Battery problem

gray198

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out yesterday on Oxygen bike. Suddenly battery went dead although there was plenty of charge in it. Fortunately not far from home. Battery taken off bike and re charged. Put back on and all well. One thing I did notice was that , on top of battery is a button to indicate power in battery This was not working. I wonder if the battery has developed a fault or could it be a problem with the mounting.
 
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Andy-Mat

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Do you have a meter and know how to use it? If yes, tell us the voltage on the fully charged battery please.
This is not a 100% check, but it's a start and might lead us further on to the problem, and you have got to start somewhere!
regards
Andy
 

gray198

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I do have a meter. Not sure how to use it. Will give it a try and post results

thanks gray
 

Andy-Mat

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I do have a meter. Not sure how to use it. Will give it a try and post results

thanks gray
Insulate the lead tips with insulation tape so that only the last millimeter of the metal tip is visible, as it is easy to create a dangerous short circuit.
Make sure that the leads are in the correct holes on the meter.
Ask us any question first.
No questions are stupid, but sometimes the anyser is!!
regards
Andy
 

gray198

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spoke to Oxygen about this. Very helpful and has said he will check it out for me if I take it to depot at Rotherham. Thats a bit of a distance for me, but may try and get up there next week
 

gray198

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Having a problem with this battery again. Cannot charge it. Charger goes straight to green as if fully charged. Noticed when I turned it on it came up with BMS error, but could not see any code and it didn't stay on long enough to check it. I don't think it's the charger that's faulty but don't know how to check. Any advice much appreciated
 

Bikes4two

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I'm suspecting a BMS problem for several reasons:
  1. In first post you said battery had died but showing plenty of charge. I'm guessing you mean the motor assist stopped rather than the battery died?
  2. Then the charger led staying green. It normally goes green (from red) to show charging is complete and the circuitry determines this because the battery is no longer taking charging current (a function of the BMS) from the charger.
  3. If the charger led is not going to red as expected but staying on green, then the BMS isn't 'switching on' to allow charging
  4. And the you had the BMS fault message.
When the problem is resolved, please feed back so we all learn from this - thanks.
 

gray198

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Apr 4, 2012
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I'm suspecting a BMS problem for several reasons:
  1. In first post you said battery had died but showing plenty of charge. I'm guessing you mean the motor assist stopped rather than the battery died?
  2. Then the charger led staying green. It normally goes green (from red) to show charging is complete and the circuitry determines this because the battery is no longer taking charging current (a function of the BMS) from the charger.
  3. If the charger led is not going to red as expected but staying on green, then the BMS isn't 'switching on' to allow charging
  4. And the you had the BMS fault message.
When the problem is resolved, please feed back so we all learn from this - thanks.
Yes you have summed it up right. I have also had instances where battery will not turn on as if there is a bad connection, and I suspect that is what happened in the first instance. I have contacted Oxygen about this and will post any info I get regarding it

gray
 

Manchester lad

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Mar 6, 2019
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Yes you have summed it up right. I have also had instances where battery will not turn on as if there is a bad connection, and I suspect that is what happened in the first instance. I have contacted Oxygen about this and will post any info I get regarding it

gray
I have an Oxygen emtb which is now coming up for 10 years old. The switch on my battery started to play up a few years ago. It wouldn’t switch on sometimes and then occasionally it would switch itself off. I pulled the rubber covering back and sprayed in some contact cleaner. I worked the switch a few times which sorted it out.
On my battery I have to have it switched on when charging otherwise the light on the charger stays green. Hope this helps.
 
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gray198

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I have an Oxygen emtb which is now coming up for 10 years old. The switch on my battery started to play up a few years ago. It wouldn’t switch on sometimes and then occasionally it would switch itself off. I pulled the rubber covering back and sprayed in some contact cleaner. I worked the switch a few times which sorted it out.
On my battery I have to have it switched on when charging otherwise the light on the charger stays green. Hope this helps.
Thanks for response
I have contacted Oxygen and am going to take it in for them to check. Will let you know result

gray
 

gray198

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Been confirmed that BMS is faulty. Awaiting a quote for repair. Is BMS a chip to control battery
 

Nealh

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BMS is a safetyboard to prevent over charge and discharge of the battery .
 
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gray198

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Just had quote to do this £172. Seems a bit high to me. Does that man down London( can't remember his name) still repair batteries
 
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Bikes4two

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As a basic principle, to replace a BMS requires a bit of a strip down to get to the module and then some unsoldering of some cables and usually just unplugging the battery sensing wires.

One would have thought that for the supplier to do this would take an hour's work?

The BMS it's self may be a rather bespoke item at who knows what cost but if I were replacing my BMS on my own battery build, I'd be looking at around £25 plus the cost of ancillary items like shrink wrap.

I'm guessing you are looking at the higher costs associated with off-the-shelf bespoke systems!

Try the trick described above about lubricating the switch first - switches do fail as they are generally cheap, not well engineered items.
 
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