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[evtricity]

Has anyone set up their Zero to utilise the Sevcon analog outputs to turn on their brake light when regen is engaged.

The Sevcon manual states:

"Brake Lights
A brake light output object is available (2404h) and can be mapped to an analogue output. The brake
lights will illuminate whenever the footbrake is pressed (providing either an analogue or digital
footbrake input is available) or the system is in direction change braking"

I've implemented an analog footbrake by using a left hand clutch master cylinder and pressure transducer which works very well, so well that it's probably a little dangerous on the road without triggering the brake light.

If anyone has set something up from the Sevcon analog outputs let me know as that may help in setting up the regen brake light.

Thanks.

[Burton]

There is a setting under throttle which says something like brake light on with regen but I don't think it works like we would expect it to. Right now I use the left clutch for engin braking and just like with my ICE bike if I want the brake light to come on just pull my front brake lever in a little (since I modified it to turn the brake lit on before applying brakes)

[trikester]

How about using a brake light pressure switch (like from VW, etc.) to activate the brake light?

Trikester

[Burton]

How about using a brake light pressure switch (like from VW, etc.) to activate the brake light?

Trikester

The clutches we are using actually come with a switch installed on them the question is when does it come on but that could be adjusted by shaving down the switch rod.

[benswing]

Check with ultrarnr.  He set up his brake light to flash while in regen mode, then solid when braking.  I rode with him on the Tail of the Dragon in NC & TN and it was pretty effective.

[ultrarnr]

benswing,

I actually have a brake light modulator on my SR which goes through this funky flash pattern and then goes solid after a few seconds. But when you first touch the front brake lever the brake light comes on, then the regen kicks in, then the front brake kicks in. Pretty easy to have the brake lights on when the regen is going. Obviously this doesn't work with the regen from closing the throttle.

[RNM]

How about a proper regen lever?
http://endless-sphere.com/forums/viewtopic.php?f=1&t=61397

[Burton]

RNM how is it not a proper regen lever?

http://www.diyelectriccar.com/forums/showthread.php?s=89663a2ab4ca7d525e46651c9a9ceed9&t=124073&page=4

Also note the built in switch not being used in the pictures included. It would take a couple minutes to run wires to it if you wanted a brake light.

Parts: Clutch, psi guage, brake fluid and wire ... and no need to convert from digital to analog.

[RNM]

RNM how is it not a proper regen lever?

http://www.diyelectriccar.com/forums/showthread.php?s=89663a2ab4ca7d525e46651c9a9ceed9&t=124073&page=4

Also note the built in switch not being used in the pictures included. It would take a couple minutes to run wires to it if you wanted a brake light.

Parts: Clutch, psi guage, brake fluid and wire ... and no need to convert from digital to analog.

Haven't seen that before, it's nice!

But would it be heavier than the other link?

[Burton]

If weight is an issue maybe ... but weight also saves parts when you drop the bike. If it is formerly a clutch it might survive more abuse than something from a bicycle.

Both dgh and I have this set up. I have not released any notes on how to set it up as I am still testing it. That said it works just like it does in the video of the one you posted only it took me about 10  minutes to cobble together.

[RNM]

We can save weight by using an adjustable motorcycle cable clutch lever and a strain gauge. Cleaner looking, simple, robust (no leak, no oil), etc.
Your solution is also valid and a good one, ok?

Either way, the mechanical bit is the easiest, what I would like to see is sevcon programming mods or some kind external adjustable "knob",  vehicle speed readout to get constant torque regen (or phase current monitoring).

Good luck to you guys!

[Burton]

RNM is the strain gauge your design? Do you have any write-ups on how to make one outside the videos?

I have seen someone use a clutch with cable to a box where they assembled a lever / gears to turn a pot switch. I was going to go down that route myself till someone exposed me to the clutch pressure sensor solution.

I am not sure if I have seen someone using a strain gauge with a cable actuated clutch lever. Do you have details on how this might be done?

When you say constant torque regen are you talking about at every speed / SOC ? If I recall there is a 4000rpm limit built into the sevcon where it will not regen anything higher and the closer you get to 4000 the less you will feel the regen. This is in place to prevent the sevcon from throwing faults which might cause it to restart or shutdown. As for different torque based on SOC that is a more complex issue which would require real time monitoring and changing of values on the fly. I know of someone who has interest in this and who has indicated to me of ways it might be done but it would be a lot of work to develop and still would be slaved to the rpm limitations.

[RNM]

RNM is the strain gauge your design? Do you have any write-ups on how to make one outside the videos?

It's not, but I really like the idea of a brake that "will not move at all, it will just sense how hard you are pushing or pulling on it..."

I have seen someone use a clutch with cable to a box where they assembled a lever / gears to turn a pot switch. I was going to go down that route myself till someone exposed me to the clutch pressure sensor solution.

I am not sure if I have seen someone using a strain gauge with a cable actuated clutch lever. Do you have details on how this might be done?

Right now, I have the same info as you, the topic in the other forum and the videos... I try to get more info out Arlo1, let's see if he can help us.

When you say constant torque regen are you talking about at every speed / SOC ? If I recall there is a 4000rpm limit built into the sevcon where it will not regen anything higher and the closer you get to 4000 the less you will feel the regen. This is in place to prevent the sevcon from throwing faults which might cause it to restart or shutdown. As for different torque based on SOC that is a more complex issue which would require real time monitoring and changing of values on the fly. I know of someone who has interest in this and who has indicated to me of ways it might be done but it would be a lot of work to develop and still would be slaved to the rpm limitations.

I meant constant mechanical torque to produce a constant braking force, just like a normal brake. To achieve this, one way is to measure phase currents (2 sensors in motor wires) and a micro controller.

After 4000rpm there's not regen in a standard bike? 
What speed is that on a Zero S?

[Burton]

Ah ... the clutch setup moves slightly but it is tension based since the fluid doesn't have anywhere to go. So the harder you pull the higher the pressure and the higher the voltage goes to the sevcon.

I messaged Arlo1 on youtube and got nothing out of him :/ Which was part of the reason I didn't go with the strain gauge route.
Had I though I would have used a clutch lever and not a bicycle brake lever.

A microcontroller would be required but it would have to change the sevcon torque settings on the fly in order for that to happen :/

4000 on a standard bike with stock gearing ... I know with my high speed gearing 25/98 it is about 70mph, so I will presume 60mph. I am going to try 28/98 gearing which should bump up my 4k speed to around 80-90mph. But I have an equivalent of an SR so ...

[RNM]

I know that hydraulic clutch doesn't move also, still I think the other solution is lighter, more robust, no leak possibility, etc.

With strain gauges and a load amplifier I think it's the same, higher pressure = higher voltage.

Like you said before, motorcycle levers are more robust, so a cable clutch lever would be perfect.

Microcontroller = "on the fly" changes (few micro seconds delay)

Do you have a build thread of your bike? Thanks