Solar port wiring

[AJMike]

I just got off the phone with Zamp and was told that the documentation in the Winnebago manual for my 2018 Fuse is old and has not been properly updated.

They said that the limit on each port is 20 amps with a 30 amp limit on the entire system. A 20 amp input limit on each port means that it is more than robust enough to handle 200 watts.

Just wanted to post this to let everyone know what I was told.

[Winterbagoal]

Zamp's own manuals (for ZS-30A CC) suggest a 510W limit at the roof combiner. Downloaded from their website. Max input 25A, max output 30A. 25A in would be about 500W worth of panels, in good sun, if my math is sound. My 100W panels each put out around 5.5A each in good sun. I guess their manuals are wrong. I'd get it in writing from Zamp before proceeding.
However, if you're going to let your installer gut the existing system, and replace it, that's a different animal.
My usual comments/advice caveats apply. I'm no expert.

[DavidM]

Let me repeat some things I have said on similar threads:

A rough way to figure if your solar controller can take the panel loads connected to it is to divide total wattage by 12 and compare that with the controllers nominal amp rating. Some controller manufacturers like Victron supply a controller sizing program and that one usually exceeds watts/12 by 10-20%.

What is important in wiring solar panel is voltage drop in the wire. I would shoot for a 1/2 volt drop or less in the circuit from the panels to the controller. Use the Imp value for the panels times the number of panels (if wired in parallel) and use a wire sizing table or program to find the voltage drop. For example for 500 watts of panels producing about 30 amps to the controller you can go only 13 feet and stay within 1/2 volt drop.

If you have an even number of panels and don't expect much shading, wire them in series/parallel (two wired in series connected in parallel to two more wired in series) which doubles voltage and halves the current. You can easily carry 500 watts of panels with 8 gauge if you wire them this way.

Just as important, probably more so, is the voltage drop from the solar controller to the batteries. I like to keep that drop down to 1/4 volt. In this case, the current is about 40 amps at 12V (the controller converts the 17 volts input to 12-14 volts output so the current goes up with the same wattage and lower voltage). You need #6 wire to go as much as 8' and stay within 1/4 volt.

Keeping the voltage drop to the batteries is extremely important. Another member upgraded his converter for lithium batteries. With a 55 amp rated controller he could only get 30 amps output through the original battery wiring. When he jumpered the wire with heavy cables, it shot up to 50 amps. The same thing happens with solar controllers.

David

[Elkman]

With four 100W panels the expected combined output of 400 Watts is within the capabilities of the Zamp ZS-30 PWM charge controller. Unfortunately this cheap PWM controller produces 75% as much charge current as would be obtained with a MPPT charge controller during the day. be as much as 32 amps and if the Zamp controller is truly limited to 30 amps then the folks at Winnebago screwed up putting this unit into their RVs.

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[Elkman]

I will be going with the Victron 100/50 MPPT charge controller as it handles up to 700 Watts of PV output. I want to get as much solar power for the RV as possible, what with most of the factory panel output needed to keep the fridge running. The controller also can take 48 volts so 4 panels can be wired in series.

[DavidM]

I will make this point one more time.

Solar panels normally operate at about 17 volts each while charging. That means the voltage to your controller if four are wired in series is 4 x 17= 68. But when the batteries get charged that voltage rises to about 21, so the voltage is 4 x 21 = 84. Both are beyond normal DC wiring practices and if you touched the wire you would get a nice shock.

I am not saying that it can't be done. Lots of RV wiring doesn't meet NEC code. Make sure that all connections are insulated from human hands touching them.

But if I were doing this myself, I would wire the four panels series/parallel so the maximum voltage stays down to 42. But check the voltage drop in the wiring if you do this. I like to keep it down to 1/2 volt. Wire is cheaper than funerals .

David

[DKDaniels]

Originally Posted by Winterbagoal

OK, from the 2018 Navion OM, the max input of the Zamp ZS-30A controller is 510W, and the indivdual ports in the rooftop combiner is 150W per port. If you wanted to go to 450W up top, you could do that by swapping the 100W panels for 3 X 150W panels. So, whatever the wire gauges are, they can handle up to 150W each. As far as the wire gaues go, I'm thinking Zamp Solar supplies all the parts for their solar systems, including the combiner and wiring harnesses, so maybe they could give you the wire gauge, if the other limitations aren't show stoppers. I honestly believe Winnebago bought the systems as kits and installed them using Zamp parts. Here's what they use, but no specific wiring gauges are listed. You could try sending them an email and ask.
https://www.zampsolar.com/ports-wires

You need to stop and find answers for it's very difficult to get a straight answer. I bought a 2020 View last Dec and i asked Lichtsinn how much maximum watts, oh you can put as many panels as it will hold. I called Winnebago 3 times and finally was told 450 is the max. That led me to having Winnebago install only 1, 100 watt panel which was like an act of God and they charged me 100 dollars to install just one. Then Lichtsinn installed two 170 watts for a total of 440 watts. Which by the way charges my house batteries fully by noon on sunny days.

