Portable solar wiring questions for you gurus....

[radarcontact]

Here's a specific set of questions tiered to my camper's configuration.

I have a 2015 Hawk w/a 160W Zamp roof panel. My batteries are two 6V flooded 230ah connected in series. Everything below is based on dry camping with no shore power/truck battery/alternator charging.

I've done the calculations as far as an 'average' amp draw/day. I have a 110L frig, a couple of Fantastic fans, and LED lights. Won't bore you with my math, but I'm coming up short about 50-60A/day (or 3+ hours of charging time), if I figure I'm getting about 10 hours of charging time out of my solar panel in direct sunlight. If it's a sunny day and the day is long, I can get into absorption and sometimes float if all that's running is the frig on medium temp. setting. Otherwise, there's many days where I stay in bulk for a long time.

Because of this I'm thinking about adding on a portable panel. Here's my questions:

1) I have a Blue Sky MPPT controller. I also have a rear Zamp plug on the back of the camper, for adding additional panels. Looks like I would need a separate controller for that plug, as I don't see any additional wires that I could connect into the Blue Sky controller. As far as I can tell from my research here and other places, I can connect, say, an 80W panel with, say, a 10A controller into that plug, as long as I put a Zamp-type plug on that controller. Mixing two controllers of different amperages shouldn't screw anything up, because each controller operates independently, and senses the battery voltages independently....?

2) Zamp has a parallel Y connector that I'm wondering would be of use:

https://backcountrysolar.com/products/parallel-solar-panel-y-connector

If I plug this into my rooftop Zamp connection, could I forget about the rear plug, connect both the rooftop and portable panels to the Y connector, and run them both off the Blue Sky controller? Seems like a more elegant solution. I would be mixing 160W panel with an 80W or 60W, but I think I'm OK on that.

3) If I didnt do #2 above, does anyone know of a not-too difficult way to tap into the rear Zamp plug line that goes directly to the battery, and wire it so that it goes to my Blue Sky controller first?

Sorry for the lengthy post. I think you electrical guys out there get the gist of what I'm trying to do. Any thoughts/input would be greatly appreciated.

 

[knoxswift]

I just did some checking on this problem the other weekend too...
My camper the rear plug is wired in parallel.
So I think that the intention was to add a panel to a pwm controller with matching voltage panels to gain the most amps possible.

Since you have a mppt controller I would think you might want miss matched panels to be in series for more voltage to that type of controller which will result in more amps with that type of controller.
I would say find out how the port is wired and you may not need a second controller you could use hire voltage panel as your secondary with better results on a mppt.

 

[longhorn1]

First, if the 160W Zamp and controller were installed at FWC, and the rear solar plug, then the rear solar plug should be wired to your controller. When I purchased my Zamp 80W portable I spoke to Zamp and FWC. I was told by FWC the plug was wired to the controller and to purchase a portable panel without controller. You should confirm with FWC.

 

[Old Crow]

This Solar Wiring Discovery 2017 Hawk thread may be helpful. The first photo shows the solar wiring on the 2017 Hawk connected together via push-in connectors ( 'Wago Pushwire Wall-Nuts' ). Further down the thread is a diagram of Karlton's setup with MPPT controller and battery monitor.

 

[ntsqd]

Those polarized rubber electrical connectors, as shown on the one leg of the linked Y above, existed LONG before Zamp came along. I've seen a few here refer to them as "SAE" connectors, I don't if that's technically correct or not. The biggest wire I've ever seen them offered in is 10 ga. Which just happens to be the largest wire that the solar industry std "MC4" connector can handle as well. IMHO that's too small for less than 3% voltage drop over any reasonable run length. See: "Handy Bob".

I see no reason why the wires from the portable connector can't also be terminated directly at the charge controller. Of bigger concern is can the existing charge controller handle the additional power input?

 

[radarcontact]

First, if the 160W Zamp and controller were installed at FWC, and the rear solar plug, then the rear solar plug should be wired to your controller. When I purchased my Zamp 80W portable I spoke to Zamp and FWC. I was told by FWC the plug was wired to the controller and to purchase a portable panel without controller. You should confirm with FWC.

I spoke with someone at FWC yesterday, who seemed a little unsure about his response IMO, and he told me that, as far as he knew, the plug wasn't wired to the controller. I wish I could get a definitive answer without trying to go into the cabinet and trace wires, but I may have to do that. If anyone out there can tell me a simple way to determine that I'm all ears.

