I guess it is the source of the spark when I opened it. But looking inside the case, there are corresponding scorch marks which suggest it has happened when it was in place, not when I took apart. I can't see how this has happened, unless it is from vibration over time or impact. I am now going to try and check if these cells are in the groups that are showing low voltage, but then not sure if it really matters, I guess it is no good without replacing these cells? Even then I would have to work out what happened and resolve it when rebuilt.
Mystery power cuts
- Thread starter tomtag
- Start date
See the ends of those plastic bits? When closed up, the lower flat end is supposed to sit under the other, thin end. This spreads the load a bit when impact forces causes the cells to bash against the casing. I suspect the thin end was sitting directly against the cells, causing high loads against that part of the cell wall.
The design is poor, not offering good physical support to the cells, and allowing misassembly. On bumps, this kind of failure is inevitable when the plastic is not properly seated. It would last longer in road use than off road.
Assuming those plastic parts are complete albeit split rings, if the joint was at the upper side when on the bike rather than lower side it would do better, as the plastic may be completely smooth that side.
Those cell can burns are due to shorting out, the battery is unsafe and a liability.
It needs recycling, as is it is a potential fire hazard.
It is one reason as to why, that when folks have battery charge or cut out issues I always ask users to carry out a part battery autopsy to find a reason as to why.
Batteries when in the blink need to be taken seriously and not an easy way out to charge without actual knowledge of the cause.
We did have one member who's answer was to buy an expensive reverse charge to carry out balancing which imhv very poor advice and tells one nothing as to why the battery is acting in such away and doesn't help in remedying an issue. He was called out a few times but continued to offer his bad advice along with another of his crackpot ideas of fitting brake rotors backwards.
It needs recycling, as is it is a potential fire hazard.
It is one reason as to why, that when folks have battery charge or cut out issues I always ask users to carry out a part battery autopsy to find a reason as to why.
Batteries when in the blink need to be taken seriously and not an easy way out to charge without actual knowledge of the cause.
We did have one member who's answer was to buy an expensive reverse charge to carry out balancing which imhv very poor advice and tells one nothing as to why the battery is acting in such away and doesn't help in remedying an issue. He was called out a few times but continued to offer his bad advice along with another of his crackpot ideas of fitting brake rotors backwards.
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Those burnt cells are very likely dead and would read 0v, they will pull the parallel group down and no manner of balance or charging will alter the pack.
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An expert in battery pack build/dismantle would probably find many of the individual cells to be OK, but that is really not DIY work.
In this state, the battery is not safe to post.
Just less than 2 years, but only had an 18 month warranty. I will contact Yosepower & see if there is anything can be done, but not sure if I will get anywhere.
Worth sending the pics of the cell damages as they may offer a replacement or a good discount on a new one, from what we hear they have good CS so wouldn't surprise me if they simply replace it.
Worth letting them know and sending some photos of the damage to the cells even if just to make them aware of the design problem of the case. A couple of layers of kapton tape over those vulnerable cells would have saved the damage to the shrinkwrap insulation. If it's any consolation, cell replacement in that style of battery pack is a real pita as most of the nickel strip needs to be removed in order to removed the plastic cell holder and fit the new cells.
So I have had a response and they won't replace, as out of the 18month warranty, but have suggested a discount on a new one. Not sure how much yet, I need to choose one & I think they will let me know.
So I have looked at the website, my current battery is 36v 11.6Ah. The one I had was already a tight fit, so I was considering the same size again to be sure it fits. But, would anyone be able to offer any advice on what is best to get?
This would I think be a direct swap:
36V 10.4Ah Bottle Battery E-Bike Li-ion Accu (yosepower.com)
Or would I be better with this:
36V 13Ah Hailong Li-ion Battery E-Bike with 5 Gold-plated Round Plug (yosepower.com)
They both say 10A/20A. I guess without actual cell details it is hard to say what is best? It is a MXUS XF08C 250w motor I have.
Also, is this a good opportunity to move to 48V, would there be any benefit in that?
So I have looked at the website, my current battery is 36v 11.6Ah. The one I had was already a tight fit, so I was considering the same size again to be sure it fits. But, would anyone be able to offer any advice on what is best to get?
This would I think be a direct swap:
36V 10.4Ah Bottle Battery E-Bike Li-ion Accu (yosepower.com)
Or would I be better with this:
36V 13Ah Hailong Li-ion Battery E-Bike with 5 Gold-plated Round Plug (yosepower.com)
They both say 10A/20A. I guess without actual cell details it is hard to say what is best? It is a MXUS XF08C 250w motor I have.
Also, is this a good opportunity to move to 48V, would there be any benefit in that?
For 48v your controller would need to be dual voltage model, if not one would have to change it. upping the voltage will increase the motor rpm and torque by 33%, on flatish terrain it will be good but on steep hills the motor may feel a bit lacking despite the torque increase as the motor rpm will bog down unless the overall bike speed can be kept high.
A discount on a new one is not a bad offer but guess it depends on how much they propose, 10/15% wouldn't be so great but 20/25% is a start.
For the bottle type if opting for the same one, one should ask them if the design has be changed to prevent the cell rubbing and possible shorting and fire that could arise. As clearly there is a design fault which should be taken lightly.
For the bottle type if opting for the same one, one should ask them if the design has be changed to prevent the cell rubbing and possible shorting and fire that could arise. As clearly there is a design fault which should be taken lightly.
The 13 Ah Hailong offers better value, but it's a 32mm longer, so make sure it will fit. You need to allow a little more length to slide on/off the mounting base plate. The centre of the battery case is a little lower at the top/centre, which does allow the case to slide a liitle further towards the headstock which may help if your frame is small. It may also help if you can fit the battery lower down in the frame, but this may mean fitting extra rivnuts.
Hi WheeliePete, thanks for the feedback on battery choices above, very useful. I may well have to stay with the bottle version due to space, but will spend a bit of time measuring up to confirm.
Yes I have sent photos & an explanation. TBH they didn't seem overly interested, just said cannot replace for free but may offer discount. I have asked if the design has now changed if I do look at going for the same again. I think they have now closed down for Chinese New Year, possibly until Feb 7th, so I may be waiting for a little while for the next response.
If going with the same battery and having opened the old one, I would open the new one and introduce an insulator between where the rubbing has occurred.
- I've been following this thread with great interest as my own 36v 10Ah bottle battery has been suffering from the ocassional power failure.
- The battery came from PSW Power and is silver in colour but otherwise looks much the same as the black case one in the Yose Power link posted by the OP
- My next step was to change the BMS (on it's way from GreenBikeKit) but at the same time, I'll definitely have the batteries out of the case to look for any damage to the battery cells.
- And this is a question for @tomtag - looking at one of the pics you posted (copied below) is the arrow pointing to the thick yellow wire from the BMS C+ terminal running down the battery case to the charging port?
- The reason I ask is, was the yellow wire running down the side of the battery to the charging port were the two burn marks were and if so, is the wire damaged too?
- Given that the BMS is at the top of the battery pack and the connection points to the motor/control are at the base, then there are several thick wires (B-, P-,C+) that have the potential to become chaffed over time (and I supose the BMS balance wires too)
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If I understand the question correctly, the answer is no. All of the thick wires from the BMS run down a different side of the battery where there is no damage to cells. This side has a fully enclosed 'groove' so no chance of the case grounding onto the cell surface. The other side had an open section in the groove that allowed the contact. Is this an answer that makes sense?
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