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!!

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.

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!

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.

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.

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!

New to us TT with Solar system. Lots of ????'s | Good Sam Community

westend
Explorer
Apr 24, 2015
SFGiantsfan925 wrote:
After thinking about my system, I came up with an idea. What if I ran my house, inverter and solar all to a buss bar. Then 1 single main to the battery. This would be to clean up my battery box and just have 1 single connection going to the battery positive. Another reason I was thinking of doing this is because when I replaced the batteries last week, pretty much all the connection lugs and wire are very corroded and need replacement. I saw those and was NOT happy. I want to replace them with tinned marine style to help prevent further issues. It looked as the previous owner didnt really take care of the lugs or the connections.

I am also thinking of installing a Blue Sea battery type switch to the inverter positive so I can just use the switch to turn on the inverter. It would be between the inverter fuse and the battery. The current setup to get the inverter to run is to go outside, open the battery box, and attach the inverter cables to the battery when I want to use it. Then disconnect everything to turn it off. This way I could control it all from inside, andeliminate having to open the battery box every time I want to use it.

What Im thinking:

House ----->
Inverter ----> All to high amp buss Bar -----> Battery
Solar ------->
Yes, this is a good solution for many reasons. Best practices would have a fuse installed at the bus and not at the battery. I made my own bus boxes using a length of copper bar and inexpensive 4" weather proof boxes.

Bus box:
rbpru
Explorer II
Apr 24, 2015
Probably a few different definitions out there but boondocking is no hookups usually in remote location. Though I have been in state parks with no hookups.

Dry camping often means electric only, no water but even that varies.

As I mentioned, if you are camping with no hookups, rather than using the system as a battery maintainer between trips; then chances are you will want every last watt you can get.

The next question is how much power do you need. How many watts per hour do you use? 160 watts time the number of sunny hours give you the number of watt/hours you have, minus losses. Cloudy skies will reduce the output.
All_I_could_aff
Explorer
Apr 23, 2015
Another way you can look at it is, let's just say you were wiring up a new stereo system for outside your trailer and we're planning on using it on the side near the refrigerator. The stereo system would draw 160 W maximum. In this situation would you run a new power supply to the stereo or would you be comfortable with the idea of tapping into the refrigerators 12 V power supply, simply for convenience, even though it very well may be a 16 or 18 gauge wire.
ewarnerusa
Nomad
Apr 23, 2015
I think the motivation for wiring the controller into the wiring behind the fridge was simply for convenience. It sounds like they just tied into the connection between the 12V distribution system and the battery. My father's TT with dealer-installed solar was wired like that and I watched a dealer installation video and that is exactly how it was wired. So the existing wiring DOES lead directly to the battery; however, there is a long cable run and your system will experience voltage drop due to that length. Rewiring an independent connection from the existing controller location won't gain you anything unless you are going use fatter gauge wires to decrease the resistance from the long wire run. You have adequate panel wattage to provide you useful daily charging during boondocking, but if you don't camp like that then I don't think it is worth the effort to change anything. If you do boondock, I suggest relocating the controller to as close to the batteries as possible and then using fat gauge wiring between the controller and batteries. If the controller can't be easily relocated, the using fat gauge wiring from its current location might be the best you can do.

Both inverters and solar charge controllers should have minimal wire runs with fat gauge wires to minimize voltage drops. Particularly inverters because depending on the size it could be drawing well over 100 amps. Both my solar controller and 1500 watt inverter are installed with about 5' each of positive and negative wire length. Solar controller uses 4 gauge wire, inverter uses 0 gauge. My inverter wiring should probably be fatter still, but I don't ever actually run it at max capacity so it hasn't been an issue.
SFGiantsfan925
Explorer
Apr 23, 2015
After thinking about my system, I came up with an idea. What if I ran my house, inverter and solar all to a buss bar. Then 1 single main to the battery. This would be to clean up my battery box and just have 1 single connection going to the battery positive. Another reason I was thinking of doing this is because when I replaced the batteries last week, pretty much all the connection lugs and wire are very corroded and need replacement. I saw those and was NOT happy. I want to replace them with tinned marine style to help prevent further issues. It looked as the previous owner didnt really take care of the lugs or the connections.

I am also thinking of installing a Blue Sea battery type switch to the inverter positive so I can just use the switch to turn on the inverter. It would be between the inverter fuse and the battery. The current setup to get the inverter to run is to go outside, open the battery box, and attach the inverter cables to the battery when I want to use it. Then disconnect everything to turn it off. This way I could control it all from inside, andeliminate having to open the battery box every time I want to use it.

What Im thinking:

House ----->
Inverter ----> All to high amp buss Bar -----> Battery
Solar ------->
westend
Explorer
Apr 23, 2015
Just ask yourself if you would connect the generator and back feed it into a 120V receptacle? It is the same with the solar connections. Besides the loss of power through the fridge wiring, you probably don't have adequate circuit protection using that wiring.

Yes, you can connect the controller's output wiring along with other connections to the battery terminals. It is easy to buy a fuse that connects to the battery terminal and connect the solar wires to that fuse.
SFGiantsfan925
Explorer
Apr 23, 2015
rbpru, That does make a lot of sense. I am not really sure what type of camping the previous owner did. I never really asked him. My wife and I will primarily be dry camping. Not really boondocking I guess. Since I am new to the term, I think of extended times with no hookups being boondocking. Maybe I am wrong though. We may look for places with hookups every now and then, but for the most part the places we go every year and return to do not have any hookups at all. So, I guess I am just trying to maximize the system to prepare for 6-7 days of camping with no hookups.

But we do have a Yamaha 2800i generator as well, so that would help where the solar lacks I guess.
rbpru
Explorer II
Apr 23, 2015
Keep in mind the original owner faced the same problem and decided that the losses on a 160 watt system were not worth the extra cost and work of heaver wiring. Assuming that the system did what he wanted it to do; there was no need to improve on it.

One would have to look at the power loss in the present system’s wiring vs. the planned system’s losses and decide if you need the improved efficiency.

A boondocker may certainly need as efficient a solar power system a possible. But a shore power user, who’s solar power is used to top off the battery between trips, can afford a few extra hours of charging time.

The question becomes just how critical to your end goal is maximum efficiency and is it worth the cost.
SFGiantsfan925
Explorer
Apr 23, 2015
Westend, thanks for the info. I will be visiting those sites in the near future and learning as much as possible. Its funny that all this is so strange. My father is an electrician by trade and is very good at this. But I am trying to learn on my own as much as possible instead of taking the easy way out and just asking him. That doesn't help me much down the road. I like to be able to troubleshoot and know WHY something happened. And if something goes wrong not just the why, but how to troubleshoot and fix the problem. The only way to do that is to completely understand the entire system.

I am still wondering about the connections to the battery though....
westend
Explorer
Apr 23, 2015
Jack Meyer's website about RV electricalSome of it will be pertinent to your installation and some will not but all the "Golden Rules" of solar are handled.

RVnet member's solar intallations Lots of good examples in these installations.

If you have an active solar charging system and it is set to charge your batteries correctly, it is the best method of keeping your batteries charged and will increase their longevity. My solar system has been constantly connected since I installed it two years ago.

Battery University has all the pertinent information about batteries and how to use them.

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