Zamp Solar Connections - Explained

Michigan_Mike

This information has been discussed many times here on the forum and in an effort to preserve and reference it (in the future) I wanted to provide additional information and clarification on Zamp Solar's panel connections and when using a battery tender. This is basically an extract of the information I previously had posted up over on the Little Guy forum back in 2016.

Zamp wires their solar panels in an effort to make them safe to use and in an effort to avoid accidents since the panels do convert sunlight into energy and it is possible for a user to put themselves in series with a solar panel and receive an electrical shock should they become part of the circuit when hooking up and using a solar panel. This is true whether it is a Zamp solar panel or any solar panel you may be using since they are able to generate energy when in sunlight or for that matter, any ambient light they come into contact with.

The photo below shows the stock Zamp Solar Port wiring harness that comes on all of the trailer units and is located either on the battery box, sides of some trailers and on the tub of the T@B and T@G trailer units. This piece wires directly to the trailer battery and as you can see in the photo the positive (+) side (red wire) of this harness is the bare contact terminal, negative (-) side (black wire) is the female part of the solar port.

The photo below shows the style of connector that would come off the end of the newer Zamp solar panels. In this photo the positive (+) connector (red wire) is the female style end. Zamp wires their solar panels in this manner to protect users from accidental shock accidents. The bare end of the connector shown is the negative (-) terminal (black wire) and this is where some of the confusion comes into play when people discuss the "Battery Tender" brand of trickle charger, as their terminals are wired directly opposite of the Zamp wiring scheme shown below.

Note: The gist of Zamp's safety intent here is that should you deploy "any" solar panel and have wires connected to it in full sunlight it is producing electrical power. If the above wiring is connected to a Zamp solar panel the risk of being injured is reduced here because the "positive end of the cable" coming from the panel has an insulated plastic coating over the energized (+) cable end. By wiring their panels in this manner it greatly reduces the potential of accidental contact should you have the cable ends in your hand.

Battery Tender brand trickle charger wiring explained

In the photo below you can see that the Battery Tender units are wired opposite the Zamp solar connections and unless these terminals are wired in reverse you will not be able to charge up your trailer battery if you plug a Battery Tender into the Zamp Solar Port on your trailer. In other words you would need to do the following with the battery tender trickle charger unit:

1. Cut the charge wire coming off the back of the Battery Tender unit, reverse the wires and splice them back together.

2. Use the clip on style connectors shown just to the right of the tender unit and attach them to your trailer battery when charging the trailer battery.

Unless you follow the above steps the Battery Tender unit will not charge your trailer battery if the tender is plugged into a Zamp Solar Port and this issue has confused many trailer owners as a result of the way Zamp wires their solar panel wiring harnesses.

The bottom line here is that Zamp Solar does not wire their solar ports for use with the Battery Tender brand trickle charge units, but only wires them for Zamp Solar equipment and apparatus. Therein lies the difference and hopefully the above information will help people understand the reasoning behind Zamp Solar's wiring set-ups and provide them with enough knowledge to use a Battery Tender in charging a trailer battery when it has a Zamp Solar connector wired into the trailer and hooked to the battery.

AnacortesArmyGuy

Thanks for the detailed explanation Mike. I’ve been looking for an adapter that wouldn’t require any cutting and splicing of either a battery tender cable or the Zamp connector on the tub. The following adapter on Amazon appears like it might be a solution - what do you think?

https://www.amazon.com/OptiMATE-CABLE-27-Adapter-polarity/dp/B00AHCWGOO/ref=cm_wl_huc_item

BBsGarage

Looks to me like that would do the trick. But being a loyal pessimist I would check it with a meter or continuity checker just to be sure before running current through it.

SueBHunny

I'll be curious to see your results on this!

AnacortesArmyGuy

I just noticed that there is a review for this item on Amazon by someone who bought it specifically for this purpose.

LuckyJ

This is in my mine the best way to do it. Could be done for cheaper with the same type of connector and some soldering, but not by much.

Best way to do it, cause you will not have to remember that either the trailer solar connector or the charger was modified. That little polarity wire will remind you of that every time you use it.

Nice find!

AnacortesArmyGuy

Just purchased it and will let people know how it goes.

