Charging batteries from the sun
Modern photo equipment require electric power to work. And if you use external flash units, you will find that they too consume a lot of electrical power. When you're hiking, mountaineering or on a safari, you may not want to carry a truckful of spare batteries. A handy alternative is to use solar power to recharge your batteries. Here is what you need.
To charge batteries from solar power you need two things:
- A portable solar panel providing 12 volts output.
- A 12 volt travel/car charger for the battery you want to charge.
Hook the two together, and you've got a portable charging kit where you are able to recharge batteries whenever there is sunlight.
Some of the best portable portable solar panels around are SunLinq from Global Solar. They come in various sizes (from 2 to 30 watt), but most output 12 volt, making them compatible with standard travel and car chargers. They are flexible, so you can hang them on your backpack when hiking.
The most suitable SunLinq chargers for charging batteries are those providing 6.5 or 12 watt. These models come with a 12 volt DC socket, 12 volt DC plug, and a standard barrel connector for devices designed to be plugged directly to a 12 volt “cigarette lighter” socket. The 6.5 and 12 watt solar panels also have a built in regulator so you can plug them directly into a device or charger. The more powerful 25, 30, 62, and 124 watt models are unregulated and will require an additional voltage regulator attached to avoid harming the equipment.
You also need a 12 volt car or travel charger for the type of batteries you plan to bring on the trip.
Below is a list of ready-to-run eBay searches for travel chargers for many popular battery models. To search for another battery, just substitute the name of the battery in the search field when on eBay:
- NiMH (rechargable AA and AAA batteries)
- BP-511 (Canon 10D, 20D, 30D, 40D, 50D, 300D, G1, G2, G3, G5)
- NB-2L (Canon 350D/XT, 400D/XTi)
- LP-E4 (Canon 1D III-series, 1D IV)
- LP-E5 (Canon 450D/XSi, 500D/T3i, 1000D/XS)
- LP-E6 (Canon 60D, 5DII, 7D)
- LP-E8 (Canon 550D/T2i, 600D/T3i)
- LP-E10 (Canon 1100D/T3)
- EN-EL3E (Nikon D50, D70, D80, D90, D100, D200, D300-series, D700)
- EN-EL4 (Nikon D2-series, D3-series, D300-series)
- EN-EL9 (Nikon D40-series, D60, D5000)
- EN-EL15 (Nikon D7000, V1)
To charge, you connect the 12 volt output of the solar panel to the 12 volt input of the travel charger. Note that the charger itself requires some power to operate, and so the first 2-3 watt of your solar panel's power output will be consumed by the charger, and only power above this threshold will actually charge the battery.
Charging times will obviously depend on both the capacity of the solar panel, the capacity of the battery, and the strength of the sun. Around noon, in good light, the 6.5 watt model outputs 0.4 amps and charging times for 4xAA batteries or a single digital camera battery will be about 2 to 4 hours. The 12 watt model outputs 0.8 amps and charging times for 4xAA batteries or a single digital camera battery will be 1-3 hours.
Because the charger itself draw some power, you will only be able to charge effectively in the 4-5 hours around noon, and you will need a fairly bright sky.