cells in series and parallel wiring

[pklem]

Folks, I have some questions re: series and parallel wiring for a homemade panel. I have purchased (40) .5 volt 100ma and (10) .5 volt 400ma cells. Can anyone recommend a series and parallel wiring combination to get a good wattage panel out of this? My thinking was that I would string the (40)100ma cells in series in 4 rows to get approx 20 volts. I would then string the (10) 400ma cells together in parallel to get 4 amps. Does this wiring combination make sense or am I way off base? What is the highest wattage panel I could get out of these cells? Can I have cells of different amperage in the same panel? I'm having a hard time getting my head around the series and parallel wiring method when combined. Thanks!          PK

[Bruce S]

PK;

   It can get confusing at times.

Here the easy. Series always makes the voltage add, so by adding those + - + - of the .5v you would be making the voltage go up.

The Parallel is what makes the current levels add up, however there is caveate for both. The lowest producing panel will hold the others down to it's level.

Ity would probably help you to put them all in a nice area where you can personally measure the outputs of each panel and marry the like panels, then with diodes keeping the unlike units from back feeding each other start linking the panels up.

Of course if all the panels are close enough in output you can wire them all together and then check the output for your desired levels.

The rated output may not reach your hopes as these small units hardly ever reach the max all the time.

Put one of those trackers in with these may help, but go for it and don't forget to share pictures.

Hope this helps:--))

Bruce S  

[amiklic1]

It's impossible to connect the cells you have into one panel. I suggest to buy 16 more 100ma cells, and to connect them like this.





If you connect 10 cells of 400 ma, as you said, in series, you'll get 400ma/5V, and if you connect them in parallel, you'll get 4A/0.5V It just doesn't work that way. You should ask before. Now, to have a panel, it's complicated to arrange it. But, it's not impossible. This way, you'll get somewhere between 6 and 7 Watts Pmax panel

[ghurd]

PK,

There should be 36 cells in series for a 12V panel. Count the cells on standard commercial panels.

The open voltage (~0.55V) is before any power is being taken from the system.  36 cells in series will have max power at about 17V to allow for wire and diode losses, while still retaining enough voltage to charge a 12V system.

A cell is like a water pipe. Only so much can go through a 1/4" pipe (100ma), even if the pipe on both ends is 8" (400ma).

Bruce explained it well and Amiklic's diagram shows this nicely.

It takes 4 little cells to carry the same amps as one larger cell.

However, the peak power will be at 11.3V, more suited to a 9V battery system.

G-

[craig110]

Hi pklem,

I won't be quite as dogmatic as the others and so I'll say yes, you can put these into a panel.  You haven't said what you want to use it for, so nobody can say whether it will work for what you want it to do.  (That isn't a slam against you, by the way, just an observation about some of the other replies.)

Now, what can you do with those cells?  As was already mentioned, four of your 100ma cells equals one of the 400ma cells.  This means you can cluster the cells in groups of five: four little ones in parallel (giving .55v at 400ma) feeding into a bigger cell in series.  This gives you 1.1v at 400ma out of each cluster of five.  Since you have the potential for 10 of these clusters, how you connect them together depends upon whether you need higher voltage, higher amperage, or both.  Here are some possibilities:

• all ten in series results in 11v at .4A.
  
• all ten in parallel results in 1.1v at 4A.
  
  

You also mix series and parallel, but as the other replies pointed out, each row needs to have the same voltage and amperage number for the combined volts and amps of all the rows to add up cleanly.  For example, you can arrange 9 of the groups in a 3x3 grid (three rows in series with each of the three rows having 3 groups in parallel).  That would give you 3.3v at 1.2A.  Other combinations include:

2. x4 (two rows, four groups in each) = 2.2v at 1.6A
   
4. x2 (four rows, two groups in each) = 4.4v at .8A
   
   

Note that in all of these, the resulting output is between 3.52 watts and 4.4 watts.  (The difference between them being how many groups don't "fit" in the desired number of groups per row.  If you want three groups per row, the 10th group has to go unused.)  The bottom line is that if you start with 4.4 watts of individual cells (40 of the small ones at .055 watt each and 10 of the large ones at .22 watt each), the best you can get out of the total panel is 4.4 watts.  You can adjust the voltage and amperage that the panel produces, but the total wattage is a cap that you can't change without adding more cells.  Sad to say, there is no special panel wiring layout that gets around this.

Craig

[craig110]

Oh, the board's formatting engine messed with what I wrote.  The two lines that look like bullets numbered 2 and 4 should read (using words instead of the number):

Two x Four (two rows, four groups in each) = 2.2v at 1.6A

Four x Two (four rows, two groups in each) = 4.4v at .8A

Craig

[pklem]

Thanks for the info guys! I think I have better understanding now of stringing cells together in parallel ans series.