Bike cutting out when battery on 3 bars
- Thread starter bikemerchant
- Start date
He said
"I don't think there is any official datasheet for these cells, as they're used solely internally in the Tesla factory for their own cars.
Various sources describe them as "Panasonic NCR21700T" or with "A" at the end of this model number as the closest possible match.
I have them as new, never used. Using them for some time and so far no issue. Tested performance and capacity show solid and steady results and got very similar as in this video:
or
https://www.youtube.com/watch?v=cdFTrjZoTE"
"I don't think there is any official datasheet for these cells, as they're used solely internally in the Tesla factory for their own cars.
Various sources describe them as "Panasonic NCR21700T" or with "A" at the end of this model number as the closest possible match.
I have them as new, never used. Using them for some time and so far no issue. Tested performance and capacity show solid and steady results and got very similar as in this video:
https://www.youtube.com/watch?v=cdFTrjZoTE"
Anybody got a recommendation on what I should go for here?
"After testing your pack I can see that original pink cells are roughly ok, no need to throw them away.
I even have some Samsung 35E cells to replace those 2 green chinese cells.
So the battery would be repaired faster and cheaper.
So please let me know, what final way of repair you want.
Make backup battery from your cells and put new cells into your battery case?
Or just replace those two cells and run full test for performance and capacity?
What I also found during testing your battery is that bms doesn't cut out charging power on 4.2V. It going higher, up to 4.22 and only then it cut power.
As I mentioned before, such voltage is not dangerous, but significantly shortening battery life.
Most bms's cutting out power at 4.12-4.16V, which is great for battery lifecycle and sacrifice only small portion of capacity.
I can keep your bms, no problems, but my recommendation is to replace it for different, with lower cutting out voltage limit.
I have such bms, it cost €45."
"After testing your pack I can see that original pink cells are roughly ok, no need to throw them away.
I even have some Samsung 35E cells to replace those 2 green chinese cells.
So the battery would be repaired faster and cheaper.
So please let me know, what final way of repair you want.
Make backup battery from your cells and put new cells into your battery case?
Or just replace those two cells and run full test for performance and capacity?
What I also found during testing your battery is that bms doesn't cut out charging power on 4.2V. It going higher, up to 4.22 and only then it cut power.
As I mentioned before, such voltage is not dangerous, but significantly shortening battery life.
Most bms's cutting out power at 4.12-4.16V, which is great for battery lifecycle and sacrifice only small portion of capacity.
I can keep your bms, no problems, but my recommendation is to replace it for different, with lower cutting out voltage limit.
I have such bms, it cost €45."
The tesla cells will be reclaimed cells, they are not available to buy direct. Again the recommendation is to limit cell use to 7a or less as they are only a 10a max rated cell.
End of the day you have little choice either go with the PF cell or the larger format tesla either way they both have a similar current rating though the tesla will give you more ah.
If one can afford to then the bms balancing at a lower voltage will be better, there is little to be had in the last 0.05v - 0.01v of a battery charge. the last 0.01v of the charge will only give about 2km of useful range.
For the original battery if keeping it I would simply reduce it to 5P battery and have the bad cells group removed.
End of the day you have little choice either go with the PF cell or the larger format tesla either way they both have a similar current rating though the tesla will give you more ah.
If one can afford to then the bms balancing at a lower voltage will be better, there is little to be had in the last 0.05v - 0.01v of a battery charge. the last 0.01v of the charge will only give about 2km of useful range.
For the original battery if keeping it I would simply reduce it to 5P battery and have the bad cells group removed.
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How would I switch the packs inside my case if I needed to use the backup?
At present, battery pack is permanently attached to both connectors (charging port and output port), plus some wiring for light and switch etc.
I cannot find an exact replacement for my battery case.
At present, battery pack is permanently attached to both connectors (charging port and output port), plus some wiring for light and switch etc.
I cannot find an exact replacement for my battery case.
Oh and he can either fit 4x13 Tesla cells or 6x13 Panasonic - still not really any difference in either of these packs?
New battery is ready for collection so I will update in a few days how it runs.
Update on the backup battery, is it still worth it?;
"Those green cells are not chinese 2.6Ah as you sent me photo, but Panasonic NCR18650B.
Those "Samsung 35E" cells are actually rewrapped Panasonic NCR18650B.
Plus I found that they have been refurbished or salvaged from another battery pack, they have signs of previous usage.
