Solar panel charge ???

[chris2014]

hi
its possible to charge the bicycle battery with a solar panel when you ride ?
There is 10W-20W semi-flexible very light panels that the rider can have in his or backpack and that way get some extra miles of range in a sunny day.

 

[Alan Quay]

It's a nice idea, but it is 10w really worth having? You would be lucky to be putting 5% back in, and you would be carrying extra weight. This might even negate the benefit.

Better idea would be to get a bigger battery, and charge it with a solar cell that you don't have to lug about. Even that has it limits.

To put it in context: Assuming its summer, and the cell puts out 10w, for 12 hours (unlikely) that's 120 watt hours. If you have a 36v, 10 ah battery (360wh), and perfectly efficient charging system you could re-charge the battery in 3 full days.

I'n reality in the UK its more likely to be a week or three.

Sorry to be so negative, but that's just the reality of solar I'm afraid.

 

[chris2014]

the idea is to get extra miles (like the brakes regen system), not fully charge the battery.

But is it possible to directly connect a solar panel to the battery or you need lots more components ?

 

[Alan Quay]

the idea is to get extra miles (like the brakes regen system), not fully charge the battery.

But is it possible to directly connect a solar panel to the battery or you need lots more components ?

Brake regen is probably not worth having either.

The reason I gave the illustration of the full re-charge is to put in context the tiny contribution this panel would make.

...and yes, you would need some extra components to make it work.

Sorry to be negative.

 

[flecc]

I agree with Mike, you'd be adding little distance, hardly worth the trouble and expense.

Assuming your battery normally lasts for a two hour continuous ride and the sun on the panel remains at maximum, that might give perhaps 2 extra miles at a typical 12Wh per mile in a theoretical ideal situation.

In a real world situation with the direction of the sun onto the panel changing and the brightness varying, probably more like one mile at best.