Now someone was having problems who had over 510 watts of solar and had to unplug one panel. He called Zamp and was told they make 3 types of ports on the roof a 450, 480 and 510. not sure on the 480 but the point is Winnebago uses all 3 ports. Crazy isn't it. I was told that number is stamped on it but after inspecting mine I see no number just the name Zamp. See this is so important in deciding how much to put on the roof for I was thinking of removing the one 100 watt and replacing it with a 170 to max out at 510 but now that it's unclear as to what port Winnebago installed and how great my current 440 watts are doing I'm leaving what I have.
Winnebago Dan 20J

[AJMike]

Originally Posted by DKDaniels

You need to stop and find answers for it's very difficult to get a straight answer. I bought a 2020 View last Dec and i asked Lichtsinn how much maximum watts, oh you can put as many panels as it will hold. I called Winnebago 3 times and finally was told 450 is the max. That led me to having Winnebago install only 1, 100 watt panel which was like an act of God and they charged me 100 dollars to install just one. Then Lichtsinn installed two 170 watts for a total of 440 watts. Which by the way charges my house batteries fully by noon on sunny days.

Now someone was having problems who had over 510 watts of solar and had to unplug one panel. He called Zamp and was told they make 3 types of ports on the roof a 450, 480 and 510. not sure on the 480 but the point is Winnebago uses all 3 ports. Crazy isn't it. I was told that number is stamped on it but after inspecting mine I see no number just the name Zamp. See this is so important in deciding how much to put on the roof for I was thinking of removing the one 100 watt and replacing it with a 170 to max out at 510 but now that it's unclear as to what port Winnebago installed and how great my current 440 watts are doing I'm leaving what I have.
Winnebago Dan 20J

I have 3 100 watt SunPower panels on the roof of my 2018 Fuse. I added the 3rd panel shortly after getting the RV because I wanted to make sure that we were able to charge our batteries as quickly as possible, given the compressor fridge in the Fuse. Since that time my wife has started using small electric appliances like our toaster and her tea kettle so I thought I should install a 4th panel, just to be sure.

I know the manual states that each port on the solar cap can handle 150 watts with a total of either 500 watts, depending on where you look (the solar cap is stamped with 510 watts on my Fuse), so I called Zamp. The first thing they asked me was what color the port cap was, and when I told them it was white they told me that the system could handle 510 watts and each port could handle 20 amps. Yes, 20 amps.

I asked what the differences were with the different color caps, and was told that the functionality varied, not the power. When I mentioned what the manual said they told me that apparently it had not been updated, but that each port was capable of 20 amps, which translates to a max of about 300 watts, given about 6.2 amps/100 watt SunPower panel. They also told me that they do a lot of 3 170 watt installations because that gives the user the max of 510 watts.

I unscrewed the Zamp solar controller from the wall to see what kind of wiring is involved and it turns out that the solar cap has 8 gauge wire running from it to the solar controller.

All of this has left me more than a bit confused, and I would be reluctant to run 20 amps through a single port on the device, regardless of what Zamp tells me, but I will try a second 100 watt panel. If that causes me any trouble then I will have the installer (I don't have the expertise to do this myself) replace the port with a regular MC4 plate, but I think that 400 watts may be the max I try to put on the roof. As it is I have no place for any more, given the 3 flex panels already up there.

[Winterbagoal]

"I know the manual states that each port on the solar cap can handle 150 watts with a total of either 500 watts, depending on where you look (the solar cap is stamped with 510 watts on my Fuse), so I called Zamp. The first thing they asked me was what color the port cap was, and when I told them it was white they told me that the system could handle 510 watts and each port could handle 20 amps. Yes, 20 amps."

So, the cap ports can handle 20A each? Did they say whether the ZS-30A PWM CC could handle that much amperage? At face value the answer should be "no".
You're not the only one that's confused by Zamp's answers.

[powercat_ras]

Beware, many posts on this thread contain bad information and/or bad advice for your specific situation. In particular the post/posts suggesting the whole thing be re-worked from parallel to series. Not good advice since you already have 3 100 watt panels and you don't intend to add more of exactly the same type of solar panel as you have now, or remove the existing and go with all new solar panels of the same type.

If he wants to remove the Zamp connectors and go with hard wiring or standard solar connectors that would be fine, it's just money and time. The main thing is that the additional solar panels need to have good solid watertight connections to the same wiring that goes down to the charge controller, which I suspect is why the installer wants to re-work the Zamp roof connector box since it seems that all 3 ports on it are already in use and you want to add 2 more solar paels.

Why not just let your solar installer who you state knows what he is doing do it the way he recommends ??? Trusting free advice off a forum like this in particular regarding electrical questions can sometimes be very bad for you.

