My DIY Electric Brompton project
- Thread starter Pedalo
- Start date
Hi Pedalo,
I have one of those throttle controls on my e bike, and the button switches the front llight on, which seems a bit daft as the light is run by a dynamo off the front tyre.
could I change the function to use as a power switch to the throttle,if so can you give me some pointers as I'm new to electric bikes,
Rgds Rob
I have one of those throttle controls on my e bike, and the button switches the front llight on, which seems a bit daft as the light is run by a dynamo off the front tyre.
could I change the function to use as a power switch to the throttle,if so can you give me some pointers as I'm new to electric bikes,
Rgds Rob
Attachments
Hi Rob,
I made use of the circuit Dan spotted and posted here:
http://www.pedelecs.co.uk/forum/electric-bicycles/5098-building-small-a123-battery-pack-9.html?highlight=mosfet#post67644
This effectively allows the 36V supply to be switched on and off remotely (i.e. via the low current switch). The circuit also eliminates the nasty spark seen when the battery is connected.
If you just want to disable the throttle control I expect simply using the switch to switch on and off the 5V supply to the hall sensor in the throttle would work. If you have a steady hand and fine soldering skills you could make this modification entirely within the throttle/switch unit.
Whatever you do, don't use the switch to directly disable the main power supply as it will not be able to handle the large current.
Hope that helps,
Cheers for that Pedalo, will give it a go as I'm quite handy with a soldering iron,
Rob
Some refinements
Controls
After much messing around with various throttles and switches I've settled on this:
This is usually a control unit for horn, lights and indicator but I've got it arranged as follows:
Lights on/off - this switch applies power to the controller (via the MOSFET switch circuit described earlier in this thread)
Horn - Push this button and the motor runs.
Indicator - Left/Off/Right controls the speed of the motor as low/medium/high. I simply replaced the hall throttle with a potential divider made from a couple of resistors. Then, the indicator switch switches in or out additional resistors to set different speeds.
The nice thing about this switch is that it doesn't take too much room on the Brompton handlebars. I was finding the thumb throttle controls were obstructing the gear changers. I also found I was using the thumb throttle mainly on full power so having a simple push switch as a replacement works quite well. I nearly always have the speed set to maximum but the switch gives me the option of conserving energy if I think I want to get more range from the battery.
I've replaced the brake levers with Shimano ones which give a bit more space to play with and the grips have been replaced with Ergons - which are just great! I chose the ones that are usually used with gripshift gears which fit nicely on the Brompton handlebars without trimming.
Controls
After much messing around with various throttles and switches I've settled on this:
This is usually a control unit for horn, lights and indicator but I've got it arranged as follows:
Lights on/off - this switch applies power to the controller (via the MOSFET switch circuit described earlier in this thread)
Horn - Push this button and the motor runs.
Indicator - Left/Off/Right controls the speed of the motor as low/medium/high. I simply replaced the hall throttle with a potential divider made from a couple of resistors. Then, the indicator switch switches in or out additional resistors to set different speeds.
The nice thing about this switch is that it doesn't take too much room on the Brompton handlebars. I was finding the thumb throttle controls were obstructing the gear changers. I also found I was using the thumb throttle mainly on full power so having a simple push switch as a replacement works quite well. I nearly always have the speed set to maximum but the switch gives me the option of conserving energy if I think I want to get more range from the battery.
I've replaced the brake levers with Shimano ones which give a bit more space to play with and the grips have been replaced with Ergons - which are just great! I chose the ones that are usually used with gripshift gears which fit nicely on the Brompton handlebars without trimming.
Computer Light
Computer Light
Now I'm cycling home in the dark again I was really missing the cycle computer light I used to have on my Cytronex bike. So I implemented my own.
This is simply a white LED with series resistor powered by the same 36V that goes to the motor controller. It's wrapped up in adhesive lined heatshrink. It's also got a piece of stiff wire enclosed within the heatshrink so the whole arrangement is rigid but easily adjustable.
As well as lighting the computer in the dark it also provides a useful visual reminder that the power is switched on.
I think I'm pretty much done now until I decide to tinker again!
Computer Light
Now I'm cycling home in the dark again I was really missing the cycle computer light I used to have on my Cytronex bike. So I implemented my own.
This is simply a white LED with series resistor powered by the same 36V that goes to the motor controller. It's wrapped up in adhesive lined heatshrink. It's also got a piece of stiff wire enclosed within the heatshrink so the whole arrangement is rigid but easily adjustable.
As well as lighting the computer in the dark it also provides a useful visual reminder that the power is switched on.
I think I'm pretty much done now until I decide to tinker again!