The cells are glued together with superglue, and some cells exposed to heat from hot glue are partially ruined and can't be reused.
Extra work and cells for spare battery brings cost of the extra battery up to €200."
Update on the backup battery, is it still worth it?;
"Those green cells are not chinese 2.6Ah as you sent me photo, but Panasonic NCR18650B.
Those "Samsung 35E" cells are actually rewrapped Panasonic NCR18650B.
Plus I found that they have been refurbished or salvaged from another battery pack, they have signs of previous usage.
The cells are glued together with superglue, and some cells exposed to heat from hot glue are partially ruined and can't be reused.
Extra work and cells for spare battery brings cost of the extra battery up to €200."
Nightmare, just paid for the new battery and I still have the exact same issue.
What next? I assume it's either a wiring or controller issue.
What next? I assume it's either a wiring or controller issue.
Remember way back, you measured the cell group voltages, and there was a standout bad cell group?
That was a genuine battery issue, the controller etc cannot make that happen. A defective BMS could, but nothing outside the battery can cause that problem.
So: new BMS fitted? If not, suspect the old BMS. If yes, then either the new battery also cannot handle the current because the demand is so high, which is just a parameter of the motor, or there is a problem with the new battery.
How to tell?
1. Fully charge battery and run around really gently until flat. I.e. treat it gently, low current, and see what range you get. Or,
2. Get one if those cheap wattmeters and set up a discharge test rig, and do a full discharge at about 1A, and see what capacity you get.
3. If all points to a battery issue, open it up , test the cell group voltages, and so on as before.
My guess is that the battery cannot supply enough current when you use the throttle and it is under 60% charge, so the voltage is pulled down to the BMS cutoff, so it cuts off. I think if you open up the new battery, assuming it has a new BMS, the balance will be fine, but the cells are just not capable of sufficient current delivery. That is not necessarily a cell problem, so much as just a very demanding type of motor.
If that is so, nothing for it but a massively expensive battery or chuck the motor.
Yep, new 35A BMS,
Fully charged it and the controller screen shut off the second I turned it on, without the throttle.
So I should open up the brand new battery now and test group by group?
Fully charged it and the controller screen shut off the second I turned it on, without the throttle.
So I should open up the brand new battery now and test group by group?
No. I interpreted 'exact same problem' literally, and this sounds different.
I would want to check out the battery first, to have confidence in it, and then see what else to do.
So, what voltage are you getting at the connector when fully charged, for a start?
Then if correct, I.e. about 54.6 max but likely a few tenths less, ideally do a capacity check, but if that's not straightforward then await ideas here, not necessarily from me!
If the screen shuts off straight away then there is power supply issue and an interruption between the controller and display . It might be a wire issue in the 1t4 cable. Check for bent pins or misaligned pins in the connectors also use a meter and check continuation on all pins or it might be the voltage regulator in the controller.
No load is being applied so it is wiring or controller, the battery I doubt is at fault.
I had similar once with an oxydrive kit, two charged batteries and the display simply switch on and then off. I tried a another controller and all was ok, the voltage regulator or supply fet had failed.
No load is being applied so it is wiring or controller, the battery I doubt is at fault.
I had similar once with an oxydrive kit, two charged batteries and the display simply switch on and then off. I tried a another controller and all was ok, the voltage regulator or supply fet had failed.
Andy is the last person I would take advice from.
All his theories are cut and paste.
All his theories are cut and paste.
Thanks.
Booked an appointment with the technician at Halfords, although won't get it looked at until Monday.
If there's any simple tests I can do myself in the meantime please let me know!
So Halfords was useless, the technician didn't know how to use a multimeter!
No idea where to go with it now, trying to source somebody near North Dublin to assess and ideally fix the wiring/controller as I don't know how to myself.
No idea where to go with it now, trying to source somebody near North Dublin to assess and ideally fix the wiring/controller as I don't know how to myself.
WIth diy ebikes one has to learn how to test and fault find, most technicians are only ale to say what is wrong by a computer.
You will have to remind us again as I'm not going to read the whole thread again is it a kt controller and lcd ?
You will have to remind us again as I'm not going to read the whole thread again is it a kt controller and lcd ?
Attached is a photo of the setup the seller put together.
He recommends I buy a new controller with similar specs and try to replace it myself.
He recommends I buy a new controller with similar specs and try to replace it myself.
