Do solar chargers really work?
 

I am considering a long ride this summer which will leave my outside for several days. I will be relying on a GPS as I will be in China. I need some way to keep the GPS working.

This brings me to the question, do those battery / solar cell combos, like the one pictured, actually work?

I intend to put it on the top of the stuff on my rear rack on a recumbent and use it on a GPS like this one.



http://bikeforums.net/attachment.php...hmentid=322065
General

Product Name
Portable Mobile Solar Power Charger

Brand/Model
NA

Color
Black

Basic Specification

Battery Type
Lithium Battery

Capacity
2600MAH

Input Voltage
5.5V/300-500mA

Output Voltage
4.2V,5.5V,9V /400-800mA

Charger Time
Around 2 hours

Charging Mode
USB or Adapter

Port
1 x USB Slot

Dimension(L x W x H)
120 x 65 x 11 mm

Suitable For
iPhone/iPad/PDA/PSP/MP3/Mp4/Laptop/Notebook

Features
- Portable mobile charger for your item
- Easy to take and charge conveniently
- LED lights flash when charging the mobile.

Package Included
- 1 x Portable Mobile Charger
- 3 x Cables
- 1 x Charger
- 4 x Adapters

That things is Earthquake proof but not waterproof?

You're better off going for an AA powered GPS like an etrex.

etrex does not have China maps. Part of the trouble is that maps are a state secret. As such, GPS units that are offered outside of the Chinese market will not do what I want. Also, the batteries purchased in China are of very poor quality. You cannot plan on a battery in China lasting more than half as long as a similar battery purchased on the US.

I have a small GPS with good battery life; however, it does not display maps. I actually doubt that I need the maps display; but, The last time I made a similar trip I ran into trouble when the road detoured at one point.

Yes they work howbeit slowly and on sunny days.

Maybe the free open source ones?
http://garmin.openstreetmap.nl

I followed Mike's blog as he rode the Tour d'Afrique. His equipment page may be of interest - it mentions a Goal Zero charger.

http://www.bike2013.com/equipment/

I like using an auxillary AA battery pack like this one:

http://www.gomadic.com/garmin-edge-7...-extender.html

More Gomadic chargers/accessories for the 705, solar too...

http://www.gomadic.com/manufacturers...ame=Edge%20705

I just bought a Revolve Sol-sport 5 kit for $35. folding solar panel, cables & 2200mah lithium poly battery came with it. :)
Meijer.com has them on clearance.

I check

I checked, it appears that they don't have them anymore.

Some of these things are battery packs that you charge from mains power, that also happen to have a fairly useless solar panel on them.

Try to get a solar cell with a bigger output than your GPS' power requirements and maybe you can keep it running properly through cloudy conditions. You will want a battery in there to get you through the dark spots too. You need to do some math to decide how big a solar cell and battery you need.

Yes. You need a pretty large panel in the first place, and even larger to allow for non-ideal conditions (shade, clouds, not pointed directly at the sun). Check the spex of the Gomadic solar panel, 13" x 12" and weighs 4 lb. http://www.gomadic.com/garmin-edge-705-sunvolt.html



AAs are small, lightweight, universally available and can get you through periods where you can't charge from an electrical outlet. The 705 will run nearly 3 times as long on a set of 4 external AA batteries as it will off its internal battery.

Bigger the panel the better , bike trailer with a 4 square foot size perhaps?

I think the flexible brown cell is less efficient than the Rigid Blue ones.


maybe a Hub dynamo for juice when you are moving, the Panel for the campsite

??? Typically, one is at the campsite at night.