ADVICE/ADVICE - Think my battery has Finally died !!!

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Hi All

I've been using my brothers 'cheapy' Chinese 48v(10/11Ah) bike for the last few months. Apart from having zero brakes and a rust bucket it's been fine !!!

I put it on charge last night and it was still still dead/flat ?

I do not have a Multimeter handy atm (all out on jobs) BUT i just tried a 36v charger (got a load of them from BMSBATTERY when i did a self build) and it showed RED led for power, then once i plugged it into the battery it showed GREEN led/fully charged (not another red LED as charging)....

This is the same for 48v Charger, shows GREEN/Fully Charged ?

It's Cyclocity branded/lockable battery..(Pics Attached/no key atm so could not access the contacts).

What is my CHEAPEST option to replace the battery ?
 

Attachments

flecc

Member
Oct 25, 2006
53,260
30,648
Yes, a sudden failure of this type is most often just a blown fuse or open connection.
.
 
  • Like
Reactions: bilabonic

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Yes, a sudden failure of this type is most often just a blown fuse or open connection.
.
Yea, i'm not fussed on the fixed connection as well, the NEG term lokks burnt/barely attached tbh..

Not sure what inner diameter the + is ? I can measure the outer with a Micrometer.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
2,214
562
78
Hi All

I've been using my brothers 'cheapy' Chinese 48v(10/11Ah) bike for the last few months. Apart from having zero brakes and a rust bucket it's been fine !!!

I put it on charge last night and it was still still dead/flat ?

I do not have a Multimeter handy atm (all out on jobs) BUT i just tried a 36v charger (got a load of them from BMSBATTERY when i did a self build) and it showed RED led for power, then once i plugged it into the battery it showed GREEN led/fully charged (not another red LED as charging)....

This is the same for 48v Charger, shows GREEN/Fully Charged ?

It's Cyclocity branded/lockable battery..(Pics Attached/no key atm so could not access the contacts).

What is my CHEAPEST option to replace the battery ?
Check if an internal fuse is blown. Replace if yes.
Check battery voltage with a meter, There is a minimum allowed, when below this, the charger will not charge! I only know that this is 28 volts for a 36 volt battery pack.
For a 48 volt it will be around 38 volts, guessing only.
To recover such a "state" will usually need a zero volt charger.
I do have some other "ideas" but they need someone technically top to try out......
regards
Andy
 
  • Like
Reactions: bilabonic

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Hi Andy,

It is STILL working in pulses, so i don;t think it has passed the min allowed..Just need the key to take it off/open it..

What size/shape are these fuses, probably stupid current rating atsuch a low voltage !! I have packs of 20mm quick/slow blows from 100mA to 80A...

When i open it will i be greeted with a load of 1850's !!

Thanks for the reply..

p.s. I have had to resort a the Khallkoff..HATE the overpriced thing !!
 

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Managed to borrow a 'meter' of sorts...

The main 30A fuse is OK (this is a an old car style shape) and is accessible easily via removing a grommet/seal on the battery case.

The battery is measuring 37.6v on the output side (2 connections that plug into the base).

The 36v gives out 42v as expected.

The 48v just makes the meter 'flash'...NO READING at all ??

Also when i plug the in the 36v charger and measure the output of the battery remains the same, 37.6v. The charger also displays a RED led (POWER ON) and a GREEN led (Fully Charged) ?

I only use fluke meters BUT the one i borrowed is giving these readings and i am 99.999% the 48v charger is faulty.

BUT why does not the 36v/42v charger work at all or alter the battery voltage when plugged in ?

Is the BMS stopping it to charge/alter voltage ??

Cheers
 

wheeliepete

Esteemed Pedelecer
Feb 28, 2016
2,047
757
61
Devon
The charger voltage is not reaching the battery pack for some reason, hence no change in the output voltage. Poss. faulty BMS or broken/loose wire somewhere in pack. There could be a charging fuse in the pack, but unlikely. If you are seeing 37.6v at output, then you may well have some faulty cells and suffering voltage sag under load, as the bike should still run OK at that voltage. How was the battery performing before this?
 

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
The battery has been fine, this seems to have only happened when i plugged in the 48v when slightly wet and had the 'surge'...

Surely getting a new 48v charger is a must to begin with as it has NO output.

Bike will still run in short pulses and show completely dead on the LCD display.
 

Ajax

Esteemed Pedelecer
Feb 2, 2008
316
31
The charger voltage is not reaching the battery pack for some reason, hence no change in the output voltage. Poss. faulty BMS or broken/loose wire somewhere in pack. There could be a charging fuse in the pack, but unlikely. If you are seeing 37.6v at output, then you may well have some faulty cells and suffering voltage sag under load, as the bike should still run OK at that voltage. How was the battery performing before this?
If the poster is trying to use a 36v Charger on a 48v battery, then it will not work.

The 36v charger is designed not to over-charge and so it should stop charging once 37v is reached.

The 48v battery will also have a low voltage setting to prevent damage to the battery. This means once the voltage falls below a certain value [39v ?] it will cut out to save the battery.

The poster really needs a 48v charger.

(Also you should not Charge a 36v battery with a 48v charger. Don't even think about doing this.)

As an extra thought, there really should be a special thread at the start of this forum on 'e-bike safety' with a special mention for 'Li-Ion batteries'.
 
Last edited:

Ajax

Esteemed Pedelecer
Feb 2, 2008
316
31
Hi All

I've been using my brothers 'cheapy' Chinese 48v(10/11Ah) bike for the last few months. Apart from having zero brakes and a rust bucket it's been fine !!!

I put it on charge last night and it was still still dead/flat ?

I do not have a Multimeter handy atm (all out on jobs) BUT i just tried a 36v charger (got a load of them from BMSBATTERY when i did a self build) and it showed RED led for power, then once i plugged it into the battery it showed GREEN led/fully charged (not another red LED as charging)....

This is the same for 48v Charger, shows GREEN/Fully Charged ?

It's Cyclocity branded/lockable battery..(Pics Attached/no key atm so could not access the contacts).

What is my CHEAPEST option to replace the battery ?

Cheapest option would be a new 48v Charger.

I was also thinking of changing the controller to 36v, but the battery's onboard bms would still act on the Battery's 'Cut off voltage' (39v - 36V)
 

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Yea, i've ordered a new charger.

Just had to use my Kalkhoff Endeavour, nearly had a heart attack !

Think it will be going up for sale as i NEVER use it and t's a great bike...

Nice to have decent brakes as well, nearly went over the handlebars..lol

https://www.cyclotricity.com/uk/no-charge-green-light

Looks like there is also an input fuse in the battery/BMS as well that causes NO CHARGE state as i have, highly unlikely though....

Can seem to find a battery though ? Just in case it is faulty/dead..
 

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Opened the charger and could smell the 'burn' straight away, plus the input 3.15 fast blow 20mm fuse is OK.
 

bilabonic

Esteemed Pedelecer
Feb 20, 2013
294
6
Had new charger, plugged in STILL just a Green LED...Replaced the charging plug (in case inner/outer was differing size). STILL Green LED.

Next step is top open the battery tomorrow and see if the input fuse has blown on BMS/INPUT side !!!

It's NOT looking good TBH...

Anyone repair these batteries or now of where to get a cheap replacement (48/11-12aH)..

Cyclocity are NOT replying to me ?

Thanks guys.
 

soundwave

Esteemed Pedelecer
May 23, 2015
16,998
6,536
  • Like
Reactions: bilabonic