When you plug these chargers in there is a sequence of events.

Plug into the mains, then into the battery. There is a rocker switch on the charger to turn on. A red and a green led come on, there is a pause then the green led goes yellow and the fan starts up - I assume that's when charging starts. Yellow led goes green on completion, though it's difficult to tell and I normmally wait for the fan to stop - presumably when the charger has cooled down.

Does this help Neal?

 

Oh and they are a 4A charger.

 

I think the 36.8v was the battery charge socket pins - no charger connected. It was a lower voltage than the battery output terminals.

I've just measured my charger at the output pins and got 41.7v. With the same meter I measure 41.5/6 fully charged battery, the OP's charger was readin 42.3v if memory serves, so 0.5v higher - could that upset the bms and stop it accepting charge?

the OP's charger was readin 42.3v if memory serves, so 0.5v higher - could that upset the bms and stop it accepting charge?

 

If the bms has a definite 42v max and doesn't allow for over charge then yes it would prevent charging that is why the trim pot was mentioned, Nigel needs to adjust the trim pot down to see if it works.

I've posted on a couple of forums to see if I can find someone local with a charger I could borrow for a couple of minutes, but no luck so far, which is understandable since borrowing a charger is not yet on the approved list of reasons to leave home..

 

Would it be a fair conclusion that the problem most probably lies with either the charger or the BMS?

When you plug these chargers in there is a sequence of events.

Plug into the mains, then into the battery. There is a rocker switch on the charger to turn on. A red and a green led come on, there is a pause then the green led goes yellow and the fan starts up - I assume that's when charging starts. Yellow led goes green on completion, though it's difficult to tell and I normmally wait for the fan to stop - presumably when the charger has cooled down.

Does this help Neal?

 

Yes, that';s the sequence I've always employed, but the yellow light doesn't come on any more

 

Oh and they are a 4A charger.

 

I think the 36.8v was the battery charge socket pins - no charger connected. It was a lower voltage than the battery output terminals.

 

Yes, that's right, except that the yellow light and fan no longer kick in, but I've always used the same sequence you suggest.

Edited May 12, 20205 yr by Pink Nigel Dean

I still need to know which pot to adjust to what, but who is Nigel?

 

Elaine

 

If the bms has a definite 42v max and doesn't allow for over charge then yes it would prevent charging that is why the trim pot was mentioned, Nigel needs to adjust the trim pot down to see if it works.

I still need to know which pot to adjust to what, but who is Nigel?

 

You are it says so in your name, Pink I'm sure isn't your first name so it must be Nigel Dean.

 

The bot pot UR1 first note the how much you turn the pot and see if it tones the voltage down if not turn it back.

Edited May 12, 20205 yr by Nealh

Just noticed in an earlier post you aren't a Niggle but an Elaine, I can understand the pink but not ND.

Just noticed in an earlier post you aren't a Niggle but an Elaine, I can understand the pink but not ND.

 

Here you go, my pride and joy....

 

It's a classic 1990's Reynolds 531 road bike, which still fools most of the boy racers nowadays, which is why I'm so fond of it and so keen to get it back on the road.

 

 

Thanks for the sensible pot turning advice, what voltage would you take it down to?

Now I understand Elaine.

 

For balancing all the time 41.8 - 42v though I have set two of mine to 41v for better cell cycle life, hopefully once you trim the voltage down the BMS will paly ball.

Now I understand Elaine.

 

For balancing all the time 41.8 - 42v though I have set two of mine to 41v for better cell cycle life, hopefully once you trim the voltage down the BMS will paly ball.

 

You were right, it was the bottom pot, but I turned it down to 41.7v and the charger still refuses to play.

Nice VERY pink bike, kit is exactly the same as mine. I think they are not common as they aren't the cheapest by any stretch, but they last don't they?

Being not common is probably why you can't find a charger to borrow.

At the end of the day, if this charger can't be got going, then an alternative can be sourced, once pin polarity has been checked.

 

On another note, I see your motor cable exits the axle directly upwards. It would be best if you found a bit of slack to form a drip loop, so the cable exits the motor downwards then turns up. Helps to keep rain and condensation out of the precious motor.

When the charger normally starts up there's the click of a relay coming in. Might be worth giving it a nudge/sharp tap on the side just to see if it achieves anything.

Nice VERY pink bike, kit is exactly the same as mine. I think they are not common as they aren't the cheapest by any stretch, but they last don't they?

