On board recharging......

Maybe a stupid question and possibly already covered but............

Any way we can fit a big mama honker dynamo onto the bike which is plugged into the battery pack so that when we are going downhill or free wheeling etc. the battery is getting a little bit of charge. In an ideal world the bike should be able to run for hundreds of miles if the onboard recharging system generated enough juice. Could be from a combination of dynamo on the front wheel, one on the rear wheel, a solar panel on the back of the bike and a mini windmill.

It may be a crazy thought but if they can put a man on the moon I'm sure something like this can be achieved with a bike.

Comments appreciated.
 

Ian

Esteemed Pedelecer
Apr 1, 2007
1,333
0
Leicester LE4, UK.
A few bikes do use the motor as a generator to supply a charge to the battery when braking or going downhill. The problem is that the amount of energy recovered is very small and in practice makes little difference to the range. Most cyclists would agree that the best way to harness the energy gained going downhill is to use the momentum to help going up the other side.
It would be rather difficult to implement a windmill on a bike, perhaps a sail would be a better bet.:D
Solar panels certainly can be used to charge batteries but only large and heavy ones have sufficient output. I have panels measuring a total of approx 700mm x 700mm but these need 20 hours of sunshine to fully charge a bike battery and are far too large to carry on the bike, not to mention the difficulties of keeping them facing the sun.

It's a nice idea but I fear not really practical, at least not in the UK and not with an e-bike as we know it.

Having said that a pig has been known to fly.;)
 
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Ian

Esteemed Pedelecer
Apr 1, 2007
1,333
0
Leicester LE4, UK.
I believe a marksman was standing by in case it became a hazard to aircraft, not sure if he tried to shoot it down though.

Last thing I saw like that was the Aussies kangaroo.
 
Sep 24, 2007
268
0
Yeah, the last bloke to try using solar panels to charge his bike ended up catching fire at the very moment the solar panel salesman was shaking his hand......
 

llward3

Just Joined
Apr 28, 2011
3
0
Solar On Board Recharging- Another Look?

I live in Arizona, and am electrifying an old adult tricycle with 1000W motor and 48V20AH LiFePO4 battery. I am planning to add a frame for an "awning", i.e. sun protection. I estimate I will have 24in x 42in area - potential area for solar panels for on-board recharge.

Most workable panels here are 12V, and I could fit 2 on the awning. Anyone out there with the brains and/or experience to suggest what I need to use the output of the panels to charge the battery, even wiring diagrams if available?? I will happily post pics if I get this beast built.

BTW, I have finished updating a 24V EV Global Ebike from its 400W brushed motor and 7AH lead acid battery to 100W brushless and 48V20AH Li battery- wow! The old beast would not make it up the hill home- the new version went up at 44kph without pedaling!
 

eTim

Esteemed Pedelecer
Nov 19, 2009
607
2
Andover, Hants.
I have been thinking about recharging when touring and using a tent and I think I've found the answer:

Use an oxtail trailer (capable of carrying 70Kg) Oxtail Bicycle Trailers - The Market Leaders in Bicycle Trailer Design And Technology
carrying a Honda suitcase generator weighing 13Kg Specifications | EU10I | Generators | Energy | Honda (UK)

I already own one of the generators and they are very quiet and fuel efficient and small, two hours of running will burn less than a litre of petrol and as a bonus you can charge other items, power lights etc. They are expensive new, but I picked mine up from Ebay for around £300.
 

flecc

Member
Oct 25, 2006
53,260
30,648
Those little Honda generators are great and ideal for this purpose, scary price though as you say.

That Oxtail link tube to the bike looks too frail and insecure for a banking trailer, and their claim to be design leaders in trailers is just silly. The well established and popular original of this type of trailer is the Bob Yak which uses a very secure linking to the bike as you see in the photo, giving stable banking on corners :