What volts should I be getting and across which wires?

[OxygenJames]

Good morning all,

So I just got one of our bikes out of hibernation - I'd brought the battery inside a couple of weeks ago but it may have been through a couple of very cold nights in the shed before I did so. Now that I am trying to charge it the battery charger is showing a green light which usually means it's fully charged - but I don't believe that.

So I got my multi-metre out - put it on the setting to measure volts - but it seems no matter which of the four terminals (coming out of the battery - see pic) I put the two wires onto - I think I've tried all combinations - nothing.

It should show 36V with one of the combinations right?

My only other thought is that it's so flat it may take a while for the charger's light to go red - and that once it gets some juice into it - it will then go red - and then go green again finally when fully charged. Although it's been on there about 30 minutes and it still shows green but every time I take it off and try some combinations of those four wires I get no voltage showing.

Any thoughts?

Have I got a dud battery or might it come to life if I leave the charger on there some more (even though the light on the charger is showing green?).

Any help/ideas much appreciated. Thanks.

 

[mike killay]

Have you switched the battery on?

 

[OxygenJames]

Have you switched the battery on?

Yup. Did that. Found one broken connection (one of the black wires from the battery to the connector was broken) - so that's soldered back on now. It is now showing 24.4V. On a 36V battery. Green light still on charger when charging. Weird. Will leave it charging for a bit more.

 

[OxygenJames]

Yup. Did that. Found one broken connection (one of the black wires from the battery to the connector was broken) - so that's soldered back on now. It is now showing 24.4V. On a 36V battery. Green light still on charger when charging. Weird. Will leave it charging for a bit more.

And when I connect it up to the bike - nothing. No lights showing the battery has any charge - no movement of the wheel when throttle activated. Me thinks I have a busted battery.

There's another £160 out the window.

 

[Andy-Mat]

Yup. Did that. Found one broken connection (one of the black wires from the battery to the connector was broken) - so that's soldered back on now. It is now showing 24.4V. On a 36V battery. Green light still on charger when charging. Weird. Will leave it charging for a bit more.

That is far too low.
The BMS or the charger (most likely the BMS!), will not allow charging from a normal charger for safety reasons when the battery is too low. You need to keep it around 35 volts during long periods on non usage.
There are special recovery chargers around, but a bit "thin on the ground" apparently. Tll I first mentioned them on Pedelec, nobody here had heard or one.
I cannot guarantee it will recover your battery either, sadly. I do not know what the lower limit is!
The only company I know that sells one is in Sweden, but the connector is wrong, you will need to have a small adapter made to allow it to go on your battery, or make an adapter, with two powerful crocodile clips, and be most careful, making sure that + goes to +, and - to -! Double check!
Its called:- 0V Recovery Charger $95.00

Accessories

When purchasing an accessory from our website shipping is not calculated or added during the checkout process We will manually calculate shipping costs and revert to you with these costs due to changing costs from our shipping partners If you order your accessories with a bike on the same invoice

starkdrive.bike

I had to borrow one when my bike was first delivered, as the delivery took so long, and the battery had gone below the minimum allowed for normal charging. It had my battery working in a trice, and the battery has been perfect ever since.
Your choice what to do!
Andy

 

[OxygenJames]

That is far too low.
The BMS or the charger (most likely the BMS!), will not allow charging from a normal charger for safety reasons when the battery is too low. You need to keep it around 35 volts during long periods on non usage.
There are special recovery chargers around, but a bit "thin on the ground" apparently. Tll I first mentioned them on Pedelec, nobody here had heard or one.
I cannot guarantee it will recover your battery either, sadly. I do not know what the lower limit is!
The only company I know that sells one is in Sweden, but the connector is wrong, you will need to have a small adapter made to allow it to go on your battery, or make an adapter, with two powerful crocodile clips, and be most careful, making sure that + goes to +, and - to -! Double check!
Its called:- 0V Recovery Charger $95.00

Accessories

When purchasing an accessory from our website shipping is not calculated or added during the checkout process We will manually calculate shipping costs and revert to you with these costs due to changing costs from our shipping partners If you order your accessories with a bike on the same invoice

starkdrive.bike

I had to borrow one when my bike was first delivered, as the delivery took so long, and the battery had gone below the minimum allowed for normal charging. It had my battery working in a trice, and the battery has been perfect ever since.
Your choice what to do!
Andy

Thanks Andy - much appreciated.