Being not common is probably why you can't find a charger to borrow.

At the end of the day, if this charger can't be got going, then an alternative can be sourced, once pin polarity has been checked.

 

On another note, I see your motor cable exits the axle directly upwards. It would be best if you found a bit of slack to form a drip loop, so the cable exits the motor downwards then turns up. Helps to keep rain and condensation out of the precious motor.

 

You obviously have excellent taste. This one has lasted since 2012 albeit with a replacement LED display and controller. Thanks for the tip, but it isn't going out in the rain, in fact right now it isn't going anywhere..

 

The relay still clicks, as usual, but normally that precedes the yellow light and the fan, which aren't following now.

 

This morning I wired the charger up to an incandescent bulb to simulate a load. It lit the bulb dimly, and entered a repeating cycle of relay click, bulb on, relay click, bulb off, but at no point did it turn on the yellow light or the fan.

 

Presumably the issue could still be either the charger or the BMS, and another charger is probably the best way of working out which.

Thank you both for all your help so far, which is much appreciated, but I need to decide on the best way forward from here.

 

Would you agree that the fault most probably lies with either the charger or the BMS, and that the result of the bulb test points a finger towards the charger?

 

That being so it might be worth buying a new charger, since I've failed completely on borrowing one, but do I need an expensive 4A unit or would a much cheaper 2A charger do the job, albeit slower?

 

Your opinions would be much appreciated.

2a charge input is kinder to the cells then 4a, all my chargers are 2a and I have a few.

So long as the voltage and pin configuration are the same the a 2A would be fine.

I got one for another battery that seems good quality and has a cooling fan. It's a YZPOWER-42 2Amp.

Haven't been able to find it again otherwise I'd link it for you.

Any charger for 36v li ion with an XLR connector will do it.

 

Can't think of any other way to check the bms, so I guess it's suck it and see.

It's much kinder to the wallet too, so this is welcome news thanks Nealh..

 

2a charge input is kinder to the cells then 4a, all my chargers are 2a and I have a few.

Thanks Benjahmin - I also had a look to see if i could modify my cable run as you suggest, but it isn't long enough, and only just reaches the battery as it is.

 

 

 

 

So long as the voltage and pin configuration are the same the a 2A would be fine.

I got one for another battery that seems good quality and has a cooling fan. It's a YZPOWER-42 2Amp.

Haven't been able to find it again otherwise I'd link it for you.

Any charger for 36v li ion with an XLR connector will do it.

 

Can't think of any other way to check the bms, so I guess it's suck it and see.

My 2A charger arrived today, and I was hoping to be posting to say that all was well and the bike was charging again, but alas no. I checked the polarity and output of the new charger, plugged it in, and it sat there shining its annoying green light at me just like my original charger.

 

Is there anything else it could be, other than the BMS, since the cells appear well-balanced? The fact that I measured a voltage at both the battery output lead and the battery charging port with the charger disconnected clearly shows that the cells are in contact with the charging port, so it can only be the BMS itself refusing to accept the charge can't it, or is there some other possibility?

Ah bummer! I don't know how or if you can test a bms or how to replace. Let's hope Neal comes along.

Ah bummer! I don't know how or if you can test a bms or how to replace. Let's hope Neal comes along.

I know, I'd convinced myself that the cheap charger was going to save the day, but I need some idea of where the problem actually lies before I start investing in battery resurrection. Let's hope Nealh can help...

 

I believe a BMS can be replaced, but with an 8 year old battery it might not be easy to find one.

Testing a BMS afaics is impossible.

If it works it works, all I can think is something is a miss then on the input side of the BMS or there is an issue with charge port or charge wiring to the BMS.

 

For your battery you can use any BMS 10s /36v BMS currently available it doesn't have to be the same model.

Thanks Nealh, but is there anything else it could be now, apart from the BMS?

Well, let's review.

You have battery voltage (or nearly) appearing on the charge socket pins. So no broken connection there.

The cells are well balanced, no low group to stop charge, also no apparent broken connection.

The charge fuse was OK.

From Neal's last post the only other thing I can suggest is a really close examination of charge side wiring and soldered joints. Do continuity tests, say from charge pin to soldered connection on bms. Do any appear resistive?

What happens if you wiggle said wires and connections?

Examine the tracks on the circuit board, do any look lifted?

It's clutching at straws but worth a go.

Otherwise probably good to get a good close up picture of the bms and perhaps Neal will be able to steer you to a replacement.