Is this "normal" polarity?

Ttown

This is a great forum and I've learned alot about my recently purchased 2018 tab CS, including about the issue of the reversed polarity on the Zamp solar connectors. Before using my new Goal Zero portable solar panels, I wanted to check the polarity of the connector to confirm whether it was indeed reversed. 
But if I'm reading my meter correctly,  my Zamp connector has "normal" polarity - the positive connector is the bare post on top and the negative is the coated connection on the bottom. 
Here is my Zamp connection. 



So am I reading my meter right? I first put the red, positive probe in the top, bare post.


Now here it is with the probes switched and I get a negative reading.


Here is the battery connection. Where I've circled the Zamp connection.



I'm not great with electronics but I was expecting a different reading on my meter, so i was guessing someone did the wiring so the polarity would be conventional. 

Any help would be appreciated! I'm actually taking the tab on its inaugural trip tomorrow and am really looking forward to it. Hoping for nice weather! 

pthomas745

Welcome to the Forums, and congratulations on a great first post.

That is correct.  The big metal part inside the "port" is the positive side from the battery.

Now, have a look at the SAE cable that will connect into the port:  The big metal part of the SAE cable is the negative lead (it will go in the round hole in the bottom of the port).  The positive lead from the controller (inside the plastic housing of the SAE cable) will go in the top.

Just ignore the phrase "reverse polarity."  It really means....nothing, as far as I can tell.

I've wired all my panels without adapters for  the last 4 years.  Your method of using the mulitimeter puts you a year or so ahead of me!

Here is my solar panel wiring from the controller.  Note the wire with the white lettering goes to the big metal part of the cable.   That wire is connected to the negative output of the controller.  The unmarked wire goes from the positive output of the controller to the plastic "female" part of the cable.  Works just fine.

Ttown

Thank you @pthomas745! One less thing to worry about! I appreciate the quick response!

Sharon_is_SAM

@Ttown - we reversed our wiring at that port and removed the Zamp sticker.  Always smart to use that meter.

ScottG

Good work with the meter! I've preached ad nauseam to always confirm all + and - connections electronically or visually before hooking anything up, and not get confused with terms like "reverse polarity" and out-of-context recommendations to blindly purchase some adapter or another.

Now that you know exactly what is what you can be certain to configure your wiring correctly.

Ttown

Thanks @ScottG but I have a confession- I actually did buy an adapter because I assumed the polarity would be reversed! Using the meter to confirm was an afterthought just to be careful. Lesson learned!   

ScottG

That works--as long as you checked at some point before plugging in it's all good!

In most cases the common "reverse polarity" SAE adapters sold on Amazon work just fine with the stock Zamp ports. However, you never know (as was the case with Sharon_is_SAM) if a previous owner has modified something for their own needs.

pthomas745

The adapters just take you down the rabbit hole.  If you have an adapter that "reverses" the polarity...or whatever:  you would have to look at the SAE cable...and wire it so that the positive side of the cable ( the one with the big metal part) is now attached to the positive side of the solar controller.    The "adapter" would then "reverse" it, and put the negative and positive in the proper places on the port.  This is completely nuts.  (I understand the confusion of all the millions of Google hits on this issue.)

Every plug in my home has  "polarized" outlets, and electrical devices have polarized plugs.  Not once have I ever looked at a plug, figured out the wide, bigger prong is the negative part of the cable, and said to myself:  "Oh, noes!  The polarity is reversed!  I must rewire so the big prong is the positive!"  Which is exactly what happened here with the solar port on the Tabs ( and many others.)

Thanks again for those great photos.  My port is cramped behind my cargo boxes on the rack and pictures would be difficult, so I plan to steal yours. 

PS:  that little port and a multimeter is a perfectly easy way to measure your battery state of charge.  No need to open the battery boxes, just meter it.