Nokia's research project on phone charging using
harvested solar energy has now been completed. Can the
sun be relied on to charge your phone?
Nokia is searching for improved energy efficiency and
more sustainable alternatives for mobile phone users.
Last June, the company announced the Nokia Solar
Charging Project, a research project designed to assess
the viability and ease of solar charging for mobile
phones. The idea was also to look at the possibilities
for phone charging in conditions where it's not
possible to plug in to recharge the phone, or where the
electricity supply is uncertain.
Nokia's testers started with developing a prototype
phone for the project featuring a solar charging panel
integrated in the back cover for harvesting solar
energy. The small solar charging panels developed for
this project have been integrated to Nokia C1-02
devices, while a data logger will report the harvested
solar energy. The phone was tested last summer by a
team of five people in a range of different
environments. Two of the phones were tested up north at
the Arctic Circle, one in southern Sweden and one in
Kenya, and the fifth member of the test team was
sailing in the Baltic Sea.
Nokia's tests showed that charging a mobile phone by
simply using a solar charging panel on the back cover
is possible but challenging.
When carefully positioned, the prototype phones were
able, at best, to harvest enough energy to keep the
phone on standby mode but with a very restricted amount
of talk time. This means there's still some way to go
before a workable and care-free solution is achieved.
The most substantial challenge was the limited size of
a phone's back cover, which restricted the extent to
which the battery can be charged. What's more, to
ensure mobility, it is essential that the phone's
weather protection doesn't cover the solar charging
Nokia concluded that the amount of charge generated for
use by the phone is not solely dependent on the weather
conditions and the amount of sunlight. Factors such as
lifestyles and the angle of light also have a
significant impact on the amount of charge generated,
the company said.
The greatest amount of charge was generated in Kenya,
as there was no shortage of sunlight. From the energy
profile of the phone, Nokia 's tested in Kenya was an
active phone user, listening to the radio and making a
lot of calls. Nonetheless, in 59 days, Nokia's
kenya-based tested gained 20 hours talk time or
sufficient standby for 41 days.
On the Arctic Circle, by contrast, the amount of
sunlight depends very much on the time of year. But
even during the light summer months, the sun's angle is
relatively low, which means a lot of shadows. If the
user is frequently on the move, the phone will receive
a fairly low charge. Nevertheless, a test record was
achieved at the Arctic Circle, as Nokia's tester, was
able to move his phone from one side of the house to
another to track the summer sun as he got on with his
Reasonably good results were also obtained when the
tester was able to carry the phone while moving around
outdoors, for instance in a holder around his neck.
However, this isn't necessarily the most stylish or
convenient arrangement, and another solution is needed.