Forum Discussion

rich85704's avatar
rich85704
Explorer
Mar 04, 2018

Where is best location for solar controller

I'm putting together a new solar system for use with my Class C. I had a Renogy 100W solar suitcase which I had extended with a second 100W panel... this worked great until it was stolen this week :(

I know from my previous system that I'll want a longer cable from the PV panel to the rig's battery bank. I'd also like something more like 200W of PV. I'm scanning solar posts on here, and I see three possibilities:

1. Mount the controller on the solar suitcase and run a cable from the controller to the batteries. This is what I had before: I replaced the stock Renogy 12AWG cable with a longer run of 10AWG cable and it worked pretty good.

2. I'm seeing suggestions to mount an MPPT controller right near the batteries, run two 100W panels (available from Renogy on eBay only) in series, run 24VDC back to the batteries and controller.

Is there less loss by putting the controller nearer the batteries? If I want 200W, what about running them in parallel and running 12V to a PWM controller, located at the suicase OR near the batteries? Are there other possibilities I should consider?

Rich
  • mbopp's avatar
    mbopp
    Explorer
    Mar 04, 2018
    I plan on doing #2 myself. Controller will be mounted in the pass-through. Our son works for a solar company so MP4 connectors & crimping won't be an issue.
  • DrewE's avatar
    DrewE
    Explorer II
    Mar 04, 2018
    #2 will have less loss because the connection through the long wire is at a lower current level (and higher voltage), so the ohmic loss in the wire will be lower. It's the same basic reason that the power lines on the poles to a house are usually operating at 7500 volts or so, rather than 240 volts.
  • 2oldman's avatar
    2oldman
    Explorer II
    Mar 04, 2018
    rich85704 wrote:
    2. I'm seeing suggestions to mount an MPPT controller right near the batteries, run two 100W panels (available from Renogy on eBay only) in series, run 24VDC back to the batteries and controller.

    Is there less loss by putting the controller nearer the batteries?
    Yes, I like #2. Yes, less loss both in 24v and controller near batteries.
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Mar 04, 2018
    Yes, as near to the batteries as possible but weather protected. If you are not install8ng an in RV monitor mount where it can be checked by you.

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