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

[Nealh]

When soldering the sense wires together, you must check the original wires connected to the battery to ensure the voltage of each one is correct to start with otherwise a misplaced wire can bugger the BMS. Once the order is confirmed just jot it down so no mistakes are made.
On the new BMS, the board should be marked with a small B- & B13+ either end of the jst connection to indicate order of wires and most likely likewise on the old one they can be on the face or reverse side.

 

[Andy-Mat]

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

The 48 volt battery is below the level that allows charging. It needs a special charger that starts "Low & Slow". I have no idea where you will find one for 48 volts.
For 36 volts, Stark sells one from Sweden for US$95 plus postage.
https://starkdrive.bike/accessories/
But it will not work on a 48 volt battery.
I know that it does a good job on 36 volt batteries and brings them up to 42 volts, just as it should! But yours is still almost 10 volts above the level at which a 36 volt charger will charge normally....
This "not charging" is a safety feature to prevent fires and explosions....The batteries need a lower voltage, lower current charger to start to recover.....
If you know an electronics engineer, with a laboratory power supply, I might be able to help him to help you, but it could be dangerous...I have never tried it myself as the battery I had was fully recovered by the special charger....

Regards
Andy

 

[Steve Dyson]

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 ?

Best option is to get into the battery and see what its made from and test each cell bank to find which are at zero volts or most likely .7v

I build my own batteries and balance each bank up individually every 3-4 weeks...

 

[Andy-Mat]

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.

What voltage do you measure at the output plug? If 3 pins, make sure you identify the + and -.. I am unaware of what the 3rd pin does as I have only ever had 2 pin charger cables on both my e-bikes!
This may prove useful to some people here:-
https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
My two pin 36 v charger has exactly 42 volts showing at the charging plug (no battery connected!) when plugged in to the mains.
regards
Andy

 

[Andy-Mat]

Same as before 54.7v in/48.7v out.

Charger LED constant GREEN even when unplugged (it only has one LED view hole BUT surely there is a RED led which should be on when disconnected/not fully charged ??

The battery has charged overnight with a constant green LED....

I also remember my old 36v battery would show 42/43v when fully charged..

The single LEDs are usually dual, with a red and a green function, and with a bit of trickery, orange when both are lit!!
regards
Andy

 

[Andy-Mat]

Should buy being correct, i've just had new boiler fitted on Monday..lol

The old one was 9Ah looking at it, which was fine as i do short trips...I Always stick it on charge everytime as well as the battery monitoring is rubbish..

I am amazed the faulty battery had Samsung Cells !!

It was a crappy/cheap Chinese bike (even though it is STILL better than my Khalkhoff..

The quickest way I know to destroy a Li-ion battery, other than an Axe, is to charge it every time you use it.
On my last bike, I gave it away at 7 years old and the battery was fine. Only charged when empty. If that is a problem, always buy two batteries....
The mother of a friend managed to ruin her battery in 12 months....exactly the same battery!! New on the same day as mine....She ruined the replacement the same way some time later....expensive batteries! Charged each time she used it!!
regards
Andy

 

[bilabonic]

Like this mate ? I am confused about the 14 JST plug, It does have BC0 and BC13 each end as in pic...I thought i could just plug that in as it fits fine ?

Cheers

 

[bilabonic]

Best option is to get into the battery and see what its made from and test each cell bank to find which are at zero volts or most likely .7v

I build my own batteries and balance each bank up individually every 3-4 weeks...

I have measured each 13s and put the readings earlier mate, they all look OK...Also i understand when i drops below a certain voltage and charging each time is no good due to the number of cycles.

 

[bilabonic]

When soldering the sense wires together, you must check the original wires connected to the battery to ensure the voltage of each one is correct to start with otherwise a misplaced wire can bugger the BMS. Once the order is confirmed just jot it down so no mistakes are made.
On the new BMS, the board should be marked with a small B- & B13+ either end of the jst connection to indicate order of wires and most likely likewise on the old one they can be on the face or reverse side.

Like this mate ? I am confused about the 14 JST plug, the existing BMS does have BC0 and BC13 each end as in pic...I thought i could just plug that in as it fits fine ? BUT the new BMS has B- and B+ either end of the JST.....At opposing ends though ? ( B- is at BC13 end and B+ is at B+ end) Surely they are ALL the same/standardised ??

I done the order of EVERY connection/voltage in a previous post, looks like it is reserved then !!!

I will BIN the LOT if it is !!!....lol

Cheers

 

[wheeliepete]

Afraid there is no "standard" .It does sound like the new BMS is reversed, It's a bit confusing because some call pin 1 B- and others B0, and some BMS's don't have that connection at all. There's no easy way to rectify this, you have some soldering to do

 

[bilabonic]

Afraid there is no "standard" .It does sound like the new BMS is reversed, It's a bit confusing because some call pin 1 B- and others B0, and some BMS's don't have that connection at all. There's no easy way to rectify this, you have some soldering to do

Oh better dig some heatshrink out then !!!

Unless i can 'butcher' the plug/socket so it connects in reverse...lol

I BET after ALL this it still will not work...lol

 

[wheeliepete]

I BET after ALL this it still will not work...lol

Yep, that's always possible, but think of the FUN you've had!!

 

[bilabonic]

Well after digging out an ANCIENT 60w iron with hardly tip and a 50cm lead, an old reel of dirty solder with hardly any rosin in it, i botched it on for know, i just plugged charger in and the fan has started and RED led is on !!!

I will plug it on bike tom and and test.......

Cheers guys

 

[wheeliepete]

Nice one, looks promising. I knew you could do it, have more faith in your bodgery.

 

[Nealh]

Yes as mentioned if bms has one extra pin then series connections, then the pins outs can be B0 to B13 or B- & B1 to B13 really depends on the maker.

Any how sounds like you have it sorted out for now, when there is an extra wire I always call pin #1 B- as this always connects to B- , but as you have sussed B0 = B-.

 

[bilabonic]

Yes as mentioned if bms has one extra pin then series connections, then the pins outs can be B0 to B13 or B- & B1 to B13 really depends on the maker.

Any how sounds like you have it sorted out for now, when there is an extra wire I always call pin #1 B- as this always connects to B- , but as you have sussed B0 = B-.

Yes i metered the the balance - and main battery -, there were plenty of schematics on Ebay when i was looking at the BMS's...

When i removed the old BMS the board had a blown component as well with would make sense, it had blackened the white double sided tape, looked like an SMD Cap....

I live in hope...lol

Cheers

 

[Steve Dyson]

Yes i metered the the balance - and main battery -, there were plenty of schematics on Ebay when i was looking at the BMS's...

When i removed the old BMS the board had a blown component as well with would make sense, it had blackened the white double sided tape, looked like an SMD Cap....

I live in hope...lol

Cheers

Glad you sorted it, are you all back up and running now?

 

[bilabonic]

Glad you sorted it, are you all back up and running now?

Yes all up and running with no problems at all.

 

[Nealh]

A good outcome Bilabonic, problem with fault finding is it can be time consuming and frustrating.
With unusual voltage readings I have a set order of faulting.

1. Check charger output with a meter if reading strange I try another meter or new battery source.
2. Charge fuse if fitted.
3. Next check is the cell volatge/balance via the jst connector.
4. Check wirig for continuity.
5. Last but not least if all above fails suspect a component failure oo the bms. Following removal inspection by eye glass can pick up a small damged item.