Author Topic: MPIII problem with battery or something else?  (Read 2181 times)

Offline mnovina

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MPIII problem with battery or something else?
« on: May 28, 2012, 07:25:38 AM »
Hi

I have bought (from local dealer) MP III rear with LPF 48V 12AH battery and installed it to bike.
When I went to test ride battery quickly went out, so I charged it and tried again day after and the same thing happend again (probbaly some battery cells where weak and BMS cut power).
Dealer changed battery for another one, I asked for LFP 48V 10AH.
After battery change I used bike for two weeks.
One day when I was returning from my job, Rain was falling, I covered battery with plastic bag so battery was dry.
When I was near home it just stopped, then I turned key off and on and it suddenly worked for a while.
I leaved battery to charge trough night and morning after was pretty the same story.
So with fully battery charged when I hit throttle under load it sometimes won't work, when I wait for about half minute it works and goes uphill like nothing is happened, and after 10 meters it stops. Sometimes when I take rear wheel up and hit throttle it won't start, sometimes it works fine and when I hit breaks hard it spins just normaly. I tried to switch key off and on several times, even unplug the battery, but it sometimes work and sometimes don't. I didnt manage to measure battery voltage but it was on charger trough night.
Interesting is that the day before rainy day (it was no rain) when I was going home MP also stopped some 1km before my home (for two week of riding it this didn't happend ever but on rainy day and the day before).
On rainy day I got to work without problem (it was no rain in morning), I tought this is because I live uphill from my work, but that are no realy big hills.

Could it be because of rain, is it problem with throttle lever, or internal controler?
Also sometimes throttle lever when I slowly let it to go in starting position it doesn't return, it stops some 5mm before end and gives some throttle to motor but I can live with that.
I found some post where people say that they are using MP without any problem trough the rain....

That all was before two weeks, las week it was rainy and I didn't manage to test bike and I didn go to service because I wanted to try it more.

So Yesterday I tested it, don't know how much battery lasted, and today I managed some 5 km with battery. 
Once when I mounted battery it droped me on floor could that be cause of bad battery capacity?
After drop of battery, I used bike for two weeks normally and it lasted for 10 km without pedalling, so I concluded that drop isn't cause of weak capacity
Now it's definetly BMS make cutover, yesterday I measured voltage of battery after immediatley after cut and it was 51 to 52 V.
And everything I wrote in las PM didnt appeared today, cutovers were because of BMS not like before when the motor just went dead.
When I gave throttle motor was going , I notced delay when I hit throttle to moment whwn motor starts to run faster.
Now I don't know what to think, or what to demand from store wher I buyed kit.
I already changed battery once, now they would say that weak battery is because I droped it.
Motor is little bit noisier in comparation to beginning, throttle leaver doesnt work properly.....
I bought this kit to reduce costs of my traveling to work and now I must use my car.
Does anyone some opinion or sugestion, I don't have bike computer, and don't know how many km can I make with fully charged battery.
And I don't know what is maximum speed of bike.

And one thing I mounted battery upside down on bike is that cause? I belive not.

And just one thing when I changed battery they left me same charger, they didn't gave me another one.
On charger is label which says 54,6V.

So many questions and I would be thankfull for any advice.

I bought kit on 23. april and I am little bit disappointed.

Thanks,

Mihael

Offline Henry Chang

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Re: MPIII problem with battery or something else?
« Reply #1 on: May 28, 2012, 02:25:48 PM »
I want to say about your charger, why local dealer doesn't give you new a  LiFePo4charger, the old charger output voltage 54.6, but LiFePo4 charger output voltage 58.4,logically speaking, the old charger can work at the new battery and charge it for a long time, but after many times of charging, it must be no good.

Offline mnovina

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Re: MPIII problem with battery or something else?
« Reply #2 on: May 28, 2012, 06:26:19 PM »
Thanks for information.
I knew something is wrong with battery and charger.
I will ask for new battery and charger.

But does someone else know why it is acting so strange.
Sometimes work and sometimes dont?
What about driving bike on rain?
I read that some people don't have any problem as long as batery is dry.

Does someone have some other advice?

Mihael
« Last Edit: May 29, 2012, 06:36:59 AM by mnovina »