Carry weight for regenerative brake improvement

[Demargon]

Agree with that @Gimlet, nothing like low weight for long rides. There's only one question left: what is the best speed for regenerative braking?

I noticed the best speed for improving ranges in flat are close to 12/15 km/h. Can I presume is also the best speed for regenerative braking?

My best trick to improve range is walk (uphill mostly)

[Gimlet]

My trouble is that the only way I seem to be able to get below 95Kg is to strip naked. I'm sure that would be too much of a shock for most people!

[ubertoad]

I just want to calculate that mass *gravity *height Suppose you carry 30kg down 100m hill

30 kg * 9.8 m/s^2 * 100 m = 29400 joules = 8.17 WH

It is proportional to weight and hill height. 1kg per 1m hill is 0.00272222 WH (or WH/(m*kg)), you can multiply that by weight and height.

This is absolute theoretical limit.

Generators are actually quite good in mechanical energy conversion efficiency (up to 98%). So are the lithium-ion accumulators. So I think you can take 50% as pessimistic coefficient, 70% as some average and 90% as optimistic coefficient.

But even optimistically with 30kg big weight and 100 m big hill and 80% of rather small 240 WH accumulator the help is like 4% of capacity.

elevationmap.net might provide you your hills height if you want to play with that.

[Gimlet]

I read somewhere that if you go down and up the same hill the likely regen is roughly 25% of the energy used going up!

[kasenutty]

If I start on a mountain top with a dead battery, will it charge itself up by the time I get to the bottom?

[meepmeepmayer]

2 hours ago, kasenutty said:

If I start on a mountain top with a dead battery, will it charge itself up by the time I get to the bottom?

If the way down is long enough, and if you have enough battery at the start to begin riding (otherwise you can push the wheel to generate a little bit of electricity to get there), then yes. It will charge, until it beeps at you due to overcharge when he battery is full and you still go further down.

2 hours ago, Gimlet said:

I read somewhere that if you go down and up the same hill the likely regen is roughly 25% of the energy used going up!

My 7% average incline standard hill gives me approximately 8% back for 20-25% used (if I remember correctly), so 33% may be a good lower estimate. It probably depends a lot on route and temperature and can go a lot higher, other people say 60%, so who knows.

[The Fat Unicyclist]

4 hours ago, meepmeepmayer said:

My 7% average incline standard hill gives me approximately 8% back for 20-25% used (if I remember correctly), so 33% may be a good lower estimate. It probably depends a lot on route and temperature and can go a lot higher, other people say 60%, so who knows.

The amount generated on my regular downhill can vary a lot... speed, temperature, weight carried and even wind resistance seem to be significant factors.