Recharge
- Thread starter Biker man
- Start date
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KnittyNorah
Über Member
- Location
- The Frozen North (of England)
Have a look at this you-tube vid - and at others made by him (Barnabe Chaillot) and his pals! Great fun even if not exactly practical for most UK conditions - yet.
ebikeerwidnes
Guru
- Location
- Z’ha’dum
I have seen a lot of people on all sorts of forums asking about ebikes recharging themselves
The answer seems to be that the extra effort required to power the dynamo - plus the extra weight etc - uses up more power than you gain in recharge
As far as a solar recharge - the size of the panel needed to provide any worthwhile level of charging would be far too big to put on a bike - even on a trailer!
There is a concept of the motor switching to a generator mode when going downhill - which would work as motors and generators are quite similar in some ways.
However, it seems that making an efficient motor is a known science - making an efficient generator is also a known science
but making one efficient involves doing things than make ot rubbish at the other thing
so, again, you can do it but the amount that you gain is less than what you loose.
Also - the electronics and battery systems need to be more complex to work it all out and cope with it
Having said that I did read something a few months ago (sorry - can;t find it now) that said they were getting closer to being able to make an ebike sized motor that could provide significant recharge power on decent downhill sections - and the other stuff needed to make it work
But not yet!
As we know they do this in electric cars - but they are way heavier and more expensive so adding extra weight and cost can be absorbed more easily.
You need to remember that there are always losses in systems - so whatever you do you never end up with a perpetual motion system
even with an ebike working in a vacuum (no air resistance) and with zero rolling resistance (basically no gravity - dunno how that would work anyway!) then you will still loose power generated due to electrical factots and heat
The answer seems to be that the extra effort required to power the dynamo - plus the extra weight etc - uses up more power than you gain in recharge
As far as a solar recharge - the size of the panel needed to provide any worthwhile level of charging would be far too big to put on a bike - even on a trailer!
There is a concept of the motor switching to a generator mode when going downhill - which would work as motors and generators are quite similar in some ways.
However, it seems that making an efficient motor is a known science - making an efficient generator is also a known science
but making one efficient involves doing things than make ot rubbish at the other thing
so, again, you can do it but the amount that you gain is less than what you loose.
Also - the electronics and battery systems need to be more complex to work it all out and cope with it
Having said that I did read something a few months ago (sorry - can;t find it now) that said they were getting closer to being able to make an ebike sized motor that could provide significant recharge power on decent downhill sections - and the other stuff needed to make it work
But not yet!
As we know they do this in electric cars - but they are way heavier and more expensive so adding extra weight and cost can be absorbed more easily.
You need to remember that there are always losses in systems - so whatever you do you never end up with a perpetual motion system
even with an ebike working in a vacuum (no air resistance) and with zero rolling resistance (basically no gravity - dunno how that would work anyway!) then you will still loose power generated due to electrical factots and heat
It would require a dynamo with windings to give a higher voltage 36/48 Volts. Dynamo are usually 6 Volts. This increased voltage requires a larger dynamo due to extra windings of copper. Now the current requirement to actually charge a ebike battery. To,gain any real benefit you would need more than 1 Ampere, again increasing copper winding thickness. Rotation of the wheel is also a factor in producing the required Voltage and current. Maybe if you could get several thousand RPM of the wheel, but it's more in the range of hundreds of revolutions per minute, not sufficient.
Then there are losses of generating the Voltage /current
KnittyNorah
Über Member
- Location
- The Frozen North (of England)
Have a look at Barnabe Chaillot's you tube channel - link to one of his vids above - and see his solar-powered trailer-mounted charger! Mind you, the conditions where he is, are rather different to the conditions we find here in Britain.
Nevertheless, it's certainly possible to have a solar-charged e-bike. How practical it would be in Britain is a question to which a positive answer has yet to be found, but that doesn't mean it won't be found ...
Yes with today's tec why can't it be done.
newfhouse
Resolutely on topic
cougie uk
Guru
It's been explained above.
You could have solar panels on your house and charge your bike off those ? Like some people do with electric cars - but it's a bit expensive.
Drago
Legendary Member
- Location
- Suburban Poshshire
Its called 'perpetual motion', and is against the laws of thermodynamics.
To recharge itself, while expending significant energy moving rider and bicycle, and with all the inefficiencies and losses, is impossible. At best the energy recuperated would be negligible, nowhere near enough to rechqrge a battery.
Its like usimg your own house lights to energise your solar panels to power your lights...it just ain't happening.
To recharge itself, while expending significant energy moving rider and bicycle, and with all the inefficiencies and losses, is impossible. At best the energy recuperated would be negligible, nowhere near enough to rechqrge a battery.
Its like usimg your own house lights to energise your solar panels to power your lights...it just ain't happening.
I would have thought with all the clever tec today they would have come up with something.
numbnuts
Legendary Member
- Location
- Gone over the hill and far away
They did it's called a "long lead"
Drago
Legendary Member
- Location
- Suburban Poshshire
Mr Scott above sums up the problem perfectly. Even the cleverest engineer cannot chamge the laws of physics.
😄They did it's called a "long lead"
F1 cars have something that stores energy up in the braking think it's called DRM something like that maybe?