eBike to simulate motorbike

[Easy-X]

So upgraded the tyres on my ebike at the weekend from E-marked 50kph tyres to 75kph as top speed now is ~30mph. And was giving it a bit of a test ride...

Then I realised a crucial difference: on a motorbike if you ease off the throttle you start to get engine braking so the throttle regulates speed in both a positive and negative manner.

For the ebike you have no such effect. It's the equivalent of getting up to 30mph, letting go of the throttle and, at the same time, grabbing the clutch and coasting. Not great! Now the thing about my latest build is that the motor has a regenerative braking feature: when you hit the brake lever [switches] the motor goes into reverse and turns into a generator.

I'm wondering how close I can get to the "motorbike experience" by having throttle zero = activate regen. Unfortunately this is binary - either the regen is on or it's not - unlike a motorbike throttle.
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Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[thx1138]

You think that's bad, try cornering on a front wheel drive ebike.

[G]

With a decent programmable controller you should be able to setup it to do, well, whatever you want.

I've got a decent slipper clutch on my (most-used) ICE bike to prevent too much engine braking.

Even without regen, my direct drive hub motor e-bike definitely does offer some 'engine braking' - one of the reasons I went for geared hub motors on the trailer!

[Easy-X]

[Easy-X]

[Easy-X]

So looking at basic controller programming I can affect the strength of the engine braking / regen but it will only trigger on a brake signal. Other than going with custom firmware the easiest way is to link the throttle to the brake signal externally. I have an opto-isolated relay circuit kicking about that I was going to use for the brake light and it's configurable to trigger on either high or low inputs... should be pretty easy to test how "low" low is by wiring it up to the throttle and hearing when the relay clicks...

On the plus side I was thinking about this riding the 125 this morning and you only really notice engine braking completely off the throttle (at lowish speeds at least) so "zero throttle on ebike triggers regen" at least has a chance of simulating the feel of conventional engine braking.

The experiments continue...
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Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[G]

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Experiment 1: at what point will an off the shelf circuit (like an opto-isolated relay) activate from the low signal from the throttle? (Throttle position generates a voltage from 0v to 5v.) Hopefully lower than a typical LED trigger voltage of 1.2v otherwise the bottom 24% of the throttle is dead zone

Experiment 2: run a manual push button to the controller's ebrake input. Ease off the throttle and stab button. Use imagination to consider if this was the effect I was looking for.

Bonus news item: my boss is on holiday and he's left a stack of ebike connectors and wiring and things on his desk where he rigged up a relay switched 12v headlamp from his 6v Bafang lamp output
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Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[G]

Depending on how your controller works - something you could very easily setup using Arduino, but potentially also creating a variable effect using a PWM style output. (Or the PWM might blow up your controller, or make it really jerky to ride.)

[GettinBetter]

[Easy-X]

Nobody with any sense connects lithium-ion batteries to anything directly

I have a 2-wire BMS (battery management system) which handles both charging and discharging, over & under voltage, etc.

As an aside you can also get 3 or 4-wire BMS boards where the charging and discharging circuit are separate which obviously would be no use in a regen scenario.
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Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter