GreenEdge CS2 battery cradle change

kingfisher314

Just Joined
May 21, 2024
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Hi all,

I have a Greenedge CS2 ebike whose battery (36v, 9Ah, 2 pin - old style) stopped working as it was quite old and had been dropped a few times. So I ordered a new battery from eBikes direct (after a lot of faff), the only one they had was a 36v 11 Ah (still 2 pin old style). When it arrived in the post it came with a new cradle. Originally, I wasn't going to install this new cradle since the new battery fit in the old cradle (which is rated for 7-15 Ah so should be fine for both 9 Ah and 11 Ah battery), but when the new battery is in the old cradle the connection is very bad and it often cuts out or doesn't start at all.

So I need to change the old cradle with the new one. I though this would be an easy change over until I looked at the two cradles more closely: The old one (currently connected to my bike) has three wires between it and the bike, but the new one only has two wires. And the connectors between the wires look different.

Does anyone know how I might first disconnect the old cradle, then connect three wires from the bike to two wires on the new cradle?

I've tried asking eBikes about this but they are very slow to respond (as I found even when trying to buy the battery). Any suggestions would be much appreciated, I can send images if that would help.
 

kingfisher314

Just Joined
May 21, 2024
4
0
The current wires connect into the old cradle like this (below):
57817
All with connections like this from the wire on the cradle to the wire on the bike:
57818
(these don't pull apart -or at least not easily- as far as I can tell)
One wire goes to the pedal sensor, one to the motor in the rear wheel and one to the components at the handle bars.
The collection at the handle bars is connected as pictured below
5781957820
The new cradle and wires look like this:
5782157822

Sorry for so many images, I didn't want to leave anything out.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,797
3,133
Telford
One has the controller in it and the other doesn't. Obviously, you need the controller.

The controller is removable by undoing the 4 screws in the aluminium bit, but it will remain hanging by the two battery wires. You'll probably have to cut the wires, then solder to the new ones. You might be able to unscrew the nuts that hold the spring-pins in and remove the ring terminals to avoid soldering the wires, but remember which side the red wire goes. You have to hold the pins on the other side with pliers while you unscrew the nuts, otherwise they go round with the nut and nothing unscrews.

Alternatively, you can unscrew the whole black bottom part from the aluminium rail and only swap the top part if it's broken. You can also just swap over the top part if the catch/lock is broken.
The connection system is in that black bottom part above the controller. It's only two pins with springs underneath, so if you're not getting a good connection, it's probably because the pins are a bit jammed by dirt. That can easily be fixed by cleaning and oiling and a bit of pressing in and out with your fingers until they're free.
 
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kingfisher314

Just Joined
May 21, 2024
4
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Hi,
Thanks for all the info! I didn't know the new one didn't have a controller.

I tried swapping over the top part of the cradle and cleaning off the pins so they move smoothly but unfortunately it still wouldn't start. so I took the controller out a little to look closer at the wires and noticed (I think) at least one is broken (the yellow wire in the pic below):
57823
I imagine this could be the issue?
I'm also guessing it could only be fixed by soldering (a skill I do not possess).
Do you know if a new generic controller would be purchasable anywhere?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,797
3,133
Telford
Hi,
Thanks for all the info! I didn't know the new one didn't have a controller.

I tried swapping over the top part of the cradle and cleaning off the pins so they move smoothly but unfortunately it still wouldn't start. so I took the controller out a little to look closer at the wires and noticed (I think) at least one is broken (the yellow wire in the pic below):
View attachment 57823
I imagine this could be the issue?
I'm also guessing it could only be fixed by soldering (a skill I do not possess).
Do you know if a new generic controller would be purchasable anywhere?
If you buy a replacement, you always need to solder. If you can solder, there are many options open.

Repair is one option. First, you would need to completely remove the controller by unscrewing the nuts on the pins and disconnecting the three connectors. I think the PCB is potted with silicone, which makes repair much more complicated.

Your control system is pretty bad. You can get a slightly better solution with LCD for about £50 or a much better one for around £80. Both would require the controller to be mounted in a bag or box externally somewhere and would require the battery wires to be soldered and probably the pedal sensor replacement, and, of course you'd have re-route the cable to the LCD

The only replacement controller I can find is this one, but it's for a bike with an LCD, and I bet the pedal sensor connector doesn't match, plus it's ridiculously expensive, especially as you'd have to pay about £100 more for their LCD to go with it.

You can still buy KT controllers for bottle batteries from BMSBattery, but that would need a new LCD and every wire soldering because they use block connectors. I think it would be better to use the box type external one.

Where do you live? There's always a chance that a forum member, who lives nearby, might help.
 

kingfisher314

Just Joined
May 21, 2024
4
0
Ok thanks
I have a few electrical engineer friends so I think I'll ask them for their help trying to repair it by soldering it first, that seems like the most simple solution. But its nice to know I can upgrade to an LCD with a new controller in the future, I thought that option would be lost for my bike model.
Thanks so much for all your responses!
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,797
3,133
Telford
Ok thanks
I have a few electrical engineer friends so I think I'll ask them for their help trying to repair it by soldering it first, that seems like the most simple solution. But its nice to know I can upgrade to an LCD with a new controller in the future, I thought that option would be lost for my bike model.
Thanks so much for all your responses!
All controllers work the same in principle, so it's very easy to mix and match them as long as you can solder. Your bike has a standard motor and standard battery. That's the advantage of a bike like that. You will always be able to keep it going with spare parts.

It's a shame you didn't tell us about the problem before you got your new battery because you could have used any downtube battery you want, which would have given you the opportunity to get a much better one, or even upgrade to 48v.
 
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