Adding panels to cabin solar

[Donaldedwards90]

Hi. I have a 200 watt solar setup using 2 renogy 100 watt panels and a renogy wanderer 40a mppt charge controller. I want to add some more panels to my system but the charge controller says it can do 550 watt max at 12v. I already have a 12v inverter that I'm using so I wouldn't want to change to 24v.

Can I add 3 more panels to get a total of 500 watts? I was going to connect 2 panels parallel and then 2 in series so that would take care of 4 of them. But how do I connect the last one?

I think I would need 4 additional panels and connect 3 in parallel and 2 series. I think the amperage connections need to be balanced out. Is that right? The charge controller has a max voltage input of 75 vmp.

Thanks for the help.
Donald

 

[svetz]

Welcome to the forums!

See if this helps you out: Figuring out how many panels in series and parallel based on your MPPT

 

[MichaelK]

My advice would be for get rid of the 100W panels completely. For the cost of two Renogy panels, I can buy 1000W of grid-tie panels. My last purchase a few weeks ago was two 260W Astronergy panels for a neighbor. That was 120$ for 520W of panels.

If you got two grid-ties, you could wire them in series to get 60VDC, then let your controller transform it down to battery voltage. You'll save on copper wire, and maximize your power production.

BTW, you can NOT do this. I think I would need 4 additional panels and connect 3 in parallel and 2 series. I think the amperage connections need to be balanced out. Is that right? The charge controller has a max voltage input of 75 vmp. All your strings going into the controller must be the same voltage. If you have two different controllers, then yes.

Are you sure though that your controller is MPPT? The Wanderer's I see on Renogy's site are all PWM, not MPPT? Did you mean the 40A Rover? If in fact your controller is PWM, then no, you can't use the grid-ties.

 

[Donaldedwards90]

My advice would be for get rid of the 100W panels completely. For the cost of two Renogy panels, I can buy 1000W of grid-tie panels. My last purchase a few weeks ago was two 260W Astronergy panels for a neighbor. That was 120$ for 520W of panels.

If you got two grid-ties, you could wire them in series to get 60VDC, then let your controller transform it down to battery voltage. You'll save on copper wire, and maximize your power production.

BTW, you can NOT do this. I think I would need 4 additional panels and connect 3 in parallel and 2 series. I think the amperage connections need to be balanced out. Is that right? The charge controller has a max voltage input of 75 vmp. All your strings going into the controller must be the same voltage. If you have two different controllers, then yes.

Are you sure though that your controller is MPPT? The Wanderer's I see on Renogy's site are all PWM, not MPPT? Did you mean the 40A Rover? If in fact your controller is PWM, then no, you can't use the grid-ties.

I'm sorry the charge controller is the rover.
As well, can two charge controllers be used on the same battery bank? I'm using lifepo4 cells for a 12v connection.

 

[MichaelK]

As well, can two charge controllers be used on the same battery bank? I'm using lifepo4 cells for a 12v connection.

Yes, as long as they are programed with the same settings. I have to say though that as soon as your solar application requires more than 2-3 100W panels, it's more cost effective to switch to grid-ties.