Advice please B TWIN

[Itsshreck]

Bike battery
Hi guys hope you can help me again
I have just acquired all be it an old bike
`B’ TWIN 24 volt electric bike and after checking and opening up the sealed battery case
and charging it
It’s loosing charge quite quickly so I am assuming either one or more battery cells are knackered
Samsung 18650 batteries cells
So my question is with my (limited) skills
Do I try and check each individual cell hoping there is only 1-2
That need replacing ( looks tricky for me )
Or do I just buy another completely different battery and put it on the rear rack ?
At the moment it’s in a big bulky bag hanging from the handlebars
Ordinary I would send it in to be fixed
But here in Spain when you ask an electrical shop can they replace either 1-2 cells or all of them they look at you has though you have 2 heads then say no
Hope my picture load this time

 

[sjpt]

Usually if one or two cells are gone the others are going and an attempt to mix them with new is not likely to work well. A new battery might be best. You might be able to get the old one recelled (maybe not easily in Spain). That is usually only worth it for batteries that are very difficult or expensive to replace.

I'm sure one of the more expert people will be able to say if it is worth upgrading to 36v. You will probably need a new controller, but it may not be too expensive and well worth it; and 36v will give a bigger choice of batteries.

 

[Nealh]

New battery.

 

[vfr400]

You can buy a complete new cell-pack with BMS and charger on Ebay for about £100, so it's not worth messing about with your knackered one.

It might be worth going up to 36v, which would give 50% more power and speed. 24v systems are normally gutless. If you want to do that, get a KT controller too (about £80), which will completely transform your bike into a new one.

 

[Itsshreck]

You can buy a complete new cell-pack with BMS and charger on Ebay for about £100, so it's not worth messing about with your knackered one.

It might be worth going up to 36v, which would give 50% more power and speed. 24v systems are normally gutless. If you want to do that, get a KT controller too (about £80), which will completely transform your bike into a new one.

Hi vfr400
is it possible to buy what you recommend from Amazon
getting hammered with tax on importing things at the moment
any chance of a link
to what you are referring to would be really helpful
thanks

also it is only a 250 watt motor will this be an issue ?

 

[StuartsProjects]

But here in Spain when you ask an electrical shop can they replace either 1-2 cells or all of them they look at you has though you have 2 heads then say no

Good.

The cells in the pack need to be matched in terms of voltage, capacity and internal resistance.

So with an old pack, where the batteries hav all aged, whilst in theory you could possibly find a matching replacement cell, in practice its extremly difficult.

+1 on New Battery.

 

[Itsshreck]

Good.

The cells in the pack need to be matched in terms of voltage, capacity and internal resistance.

So with an old pack, where the batteries hav all aged, whilst in theory you could possibly find a matching replacement cell, in practice its extremly difficult.

+1 on New Battery.

Thanks for your advice
looking for recommendations links to Amazon preferably I can order from I do not know what battery and controller are compatible
cheers

 

[Itsshreck]

Hi
thanks for your help can anyone recommend a suitable 36 volt battery and controller
hopefully via Amazon has I am not sure what is the correct one to purchase ?
thanks again

 

[Nealh]

example of a KT controller with neat small display.

Tomanbery KT LCD4 Display Screen 15A Durable Anti-rust 36V/48V Lightweight Controller for E-bick: Amazon.co.uk: Sports & Outdoors

 

[Nealh]

For the battery you may have to fit a rear rack battery, one could try fitting to the down tube but may interfere with the step thru ?
A rear rack with integrated battery and then you can mount the rear basket on top of the rack.
Agree the front bag mounting is too high and affects the balance & steering control with the weight.

 

[Nealh]

Example battery/rack.

Season E-Bike Pedelec 36V 12.5Ah 462W High Capacity Li-Ion Rechargeable Battery Set With Rear Rack Carrier + Charger: Amazon.co.uk: Sports & Outdoors

The only thing with Amazon is that spec details are not always very clear, what we we can see from this one above is that it uses 50 18650 cells of 2500mah capacity.
Discharge is 20a continuous so fine for the KT controller, the controller box will fit in the front compartment of the battery.

 

[Nealh]

Before you buy a controller we need to see all the controller wiring from the box, we need to know if you have sensored or unsensored motor/controller.

The KT will give a better ride feel then your current set up and will give you five nice power levels for a nicer ride feel as they use current control, this means you select the level of current /assist that suits your needs.

Some minor wiring /soldering will likely be needed but first show us all the controller wire connection you have at the moment. That way we can tell you if the PAS system will work, hopefully it is a simple magnet disc and sensor attached to the bottom bracket crank area.

 

[Itsshreck]

Hi
thankyou very much for taking the time to reply
here is more information ( pictures)
if you need anything else please let me know

 

[Nealh]

It look like you have a std PAS sensor /disc set up so that can stay, one would just wire up the three wires accordingly in the correct sequence.

The wires to the controller one can't fathom out, one must be the motor cable and there is one with 10 wires, 2 off which are cut.
Is there a connector from the front hub motor cable to the controller or does it go direct to a Molex connector at the controller end ?

If there is a motor connector near the hub/front forks we need to see it and know how many wires/pins. If not then quite a bit of soldering wires will be required.

 

[Nealh]

You may have to unscrew the two parts of the controller covering so we can see inside better.

 

[Itsshreck]

Hi pulled it all out
one goes to front wheel
one to throttle
one to lcd display
one to pedal censor
one to battery that was on handlebars
one goes to mudguard (earth) I think

hope this helps

 

[Itsshreck]

More pictures

 

[Nealh]

If changing controller to go to 36v then the only connection that really matters is the motor one and whether it will be compatible for a standard 9 pin Julet motor connector. I have a spare one in , my parts so will look to see if it marry's up to the your one in pin layout.
Your PAS and throttle will be easy to wire up and you would need to buy the KT display to be compatible with KT controller.

 

[Itsshreck]

If changing controller to go to 36v then the only connection that really matters is the motor one and whether it will be compatible for a standard 9 pin Julet motor connector. I have a spare one in ,y parts so will look to see if it marry's up to the you one in pin layout.
Your PAS and throttle will be easy to wire up and you would need to buy the KT display to be compatible with KT controller.

Hi nealh
So in layman’s terms
It should be straight forward and compatible
With the stuff you recommended
Ie battery/ controller
But I would also need to buy a KT display
Do you have any links for the correct display ?
My next problem is actually purchasing the stuff I can’t buy of Amazon uk has most people won’t even post over here and if they do I get hammered now with taxes
and Amazon es is not very good
I have a friend driving over from uk so if I can get the equipment to him that would be good
Once again thanks for your help I really appreciate it

 

[Nealh]

The example controller I linked to comes with a discreet lcd4 display, it is best to buy the two as a pair to ensure connections are correct if not familiar with buying parts.