[AJMike]

Originally Posted by Winterbagoal

"I know the manual states that each port on the solar cap can handle 150 watts with a total of either 500 watts, depending on where you look (the solar cap is stamped with 510 watts on my Fuse), so I called Zamp. The first thing they asked me was what color the port cap was, and when I told them it was white they told me that the system could handle 510 watts and each port could handle 20 amps. Yes, 20 amps."

So, the cap ports can handle 20A each? Did they say whether the ZS-30A PWM CC could handle that much amperage? At face value the answer should be "no".
You're not the only one that's confused by Zamp's answers.

Almost by definition the CC can handle 30 amps, being a 30 amp solar controller. I suppose the question really is how much current can each port itself handle since I would think that the wiring itself, at 8 gauge, is more than sufficient for 200 watts/12 amps. Of course I don't know and I have some concerns because I am planning to add that second 100 watt panel to one of the ports. I guess I will need to keep a close eye on this.

If Zamp does a lot of 3 170 watt panel installs I assume they believe that the roof device itself can handle 510 watts and that each individual port can handle 170 watts.

[AJMike]

Originally Posted by powercat_ras

Beware, many posts on this thread contain bad information and/or bad advice for your specific situation. In particular the post/posts suggesting the whole thing be re-worked from parallel to series. Not good advice since you already have 3 100 watt panels and you don't intend to add more of exactly the same type of solar panel as you have now, or remove the existing and go with all new solar panels of the same type.

Why not just let your solar installer who you state knows what he is doing do it the way he recommends ??? If he wants to remove the Zamp connectors and go with hard wiring or standard solar connectors that would be fine, it's just money and time. Good luck.

I completely agree with this, and in fact was thinking this morning of telling him to do exactly that.

The original plan was to splice in this 4th panel and when the flex panels died (they only have a 5 year warranty which, I assume, means that I can expect them to die after about 5 years a 1 week) to replace them with 2 200 watt panels and keep the single 100 watt panel. To do that the installer was going to remove the Zamp port device and replace it with whatever he normally uses, so perhaps it is safest to just do that now and not worry about how much current each individual port can handle. As you say, it is either "pay me now" or "pay me later".

[DKDaniels]

you should do great with 400 watts but I'm telling you we learn new information all the time. Interesting on the different color port and I had lithium batteries factory installed so one would have thought they would install a 510 watt port but I'm sure they used what they had at the time. Interesting you do see it stamped with 510. I would love to see a pic as to where exactly it's located.

[AJMike]

Originally Posted by DKDaniels

you should do great with 400 watts but I'm telling you we learn new information all the time. Interesting on the different color port and I had lithium batteries factory installed so one would have thought they would install a 510 watt port but I'm sure they used what they had at the time. Interesting you do see it stamped with 510. I would love to see a pic as to where exactly it's located.

I went to take some photos of the wiring 2 days ago to send to the installer so he could be sure that the wiring was robust enough to handle 200 watts on a single port and as part of that I checked the roof for space measurements. That is when I saw the embossed value and thought about taking a photo but did not.

However I will be going back there later today to bring the RV home in preparation for taking to the installer in the morning and I will take some additional photos to post here.

In the meantime here is a photo of the wiring behind the controller inside the RV and as you can see it is fairly robust.

[DKDaniels]

Thanks well appreciated...

[Winterbagoal]

Originally Posted by AJMike

I completely agree with this, and in fact was thinking this morning of telling him to do exactly that.

The original plan was to splice in this 4th panel and when the flex panels died (they only have a 5 year warranty which, I assume, means that I can expect them to die after about 5 years a 1 week) to replace them with 2 200 watt panels and keep the single 100 watt panel. To do that the installer was going to remove the Zamp port device and replace it with whatever he normally uses, so perhaps it is safest to just do that now and not worry about how much current each individual port can handle. As you say, it is either "pay me now" or "pay me later".

Yeah, good call. Gut the system and start over. Eliminate the retrofitting, as it just adds complexity to the whole project. It will also give you more flexibility in how much power you want to put up there.
Again, if you go with higher capacity hard panels, check your OCCC and make sure the new panels aren't going to eat up more than you can spare. That would be my only other concern, because I'm OCCC challenged with my Navion, and switching from lightweight flex panels to hard panels would negatively affect my OCCC.

[AJMike]

Originally Posted by DKDaniels

Thanks well appreciated...

Happy to help, but remember that this is what is in my RV. I assume it is the same as yours, but I don't know that.

[AJMike]

Originally Posted by DKDaniels

Interesting you do see it stamped with 510. I would love to see a pic as to where exactly it's located.

It appears I was off a bit.

The port combiner (that is what Zamp told me today that they call that device) is stamped with 500 watts, not 510 as I thought I remembered. I guess 510 watts is what is in the manual and the fact that the manual and the combiner differ was just one of those sources of confusion for me.

Here are some photos of the combiner on my Fuse. You can see that the combiner is marked on mine at the top near the side facing toward the back of the RV.