So I presume that 24v is not enough to power the bike at all yes? I thought maybe it would give me perhaps 2/3 power when connected to the bike - but I get nothing at all. This is to be expected yes? Darn!

As for the special charger idea - thanks but I think I will play safe and shelve out for a new battery - it's my own fault for leaving it in the shed over the winter when I should've had it inside and charged it periodically.

Andy thanks once again for getting back to me with that information.

 

[Nealh]

You probably have a dead cell group with a 24.4v reading, min reading should be 30v - 32v. The BMS will not allow charging. To confirm the fault the battery needs to be opened and ten cell group voltage readings taken to see how bad they are, as it stands the battery is useless so opening up you loose nothing and it's free to check and much cheaper then wasting more money.

 

[OxygenJames]

You probably have a dead cell group with a 24.4v reading, min reading should be 30v - 32v. The BMS will not allow charging. To confirm the fault the battery needs to be opened and ten cell group voltage readings taken to see how bad they are, as it stands the battery is useless so opening up you loose nothing and it's free to check and much cheaper then wasting more money.

Thanks. It does seem suspicious - being exactly one third off full power - so if I open it up (which I will) and find out which bank is not working - can you buy just those cells and replace them?

Any info on what exactly I need to search for - and where I might get them (ebay?) - would be great.

And thanks once more for the reply.

 

[Andy-Mat]

Thanks Andy - much appreciated.

So I presume that 24v is not enough to power the bike at all yes? I thought maybe it would give me perhaps 2/3 power when connected to the bike - but I get nothing at all. This is to be expected yes? Darn!

As for the special charger idea - thanks but I think I will play safe and shelve out for a new battery - it's my own fault for leaving it in the shed over the winter when I should've had it inside and charged it periodically.

Andy thanks once again for getting back to me with that information.

Just for your own information, a nominal 36 volt battery is fully charged when it is around 42 volts. And fully discharged at around 30 volts. The battery only "works" when between these two voltages.

Thanks. It does seem suspicious - being exactly one third off full power - so if I open it up (which I will) and find out which bank is not working - can you buy just those cells and replace them?

Any info on what exactly I need to search for - and where I might get them (ebay?) - would be great.

And thanks once more for the reply.

You cannot do what you are thinking about. All the cells in a battery must be of one type, all manufactured by the same company, manufactured possibly on the same day, then they go through stringent tests to make sure they are as near as possible to being iden

Thanks. It does seem suspicious - being exactly one third off full power - so if I open it up (which I will) and find out which bank is not working - can you buy just those cells and replace them?

Any info on what exactly I need to search for - and where I might get them (ebay?) - would be great.

And thanks once more for the reply.

You cannot do what you are thinking about. All the cells in a battery must be of one type, all manufactured by the same company, manufactured possibly on the same day, then they go through stringent tests to make sure they are as near as possible to all being identical in all respects.
It is not as simple as many wish for, and really should be in a safe society.
Furthermore, these batteries, if you do not 100% know what you are doing, can be exceeding dangerous and even catch fire. A fire that usually cannot be put out without possibly throwing the bike in say a pond for an hour or more, and killing anything that was living in there. As there is often no time to remove it from the bike.
People have already died in electric car fires, because you may only have split seconds to react with a battery fire, rear passengers in a 2/3 door car for example....dazed front passengers. Its not dissimilar to a petrol car fire when the tank is breached....and why I drive only diesel cars since around 1987!
Let Nealh advise you further.....
Andy

 

[OxygenJames]

Just for your own information, a nominal 36 volt battery is fully charged when it is around 42 volts. And fully discharged at around 30 volts. The battery only "works" when between these two voltages.

