Solar charger for lights? Oh and first post, hi!
 

Hey folks I've been lurking here for a few weeks gaining knowledge to rebuild my 'classic' 86 or 88 (from what I've read) Fuji Cadenza hybrid commuter.

Now that I've got the dang thing in pretty nice mechanical shape I think it's time to goof around with geeky stuff, perhaps attempting a solar charger for headlight and tail light batteries? Has anyone ever tried anything like this? I've found a few schematics and what not around the web for things like this but normally it's pretty impractical.

I thought though that it would be pretty cool to be able to top off your juice during the day for the trip home. Although my commute is only about 7-8 miles round trip I think it would just be another cool thing to geek out on.

Eric

I would normally consider solar panels that are attached to your bike to be not worth the space they take up. If you're running LED blinkies and NiMH batteries, it might be easy to charging at home on the weekend with solar power, exclusively.

Here's a link to a nice little project I found on another board:

http://edcforums.com/index.php?topic=7585.0

I'm sure you could use the same project to charge AAAs as well.

There are also some you can buy that are already made. I have the Brunton Solarport 4.4, http://brunton.com/product.php?id=280, and also the Solio, http://www.solio.com/v2/. The Solarport comes with a battery charger for 4 AAs or AAAs. Of the two, I like the Solio more, because it has an internal battery, so you can store solar energy and use it later while it's dark. The battery also has the largest capacity of any commercially available product like it that I was able to find. It's almost pocket-size. You might also want to look at http://solarstyle.com/, which has similar products and right now has a liquidation sale going on.

I use the Solio for our cell phones, my Nintendo DS Lite, and I may use it for my Sony PSP later. I use the Solarport mainly as a battery charger. My plan is to use rechargeable AAs and AAAs as much as possible. I'm just about out of primary AAs, but still have quite a few AAAs left. I like the Rayovac Hybrid batteries; they're NiMHs but hold their charge much longer than typical NiMHs.

If you're using 12 to 16 volt batteries, just pick up a solar panel at Harbor Freight. The one I have is on sale for $15 right now.
http://www.harborfreight.com/cpi/cta...emnumber=44768
It only generates 1.5 watts in full sun, so if you have a 30 minute lights-on time per day and a 10 watt light, you'll barely have enough time to charge the batteries during the workday, and that's if it's a sunny day.

You could get a bigger panel, or two panels and run them in parallel, but that panel is about as big as I'd be willing to haul on the bike if necessary. Also it's glass and non flexible.

The only "circuit" that's needed is a diode to prevent backflow, and that's already in the panel.

Just leave the thing at work and plug in when you get there.

Can you give us some idea of how well these work. For example, how long would it take to charge a pair of AA batteries w/ either? If you can't charge batteries w/ the solio, how long to completely charge your cell phone?

There is a company which I really like but yet to buy a product from called GoMadic.

http://www.gomadic.com You can use 4xAA batteries and get almost any adaptor tip you need for your device and go light while riding/travelling.

Also for cellphones I recently bought a Energi To Go product by Energizer ( http:www.energizer.com ) which takes 2 x lithium cells (comes with it) and the phone adaptors for your phone. The packaging in the stores allows you to try the plug on your phone while you examine the product. It is very light weight and can fit in a cargo pocket or pocket easy. Just elasticband the adaptor you need to the device put in the pocket/purse/murse (man-purse)/bag and you're good to go.

http://www.kenkifer.com/bikepages/touring/laptop.htm

Ken Kifer used a solar panel to power his laptop on a couple of his tours from back in the day. Unfortunately he was killed in 2003 by a drunk driver so all that we have is his website. Best of luck with this!

I'm moving this to Electronics et al from Commuting.

I have a Silva II solar panel (13,6V / 350mA) and a charger I can use with it. It works, but it's slow. If you're not planning to move your setup around a lot, you can increase the panel surface area to get faster charging.

Another BF member (n4zou) has come up with a diabolical DIY charger/bike light combo that's powered by a dynohub. The plans have been posted a couple of times in the Forums, use the search function to find them.

--J, a Forum Mod

Here is my latest circuit.

http://i143.photobucket.com/albums/r.../DynamoUSB.jpg

This circuit works with bottle, BB, or hub dynamos.
The 4 Ni-MH batteries regulate and filter power from the dynamo and bridge rectifier supplying clean and safe power for the USB connector.
The headlight side shows the simplest way to use a high power LED. More circuits can be found here.

http://www.pilom.com/BicycleElectron...moCircuits.htm

Switch S1 selects the headlight, USB, or center off for dynamo hubs.

Prior circuits used the rechargeable batteries in the same way as the USB circuit to supply clean power for the headlight LED. This is no longer required as new high power LED's can easily accept up to 1,000mA or about double the current supply of a typical dynamo. My headlight will provide light at less than walking speeds with a bottle dynamo so pushing the bike up a very steep hill is safe with plenty of light illuminating the side of the road.

I've tried solar power. It's just not practical on a moving bicycle. It's impossible to keep the panel aligned with the sun enabling it to produce enough power for serious battery charging. Solar panels are pilferable items so leaving one on the bicycle outside charging in the sun will be stolen rather quickly.

Modern dynamos do not have anywhere near the drag as vintage units. Even tire driven dynamos have less drag than knobby tires on pavement. I prefer a bottle dynamo on my touring bike as there is no drag when disengaged from the tire whereas hub dynamos do have some level of drag with the lights turned off.