Wire size

[gnoeld]

1200 watt solar panels, 12 volt, wired parallel need to run 100 feet to batteries. What would be the wire size and would it benefit me to wire in series?
Thanks

 

[John Frum]

1200 watt solar panels, 12 volt, wired parallel need to run 100 feet to batteries. What would be the wire size and would it benefit me to wire in series?
Thanks

Yes series increase the voltage which would decrease the voltage drop as a percentage.

Please post a picture of the info on the back of the panel.
Also please post a product link to your solar charge controller.

 

[gnoeld]

300 watts, 18 volts, 3.12 amps 4 panels for 1200 watts total

 

[John Frum]

300 watts, 18 volts, 3.12 amps 4 panels for 1200 watts total

We need to see the keys and the values.
Please post a picture or link to a manual for the panels and the solar charge controller.

 

[gnoeld]

When I can get on the roof I'll get the info off the back of the panels. Sorry I don't have it with me
However, which is better for charging a battery bank 72 volts and 6 amps or 24 amps and 18 volts?

 

[John Frum]

When I can get on the roof I'll get the info off the back of the panels. Sorry I don't have it with me
However, which is better for charging a battery bank 72 volts and 6 amps or 24 amps and 18 volts?

Depends on your solar charge controller but if your solar charge controller can handle 72 volts then go with 72 volts.

This calculator will allow you to experiment with voltage drop by voltage, amperage and distance.

Interactive Wire Size Calculator

Battery Chargers, Inverters, Solar Components, and Wiring Supplies for Boats, RVs, and Off-Grid Applications.

baymarinesupply.com

 

[gnoeld]

Thanks
Huge help
But which is better for charging a battery bank if distance is not an issue, Amps or Volts?

 

[HRTKD]

However, which is better for charging a battery bank 72 volts and 6 amps or 24 amps and 18 volts?

It doesn't matter. A quality MPPT solar charge controller will convert whatever the PV gives it into what the battery system needs.

 

[John Frum]

Thanks
Huge help
But which is better for charging a battery bank if distance is not an issue, Amps or Volts?

You need both.
Your solar charge controller changes the ratio to suit your system voltage.

 

[DerpsyDoodler]

Watts are watts. Less current means smaller wire, less voltage drop, and less energy lost to heat. At somepoint it [voltage] will have to be converted down to the battery voltage anyway, preferably as close to the battery as reasonably possible.

 

[John Frum]

You have not given us any information on your solar charge controller.

 

[gnoeld]

Thanks for clarifying that for me

 

[DerpsyDoodler]

Thanks for clarifying that for me

You're welcome.

 

[gnoeld]

Victron Energy SmartSolar MPPT 100V 20 amp 12/24/48-Volt Solar Charge Controller (Bluetooth)​

 

[time2roll]

When I can get on the roof I'll get the info off the back of the panels. Sorry I don't have it with me
However, which is better for charging a battery bank 72 volts and 6 amps or 24 amps and 18 volts?

The MPPT controller will convert to 14 volts and the rest in amps. Watts to the battery will be the same.

The 100' transmission line will be more efficient at higher voltage as much as 10% or so.

 

[DerpsyDoodler]

If you are planning a 12v bank as stated, that SCC is way under powered for the amount of solar you have.

 

[gnoeld]

You have not given us any information on your solar charge controller.

Victron Energy SmartSolar MPPT 100V 20 amp 12/24/48-Volt Solar Charge Controller (Bluetooth)​

 

[gnoeld]

If you are planning a 12v bank as stated, that SCC is way under powered for the amount of solar you have.

What do you suggest?

 

[DerpsyDoodler]

1200W / 12V = 100A

With 1200W of solar, charging a 12V battery bank, you can push up to 100A of current. You need 1 or multiple charge controllers capable of pushing a total of 100A.

 

[gnoeld]

I thought this would work

Victron Energy SmartSolar MPPT 100V 20 amp 12/24/48-Volt Solar Charge Controller ​

Is this not enough?