You cannot do what you are thinking about. All the cells in a battery must be of one type, all manufactured by the same company, manufactured possibly on the same day, then they go through stringent tests to make sure they are as near as possible to being iden

You cannot do what you are thinking about. All the cells in a battery must be of one type, all manufactured by the same company, manufactured possibly on the same day, then they go through stringent tests to make sure they are as near as possible to all being identical in all respects.
It is not as simple as many wish for, and really should be in a safe society.
Furthermore, these batteries, if you do not 100% know what you are doing, can be exceeding dangerous and even catch fire. A fire that usually cannot be put out without possibly throwing the bike in say a pond for an hour or more, and killing anything that was living in there. As there is often no time to remove it from the bike.
People have already died in electric car fires, because you may only have split seconds to react with a battery fire, rear passengers in a 2/3 door car for example....dazed front passengers. Its not dissimilar to a petrol car fire when the tank is breached....and why I drive only diesel cars since around 1987!
Let Nealh advise you further.....
Andy

Excellent information. I was right about to open the thing up - find out which bank was not working and order some new cells off ebay. Now - I think I won't. Thanks for the info.

 

[Nealh]

The burn and die scenario promoted by some are usually isolated cases and down to misuse often during charging or discharging, the difference between auto and ebike batteries are vastly different. Method and care in undertaking the process is needed making sure no metal objects are near the battery, tbh with the nice weather at the mo do the checks outside under the patio parasol on the table. This includes all jewellery some may wear.

When you open the battery and start digging about DON'T use any metallic objects probes, use plastic tools or wooden kebab sticks or pointed lolly sticks.
Once open and laid bare you will see the BMS with its multi wire sense wire connector (you may have to peel off any card off protective layer).
If unsure post some pics.
You can check cell group voltages best via the sense wire connector ( depending on the BMS it will have 10 -12 wires , typically 11 is common), all you need is a DVM and maybe a couple of needles or pins.
Once you are ready tell us how many BMS sense wires their are as this helps in knowing where to place your probes.

 

[Nealh]

Excellent information. I was right about to open the thing up - find out which bank was not working and order some new cells off ebay. Now - I think I won't. Thanks for the info.

As long as any cell group hasn't dropped below 2v then the battery is recoverable, but 24.4v doesn't bode too well. As an exercise it is worthwhile to check out esp if you have time on your hands.

Replacing cells isn't really an option unless you have a battery spot welder, soldering cells is a no no generally as too much heat is used for too long.

 

[OxygenJames]

I feel suitably warned. I've just forked out £157 and 99p for a new 36v 10ah 33cm black bottle battery. Seems the sensible option. Thanks for all your input.

 

[OxygenJames]

OK. New battery arrived (darn that was quick) - fitted and everything working as it did.

But. ...

We are not happy with how the bike delivers the power - as in.... when you pedal the power comes on really strong and unless you want to go very fast you have to use the brakes to slow the thing down - you certainly have to stop pedalling. Then next time you start pedalling again - same thing all over again.

So here's my idea on a fix: change the controller to one that has a number of levels of pedalling assist - so that when you pedal you don't always feel like you're about to take off. We figure one of the lower settings would not have such a surge of power and make the bike easier to ride.

Thoughts anybody?

Does anybody have a link for a controller (36v) with say 3 levels of pedalling assist? Or know a good place to get one? Or have any thoughts on what to search for?

Thanks in advance.

James.

 

[OxygenJames]

OK. New battery arrived (darn that was quick) - fitted and everything working as it did.

But. ...

We are not happy with how the bike delivers the power - as in.... when you pedal the power comes on really strong and unless you want to go very fast you have to use the brakes to slow the thing down - you certainly have to stop pedalling. Then next time you start pedalling again - same thing all over again.

So here's my idea on a fix: change the controller to one that has a number of levels of pedalling assist - so that when you pedal you don't always feel like you're about to take off. We figure one of the lower settings would not have such a surge of power and make the bike easier to ride.

Thoughts anybody?

Does anybody have a link for a controller (36v) with say 3 levels of pedalling assist? Or know a good place to get one? Or have any thoughts on what to search for?

Thanks in advance.

James.

OK - so this is the best I can find so far.

