Bike cutting out when battery on 3 bars

miwklrini

Just Joined
Jan 5, 2022
2
0
I bought this custom made bike 2 days ago
https://www.adverts.ie/other-sports-...nches/25432673

Was close to fully charged, worked well day 1.
Charged for a few hours and today after about 8km it cut out, just after a stop at a shop.

The battery was showing 3 of 4 bars but the voltage started dropping quickly towards zero, it said something like controller/motor error (I can’t exactly remember) and shut itself off.

I stopped, slipped the battery out and back in and the screen would work again, showing 3 of 4 bars. It worked for less than a minute before the screen shutting off again (no error message from here on, just shut straight off).

Repeated this multiple times – it would shut off once the output reached roughly 700w each time.
No noticeable damage to any cables and it has not been exposed to water since I got it.

Charged it fully and no issue on first test - although I expect the same once i drain 20% or so of the battery.
The seller seems genuine, isn't ducking any questions now but can't troubleshoot it.

Can anybody help me?
Feeling pretty down after my new purchase :(

Advanced settings are: applinked
Lim: 72kmh, DIM 29inches, UNT:0, P1-46, P2-0, P3-0, P4-0, P5-15, C1-2, C2-0, C3-5, C4-0, C5-10, C6-1, C7-1, C8-0, C9-0, C10-N, C11-0, C12-2, C13-5, C14-3, L1-0, L2-0, L3-1, L4-5.
What voltage is the battery? Make sure all three components match. Thirdly display maybe set up wrong, you can change the settings for different voltage packs, google your displays user manual on how to change it and what to.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
I paid to have the battery rebalanced and it's been fine since then.

New issue today, the controller screen keeps turning off, either immediately, or if not as soon as I turn the throttle.

Anything I can do myself to troubleshoot it?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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If the screen switches off immediately then a connection issue, a faulty voltage regulator in the controller or a dodgy wire connection in the display. A short in nay 1t4 trunk cable.

The power failing once the throttle is used is a short possibly or maybe back to a battery issue. Having had the previous battery faults I would be inclined to first check the balance again.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
Fully charged battery gives a multimeter reading of 54.8V.

Bike will run again now, but what caused this?

I'm worried it will break down when I'm far from home

Edit: just got through a 13km cycle with no issues, still no idea why it failed earlier though.
 
Last edited:

bikemerchant

Pedelecer
Dec 17, 2021
69
2
Broke down again today when fully charged. First time I turned the throttle the screen shut off, then it would either immediately shut off when I turned it on or shut off once I applied the throttle.

I noticed the screen gave a battery voltage reading of 51V or so after failure, so I got the multimeter to it which gave a reading of 55.1V (higher than I've ever seen before!) then when I popped the battery back in the screen gave a reading of 54.3V, and the bike worked fine for my short 3km journey.

Any guesses as to what the fault is?
The seller of the battery responded to my earlier issue saying he can ship replacement cells for the faulty row - although by this stage I had already payed for the battery to be rebalanced.
The guy who balanced my cells said the cells were fake cells wrapped in Samsung wrapper, and the only way to solve the problem permanently is to repair all the cells.
 

cyclebuddy

Esteemed Pedelecer
Nov 2, 2016
1,639
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Beds & Norfolk
Any guesses as to what the fault is?
In my opinion, it's a combination of mediocre battery cells and how you're using your bike. Lower quality cells can't take as much abuse as premium cells. Neither like the high current demand placed upon them when using a throttle, especially from a standing start or "cruising" (i.e. relying entirely on the motor to provide all the power). Low quality cells get destroyed quite quickly when used in this way; high quality cells fair better, but aren't entirely unscathed by the experience.

IMHO mediocre cells are fine and can live a long time if treated with respect (i.e. not placing high current demand upon them).
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
1,855
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Broke down again today when fully charged. First time I turned the throttle the screen shut off, then it would either immediately shut off when I turned it on or shut off once I applied the throttle.

I noticed the screen gave a battery voltage reading of 51V or so after failure, so I got the multimeter to it which gave a reading of 55.1V (higher than I've ever seen before!) then when I popped the battery back in the screen gave a reading of 54.3V, and the bike worked fine for my short 3km journey.

Any guesses as to what the fault is?
The seller of the battery responded to my earlier issue saying he can ship replacement cells for the faulty row - although by this stage I had already payed for the battery to be rebalanced.
The guy who balanced my cells said the cells were fake cells wrapped in Samsung wrapper, and the only way to solve the problem permanently is to repair all the cells.
The trouble is you can't see in real time what is happening in detail in the battery, and the battery's history makes it prime suspect.

Either there is a bad connection somewhere, and the battery is innocent, or its the battery!

My approach, which is only suitable for inveterate fiddlers with time on their hands and experience of building little data loggers, would be a data logger measuring not just whole battery voltage but at some of the cell groups also, to see what is happening. Then follow the data.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
So should I keep taking multimeter readings of each cell group at different stages (when fully charged, when just failed etc) and post them here?
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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So should I keep taking multimeter readings of each cell group at different stages (when fully charged, when just failed etc) and post them here?
If you can get access to the connections to do that then the info will help.

