how to connect 12 250 watt panels together

[egywatt]

dears
i am going to install a ongrid system with a 12 250 watt panels VOC 45V , with a 3.6kw inverter , please advise the right way to connect the panels (diagram) and the precautions to avoid any mistakes
THANK YOU
ABDALLA MAHMOUD
EGYWATT

[Cariboocoot]

Welcome to the forum.

We'll need a bit more information first. Mainly what the specifications are on the inverter. Is this a grid tie unit or is it battery based?

A grid tie inverter will have information about its minimum and maximum input Voltage which is key to wiring the solar panel array properly.

A battery-based inverter (either off grid or hybrid grid tie) is another matter as it will have a battery Voltage and capacity which are necessary to know for selecting a proper charge controller and wiring the solar panel array.

The complete specifications of the panels would be helpful too, just to make sure minimum Voltages are met and any fusing is noted as well as getting the wire size right. Distance from the array to the inverter or controller is important to that too.

[ggunn]

dears
i am going to install a ongrid system with a 12 250 watt panels VOC 45V , with a 3.6kw inverter , please advise the right way to connect the panels (diagram) and the precautions to avoid any mistakes
THANK YOU
ABDALLA MAHMOUD
EGYWATT

It really depends on a lot of things. If your inverter manufacturer has an on line string sizing tool, that's where you should start. You should get that information before you buy anything; it's possible that you cannot connect 12 panels to that inverter. If the string sizer tells you (for example) that the minimum string length for that module, that inverter, and conditions at your location is 7, then your choices are 7 and 14 (or 8 and 16, maybe). One string of 12 is probably not going to work; that would be an uncorrected string Voc of 540V. If your inverter has a maximum input voltage of 600V as a lot of them do, there's a good chance that you'd go over that on a cold morning, which could damage the inverter and void the warranty.

At any rate, there is some homework you should do before you buy any gear.

[BB.]

I think ggunn intended to type MPPT Charge controller string sizing tool (here is one from MorningStar).

-Bill

[ggunn]

I think ggunn intended to type MPPT Charge controller string sizing tool (here is one from MorningStar).

-Bill

Did I? I don't think so. The OP says he wants to build a grid tied system, not a system with a charge controller (batteries). An MPPT charge controller is going to require different stringing; there aren't any that accept 600VDC, are there?

Most inverter manufacturers have their own string sizing tools. Here is SMA's: http://www.sma-america.com/en_US/pro...ny-design.html

[Cariboocoot]

Mea culpa!
I didn't see that "ongrid system" in the first post and confused the issue.

[BB.]

Sorry, missed the On-Grid Inverter... When you typed "inverter manufacturer"--I defaulted to Off Grid instead Grid Tied.

-Bill

[solarvic]

You should post the brand name and model number of the solar panels and give the colfest temp you have at your location. It would be easy then to figure if your panels would work on a 600 volt inverter. solarvic

[ggunn]

You should post the brand name and model number of the solar panels and give the colfest temp you have at your location. It would be easy then to figure if your panels would work on a 600 volt inverter. solarvic

We would need the inverter info as well; different inverters have different DC input voltage windows. It would also be useful to get the highest average high temperature he would see and the type of racking he will be using so that we could tell if his voltage would be high enough on hot days to keep the inverter running.