Michigan_Mike

@AnacortesArmyGuy said:
Thanks for the detailed explanation Mike. I’ve been looking for an adapter that wouldn’t require any cutting and splicing of either a battery tender cable or the Zamp connector on the tub. The following adapter on Amazon appears like it might be a solution - what do you think?

https://www.amazon.com/OptiMATE-CABLE-27-Adapter-polarity/dp/B00AHCWGOO/ref=cm_wl_huc_item

I've seen that adapter before. It will certainly work but it's probably not necessary as you can accomplish the same results by flipping the Zamp leads.

And if you buy the Battery Tender brand product and are merely trying to maintain the charge of the battery they do sell the tenders with the quick disconnect attachment for the battery and it's included in the package. So you could save the $11-12 you'd be investing in the adapter, use the wiring harness included in the tender and merely unplug it whenever you wanted to use the trailer.

Both plugs ( the tender and Zamp solar plug) could remain intact and you wouldn't need to do anything with the Zamp plug unless you plan to use a different panel.

AnacortesArmyGuy

True, but I’m trying to minimize the number of leads connected to the battery terminals, so if I can use the tub’s Zamp solar connector, unmodified, for both charging in my garage with the Battery Tender, as well as use it while boondocking with a Zamp solar panel, that would be my preferred solution.

Michigan_Mike

Your attachment will remedy it all or you could just save the $12 and flip the leads on the tender and resplice them.

AnacortesArmyGuy

Yes, if it was solely used for the T@G battery, but I use the battery tender for other applications in my garage, such as my motorcycle, trolling motor battery, etc.

MjL

Good Morning,
I have a Battery tender that came with an adapter like Mike may have been mentioning, but it has clips that attach to a battery rather than rings. It works well with "bench charging" as well as charging my bike. The clips are smaller than battery cables but they work for that universal app. I have had the thing for years and I think I got at a motorcycle shop it came with connectors to put on the bike (with ring terminals) and the clamp adapter. The name on the box is Drag Specialties. I hope that helps. Its been a good charger, but the adapter on amazon might be the way to go? Its only money and it's always something, right?

AnacortesArmyGuy

UPDATE - Received the adapter and it looks to be well constructed with the gauge of the wire appearing to be the same as the Battery Tender’s. Tried it out and it is doing the job. I had been using the battery post clips adapter that came with the Battery Tender, but now I can trickle charge the battery without opening the tub, removing the battery case cover and then hooking up to the battery posts. Having said that, it was never overly challenging as I left the battery cover off and the battery post clips adapter attached during the winter, but it was worth the $11.32 to me to get the adapter that allows me to hook up the Battery Tender directly to the tub’s Zamp connector without cutting and splicing any connection, leaving everything stock, and being able to still use my Battery Tender for other applications in the garage and the Zamp connector for a solar panel.

BBsGarage

Thanks for the update !!

nmmike

Mike-
I have a zamp battery box cover and a Renogy panel / kit.
Now I understand why Zamp flipped from the standard polarity on their connections.
Why can't I reverse the wiring on the zamp battery cover by wiring the wire coming out of the Zamp's positive side to the negative side of the battery? And just make sure that the solar panel is not hot when I am plugging into the battery box Zamp connector?
The only negative I see is that this would be less safe than the standard Zamp wiring?

thanks
New Mexico Mike

LuckyJ

@nmmike , you can do it. The approch mentionned here is to leav the zamp connector as is, so if someone wants to go with the zamp solar panel, you wouldn't have to switch the wire over again, nore modify the battery tender.

nmmike

Lucky- thanks for ur input,,, not a big deal to flip the wires back even though I don't plan on buying a Zamp panel soon,, I plan to stick with my Renogy panel I recently purchased and if I upgrade in the near future, I will probably switch out the 12 volt battery to two 6 volt batteries.
I am glad I read these posts because now I understand Zamp's design, and I do think they are a very good product, just a little bit pricey.

New Mexico Mike

HawkeyeEZ

It seems there must be an error on the picture above named “Battery Tender - Trickle Charger”.

On both SAE plugs in the picture the shielded and the unshielded terminals are labeled the same. Since they plug into each other one shielded and one unshielded mating pair would be positive and the other shielded/unshielded pair would be negative.

I think that the unshielded positive terminal on the cable coming from the Battery Tender plugs into the shielded positive terminal on the short cable which would then go to the positive terminal on the battery. So, again, on the short cable it’s the shielded contact that’s positive and the unshielded contact that's negative.