Solar wire sizing

[Slidegate]

I am currently using #6 wire from the charger to the battery bank. I have only 6ft to the batteries. Thanks

[Ryland]

Originally Posted by Xringer

[IMG]
Since the line loss, is the current Squared, times the resistance..

8^2 = 64, but 23^2 = 529

So, 0.1 ohms of wire resistance would be 6.4 watts of loss,
but using 23 amps w/ 0.1 ohms is 53 watts of loss..

As you can see, it's not a linear thing.

This is part of why the MPPT are so impressive! you can get an extra 46 watts out of your panels that would have otherwise been lost and chances are you are going to get even more out of them because the whole string now will start charging your battery as soon as it's above the minimum voltage.

[Drake]

This might be a good place to ask a question I have on future PV install. I am building new construction and want to install a dedicated pvc raceway from attic to basement to easily run future power line from PV roof panels to basement electrical. Have large roof area available for panels that will be grid tied. How large dia should I make it for size/number of wires needed? I know 120V AV but am yet learning about PV generated power.

[Ryland]

Originally Posted by Drake

This might be a good place to ask a question I have on future PV install. I am building new construction and want to install a dedicated pvc raceway from attic to basement to easily run future power line from PV roof panels to basement electrical. Have large roof area available for panels that will be grid tied. How large dia should I make it for size/number of wires needed? I know 120V AV but am yet learning about PV generated power.

If you are doing micro inverters up on the roof (cheapest and easiest way to go) then it will be either 120v ac or 240v ac coming down to your basement, so it's all dependent on how many panels you put up, but Wire Size Calculator says that even at 40 amps, or around 4.8kwh of PV on your roof that 10 gauge wire is good for 30 feet and 8 gauge wire is good for 50 feet, so conduit size, another site I found said that if you have 8 gauge wire with a max of 50 amps that you need 1" conduit to give enough air space for heat dissipation .