adding portable panel with a Zamp port

Thunderworks

New Member
Joined
Jul 9, 2021
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3
My camper has a 190w Go Power panel on the roof with its appropriate contoller. Additionally, there is a Zamp port on the trailer, wired through the controller so I can add a portable panel if necessary, which I now want to do . . . My roof top panel specs:

Pm 190w
Vmp 20.4V
Imp 9.3A
Voc 24.09 V
Isc 9.98A

I've read that if you add a different panel to the system, if the Vmp of the panels differs too much, then the entire system is dragged down in efficiency. I have a little information, but . . . no actual knowledge about this . . . so, are there issues if I add a panel with a Vmp of around 18V to the system . . .

Also, the Zamp port is wired with "reverse polarity". I assume there is an adapter that will allow it to be used with non Zamp branded products. True?

There are numerous 100 to 200W folding suitcase panels available and they vary widely in price. Most have Vmp numbers around 18V.

Recommendations?

TIA
 

snoobler

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Joined
Jul 10, 2020
Messages
8,395
Location
HBR, AZ
My camper has a 190w Go Power panel on the roof with its appropriate contoller. Additionally, there is a Zamp port on the trailer, wired through the controller so I can add a portable panel if necessary, which I now want to do . . . My roof top panel specs:

Pm 190w
Vmp 20.4V
Imp 9.3A
Voc 24.09 V
Isc 9.98A

I've read that if you add a different panel to the system, if the Vmp of the panels differs too much, then the entire system is dragged down in efficiency. I have a little information, but . . . no actual knowledge about this . . . so, are there issues if I add a panel with a Vmp of around 18V to the system . . .

Also, the Zamp port is wired with "reverse polarity". I assume there is an adapter that will allow it to be used with non Zamp branded products. True?

There are numerous 100 to 200W folding suitcase panels available and they vary widely in price. Most have Vmp numbers around 18V.

Recommendations?

TIA

Welcome to the forum.

On an MPPT controller, paralleling a 18Vmp panel in with that one will likely see the total array wattage reduced by about 10%. If the Zamp is a PWM controller, it doesn't matter as the panels are forced to operate at battery voltage resulting in a much larger performance penalty.
 

memilanuk

Solar Enthusiast
Joined
Apr 21, 2021
Messages
125
Are you sure the Zamp port is wired thru the controller?

I was under the impression those 'solar on the side' ports (Zamp and Furrion) were usually wired direct to the battery (maybe with an inline 10A fuse), as most commercial (aka not DIY) portable solar kits have a charge controller at the panels themselves.

At least, that's how the Furrion port on my last TT (2018 Keystone Cougar 28 RLSWE) was set up.
 

Thunderworks

New Member
Joined
Jul 9, 2021
Messages
3
Are you sure the Zamp port is wired thru the controller?

I was under the impression those 'solar on the side' ports (Zamp and Furrion) were usually wired direct to the battery (maybe with an inline 10A fuse), as most commercial (aka not DIY) portable solar kits have a charge controller at the panels themselves.

At least, that's how the Furrion port on my last TT (2018 Keystone Cougar 28 RLSWE) was set up.
I asked the tech guys at the trailer company (Escape Trailer Industries, British Columbia) that exact question. They assured me that the Zamp port on their trailer was wired through the controller.
 

MisterSandals

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Nov 5, 2019
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Location
Silicon Valley
Also, the Zamp port is wired with "reverse polarity". I assume there is an adapter that will allow it to be used with non Zamp branded products. True?
This should be easy to test at the port with a multi-meter. It sounds like its wired in parallel to the other panels in which case you should not only see the polarity but the volts and amps of the array.
Without solar (at night or panels covered), the port should have the same voltage and polarity as the terminals on the controller if its accessible.

I went thru this on a friends Winnebago Revel and it took a bit of head scratching and disconnecting panels to get a good wiring diagram. The controller was completely buried or it would have been a lot easier.

From recollection, the polarity of the ZAmp ports/plugs depended on whether it was power in vs power out. I did not like the scheme but if you look at their power supplies and loads, it makes more sense. So keep that distinction in mind, it may help understand your system.
 

GSXR1000

Solar Addict
Joined
Nov 20, 2020
Messages
753
I asked the tech guys at the trailer company (Escape Trailer Industries, British Columbia) that exact question. They assured me that the Zamp port on their trailer was wired through the controller.
I would make sure. ie trace the actual wires. or atleast measure voltage at zamp port. it out is you should see panel voltage during the day and no (very little) at night.


I do NOT trust most techs.
 

GSXR1000

Solar Addict
Joined
Nov 20, 2020
Messages
753
if it daylight out is you should see panel voltage during the day and no (very little) at night.

if you are battery voltage day and night then it is connect to the battery
 
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