The most efficient way to configure panels for higher voltage

[Usman]

I have 20 pieces of 120Watt Kyocera solar panels that I intent to connect them for 48V battery charging. I was wondering the most efficient way of doing so. I am not going to be using any charge controllers for battery charging but a Tristar-60A for battery diversion control as I have a wind turbine in the system as well.

I presume three ways of achieving that:

1. -Conneting five panels in parallel for 12V out and then connecting the four sets of these five 12V panels into series for 48V?
   
2. -Connecting four panels in series for 48V and then connecting these five sets into parallel for 48V out?
   
3. -We can also connect every two panels for 24V and have four sets of 48V that we could connect in parallel, but I see no advantage of that.
   
4. -Any other possibilities.
   
   

Not sure on the advantages and disadvantages on each type, Only experience can teach!

The distance between the solar array and the battery bank is around 10 meters only. Any help would be appreciated.

Thanks.

[wdyasq]

IF these are real panels you are speaking of a $10,000 or so hit on a wallet. You will also see some real benefit with an MPPT charge controller. It will allow higher voltage at the panel and light wiring with less loss of power and more watts in the battery.

But, you project, do as you please,

Ron

[Volvo farmer]

Am I reading something wrong here? Aren't 1,2, and 3 all different ways of explaining the same wiring scheme?

Twenty twelve volt panels need to be in strings of four connected in series and in strings of five connected in parallel for a 48V nominal output.

I noticed you have about 50A of solar there. Seems if you add a wind turbine and a single 60A dump controller, you might have more current coming in from both sources than can safely be diverted.

Solar and wind can live together on separate charge controllers. The basic idea is to set the solar voltage a few tenths of a volt lower than the dump for the wind, and they generally work OK together.

Ron has good advice. You did mention the word efficiency in your query. A $500 MPPT charge controller is a no-brainer on $10K worth of panels IMO.

[wdyasq]

You are going to ruin my image Volvo Farmer. As the Amperage to the batteries is (battery voltage)/(panel voltage), one with more than third grade arithmetic skills should be able to figure out an MPPT delivering over 90% is the way to go.

If one were to look at Usman's other posts, they might justly conclude this is one of Usman's homework assignments and he is tapping the resources of the board as opposed to tapping those supposed contained between his ears.

Each of us, except me, deserve a little slack.

Ron

[dbcollen]

The only code approved way to connect them is to series 4 panels for 48 volts.

do that with all 5 strings, combine them in a combiner box with fuses or breakers that are the proper rating (on the back of panel as "max series fuse") wire to batteries with appropriate size wire for less than 5% drop from array and fuse again apropriatly near battery bank with a disconnect. all fusing and disconnects need to be rated for the open circuit voltage af the array + 25% (125VDC is appropriate) wire TS60 to batteries and provide a diversion load of at least 10% above Isc of solar array.

Dustin