Pennwalt solar

[christopher]

Hi I was just given 48 Pennwalt automatic power solar panels with the shunt controller out of a automated lighthouse ,the panels are 24"x5" with 20   2"cells in each,they test in full sun at 10.8 volts and short circute amps at .54.
I know nothing about solar and am looking for the best way to use these on my 12 volt system (the shunt controller is rated at 14.4 volt output and 14.4 to 20 volt input at 16 amps).As these are quite heavy I was thinking of screwing together 4 sets of12 units at the10.8 volts then putting two sets together for  20.6 volts and then paraling these two sets . Is this my best option?? thanks .


        Christopher

[birdhouse]

shunt controllers kinda work.  the *best* way would be to remove the controllers, and run the panels through a MPPT charge controller like the morningstar ts mppt 45.  then you can series wire them with multiple strands (paralell) up to 150 volts per series strand. 

the mppt controller will turn that high voltage into exactly what your battery wants to see in voltage.  this will give you the most charging amps even in less than ideal conditions. 

adam

[rain1224]

Maybe you can read books about solar panel to konw it better before you start your plan.

[Bruce S]

Maybe you can read books about solar panel to know it better before you start your plan.

I'm going to ask you NOT post this type of response until you've read what these people are asking. 
This is post number 3 of yours and you're not really explaining yourself very well.
Perhaps READING the FAQs would help you?
IF you had read the entire post you would know he has a system and is asking others for better ways to use these other panels.
This one is bordering on being rude!

[richhagen]

Rain1224, of course we could all look up everything we ever wanted to know if it has been done before and written about, and most folks try to do a bit of research before posting a question, but it is often more informative to discuss it amongst people doing similar things to get the best outcome. The question asked here is a good example, because you can get more than one conflicting answer out of different books.  Discussing it among people doing similar things is a good way to come up with a reasonable solution.   Besides you get to meet folks from all over the World here.   

As for the question at hand:
The one modification I would make to your plan with the modules would be to measure the short circuit current and the open circuit voltage of each module under similar conditions.  Any that are low on output that I believe would not reach sufficient voltage to contribute to the current I would exclude, say any under 8 volts under reasonable daylight, and then I would divide the remaining into two sets of modules which I would parallel such that each of those two groups put out approximately the same current. 

Should there be three or more modules with low voltage I would hook those in series by three (or more) in a separate string if I could arrange it to reach charging voltage so that it would contribute current and then parallel that with the main group.  Anyway, just my thoughts on it.  Rich

[richhagen]

I did not like the wording on my response paragraph so I edited it to try and articulate my thoughts more clearly:

The one modification I would make to your plan with the modules would be to measure the short circuit current and the open circuit voltage of each module under similar conditions.  Any that are low on output that I believe would not reach sufficient voltage to contribute to the current I would exclude, say any under 8 volts under reasonable daylight, and then I would divide the remaining into two sets of modules such that each of those two groups put out approximately the same current when the modules in each group are connected in parallel.  I would then series connect the two groups of paralleled modules. 

Should there be three or more modules with low voltage I would hook those in series by three (or more) in a separate string if I could arrange it to reach charging voltage so that it would contribute current and then parallel that with the main group.  Anyway, just my thoughts on it.  Rich

[christopher]

 Thanks guys I have tested all of the units seperatly and they all test within about .5 volts and very close in shorted amps. these seem to be very well made backed with 1/8" aluminum which should help to keep them cool. thank you for the help
    Christopher

[ghurd]

They sound like 6V nominal panels to me.

For a 12V system with a standard type controller, they need connected in series pairs to be 12V nominal.

"the shunt controller"
It could be a 'series' solar controller.  It would be more standard than a solar shunt controller in the US/Canada.  Though shunt solar controllers not uncommon in the UK.

The AL backing is for protection from the weather, not to keep them cool.
I only saw a few versions with AL or SS backing, all mil-spec, and all less reliable than 'consumer grade' stuff for use in this location.
In those the cells were coated with something soft and rubbery like silicone.  The seal around the frame failed.
IMHO, current commercial production is better than 'soft rubbery' front materials.
G-

[christopher]

I have put two sets of panels together so far I get 10.9 volts on each one in full sun. One panel into a 6 volt battery shows 7.1 volts and 8.3 amps, both are equil two more to go. the controler says input is 14.2 to 20 volts input, output 14.2  max 16 amps.so must have been made for these panels.   

[thirteen]

sounds like things are working. Best of luck with them.