Solar panels can juice up your notebook battery life
- By Jason z_rne
- Feb 23, 1998
Off the grid doesn't necessarily mean out of luck.
Say you're working at your notebook computer, with no electrical outlet nearby, when
the low-battery light starts flashing. Just step to a sunny window or go outdoors, connect
SunWize Technologies' Portable Energy System (PES) and keep working.
One of the PES solar panels can extend notebook battery life as much as twofold.
The panels would be particularly useful to government employees such as Forest Service
officers who work outside.
The whole kit of two photovoltaic solar panels, voltage controller and cables weighed
in at less than 5 pounds, including travel cases for the panels.
At first we were skeptical about getting enough solar juice to run a notebook.
That just shows how little we knew about advances in photovoltaic cells.
Tests did support the company's claim of running a computer on solar power while
The panels measured about 11 inches by 16 inches by a half-inch wide and came with a
stainless-steel stand. A built-in LCD readout called the Opti-Meter indicated the power
It was useful, because a shift of a few inches could change the panels' performance
Full sun generated 18 volts. Notebooks differ widely in power consumption, but 18 volts
should be enough to run and recharge at the same time.
The panels worked in direct or indirect sunlight, and it took a bright, sunny day to
get maximum performance.
Even on cloudy days, though, you will likely have enough power to extend the battery
The PES can even power other devices in conjunction with a notebook or separately.
The voltage controller has a multijack output and a voltage selector for two-way radios
and Global Positioning System units. Indoors, you should place the panels in a
south-facing window, because glass filters out some of the sunlight. A moderately cloudy
day produced an Opti-Meter reading of 30 for one panel.
That was too low to do much.
The second panel, however, raised the combined reading to 60--enough to recharge the
Recharge time depends both on sunlight available and on the individual notebook's
On clear winter days, we got combined readings of 200 and could run while recharging.
We haven't tested the panels in a summertime haze.
The panels were quite rugged and water-resistant though not waterproof.
They probably would survive anything a notebook can survive. They're rated to operate
at temperatures from minus 10 degrees to 140 degrees Fahrenheit. At the extreme low end,
they're supposed to continue supplying power, but the Opti-Meter and voltage controller
might not work properly.
Every advance in notebook battery technology seems to be offset by an increase in
notebook power consumption, which means average battery life has not risen over the years.
The Portable Energy System will let you get some work done instead of juggling fresh