External solar plug not working

DepoeBay

New Member
Joined
Oct 31, 2024
Posts
3
Location
Depoe Bay
Hi, done a lot of searching here but can’t find the right thread.
Have a 22’ Outback with the cold weather package and a manufacture date of 2020. I have a 200 watt external solar panel and charge controller that works great when connected directly to the battery. I tried the built-in 10 amp solar plug at the front of the trailer, and the charge controller says not connected.
Is there a switch or a fuse in the main power panel, or something I need to do to the power converter to make this work? It. Would be much more convenient than alligator clips on the battery posts!
 
If the exterior plug is a ZAMP brand, then their "proprietary polarity" is the opposite of most solar system plugs. in other words, your trailer connector is wired backwards compared to your portable solar system. That means POS is NEG and NEG is POS... You can either rewire the trailer connector, rewire the solar system connector or buy an adapter plug that does it for you....

You can verify this by using a multimeter on the trailer plug. You should get 12 VDC from the battery measured between the two plug connectors. The POS on that plug should be the same as the NEG on your portable solar system plug.
 
Thanks much. I did swap the output wires from the controller and got the same result. My multimeter shows 2.6 volts across the pin holes, regardless of which probe I put where. Charge controller still doesn’t recognize there is a battery on the other end. Still stumped - batteries are at 12.8 volts right now.
 
Welp, I guess it doesn’t make a difference. My panel is 200 watt, so I would likely exceed the 10 amp limit of the Furrion plug/wiring even if I did get it to work. So, the alligator clips on the battery posts will have to do - thanks very much for the info and help!
 
The solar panel plug near the front of the trailer has its own dedicated set of wires that feed the battery. Red (positive) goes directly to the battery and the black to frame ground. If they are not connected the portable charger won't work. My positive (red) wire also has an in-line fuse. I don't remember what gauge they are but I'm sure they are close to 10 awg.
 
Last edited:
The sidewall Zamp ports use a much smaller wire, 18awg which is sized for 10a at 12vdc. For prewired rooftop solar applications, the standard wire size is 10awg which is sized for 30a at 12vdc.

That being said, it is pretty simple to upgrade the Zamp sidewall plug and short wire run to the battery with wires having a higher capacity.

Under absolute ideal conditions, a 200w suitcase panel will only produce around 10a max at 12vdc anyway, so I would suggest measuring the panel output under various conditions before you go too far making mods and upgrades that may be unnecessary.
 
Last edited:
On my trailer the wire from the solar plug is closer to 10 AWG. I'd need to go to the trailer to be sure. I'm fairly confident it is larger than 18.

Here is a pic from my battery upgrade project. The red wire coming in from the bottom is the solar plug wire. It is also the wire with the in-line fuse. Since I'll most likely will never use a portable panel, I've since disconnected the wire from the battery and tucked it away.

So maybe no modifications would be needed to use your portable panel.

You could always put a towel over half of it. :cool:



battery-1.jpg
 
From the factory, the side port is not connected to the "SolarFlex system" and is not routed through the SolarFlex controller. It is a "stand alone connection to the battery" and requires the portable solar panel to have either a built in controller or an external controller between the panel and the plug. All that is included in that "accessory portable solar panel system" is a plug and two wires. Nothing more, no magical way to plug in a solar panel to "augment the rooftop panels through the SolarFlex system" and no interface with the SolarFlex system.

The side port, whether it's a ZAMP brand or any other "off brand" connector, is nothing more than a plug with two wires that go to the battery. The wires are usually not connected to anything (from the factory), and are either coiled up behind a removeable panel in the front passthrough or are routed to the battery box BUT NOT CONNECTED TO THE BATTERY... If the wires were connected at the dealership before delivery (during the PDI) then you will measure 12.8VDC on the pins in the connector. If you do not measure battery voltage at the plug on the side of the trailer, either your battery is dead, the wiring is damaged or more likely, the wiring is not connected. There is an "in line fuse" and it's possible it may be blown, but if the plug has never been used, it's unlikely the fuse is the problem, but check it to be sure.

So, to plug a solar panel into the connector or to measure for continuity or voltage on the plug mounted on the side of the trailer, will almost always result in "no continuity/no voltage" until the new owner actually connects those "coiled up wires" to the battery.

Also, remember that any solar panel that is plugged into that connector must have proper polarity and include a panel with a solar controller (built in or added before the plug). To just plug in a panel with no controller will likely result in a damaged battery.
 

New posts

Try RV LIFE Pro Free for 7 Days

  • New Ad-Free experience on this RV LIFE Community.
  • Plan the best RV Safe travel with RV LIFE Trip Wizard.
  • Navigate with our RV Safe GPS mobile app.
  • and much more...
Try RV LIFE Pro Today
Back
Top