Forum Discussion

SFGiantsfan925's avatar
SFGiantsfan925
Explorer
Apr 21, 2015

New to us TT with Solar system. Lots of ????'s

We just bought a used TT from a very nice guy on Craigslist. It’s a 2006 Fleetwood Mallard 23’. The previous owner had installed a solar system on the roof. He said it is 2- 80w panels, making a 160w system. In the paperwork we were given with the trailer, it looks like it was a kit bought from Amazon in 2011 using Sharp brand panels.

It looks like the wires have been run down the fridge vent to the solar controller that was installed right above the fridge. The controller is a “SunForce” brand, which says it’s a 12v 30A Digital Solar Charge Controller. It has only 2 switches. One to change the type of battery between AGM or Lead acid, the other switch changes the display from showing Amps or Volts.

So, I am totally new to solar and have never owned a TT or RV. So this is all very new. I have been reading a LOT about solar and how the systems work. It seems clear as mud haha.

After talking to him, he said he had installed the system, and when it was installed the wires from the system were tied into the 12v system on the back of the fridge. He opened the exterior panel to access the rear of the fridge and showed where it is connected. It is NOT connected directly to the battery at all.

So this created a bunch of questions in my mind. Here they are:

1. Is it normal to wire solar into the 12v system, and not directly to a battery?
2. Will this still charge my batteries?
3. Do I leave my batteries connected to this system while the TT is in storage?
4. Are there any flaws with wiring it this way and not directly to a battery?
5. Should I leave my batteries hooked up at ALL while in storage? I’m thinking yes, so that the solar will keep them “topped off”. Batteries are 2- 6V GC2 wired for 12v.

I appreciate any and all the help I can get to understand this system. I called the previous owner and he explained the system as best he could, but I still had questions. Thanks!!
  • SFGiantsfan925's avatar
    SFGiantsfan925
    Explorer
    Apr 23, 2015
    Okay, so no MPPT.

    I am already planning on replacing the wire and going straight to the battery. That would be my next hurdle.

    Is there a website that I could visit to read on how to connect to charge controllers and battery? I understand I could just directly connect to a battery, but I already have my house connection and an inverter connected to the battery. If I add a third thing to each threaded post, I don't know if that would be okay. Should I just run the wire to the post and put in on the bottom below all the other connections??

    Also, I am still wanting to know if I should leave the battery connected while the TT is not being used. I understand the solar is there and the controller should not over charge the battery. But should it be okay if i leave it connected for a month or two? Or should I just disconnect everything and leave it be?

    I really do appreciate all the help so far!
  • Ed_Gee's avatar
    Ed_Gee
    Explorer II
    Apr 21, 2015
    Yes, you should run the controller output directly to the batteries, as others have implied. For your power ( 160W). and assuming you don't plan on adding panels, I'd suggest you could get by with 10 gauge, although 8 gauge would be better. No need for larger, though. Also, unless you really need to squeeze every last amp out of the solar panels I would not recommend the MPPT controller. The MPPT controller for your system is expensive and not always necessary for smaller 12V systems.
  • SFGiantsfan925's avatar
    SFGiantsfan925
    Explorer
    Apr 21, 2015
    westend wrote:
    Connection from the controller directly to the battery is always better. You will be giving up charge current because of voltage drop in the wiring unless the owner rewired the trailer to use thicker battery cables from the controller to the distribution and back to the battery. You will get some charging, it just won't be optimal.
    If it was my trailer, installing bigger cables from the controller to the battery would be one of the first mods I'd do. With what you have for modules and batteries, that is going to be a nice boondocking system.


    Thats kinda what I was thinking. I called the previous owner. He told me that when he installed the system, he was told it was fine to just connect up to the fridge,and not run all the way to the batteries on the tongue. In my head, Im thinking that it HAS to be better to go straight to the battery, and not just connected into the system.

    If I were to run wire from the controller to the battery, what gauge should it be? I would think it would take about 20-25 feet of wire. Maybe 4 or 6 gauge?

    And is it just a direct connection the the pos and neg of the battery?? Im thinkkng I might upgrade the controller to a MPPT charge controller to maximize charging and use.
  • westend's avatar
    westend
    Explorer
    Apr 21, 2015
    Connection from the controller directly to the battery is always better. You will be giving up charge current because of voltage drop in the wiring unless the owner rewired the trailer to use thicker battery cables from the controller to the distribution and back to the battery. You will get some charging, it just won't be optimal.
    If it was my trailer, installing bigger cables from the controller to the battery would be one of the first mods I'd do. With what you have for modules and batteries, that is going to be a nice boondocking system.

    Yes, you would leave the batteries connected for charging while in storage. It is one of the best advantages of solar charging. You may also wish to add a switch between modules and controller (for battery maintenance or replacement, modules removed from circuit and then controller, it can damage controller if done any other way). You may also wish to add a fuse between controller and battery or 12v connection (if not present). Remember though, modules off line, first, and then disconnect controller to battery or 12V connection (remove a wire from modules).

    Good luck with your new trailer and the solarsystem!
  • rbpru's avatar
    rbpru
    Explorer II
    Apr 21, 2015
    I would talk to the seller and ask him those same quwestions. He knows what he did and why.

    Tell him you are a bit confused and need some clarification.

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