13 AH .. I think it's 2 1/2 years old ..With your tip I turned the charger back on I had it to 100% but your tip about letting it run is what I going to do .. It's taking 1/4 amp and I'm not sure but think the charger is going to shut off automatically ...
I have the original 2 amp charger ..perhaps I should hook that up for a while ??
Thanks Again for putting up with my problems ...Still I have never had a problem with the MP5 .. It's always been the battery or me ..the "installer" .. Thanks again ..sitting here in Florida watching hurricanes on either side of me .. Fun ..
diverdon:
Hello , I used the original 2 amp charger left it on 6-8 hours after the light turned green ... waited 2 hours and went for a test ride ... made the 40 minutes no problem last 2 days it would cut out at 30 minutes .. didn't want to push it to the regular 1 and 2 hour rides I do ..not today at 11 AM ..it's 88 and humid .. I REALLY don't want to petal against the wind in this heat "if" it gives out ...
I will take your advice and do the balancing 3-4 more times ...How low should you take a 52 volt battery before recharging ...I figured 49 volts ..that's what I've been doing ... battery was really hot to the touch in the sun .. I never thought of it before ... I have a water resistant canvas cover I use and wonder if it make the heat worse ...left it off today and the black battery was sorta/pretty hot to the touch ...
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