Brompton Swytch Controller

JStew

Finding my (electric) wheels
Sep 17, 2024
5
3
Hi there,

I think I’ve read all the relevant threads here and have not quite found the answer to my question.
I have a Gen 1 Swytch for Brompton (I think -it has the large battery pack with lcd display, rather than just led). It had a faulty controller right when I bought it 6 or so years ago which was replaced under warranty (with hall bypass).

The motor failed a while ago, and having moved to one of the hillier cities in the UK I finally got round to replacing it with an AKM 250w hub from Top Bike Kit on Aliexpress. The motor worked very well for a few weeks but then the display on the battery pack went dead mid-ride and will not revive. No power to the motor. I’m assuming it‘s the controller as this is how the first one behaved and the battery seems to charge as normal (going by the green/red led). I suppose it could just be the display. Swytch do not have any stock of this display or controller anymore.

Swytch say I can spend ££££££ on their new battery and controller (that has super limited range) or that Gen 1 and 2 battery pack/controllers will work with my old handlebar connector (there were some 2nd hand units available on eBay a while back, currently there are none).

I understand that I could get a KT controller from Top Bike Kit. But I think I’m right to say that I can’t wire this into the Swytch battery pack connector? Or could I? Being able to unclip the battery pack in some way is kind of essential when folding and carrying the Brompton. Does anyone have any suggestions?
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
6,826
3,156
Telford
Nine times out of 10, if the LCD doesn't come on or goes off, it's because it has no voltage from the battery. It works independently from the controller. The battery is connected to the controller, but a branch is taken off it inside the controller without the controller having any influence. The LCD powers the controller with the same battery wires, which are sent back to the controller when you switch on the LCD. In other words, the battery wires coming into the controller don't power it, they go direct to the LCD and the motor.
 

JStew

Finding my (electric) wheels
Sep 17, 2024
5
3
Nine times out of 10, if the LCD doesn't come on or goes off, it's because it has no voltage from the battery. It works independently from the controller. The battery is connected to the controller, but a branch is taken off it inside the controller without the controller having any influence. The LCD powers the controller with the same battery wires, which are sent back to the controller when you switch on the LCD. In other words, the battery wires coming into the controller don't power it, they go direct to the LCD and the motor.
I suppose it is possible that it is the battery on/off switch that has failed? (Which I had thought was just an on/off for the LCD but actually looks to be separate and wired from a source marked “Switch” on the battery).
 

JStew

Finding my (electric) wheels
Sep 17, 2024
5
3
I suppose it is possible that it is the battery on/off switch that has failed? (Which I had thought was just an on/off for the LCD but actually looks to be separate and wired from a source marked “Switch” on the battery).
Nine times out of 10, if the LCD doesn't come on or goes off, it's because it has no voltage from the battery. It works independently from the controller. The battery is connected to the controller, but a branch is taken off it inside the controller without the controller having any influence. The LCD powers the controller with the same battery wires, which are sent back to the controller when you switch on the LCD. In other words, the battery wires coming into the controller don't power it, they go direct to the LCD and the motor.
YES this was it. It is the switch that has failed. I can get it to come on again by bypassing the battery switch with a short wire (cable-tie) plugged into the waterproof connector. So I just need to wire some sort of new switch in there.
 

JStew

Finding my (electric) wheels
Sep 17, 2024
5
3
YES this was it. It is the switch that has failed. I can get it to come on again by bypassing the battery switch with a short wire (cable-tie) plugged into the waterproof connector. So I just need to wire some sort of new switch in there.

In fact further tinkering shows me I just need to resolder the existing switch connections.
 
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