sbhikes

I ride from my garage to my workplace which is safe enough that I can leave my bike unlocked with all my fancy stuff (light, paniers) attached to my bike and not worry about thieves. One thing I find quite annoying is removing the battery to my light and bringing it inside to charge. Do you think it would be possible to get some kind of solar-powered charger so I could just leave it out in the sun, plug my light in during the day and by evening it would be all charged up and ready to go? I have a 12W Night Rider light and I'm not electronically adept to know how to calculate the volts or ohms or whatever I'd need to know if it would work.

What do you think? Does such a thing even exist?

EricDJ

Would likely get stolen.

If you have a window at work, you could do it at work. I have a VW solar panel that charges car batteries through the cig lighter in the car. You'd have to get/make an adaptor to go to battery.

It's in the wifes car right now so I can't get the specs off of it right now, so someone would tell if it will work. IIRC is charges in excess of 14 volts. But if it works, they sell cheaply on ebay .

sbhikes

Nothing gets stolen where I work so this would work for me. I don't even lock my bike.

JohnBrooking

That's a great idea, sbhikes! I'd like to look into that, too. Maybe the manufacturer of the light would have some recommendations, if you could find the right person to talk to.

JohnBrooking

So here's a specific question about that, for those who know more about electronics projects than I do. My factory recharger is labelled with the VDC and amp output. Are those the only specs I need to match in selecting another charger, or is there more to it than that?

banerjek

Don't even think about it. The size solar array it would require would be way, way too big to be practical. Plus solar cells are fragile.

If you really hate batteries, consider a dynohub. However, these things won't generate enough juice to power your NR light.

Stick with the batteries -- it's really the way to go.

cabrilo

Here ya go!
https://www.ecotopia.co.uk/product_in...handbike-torch
If you get it, let us know how it works....

Jay H

I saw a solar powered backpack (kind of like a small daypack) but it was like $299. It was in October's issue of Outside magazine..

Brunton makes a couple of solar chargers, you can check on their website, they make a roll-up one that I've thought about using for touring..

Jay

cabrilo

On the side note, I think it would be great if they could make these work on bikes:
https://www.foreverflashlights.com/fo...shlights_3.htm

Maybe something that would collect electricity from any movement. (not just back and forth, but maybe also side to side and up and down movement)...

cerewa

I don't think that system would ever compete with a dynohub for efficiency. Dynohubs would slow you down quite a bit if you wanted 15 watts of light. But trying to get 15 watts of light out of a "shake me" generator would be worse.

cabrilo

i know.... i just WISH...

cerewa

Darn "law of conservation of energy". If it weren't for that, I could shake one of those "shake me" generators and hook it up to power transmission wires, and sell the electricity for millions of dollars.

2manybikes

+1

sbhikes

The hub generates the electricity while you use it. I just want to charge the battery while the bike is sitting out in the sun and I'm locked away in my dungeon.

slvoid

Perhaps one of these high tech gadgets..

slvoid

If you're really insisting on the solar way, look at the charger on the NR battery.
It should say something like Output: 12 V 250mah or something.
That's about 4 watts, find a panel that matches.

cabrilo

Did anybody see my post above. There IS a solar powered bicycle light!

https://www.ecotopia.co.uk/product_in...handbike-torch

We just need to find out how it works in the real world. Anyone ownes one?

mike

That is a neat looking device. I wonder if it could actually work, though.

Solar powered battery chargers have been around for years. Curiously, I have never heard anybody comments about them.

I bet a search on bikeforums.net would turn something up. Over the years, so much has been posted about lights and energy sources.

mycoatl

What about one of these?

https://www.kooters.com/solar.html

ken cummings

Stick to chargers or a generator (2nd choice). Those gadgets that convert bouncing motion into power are way inefficient. Low power to weight ratio. You carry the weight and YOU generate the power. For something extremely efficient get one of the tritium powered emergency lights. Light for 15 years non-stop then recycle it.

DannoXYZ 

The modern solar-panels are flexible, like doormats. I use a 5-watt 12x18" solar-panel on the deck of my sailboat to keep the batteries topped off. Maximum output is about 13.5v @ 0.4amp or so with a circuit that switches over to trickle-charge when the battery's fully charged. It's encased in a plastic housing and people can walk on it without any problems.



Something about half this size that fits on the flat portion of a rear-rack would be perfect for a bike. At 2-watt (0.15-0.20 amp) output, it would take a full 8-hour day to charge up a 2-ah battery-pack. Another idea would be two battery packs and you can keep on on the charger and swap it each day.

Something like this Coleman Exponent Flex 5 might be just the ticket.


Or maybe the SPE-250 model would almost fit a rear-rack perfectly:


Here's a link to tonnes of solar stuff.

HereNT

Looking at one of the links above, it mentioned that a lot of modern rechargable devices aren't made for the type of current given by solar devices. They want a constant, even input. Also, with the amount of current that you'd probably need, you'd be shelling out a fair penny for the solar chargers. For pretty much the same money, you should be able to buy a second battery. Just take one off the bike when you get to work, and put it on the charger. Put the one from the charger on the bike for the ride home.

Rinse, and repeat.