LI-Mn battery and temperature

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macnobili
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LI-Mn battery and temperature

Does somebody know if leaving the battery outside with very cold temperature (-5 to -10°C) is bad on the long run ? would it be better to take it indoor for the night ?
Thanks
macnobili

sutski
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Re: LI-Mn battery and temperature

Hi Macnobili, I just asked Bionx that very question on Monday as I rode to work (in Switzerland) in -6C conditions :o)...Peak battery performance is from -10C to +40C and I quote Bionx Tech support here:

"We recommend a temperature range from -10 C to 40 C to use our Lithium batteries , keep in mind that battery capacity is decreasing as operating temperature decrease ( even when temperature is higher than the -10 C limit ) , but the power drop is more noticeable starting around -10 C . Would it be possible to bring in the battery during the day and use this time to recharge it ?"

I definitely felt it was slower that morning, hence why I contacted them to see if there was a lower cold limit...

Cheers!!

macnobili
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Re: LI-Mn battery and temperature

Hi Sutski or shall I say Gruetzi ?
Thanks for your reply. A also noticed a clear decrease in the autonomy for my battery. I used to be able to do up to 40 km par charge and now it is down to 25km. The battery has been charged 70 times and I have the system since may 2008. I hope it is just a temperature effect and not a sign of problems beginning with the battery. Safe drive to you !
mac nobili

ItsElectric
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Re: LI-Mn battery and temperature

There is a difference between operating in cold weather and leaving the battery in cold weather. When you riding in winter, the battery heat up, it is very comfortable operating in -15c. However, if you leave the battery outside and park the bike, the voltage started to drop. The battery must be maintain 25v above. If the voltage continue to drop below, it could cause the battery damage. When it get damage, then you start to lose your mileage. If you suspected that you have damage battery, try to discharge the battery by lift the bike on a stand, and run down the battery completely. Then recharge the battery. Also, you should check the fully charged voltage before and after this procedure to make sure you were able to recover the battery.

Ken

Youtube: http://ca.youtube.com/powerinmotion
Website: http://us.itselectric.ca

macnobili
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Re: LI-Mn battery and temperature

Thanks its electric,

I have never left the battery in the cold when it is close to "empty" . In fact, my dealer told me never to empty it more than ther last mark on the display, rule that I always followed. So isn't it bad to discharge the battery completely ?
Just a question, how do I check the voltage ? with the display ore with a multimeter ? in that case, on which pins do I connect the multimeter ?
thanks again.
Serge

sutski
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Re: LI-Mn battery and temperature

Hoi MacN!

I think it is the 3772 code that should tell you the voltage when you have fully charged.

garygid
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Re: LI-Mn battery and temperature

What type battery chemistry are you discussing?
The answers to these questions depend drastically upon the battery chemistry.

Also, for good performance of most battery Packs (a group of cells connected in series to produce a higher-voltage output), one must measure and consider the "health" and charge-balance of each individual cell in the Pack.

Most simple (2-wire) chargers cannot maintain a Pack in healthy condition. A BMS and LVC for each cell is usually required.

Lead-acid batteries are not so sensitive to over-charging (at low rates).

Cheers, Gary
XM-5000Li, wired for cell voltage measuring and logging.

chas_stevenson
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Re: LI-Mn battery and temperature

For more information on the Bionx codes see BIONX Console Battery Reading Reset Instructions. More information, including manuals, may be found in our V is for Voltage DownLoad LIbrary. I hope this information is helpful.

Grandpa Chas S.

ItsElectric
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Re: LI-Mn battery and temperature

Serge:

We have these video for awhile, never had time to edit it. This video show you two methods to check for the voltage

This is part1
http://www.youtube.com/watch?v=mbZIbcGWdX4

part2 is only check for the fuse inside the battery
http://www.youtube.com/watch?v=bYBD3oGeqwI

Ken
_______________________________________________________________________________
website: http://us.itselectric.ca
youtube: http://www.youtube.com/powerinmotion

ItsElectric
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Re: LI-Mn battery and temperature

Serge:

One more thing, you can fully discharge the battery without any problem. The lowest voltage you can have for Li-Mn battery is 25v, but Bionx programmed to cut off at 31v. Same thing for full charge, it should have been 42.5 volt, but bionx change the charger to have full charge at 41.5. What it does is to increase the life of the battery. A normal Li-Mn battery had only 500 cycles, by cut it out early and not fully charge the battery. It will increase the life of the battery. If you read the claim from Bionx, it stated 800 cycles. If you read any other standard Li-Mn, it only claim 500 or 600 cycles. I hope this information help you!

Ken
_______________________________________________________________________________
website: http://us.itselectric.ca
youtube: http://www.youtube.com/powerinmotion

macnobili
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Re: LI-Mn battery and temperature

Ken,
THANKS a lot ! your videos really help. Your last message explains perfectly that I can "discharge" completely the battery (according to the levels of the controller) but in fact, it will not be discharged ! Just one more question, do you know somebody who really did 800 cycles with the bion X batteries. I have 3 friends who had to change after 2 and a half years (approx 180 cycles) because either the battery broke down, or the km range dropped significantly. So I repeat my question: does somebody out ther has reached 800 (or close) cycles with their battery ?
Thanks again Ken.
Serge

ItsElectric
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Re: LI-Mn battery and temperature

Serge:

That is correct, you should be able discharge it all the way within the Bionx system.

