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Battery Rebuild Ninebot PTR Elite +


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can anyone tell me if i can use the good halves (30cells with working BMS), of two different battery packs together to make one full unit. I know they are used in isolation but are different ratings - one high capacity ninebot elite +, one standard ninebot elite.

this would be a great short term fix if possible

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1 hour ago, Baba Yaga said:

Do i need to reset the BMS to test it? if so do i remove the bms white plugs connecting small white wires to the cells or unsolder the main red black charge/discharge leads?

BMS normally should reset with just plugging in the charger. Don't know if this special BMS has additional reset possibilities.

1 hour ago, Baba Yaga said:

can anyone tell me if i can use the good halves (30cells with working BMS), of two different battery packs together to make one full unit. I know they are used in isolation but are different ratings - one high capacity ninebot elite +, one standard ninebot elite.

this would be a great short term fix if possible

A battery configuration consist of two of this 30 cell packs? They are two times 15s2p?

So if you combine two different capacity packs :

- be sure both have the same voltage before you connect them!  With 1V difference there will be more than ~4A flowing - try to get the difference below.

- the higher and the lower capacity pack would normally discharge different and have different characteristicd, but in this parallel configuration they are forced to the same voltage.

So one will get stressed more, than in normal configuration with two equal packs.

There even could be some (?small?) equal equalization currents flowing - imho once the packs "rest" after a burden?

Everything nothing dangerous, "just" not optimal.

Peak performance could be a bit lower, as one pack has to deliver a higher current.

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yes there are two 15s2p packs in the battery. I believe they work in isolation from each other, they are not wired together, and the Elite recognizes them separately as battery pack 1 and 2. i think it is a separate pack to power each wheel, hence my thinking the different capacities of each pack would not matter and they do not interfere with each other.

can someone confirm this or tell me this is a stupid idea.

I have discovered my battery welder trips the electrics, so if the above is not an option then i will have to solder a new pack of 18650's which i am not keen on.

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Good to hear from you.  Sounds like you are experiencing all the same issues I did.   Yes, my welder also tripped breakers.  I only succeeded when I found an isolated outlet on a circuit that was rated for 30 AMPS . The outlets in most kitchens are rated 20 to 30 AMPS  due to toasters, ovens, coffee makers, etc.)   Others in the house are usually 15 AMPs - these will usually trip when you try to make the weld.

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I know the packs are separate, but the power control board sees them both and can tell difference in output, and I am not so sure about the half and half approach.   If I do not allow the charger to completely charge my packs and shut down, the pack will never get fully balanced between side 1 and side 2.   I will get the output 1, or output 2 error on the same pack until I let the pack fully charge (ie the charger turns itself off).   Thus in my opinion, you could not use two different (strength) half packs together on the some power control board.  Note, I am not sure about this and if in a pinch would certainly have tried that approach as well.  I see no one else seems to know for sure -  ohhh, my kingdom for an electrical engineer!!! Please post if you ever get that combo to be accepted by the machine.

Interesting thought about one motor to pack side, but the dual redundancy premise is that if one side fails, the other side of the pack provides the power needed to come to a safe stop.  Just like the single cells wired in parallel, if one fails, the other cell next to it will carry the load.

Keith

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  • 6 months later...

Hello all,

A while ago, I wanted to use my Ninebot Elite after a long long time (over 6 months). It did not start at all! The only thing that happened after I connected my charger was a flashing, empty battery symbol on the displat of my Ninebot. I contacted Segway but the were not very helpful. As I was pretty sure the battery was gone, I tried to find a replacement. I contacted a few dealers and there was one that had a battery in stock. As these Ninebots are a few years old, I assumed the battery they were trying to sell me were old as well. And the quoted me a battery for EUR 1400 !!

Inspired by member NinebotPTRELITE+, I rebuilt the battery of my Ninebot Elite. I bought 60 LG INR18650-M29 2850mAh - 10A cells for EUR 130 and some spacers to build the packs. I viewed some Youtube videos about battery spot welding and bought a portable, battery operated one via AliExpress. 

Next thing was to open up the original battery (it opened very easily), and disconnect al leads from the two battery packs. Of course I documented (photographed) everything very well and checked and double checked the positions and polarity of the new built packs. After a lot of spot welding and soldering, I protected the two packs with shrink wrap and put them in the original enclosure. I closed the enclosure with black tape and installed it on my Ninebot Elite to charge it (outside in case it catches fire). 

