HAROX said:
For myself, regen has an immediate benefit, if only at a small capture-rate. So, can this conversation be about "without slowing down very much", because I'm really interested in hearing about capturing enough power to handle the trivial (? :lol: ?) things like light and communications.
Using regen for those things would be a boon regardless, as they are almost imperative for an E bike, don't you think?
Using regen for them is an extremely inefficient way to power them, if you intend to get that regen at any time other than braking for the explicit purpose of slowing down.
If you are trying to accelerate or cruise at a speed, then you are wasting power by regenerating power from the motor, because every bit of power you take out will have to be replaced from teh battery, and it will take notably more power to do that than you took out. You'd be lucky if it was 60-70% efficient, and I'd bet on less than 50% (meaning you are throwing away more than half the power you could have used to simply power the devices directly from the battery).
If you are only using the power from braking, then there's no efficiency loss there, because it would ahve been either lost or put into the battery anyway.
But as I've said before, and you'll see if you try the experiments:
--Any power you take off the motion of the bike/motor/wheel will slow it down.
--To get back to speed you have to take more power from the battery.
--With a dynamometer and the right Wh measuring equipment, you can test the amount of power going in and coming out of each stage of your power conversion (battery to controller, controller to motor, motor to ground), to see the power losses at each stage, to find your actual efficiency of them. That will let you see exactly how much power you lose every time you pull power from teh battery to regain speed in the motor/wheel/bike.
--you can also use the same Wh measuring equipment to test the amount of power coming back out of the regenerative (or other) power pickup from the motor/wheel/etc., which then goes into whatever conversion electronics you build or have, and then into the devices to be powered from them or the battery if using it to recharge the battery.
--Then you can see the full efficiency of the entire cycle of power you're recapturing and re-using.
Once you know that, you can see directly how ineffficient the power recycling method is, vs simply direclty tapping it from the battery in the first place.
An alternate method is to setup the bike on a dyno (to eliminate all road and weather variables), and try the test first with:
--pulling power for all the accessories/etc directly fromt eh battery
--pulling power for them from the motor
Then you can see the Wh used for the exact same speeds and distances will go up for the latter instance, vs the former. That shows you the percentage of inefficency of the latter method.
If you don't see the problem after doing the experiments, you probably haven't instrumented correctly, or are not doing the exact same test run between the two.
Yes, you *can* power all your stuff from the motion of the bike. It's the same thing as hooking one of the old friction generators to your bike wheel, even if it's mechanically different, it is sthe same in principle. But it is less efficient than doing it from the battery directly, and will result in shorter range and lower overall usable battery capacity because of the higher drain on the system.
If you're expecting to be able to pull power from the motion of the bike/motor/wheel and use that power for something else, without having to put even more energy back into it than you got out, and still maintian the same speed, then you *are* expecting over unity.
Please, try the experiments!
