2016 Fleet pre-wired for solar

Solar newbee, here. I looked in the Ultimate Solar forum, but couldn't find anything about this...


2016 Fleet pre-wired for solar. Factory wires are10 gauge from the battery & 12 gauge from the Zamp roof port. Instructions for the Zamp ZS-30A controller list minimums of 8 from the battery & 10 from the solar array.

1. Will there be any issues with one Zamp 160W/9A panel? How about two?

2. The wires terminate in two red & clear plastic blocks. Are these removed to connect to the controller?

1. I assume you mean 160W panel - in which case there are no issues, if you have an MPPT charge controller you could also consider running two panels in series to keep the current down.

2. Yup, you need to remove the caps and attach the wires to your charge controller.

Rando

Yup. 160 Watt, 9 Amp. See, I am a newbee! I'll edit my post. Most wire gauge tables seem to agree with Zamp.

This table is based on acceptable voltage drop - which you don't really care about at least for the panel to controller run. You care about current carrying capacity:
http://www.coonerwire.com/amp-chart/

You should mount the charge controller close to the battery - you want to limit voltage drop on those wires, and you want the controller to be close to the same temperature as the batteries so that the temperature compensation works.

Rando

That chart doesn't show temps below 80 degrees Centigrade (176 degrees Fahrenheit). How does that apply? Aren't I looking at temps from 10-35 degrees Centigrade?

The temperature shown in the table is the maximum operating temperature - which you will be well under. I have been running a 150W roof mount panel in parallel with a 120w portable panel (using the side connector) with no issues what so ever.

Thanks. The portable runs through the same controller as the roof panel?

Yup. I have the Victron MPPT 75/15, and it handles both panels in parallel.

warning:

Based on this video, the Zamp pre-wired solar plug is reversed in polarity, be careful not to damage your battery

https://youtu.be/LShSQeddlgk

Thanks. I'm using a Zamp solar panel & controller, so that shouldn't be an issue. I was just concerned about the pre-wire sizes.

Play it safe, get a volt meter and check polarity at all connections before terminating any wires, there have been issues with a couple rigs in the past.

Thanks, Beach. Will do. My primary concern is whether or not 12 GA is sufficient. I'm just going to use what's in place & see how things go.

The answer to your question of, "whether or not 12 GA is sufficient" would be no, it is not.

The wire run from the roof mounted solar plug to a charge controller mounted driver side 2 feet back from the forward bulkhead is 33 feet (2 x 16.5 ft.). Now add 4 feet (2 x 2 ft.)for the run from the roof top panel to the plug,and your at 37 feet. If your controller is mounted passenger side or all the way aft add in the additional run. I prefer http://circuitwizard.bluesea.com/ and https://www.bluesea.com/resources/1437 over the hundreds of other sources of wire size. It shows that 12v with 10amp load at 37 ft with a fuse and a 3% loss gives us AWG 8 wire size.

Going by the previously posted scale it shows that 8 ga. wire is needed.

Reading the manual for the ZampZS-30A I found that wire size from battery to controller, less than 3.3ft run to be AWG 6. The wire run from controller to the solar array falls between AWG 8(30.7ft) and AWG 6 (39.6ft).

This leads to more questions:
1. How would you run a large size wire from the plug to the controller?
2. Will you be adding more roof top panels?

Cheers!

scud, take a look at the tables the other way ... given the panels you have, what percentage loss is there over the existing wires?

Captm said:

The answer to your question of, "whether or not 12 GA is sufficient" would be no, it is not.

The wire run from the roof mounted solar plug to a charge controller mounted driver side 2 feet back from the forward bulkhead is 33 feet (2 x 16.5 ft.). Now add 4 feet (2 x 2 ft.)for the run from the roof top panel to the plug,and your at 37 feet. If your controller is mounted passenger side or all the way aft add in the additional run. I prefer http://circuitwizard.bluesea.com/ over the hundreds of other sources of wire size. It shows that 12v with 10amp load at 37 ft with a fuse and a 3% loss gives us AWG 8 wire size.

Going by the previously posted scale it shows that 8 ga. wire is needed.
Reading the manual for the ZampZS-30A I found that wire size from battery to controller, less than 3.3ft run to be AWG 6. The wire run from controller to the solar array falls between AWG 8(30.7ft) and AWG 6 (39.6ft).

This leads to more questions:
1. How would you run a large size wire from the plug to the controller?
2. Will you be adding more roof top panels?

Cheers!

Click to expand...

The issue with this approach is that you are limiting your voltage loss to 3%. The voltage coming out of your panels is already going to be at 17 -19V, so you don't really care if you loose even 10 or 15% of that voltage before your solar controller. The only negative consequence is that you loose a little bit of potential solar power, but it is certainly not worth rewiring the camper to avoid that. Try the same Bluesea calculator with the more appropriate 10% loss figure, and you will see that you would be fine with 14awg wire.

my thoughts exactly

You can have 17-19 volts under ideal conditions, but what about all the other times? I want to maximize what I can squeeze out of the system I have for the longest period of time in all conditions in which case 3% or less will help achieve that.
I would hazard a guess this is why Zamp specifies AWG 8 or AWG 6 in the previously stated case - to minimize voltage loss and maximize the system.

I just did quick Google search and found 2% is most used as an allowable voltage drop for a PV system.

I ran AWG 8 through the roof into the "junction box" under the forward lift board,then out the side of the board to the thermal pack then behind the thermal pack down to the controller. It was not pretty but it worked and after a short while I did not notice it.
In order to run larger wire unseen would require the partial removal of the headliner, a pain in the rear that most people would not care to do.

Cheers!

As long as you are within the safe current carrying capacity of the wire (which BlueSea indicates is 45A for 12AWG), the wire size really plays an extremely minor role in the system efficiency, particularly when using a PWM charge controller. When you are doing most of your charging (full sun near the middle of the day) the panel is capable of providing far higher voltage than the battery can accept, so the battery is already pulling the panel voltage down from 17 -19V to ~14V for charging at close to the max current (in this case ~9A), so the wire voltage drop of 0.5V really doesn't matter.

You are correct that in marginal solar conditions that voltage maybe a little lower (see the figure below), however you will also note that at these times the current is also much lower as the current drops much faster than the voltage drops. So the voltage drop in your wires will be much lower due to the much lower current (much less than 3%), so 12AWG wires aren't going to cause any issues. If you are really concerned about squeezing every watt out, the time and money would be better spent on either more/larger solar panels, or an MPPT charge controller over rewiring the camper.

SCUD, when in doubt call the factory and have them re-explain it to you.

Most panels have 10 gauge wires. the camper connector to the solar controller are 12 gauge (little smaller in diameter). Personally before I installed a panel on my roof I was using a portable 60 watt panel connected to 50 feet of 12-2 (12 gauge 2 wires red and black ). It was rated at 3,5 amps an hour and that it what it was reading before the controller. You wont lose that much amperage dropping down to a smaller size wire.

The factory did their homework and provide a very efficient system for the owners.

If you add another panel verify that model ZAMP can handle the total rated amperage ( which they will produce on June 22nd when the sun is the highest in the sky).

We camp a lot in the desert in the winter when the sun is low in the sky. Since you cant tilt the panel towards the sun you will lose about 40% of its output. If you camp in the winter make sure your panels produce enough amperage to run all your 12 volt devices with 2-3 amps remaining to recharge the battery(s).

Well I'll have to amend my answer to SCUD's original question,"whether or not 12 GA is sufficient" to -
it depends on who you ask.

Cheers!