24V/36/V/48V 250W/350W Brushless Speed Controller Scooter E-bike Motor LCD UK | eBay

Find many great new & used options and get the best deals for 24V/36/V/48V 250W/350W Brushless Speed Controller Scooter E-bike Motor LCD UK at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Looks like the instructions are almost useless so brain will need to be engaged - whether the colours of the wires match the colours of my current set up I doubt - so that's going to be tricky.

But for £28 it looks like it might do what I want it to do - as in provide a number of different levels of power assist.

Thoughts anybody?

 

[Nealh]

The cheap £28 controller kits are crap and much the same as you will already have, they are speed controllers which mean each PAS level has a differing speed limit but you get max current all the time which means max power all the time.

What you need is a current control controller, these give max speed in all assists (which you do have to pedal for to get the max ). In each PAS level you get varying current levels so the surging is better controlled and certainly more user friendly.
These are more expensive and about three times the price with an lcd, good ones have 5 PAS levels like KT or Lishui though Lishui are OEM only.

 

[Andy-Mat]

OK - so this is the best I can find so far.

24V/36/V/48V 250W/350W Brushless Speed Controller Scooter E-bike Motor LCD UK | eBay

Find many great new & used options and get the best deals for 24V/36/V/48V 250W/350W Brushless Speed Controller Scooter E-bike Motor LCD UK at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Looks like the instructions are almost useless so brain will need to be engaged - whether the colours of the wires match the colours of my current set up I doubt - so that's going to be tricky.

But for £28 it looks like it might do what I want it to do - as in provide a number of different levels of power assist.

Thoughts anybody?

It has to be compatible, though I do not have the needed knowledge to make any sort of statement....

Sorry.

Andy

 

[OxygenJames]

The cheap £28 controller kits are crap and much the same as you will already have, they are speed controllers which mean each PAS level has a differing speed limit but you get max current all the time which means max power all the time.

What you need is a current control controller, these give max speed in all assists (which you do have to pedal for to get the max ). In each PAS level you get varying current levels so the surging is better controlled and certainly more user friendly.
These are more expensive and about three times the price with an lcd, good ones have 5 PAS levels like KT or Lishui though Lishui are OEM only.

Hmmmm. OK. Not what I wanted to hear but knowledge can hurt right?

Got a link for where I can get one of those?

 

[OxygenJames]

The cheap £28 controller kits are crap and much the same as you will already have, they are speed controllers which mean each PAS level has a differing speed limit but you get max current all the time which means max power all the time.

What you need is a current control controller, these give max speed in all assists (which you do have to pedal for to get the max ). In each PAS level you get varying current levels so the surging is better controlled and certainly more user friendly.
These are more expensive and about three times the price with an lcd, good ones have 5 PAS levels like KT or Lishui though Lishui are OEM only.

Is this what you're thinking about:

KT Controller 36V 48V 500W Controller Electric Bike Controller with display (36V, No Display): Amazon.co.uk: Sports & Outdoors

Shop KT Controller 36V 48V 500W Controller Electric Bike Controller with display (36V, No Display). Free delivery and returns on all eligible orders.

www.amazon.co.uk

It doesn't look much different to the one I linked to.

Thoughts?

 

[Nealh]

The cheaper and more expensive ones don't visually look different but the operation is certainly different. If you want more control over the current supplied for a more user friendly experience then you have to go with a current control controller.
The lcd1 is very basic ideally the lcd3, 4, 5 ,8 or 10 are better .

As I mentioned with the speed controllers you get the max current all the time in each PAS level so you will experience the surging all the time in every PAS level until you attain the max speed of each setting, on a three speed set up PAS1 will be about 8mph, PAS2 about 12 and PAS3 15.5mph.

With the KT it has five PAS levels only PAS 5 gives 100% current, PAS 4 50%, PAS 3 33%, PAS 2 20% & PAS1 13% . It delivers the current (power surge) more gently so you can select the current level that suits your riding style.
My 700c town bike I predominantly use PAS 1 as that is all the power I need, I can still pedal to 21/22mph on a benign day other wise 16mph is quite comfortable.

The difference is a like a gentle push from behind instead of a hard shove.