It will help if you post the exact manufacturer and model number of your panels.
The first thing I would do is see whether each panel is approximately correct in power. What you should do is point the panel directly at the noon sun, and measure open circuit voltage. It should be close to the voltage specified on the back of the panel. Then switch your meter to current (you may have to plug the leads into a different socket on the meter, sometimes labeled "10A".) If the short circuit current is approximately right, assume the panel is good, then test the next one. If all the panels fall short of specification, then they are just marked wrong. If the manufacturer does not specify STC (standard test conditions) for their ratings, then can make up any number they want as a rating.
If all the individual panels check out good, then possibly you have some wired backwards. If 7 panels are wired backwards, they will cancel out 7 panels wired forwards, leaving you with 2 panels producing an optimistic total of 150 watts. On a hot day, that might be 120 watts.
It would have been better if you had included exact measurements instead a broad number and percent. By this I mean "each panel should output 12 volts at 6.25 amps. 16 panels at 75 watts should deliver 100 amps at 12 volts, but we have them connected to produce 24 volts which would be 50 amps and the delivered amps are actually 5 amps." Your numbers are likely to be different, but having actual numbers will give better answers.
All of the earlier answers on physical arrangements still apply.
Plus - mounted flat? Mounted behind a glass wall/ceiling/protection?
I am not an expert. I would like to whether the panels are connected in parallel or in series? Try to connect them parallel and see whether the out put is better.
If it is based on the solar cells, it is possible some cells are weak and they give rise to an additional resistance.
Try to change the position of solar panel to get maximum solar intensity.
This can be done by using stepper motor for changing the position of solar panel where there is maximum intensity. Use LDR switches for this purposes.
still doubt then contacts me on this Email patelvir17@ymail.com
get a light meter and see how close to 1kW/m^2 the incoming sunlight is.
if you're getting less than 1kW/m^2, then expect to get less than the rated 75W
next, check that the panel is oriented perpendicular to the line connecting its location and the sun.
if the angle is not perpedicular, then expect to get less than the rated 75W
check each panel individually to confirm that no panels are broken.
then check the parity of each connection to make sure the panels are wired correctly (in parallel where necessary and in series where necessary.)
finally, check the settings of your charge controller -- if those are set wrong, then you'll only see sub-par performance from the system of panels.
are your conductors sized appropriatley? cmil=2KID/VD
*HINT VOLTAGE DROP SHOULDNT EXCEED 5%......
As per wattage mentioned on solar panel i.e 75w. In actual we are getting only 10% of actual wattage. There is total 16 panel each of 75w. we are getting 10% of total output. We have checked all the possible causes. Still no solution. Kindly if any one from the related the field can tell us the cause and solution for it.
Thanks in advance.