Battery can be unpredictable sometime, that is why not many vendors able master this. Especially in the ebike business. I personally cannot confirm if Bionx battery can meet the 800 cycles. But as I am learning more about lithium battery, Bionx battery do not have a balancer BMS. It just charge the entire pack at once. So when some of cell start getting out of balance, it can potential take down the entire pack causing it to lose voltage, which will reduce the range. That is why Bionx recommend to complete discharge the battery and re-charge the battery once awhile. This method is to hope that all of the cell become balance again. If someone can send me their dead bionx battery for further examination, I will happy to report what my finding is.

In another suggestion, we recent working on a project to bypass Bionx battery, and connect our own lithium battery to make the bionx system works. Here is the recent video on this topic. We will create another thread on this topic.

http://www.youtube.com/watch?v=W58e0mTeiLE

macnobili
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Re: LI-Mn battery and temperature

Ken,
the youtube link is not valid anymore ! did you remove the video ?
If not can you put it back ? thanks !

Serge

ItsElectric
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Re: LI-Mn battery and temperature

Sorry Serge:

Bionx have seen the video, they didn't like the idea to show the public how to replace their battery with other then bionx battery. They were politely hinting us to remove the video. So we have to remove it, otherwise we will not able to get any internal information or resell Bionx products. Our youtube site had become one of the most popular source of ebike information, had the most information on Bionx system anywhere. So most of Bionx dealers including Bionx always checking out our youtube site.

I will have to find any other video site to upload this video. Any suggestion?

We are get more Bionx customers sending us old battery to re-built them into new battery, other just want to get more range out of Bionx. I will try post more picture later.

Ken

macnobili
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Re: LI-Mn battery and temperature

hi Ken,
too bad... the video was really great. On the other hand, I can understand BionX but why don't they propose the Lipo battery themself ?? If the technology to make 300 km per charge is available, they should propose it !
You say that many of your customers give you their battery to change; do you do it for European customers too ? If yes,how is the battery sent back to Europe ? what cost ? I'm sure a lot of Swiss people would be interested !

macnobili
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Re: LI-Mn battery and temperature

Today, having made 19 km with my fully charged battery, the jauge indicated no more energy. I decided to check the voltage. To my surprise, it indicated 39,5 volts. According to Ken, the battery could be used until discharged to 31 volts. So I decided to drive the bike a little more eventhough the controller shows no more energy. I did another 10 km no problem, no sign of weakness from the motor. I checked the voltage again: 36 volts.
So... what should I conclude ?
the controller is not accurate ?
BionX is very conservative and afraid that people empty the battery to much ?
If someone could tell me what voltage (code 3772) their controller shows when the battery is apparently empty; this would help my investigation.
I suppose that next step is to try the battery until the motor stops.

ItsElectric
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Re: LI-Mn battery and temperature

hi Ken,
too bad... the video was really great. On the other hand, I can understand BionX but why don't they propose the Lipo battery themself ?? If the technology to make 300 km per charge is available, they should propose it !
You say that many of your customers give you their battery to change; do you do it for European customers too ? If yes,how is the battery sent back to Europe ? what cost ? I'm sure a lot of Swiss people would be interested !

We published the video in another web site. These are much high quality that you can watch it high res.
http://www.viddyou.com/viddstream?videoid=55074

Overall, Bionx’s philosophy is to make a simple and clean looking, well integrated, a bike friendly system. Their patent proposition assist system were way ahead of its time, it is the feeling that Bionx users could appricated. And still today, I haven’t seen any competition that come close to bionx natural pedal assist system. To have clean and simple look, a bike friendly will not work with long range distance configuration. This will means a lot of batteries, heavy weight, which conflict with Bionx's design philosophy.

Since we publicly show this is how it done, we are already line up with three more customers ready to go for a 100 - 200km range of setup. The most interesting is P350 battery conversion. Since it is a NiMh battery that already in the soft bag, it make the system ever cleaner looking with minimal modification. We would happy to provide this service to European customers. We have many European customers who purchased product from us due to our knowledge in both Bionx and Crystalyte products. All of our lithium charger are dual voltage, we carry all line of European plugs. Please contact us offline.

Here is what the converted battery looks like with quad batteries configuration.

DSC04792__1024x768_.jpg
DSC04800__1024x768_.jpg
Quad-battery__640x480_.jpg

Ken
ps: we did have some problem with the regen feature with our first conversion, I am working with an electrical engineer to review what we have missed.
____________________________________________________________________________________________
website: http://us.itselectric.ca
youtube: http://www.youtube.com/powerinmotion

Andre
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LI-Mn battery addition

Hello,

Would you think it can be possible to use this approach to add an additional 36v 10Ah Lithium LiPo battery to an existing functionnal BionX 36 LiMn battery?
The purpose would be to add extra range when necessary.

Thank you

André Tremblay
Montréal

ItsElectric
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Re: LI-Mn battery addition

Andre:

The simple answer is yes.

We spent the time to completely reverse engineer of bionx system. We now can make modification to Bionx system to extend the battery range. More information will be publish later.

Ken

oskar
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Re: LI-Mn battery addition

WOW!
Great news! I adore you for your work!
Did you also solve the regen-problem that you mentioned?
Please let us know everything!!

macnobili
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Re: LI-Mn battery and temperature

Hi everybody,
Time has passed since my last news. I have now 6000 km on my BionX. The range is still around 25 km in winter. Once the jauge indicates an empty battery, the residual voltage is 37 volts and there is no sign of a weak battery. I have done 180 cycles of charging and am quite pleased with the battery although I used to make 40 km with a fully charged battery.

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