To calculate this figure, multiply volts and amps.
Volts X Amps = Watts.
The sum is the number of watts your computer uses.
Second - Calculating how many watts of power your laptop needs - in order to perform the functions you expect it to perform.
Measuring your energy need can be a bit tricky because the number of watts your laptop uses are influenced by the activity it's performing at the time.
High energy activities include game playing, video up or downloading, burning dvd's, etc. As it performs these tasks it's need for watts of power increases.
You can save yourself a LOT of money by knowing in advance exactly how much power you need your solar laptop charger to generate..
To easily find out how many watts your computer consumes while being used for different functions try the Kill A Watt. Just plug any device into the Kill A Watt and it will display the number of watts it uses while performing any given function.
Choosing a solar charger for a laptop.
Consider how your computer is used on most days. A 15 to 30 watt charger is sufficient for catching up on e-mail or compiling text documents for 30 to 60 minutes per day. 50 watts and more will adequately power and recharge most newer model, energy conscious laptops and a 90 to 100 watt laptop battery charger is not too much for older computers and high energy draw activities.
Solar Laptop Charger Options
- Serious Solar Laptop Charger Kit If you're serious about powering a laptop with solar energy, don't get anything less than a 50 watt system. Something like the Brunton SOLARIS 52 CIGS Foldable Solar Panel will usually produce enough energy to power and charge your laptop at the same time.
Even with 50 watts there'll be times, such as cloudy or high use days, when your system struggles to make adequate energy. More is definitely better to ensure that critical functions remain uninterrupted.
- Flexible Solar Laptop and Battery Charger Thin film photovoltaic technology has led the way to super portable, flexible solar panels that fold or roll up into neat transportable packages. When you need to recharge, simply unroll (or unfold) the panel and place it in a sunny area. The number of watts your panel is rated for will determine how long it takes to recharge or top off the battery.
If you have a small, late model, efficient laptop a Brunton 26 Watt Foldable Solar Array will provide ample energy.
To power and charge a laptop such as a Macbook Pro 17 a Brunton SOLARIS 52 CIGS Foldable Solar Panel is a better choice particularly if you intend to use the laptop for several hours per day.
- Compact Solar Laptop Charger Some compact chargers that output in the neighborhood of 5 watts claim to be laptop chargers. Laptops are notorious power hogs that would laugh at an offering so puny. It would take 4 or 5 days to fully charge a laptop battery with a 5 watt battery charger. These compact chargers work for small electronics like cell phones and ipods but, as a laptop solar charger, anything that outputs less than 12 Watts is disappointing.
- Solar Laptop Bag A 14 watt panel like those incorporated into the Voltaic Generator bags will power a laptop for between 1 and 2 hours after a day long charge... but you can only recharge the battery, not run the computer. This clever design delivers even on rainy days because it's also a computer bag.