Battery tender connection in battery bin

Cmjmnew

Just bought a used 2018 320s. I found what looks like an professional (original?) install of a battery tender cable on the drivers side of the the Al battery/propane tank. When connecter to a charger, it indicates the polarity is reversed. What is the purpose of this connector? Is it a incorrectly done mod?

pthomas745

It is a solar panel port. (Could easily be a battery charger port, also...my Noco comes with SAE cables that would plug into it)   Tabs came with the ports with "Zamp" stickers on them to make the connection to a Zamp solar panel easy.  The polarity on the ports, like all SAE cables and ports, are wired in "reverse" so the user doesn't spread sparks with the metal portion of the SAE cable.  It can be easily worked around with a simple adapter or proper wiring.  After a few years, solar panels became more popular, and many owners use all sorts of different panels on the trailer.

Since that one does not have the Robertson head screws, it must have been installed by a previous owner.

And...welcome to the Forums!

Sharon_is_SAM

Follow the wires to the battery and you will see how it is wired.  As pthomas said, you can reverse the wires and use it for non-Zamp solar or a charger.  Or leave it as is and buy a Zamp!

Lil_Lucy

This is what a Battery Tender set up should look like. This is my setup. The green knob on the battery is my battery cut-off switch. Make sure your cut-off switch is set to off. I leave this on all the time my T@B isn’t being used.(year round). This way I always start off with a fully charged battery.

Verna

A Battery Tender can also use a connection similar to the SAE solar plug. That way you do not need to use the alligator clips. I consider the plug to be safer than the alligator clips as the plug has rings that are permanently attached to the battery terminals. 

Cmjmnew

Thank you for your time and for the clarification people. Super helpful.

Cmjmnew

ok so now that I know what it’s for, Are Zamp products any good? Debating solar vs staying with my generator. any first hand accounts out there?

pthomas745

Zamps are fine, just pricy.  ANY solar panel can be used with the trailer and the SAE connector.  You just need to wire it properly, or use a simple adapter.  I've used several different brands of solar panel with my trailer, wired through that connector. 

Sharon_is_SAM

There are both solar and generator fans on the forum.  Each have their place.  

Solar advantages/limitations include:
Mountable and portable available, tried and true controllers available, noiseless, do not have to transport fuel, limited weight
Learning curve, if mounted - must park in hot sun, need to know battery capacity limitations when weather does not cooperate

Generator advantages/limitations include:
Able to run A/C, ability to charge battery is not weather dependent, may be able to use it at home (multipurpose)
Learning curve, need a certain size for running A/C, full recharging may take longer than you think, noisy, pollution, limited times to run while at established campgrounds, can be heavy to lift and adds to towable weight, must carry fuel.

Zamp products are reliable, but are known to be pricey.  Many other brands out there that are quality and more affordable.