The next moment was filled with pride and joy! It immediately started to charge! :) :thumbup:

I left it charging for several hours before I started the vehicle. All worked well! I did not ride it very long but I'm sure it will be as good as new!!
 

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Congratulations to HARALDL!    No small task.  I am so glad to see someone else avoiding the crazy prices they want for old stock  manufactured batteries.  I rebuilt one using older (over 4 yrs old) cells. Even that pack lasted two more years before several more cells failed.  Pulled those out and replaced with used cells and I am again on the road.  If you have the patience and time, you can keep these packs running well past their original designed life-cycle.  Again, always use caution and all safety equipment.   

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4 hours ago, NinebotPTRELITE+ said:

Congratulations to HARALDL!    No small task.  I am so glad to see someone else avoiding the crazy prices they want for old stock  manufactured batteries.  I rebuilt one using older (over 4 yrs old) cells. Even that pack lasted two more years before several more cells failed.  Pulled those out and replaced with used cells and I am again on the road.  If you have the patience and time, you can keep these packs running well past their original designed life-cycle.  Again, always use caution and all safety equipment.   

Thanks!

Now I have 2 older packs with a total of 60 cells spot welded together. I'm sure only a few will be defective. Can you tell me what I can do to test which cells are bad? Remove all spot welded connections and test each cell separately or can I test in a different way?

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1 hour ago, HaraldL said:

Thanks!

Now I have 2 older packs with a total of 60 cells spot welded together. I'm sure only a few will be defective. Can you tell me what I can do to test which cells are bad? Remove all spot welded connections and test each cell separately or can I test in a different way?

As both packs are each 15s2p your interest is in each of the 15 cell group voltages (each group consisting of 2 paralleled cells).

Each paralleled group of two cells work and die together - so both cells have to be replaced together.

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On 6/15/2020 at 10:59 AM, Chriull said:

As both packs are each 15s2p your interest is in each of the 15 cell group voltages (each group consisting of 2 paralleled cells).

Each paralleled group of two cells work and die together - so both cells have to be replaced together.

Thanks!!

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As  Chriull explained, the paired cells should be replaced. If one is bad, its partner (paralleled) cell should also be replaced even if it does charge back to nominal voltage.  You can test cells separately without removing all the welding/solder connections.  Just test bottom to top of single cell, if below 2.0 Volts, replace it and the parallel cell.  Some people may consider a different minimum voltage, but I use 2.0 V as minimum to use in rebuilding a pack.  I try not to use New cells in a pack of used cells.  Keep New cells together in one pack on same BMS. Use similar aged cells in used rebuilt pack.  New and Used cells tend to "fight" each other when charging and discharging. Causes heat buildup as well as premature shortening life cycle of the new cells.

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  • 4 months later...

I have just received my daughters ninebot Robot PTR where the battery fails to charge.  Having read the previous posts thoroughly, I have opened the battery case and set to check the cells and the BMS. Firstly I charged up the pack directly avoiding the BMS and did this slowly, and it settled at 47.5V, by removing the white plastic plug on the BMS it is possible to monitor the increase in voltage from the first socket on the plastic plug using a pin and inserting this in the plug, and using a good voltmeter. I found the first pair to be 4.1 volts, and the voltage incremented as I went along, until i reached pin 5,6,7 on the second larger plug, there was no increase in voltage from 33.1 volts over the next pins until once again the voltage started incrementing.  This represented leads no 4,5,6 which went to the blocks of pairs of batteries. Lead one is the power supply for the BMS. Following those leads it led to the failed cells, and cutting away the insulation around those cells, the voltmeter showed no difference in voltage between the two pairs of cells which have failed.

Carrying out a similar check on the other half of the battery pack a further four cells have failed.  The BMS on both sides failed to reset after the full charge, and now we know why.

The cost of replacing the battery with a new one seems prohibitive, so it looks like I will need to get some practice into spot welding, as I have never done this before, and organise some new parts, although the comments about replacing old with new cells does sound sensible.  I do not know of anyone in the Channel Islands or the South of England that would carry out this repair, as there is a difficulty in shipping these batteries anywhere.  i will let you know how I get on with the repair. I expect the BMS to reset itself once it is satisfied that it has suitable voltage to all its circuitry.

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