Last edited:
Great job, I too miss the little trip computer light 
I love the idea of a motor on and off position with the half/full power facility. That is very like/identical to my first early Cytronex model which I loved. If you have time perhaps you could pm/email the schematics/parts list of how to do it, as that is behond my current low level knowledge of electronics
Like you I pretty much either have full throttle or no throttle. Also if you could let me know where to get the button thingy
Regards
Jerry
I love the idea of a motor on and off position with the half/full power facility. That is very like/identical to my first early Cytronex model which I loved. If you have time perhaps you could pm/email the schematics/parts list of how to do it, as that is behond my current low level knowledge of electronics
Like you I pretty much either have full throttle or no throttle. Also if you could let me know where to get the button thingy
Regards
Jerry
The switch thing was purchased from here:Great job, I too miss the little trip computer light
I love the idea of a motor on and off position with the half/full power facility. That is very like/identical to my first early Cytronex model which I loved. If you have time perhaps you could pm/email the schematics/parts list of how to do it, as that is behond my current low level knowledge of electronics
Like you I pretty much either have full throttle or no throttle. Also if you could let me know where to get the button thingy
Regards
Jerry
Lights Turn Signal Horn Switch for Scooters Bikes on eBay (end time 24-Nov-10 06:51:33 GMT)
It took a couple of weeks to arrive.
I would say it's still not quite the same as a Cytronex. Differences are
i) You have to hold the button down to have the motor running. It could be turned into a cruise control version using a circuit involving something like a reed relay. (I'd also need brake cutout switches which I don't currently have)
ii) The speed control is done with the same thumb as the motor button - so it's not so easy to change speed while the motor is running. (It's not been a problem yet as I only ever use full power). With just limited use it's not really a problem though.
iii) Mine has 3 speed levels instead of 2.
iv) Mine has a switch which cuts power to the system.
If I could find suitable small neat pushbuttons I might move it even closer to the Cytronex arrangement (which I agree is excellent) but as yet I've not really found anything quite suitable - and I've probably spent enough money on various throttles and switches for now!
I've kind of made the circuit up as I've been going along and haven't yet drawn it out. I have been meaning to do so though so I'll send it to you or post it here when I do.
Thanks thats appreciated.
I realised after I posted that the button had to be held.
Some arrangements/controllers do have a facility where when you hold the throttle open for more than 15sec or so it remains on i.e. a sort of cruise control.
Regards
Jerry
I realised after I posted that the button had to be held.
Some arrangements/controllers do have a facility where when you hold the throttle open for more than 15sec or so it remains on i.e. a sort of cruise control.
Regards
Jerry
I think my next refinement could be a change in connectors.
While the Bulgin connectors seem fairly robust and are kept waterproof by placing them in the rear pocket of the C bag, it's all a bit of a faff opening the bag pocket and connecting/disconnecting it especially when wearing thick gloves. It's even more faffy when using the waterproof cover of the C bag as I did this morning.
I'm thinking a good waterproof in-line connector would be better. I would leave the connector dangling from the pocket of the C bag so would only need to connect/disconnect it when attaching the bag to the bike. The raincover could be positioned the bag before taking it outside.
So - does anyone have any recommendations for a good waterproof in-line connector? It needs to be at least 8-way and should be robust enough to cope with many connect/disconnects.
While the Bulgin connectors seem fairly robust and are kept waterproof by placing them in the rear pocket of the C bag, it's all a bit of a faff opening the bag pocket and connecting/disconnecting it especially when wearing thick gloves. It's even more faffy when using the waterproof cover of the C bag as I did this morning.
I'm thinking a good waterproof in-line connector would be better. I would leave the connector dangling from the pocket of the C bag so would only need to connect/disconnect it when attaching the bag to the bike. The raincover could be positioned the bag before taking it outside.
So - does anyone have any recommendations for a good waterproof in-line connector? It needs to be at least 8-way and should be robust enough to cope with many connect/disconnects.
Pedalo I looked around a while myself and could only find the 8 way SPEAKON plug which is huge!
All the other alternatives like this cost a fortune
BULGIN|EXP-0911/07/S|SOCKET, FLEX, 7WAY | Farnell United Kingdom
SOURIAU and Switchcraft are two others to try but again costly.
Regards
Jerry
All the other alternatives like this cost a fortune
BULGIN|EXP-0911/07/S|SOCKET, FLEX, 7WAY | Farnell United Kingdom
SOURIAU and Switchcraft are two others to try but again costly.
Regards
Jerry
Last edited:
Thanks Jerry,
The Souriau ones look the most interesting though as you say pretty expensive. I think those are the ones used by Cytronex to connect the water bottle battery.
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