Connecting Solar Panels in Series

Read THESE & become wise to your problem.

Gave you a 'GA' for the link. Sometimes I can't get the right words to make a search effective. Other times it seems to be as easy as falling out of a chair. I suppose the trick is to think of all the ways something might be described. Sounds easier than it is...

Yeah i have been searching on the web... but wanted someone who has worked with this kind of stuff to give opinion on this

However it is not working for me

What then are you observing?

Hi MAfzal the panels you have there are Grid Connect panels, not the good old 12 volt system type panels and whilst you have not stated what "it" is that is not "working" for you, there are two immediate possible problems, - firstly, Grid connect panels are designed to work with Maximum Power Point Tracking Inverters, hence they are focused on their working voltage, - for those ones you have, probably 35 or 36 volts, (in series, say 72 volts) - though mind you also the old 12 volt panels had open circuit (when cool) of 21/22 volts, - they had to charge a 12 volt battery up to 15 volts when they were hot enough to fry an egg on. The other thing is the amperage, that will be the amperage of the smallest panel, (lowest amperage panel of the two) which is why it is best to have two panels of the same wattage and voltage to get the best out of your investment. If you are using old stuff, check them separately and also all the diodes in the junction box at the back, - also under continuous load for a good couple of minutes as if they have cell connection problems, - mismatched cells, junction resistances, etc. that will not show up on an instantaneous short circuit test nor a voltage only check. Am firing in the dark as to your actual problem as I don't know what it is but the above are common problems in this area. Cheers, Geoff Thomas

If you are looking for a voltage increase to 80V, and you have the correct lead connections (see link above) and you do not get it in sunlight, you most likely have a defective diode or diodes in one or both of the panels. It would not be unusual to have up to four diodes in each panel. A test will reveal a closed circuit.

I am assuming that your voltage expectations come from nameplate stampings, rather than from actual measurements. You may also have a bad lead or connector. Most panels of this voltage use a Tyco or MC4 type connector on each lead, which will only allow + to - (serial) connections. If these have been removed, you may simply be connecting the panel incorrectly. This cable method is to allow easy connection (construction) in the field of long strings (multiple panels in series to increase voltage). Here in the US we try to build strings that are around 500V, open circuit, in many places, string voltage can be up to 850 or so volts, depending on temps and codes.

Your solar panels already consist of many cells in series.

Under no load conditions, two cells or panels in series will have a voltage equal to the sum of the individual voltages, just as you would expect. However, under load, meaningful current flows. Therefore, the resistance of one panel can limit the flow through the entire circuit. If the panels are unbalanced, (either by spec or by shading) the total current will be limited to the current that flows through the panel with less output.

Mismatch in wattage can be a serious problem. The situation is not a lot different than in wiring batteries together. An AA battery wired in series with a 12V car starter battery will result in higher voltage but a useless combination in which the total amperage is limited by the AA cell.

What did you mean by "It is not working for me?" Do you mean that even under no load the total voltage is not equal to the sum of voltages?

That's what I asked back in #3.

All we know is it isn't working for the OP.

Guess after guess after guess and no feedback or objective.