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-   -   4 solar panels - series, parallel or series-parallel (http://www.sailnet.com/forums/gear-maintenance/73908-4-solar-panels-series-parallel-series-parallel.html)

ArgleBargle 04-25-2011 06:16 PM

4 solar panels - series, parallel or series-parallel
 
Hi

Installing 4 x kyocera 85W panels (chose this arrangement due to space availability consideration which would not easily accommodative two larger panels). They will not likely all be seeing the same solar irradiance at the same time. I have chosen not to install them on adjustable mounts and accept the reduced power output.

Using them with Blue Sky Solar Boost 3024 MPPT charge controller with Max input voltage 57V and max 12V current 40 Amps.

the panels have built in blocking diodes. There is about 10 feet of AWG 10 Ga wire from the terminal box to the battery compartment.

Three options for connecting:

1. four in parallel - does not take full advantage of MPPT.
2. four in series - less voltage drop given the lower current in series (likely negligible given the large gauge and relatively short distance i'm using). I wonder about the effects of shading on this arrangement as well. also, i wonder whether this approaches the input-side limit of the charge controller (57V, though it states preferred is 45 V)
3. series-parallel: two pairs of two in series then connected in parallel for a nominal 24V input-side configuration. also uncertain about the effects of shading on this arrangement.

any experience or insightful comments, particularly on problems if one or two panels are shaded, greatly appreciated.

cheers

MacGyverRI 04-26-2011 08:27 AM

I'm not sure why you don't wire it as 12 volts for efficiency but my thinking and I may be wrong, is...

Assuming all panels have Sun,

1. four in parallel - maximum amps (24? amps) 12 volts
2. four in series - 1/4 total amps (6? amps) 48 volts
3. series-parallel: 1/2 total amps (12? amps) 24 volts

W / V = A is based on 14V output, not 12

If the blocking diodes segregate the shaded panel/s, that will alter those numbers drastically w/ any series connection.


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