11. Notes on Solar Module Use
Note that the black surface of the amorphous solar modules is
the active one and should face the sun. The silver surface
should face down. Carefully clean the surface of the module
once every 6 months or when dust builds up. Use a soft brush.
The module can also be wiped with a soft, damp cloth at a
cool time of day. Don’t use rough or abrasive cleaners.
For portable applications, avoid frequently holding the solar
module by one edge and tilting it, as this will in time cause a
break along the top of the module. Position the solar module
where it gets no shade or shadow over it all day. Make sure
vehicles will not run into it or animals knock it over. Charging
though window glass will reduce the charging efficiency.
Position the solar module to face the sun and adjust the angle
so as to make the largest shadow on the ground behind it.
For fixed use, the module is best mounted on the roof or some
other permanent position where it will not be damaged,
moved or stolen. Mount it on a small metal or wooden frame
to keep it away from the surface of the roof to allow air to
circulate under it. This will improve efficiency by preventing
the module from getting too hot. Don't mount it direct on a
metal roof or metal surface as this will get too hot. Instead put
a wooden board or similar on the metal roof.
For fixed use, it should be tilted at an angle from the ground
according to the table below and towards the equator. This
way it will get the best total sun though out the day and will
generally give you the best solar charge throughout the year,
taking into account the worst month. Don’t mount it at less
than 15º from flat, otherwise it won’t benefit from the natural
washing effect of rain.
Get into the habit of leaving the Glowstar plugged in to the
charge all the time and only remove it when you need to use
the lantern in an other room or location. Plug it back in as
soon as you have finished. This way it will stay topped up and
ready for use all the time. It will also help to give longer
battery life. There is no problem leaving the solar module or
charger plugged into the Glowstar over night because the
Glowstar has reverse discharge protection.
Tilt Angle of Solar Module.
It is best to face it to the equator, i.e. directly north (if you are
in the southern hemisphere) or directly south if you live in the
northern hemisphere). This way it will get the best total sun
though out the day. Alternatively you can move the module
round as the day goes on – if you remember! As a rough
guide, tilt it at an angel from the ground as shown in the table
below. This will generally give you the best solar charge
through out the year, taking into account the worse month. If
it is not going to be cleaned regularly, don’t mount it at less
than 15º otherwise it won’t benefit from the natural washing
effect of rain.
Location latitude Suggested Tilt Angle
from Horizontal
0-15° 15º
15-25° Same as latitude
25-30° add 5° to local latitude
30-35° add 10° to local latitude
35-40° add 15° to local latitude
40° + add 20° to local latitude
The table below give some examples.
Location Latitude Tilted Angle Direction to
face
London, England 51 71 South
Paris, N France 48 68 South
Nice, S France 43 63 South
Madrid, Spain 40 57 South
Kabul, Afghanistan 34 44 South
Cairo, Egypt 30 37 South
Khartoum, Sudan 15 15 South
Bangalore, India 13 15 South
Lagos, Nigeria 6 15 South
Accra, Ghana 5 15 South
Nairobi, Kenya -1 15 North or South
Dar Es Salaam, Tanzania -7 15 North
Harare, Zimbabwe -17 17 North
Seattle 47 67 South
Melbourne -37 52 North
Perth -32 42 North
Darwin -12 15 North
Wellington, NZ -41 61 North
Rio de Janerio -23 23 North
Buenos Aires -34 44 North
Lima -12 15 North
Belem, Brazil -1 15 North or South
Guatemala 14 15 South
NYC, USA 40 60 South
Miami, FL, USA 25 25 or 30 South
San Diego, CA, USA 32 42 South
Portland, Oregon, USA 45 65 South
St. Louis, MO, USA 38 53 South
Which Size of Solar Module?
This depends on the Glowstar model you have and on your
location on the globe. The table below gives a guide. If you
have a module that is too small, then the battery will not be
charged fully each day and so the lamp will turn off sooner
each evening. This will also mean the battery is permanently
in a low state of charge, which over a long period, will have a
detrimental effect on battery life.
You can not have too large a solar panel, as long as you don’t
exceed the 20W max limit for the GS5 and 30W max for the
GS7.
The table below shows the recommended peak power of the
module. This takes into account the worst month of the year
for solar in that location, working on average solar data over
the past 10 years. It also assumes using 4 hours of a 5W lamp
with a GS5, or 7 hours of a 7W lamp with the GS7. The figures
in brackets are the calculated minimum module size. Some
generalisations have been made because of variations across
a region and there will also be variations due to localised
climate conditions. The table is therefore only an approximate
guide. Contact Sollatek for information that’s specific to your
location and intended use.
Location Tilted Average Insolation Module Wp
(sun hours per day) GS5 GS7
Nairobi, Kenya 4.0 5 (5) 10 or 15 (12.25)
Cairo, Egypt 5.0 5 (4) 10 (9.8)
Khartoum, Sudan 6.0 5 (3.3) 10 (8.2)
Accra, Ghana 3.5 5 (5.7) 20 (14)
Lagos, Nigeria 3.5 5 (5.7) 20 (14)
Tripoli, Libya 5.0 5 (4) 10 (9.8)
Dar es Salaam, Tanzania 4.0 5 (5) 10 or 15 (12.25)
Harare, Zimbabwe 5.5 5 (3.6) 10 (8.9)
Most of India 4.5 5 (4.5) 10 (10.8)
Kabul, Afghanistan 5.0 5 (4) 10 (9.8)
Northern France 1.5 20 (13.4) 30 (32.7)
Southern France 2.0 10 (10) 30 (24.5)
Spain 3.0 10 (6.7) 20 (16.4)
England 1.0 20 (20) 50 (49)*
* Using the GS7 with a 7W tube for 7 hours a day in winter will
require a solar module which exceeds the input rating of the
Glowstar. A 30W module should be used and ether a 5W tube
used or less that 7 hours running time per day in winter be
expected.
Actual solar module
appearance may differ
Other modules available now feature flexible solar
modules for the most unforgiving of environments.
Ask your sollatek distributor for further details.