What is even more useful is a voltmeter you can see when riding. If you had two ,one showing full pack voltage, and the other measuring voltage across one or more cell groups of interest, then it is possible to see if that part of the pack is sagging more that the average per cell group.

By moving the voltmeter around, you get an idea of whether it is all nice and even, or there is a problem somewhere in the pack.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
Would the voltmeter suggestion require some wiring on my behalf?

Also, the original battery seller responded to the original complaint (battery is still in warranty) saying he will replace the faulty group of cells if I can get somebody to replace them for me.
Unsure if I should accept this or push for more?
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Would the voltmeter suggestion require some wiring on my behalf?
Yes.

Also, the original battery seller responded to the original complaint (battery is still in warranty) saying he will replace the faulty group of cells if I can get somebody to replace them for me.
Unsure if I should accept this or push for more?
Simply replacing any faulty cells isn't a job any one can do and certainly won't be for free, in fact it is harder then starting from scratch.
 

matthewslack

Esteemed Pedelecer
Nov 26, 2021
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Would the voltmeter suggestion require some wiring on my behalf?

Also, the original battery seller responded to the original complaint (battery is still in warranty) saying he will replace the faulty group of cells if I can get somebody to replace them for me.
Unsure if I should accept this or push for more?
If the supplier is accepting there is an issue, and that warranty covers it, then you should expect a new battery from them, so follow that line to the end I would say.

A replacement will likely be of the same quality, which may not be adequate for the high current demands of your motor - which is not the battery supplier's problem, unless it is sold claiming a current capability that it does not deliver.

So ideally, you get a new battery, turn down the settings in your controller to limit max current, and ride happily ever after...
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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I agree accepting a repair on a diy basis/find your own expert is not acceptable.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
Thanks very much!
#11 is the big discrepancy at 3.61V
#10 is 4.15V and all the rest are 4.16V

#1 4.16V
#2 4.16V
#3 4.16V
#4 4.16V
#5 4.16V
#6 4.16V
#7 4.16V
#8 4.16V
#9 4.16V
#10 4.15V
#11 3.61V
#12 4.16V
#13 4.16V
Just did this test again and #11 is the weak group again - it measured 4.08V while the rest all measured 4.14V.

The total amount measures 53.8V - but it's not freshly charged - it failed from a fresh charge a few days ago and has been sitting idle since then.
Should I charge it fully and retest, or run it down more and retest?

The guy who fixed the battery for me last month has ignored 4 messages in a row now.
The seller of the bike is in touch but is essentially advising I buy a new battery.
The battery itself was sold to him by another seller on Aliexpress.

Thanks for all the help, would me more lost than I already am without all of you.
 

Nealh

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Aug 7, 2014
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Being that one paid to have it balanced, then there is an issue with the battery. Either you have a bad cell in the group or the BMS is at fault and possibly a bleed resistor isn't closing correctly and drains it down more.
The cell group can't be checked whilst all are connected in parallel, one would have to remove one of the P strips to do so, like wise it isn't possible to test the BMS so one would have to replace it in the hope it is faulty.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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The total amount measures 53.8V - but it's not freshly charged - it failed from a fresh charge a few days ago and has been sitting idle since then.
When you say 'it failed from a fresh charge', can you clarify what it said in that context.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
When you say 'it failed from a fresh charge', can you clarify what it said in that context.
It had been fully charged and I had just unplugged the charger from the battery.
Used the throttle, got about 50m up the street and it cut out.
Failed a few times immediately afterwards so i walked it home.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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Can you wire up a meter to watch what happens to the voltage ?
One can do a static test at home or if needing to put a current load on gently apply the brake as well.

When I had the oxydrive kit I had similar put on a fresh battery fully charged and cut out straight away then wouldn't work, switched to other battery which worked before and same issue. When I got home I did some testing and the controller was only out putting 20 odd V's from battery well above 34v, so the voltage regulator must have failed. I wire up a new controller and all was ticketyboo again.
 

bikemerchant

Pedelecer
Dec 17, 2021
69
2
Being that one paid to have it balanced, then there is an issue with the battery. Either you have a bad cell in the group or the BMS is at fault and possibly a bleed resistor isn't closing correctly and drains it down more.
The cell group can't be checked whilst all are connected in parallel, one would have to remove one of the P strips to do so, like wise it isn't possible to test the BMS so one would have to replace it in the hope it is faulty.
So essentially the balancing was only a temporary fix and the same series being the issue again suggests either BMS/bleed resistor/bad cell issue?

Can you wire up a meter to watch what happens to the voltage ?
One can do a static test at home or if needing to put a current load on gently apply the brake as well.

When I had the oxydrive kit I had similar put on a fresh battery fully charged and cut out straight away then wouldn't work, switched to other battery which worked before and same issue. When I got home I did some testing and the controller was only out putting 20 odd V's from battery well above 34v, so the voltage regulator must have failed. I wire up a new controller and all was ticketyboo again.
I haven't done any wiring with the bike - do I need much equipment for it, and a new type of meter?
Is it quite advanced?
It would be nice if there was an easy way to test the controller and it was a cheap fix, but seeing as the same battery series is still lower than the rest it indicates it's a battery issue and not controller?
 

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