# How to make KERS (Kintetic Energy Recovery System) for 2-wheeler?

1. Jan 11, 2015

### tdev

I want to make kers for my two wheeler.How should i start and what are the things that i should consider??

2. Jan 12, 2015

### montoyas7940

Is it an electric two wheeler?

3. Jan 12, 2015

### Doug Huffman

Ahh, KERS (capitalized abbreviation) for Kintetic Energy Recovery System.

Consider its required capacity and power (time rate). 100 kg from 50 kph to zero at 1/3 g for a bicycle HPV.

4. Jan 14, 2015

### tdev

how does that matter?

5. Jan 14, 2015

### montoyas7940

6. Jan 14, 2015

### timthereaper

7. Jan 14, 2015

### RonL

That's a great proof of concept, but for a 15 pound flywheel at any significant rpm, the support is just not good (Imho) I say this only to raise awareness for anyone that might just jump up and throw something together :)

8. Jan 14, 2015

### timthereaper

I totally agree. It's shows good thinking and it's all mechanical, but I don't quite see the allure of carrying around 15 extra pounds on a bike just to save you maybe 10 percent of the energy you expend. This link is a sexier version of the electric bike conversion kit: https://www.superpedestrian.com/. I think this might be closer to something people might invest in (but I'm not a cyclist).

9. Jan 14, 2015

### RonL

I have always liked the Hub Motor for electric, but the idea of flywheel energy storage for take off assist, is high on my list of ideas.
Biggest challenge is, most states have weight and speed limits, which cuts deeply into energy storage density.

10. Jan 14, 2015

### montoyas7940

Does the OP want a purely mechanical system? If the two wheeler is electric, a simple regen system might be easier.

We still don't know if Op is starting with a gas motorcycle, pedal bike or electric bike. It matters.

11. Jan 14, 2015

### Staff: Mentor

@tdev -- I see you are on the forum today. How about dropping into this thread and letting us know what you are wanting to do... :-)

12. Jan 15, 2015

### timthereaper

Speed limits on how fast the flywheel can turn? I was about to suggest a carbon-fiber flywheel. It's light enough to be worthwhile but you can get that thing to spin up really fast. If there's limits to flywheel speed, then that's out.

13. Jan 15, 2015

### RonL

No!, the speed and weight generally apply to electric power and a limit of around 700 watts at the motor.
A properly enclosed flywheel should not draw much restriction other than, if speeds of the flywheel cause control problems related to resistance to lean or turning.

14. Jan 15, 2015

### Staff: Mentor

Oh Jeeze! I didn't think of that. A spinning flywheel on a bicycle (road or MTB) could be a very bad thing. Maybe if it could gimbal it wouldn't be a problem. But that would make getting energy into and out of the flywheel much more difficult...

15. Jan 15, 2015

### RonL

It might be that a second flywheel spinning in the opposite direction would solve most of the problems, however that begins to increase the engineering design efforts of dual input and power take-off applications.

16. Jan 15, 2015

### Staff: Mentor

Ah, good idea! :-)

17. Jan 16, 2015

### timthereaper

Yeah the engineering would have to be more significant, but you'd have to do some sort of "balanced system" like that to make it work.

18. Jan 16, 2015

### RonL

Mount one on each side of the frame and there will be little to indicate there are two flywheels, they are rated around 2500 RPM (while making cuts in concrete) the energy storage for a bicycle should be pretty generous. Just a quick thought :)
New they price from $800.00 to as much as$1500.00, on some occasions a concrete contractor will give them away and not bother having them reconditioned.

19. Jan 16, 2015

### Staff: Mentor

I'm not adding no 30 pounds to my bike! :w

20. Jan 17, 2015

### Bystander

"Ten per cent?" This is for some sort of "Hare & Hounds" cross-country, steeplechase obstacle course? Two seconds on the throttle, two seconds on the brakes until you're seasick?