 

[radarcontact]

ntsqd, on 03 Aug 2018 - 07:02 AM, said:

Those polarized rubber electrical connectors, as shown on the one leg of the linked Y above, existed LONG before Zamp came along. I've seen a few here refer to them as "SAE" connectors, I don't if that's technically correct or not. The biggest wire I've ever seen them offered in is 10 ga. Which just happens to be the largest wire that the solar industry std "MC4" connector can handle as well. IMHO that's too small for less than 3% voltage drop over any reasonable run length. See: "Handy Bob".

I see no reason why the wires from the portable connector can't also be terminated directly at the charge controller. Of bigger concern is can the existing charge controller handle the additional power input?

Some of the sites offering these Y connectors seem to allude to them having a max wattage capacity of 200W, but I have yet to confirm that. Spoke w/someone at Zamp yesterday, and he said as long as the wiring IN THE CAMPER was a thicker gauge, there would be no problem with their brand of Y connector handling, say, a 160W panel and an 80W panel. I doubt this is the way I would go....having to reach up to the top of the camper every time to connect the portable panel seems like a pain. If the rear plug is wired into the controller that would accomplish the same objective, and I could just connect there. I need to find out.

 

[PaulT]

Measure the voltage at the rear socket. If it is zero volts, it isn’t connected. If it is 12-15 volts, it is likely connected to the factory controller as it was in my 2014 Hawk. I plug in a portable panel without a controller at that rear socket.

Paul

 

[radarcontact]

Well, lesson learned.....I should have done some more investigating before assuming my rear plug didn't link to my controller. This a.m. I pulled the controller out of the cabinet, and to my surprise found that the rear plug was wired into the controller, along with the rooftop panel:



The left yellow tab attached to the bundle says 'roof solar', and the right yellow tab says 'rear plug'. They're both interconneted, and then go into the controller (which is hanging down at the bottom of the pic).

Paul, I also measured the voltage w/a voltmeter at the rear plug....as you said, the voltage was 14.5V, which confirmed it. Thank you.

Going to KISS and wire the portable to the rear plug. Thanks for your replies.

 

[kluber]

We recently set up a portable 100 watt panel so that we could maintain batteries even if parked in the shade. It works incredibly well. Like your set up, the SAE plug on the rear of the camper (2015 Fleet with factory set up rooftop panels and controller) was connected to the controller. But there was a catch! The SEA plug on the rear of the camper was wired backwards. I initially set up the portable panel, plugged it in, and the control panel input went to zero (despite the rooftop panels still connected). After guidance from FWC, I reversed the polarity on the panel, and everything worked fine and has continued to work fine. So, if you plug in and the charge drops, you may have the same situation. Reversing the polarity was easy - cut and splice the line from the portable panel to the SEA plug. I suspect that you could reverse the wires at the control panel as I see you've pulled it out (I just looked at mine by removing the drawer). Good luck. It's a great upgrade : )

 

[Old Crow]

It makes sense that FWC would want to pre-wire campers the same and set up for the options they offer. Connect the roof and rear-plug wires together and run toward the controller location. If the customer didn't order factory solar, coil up the wire near the possible/probable controller location and that's that--- customer is happy to have pre-wiring for the future. If the customer DID order the rooftop solar option, connect the wire to the controller and controller to battery. If the customer also ordered the optional portable panel, nothing additional to do (assuming the controller can support both panels).

The question in my mind is how far back in years does that go. The solar section in the 2017 manual mentions January 1st, 2015 as the start of standard roof and rear plugs but Paul's post above suggests it was done earlier, I assume as an option before that date.


.

 

[knoxswift]

That picture also proves that it's wired in parallel.

 

[radarcontact]

We recently set up a portable 100 watt panel so that we could maintain batteries even if parked in the shade. It works incredibly well. Like your set up, the SAE plug on the rear of the camper (2015 Fleet with factory set up rooftop panels and controller) was connected to the controller. But there was a catch! The SEA plug on the rear of the camper was wired backwards. I initially set up the portable panel, plugged it in, and the control panel input went to zero (despite the rooftop panels still connected). After guidance from FWC, I reversed the polarity on the panel, and everything worked fine and has continued to work fine. So, if you plug in and the charge drops, you may have the same situation. Reversing the polarity was easy - cut and splice the line from the portable panel to the SEA plug. I suspect that you could reverse the wires at the control panel as I see you've pulled it out (I just looked at mine by removing the drawer). Good luck. It's a great upgrade : )

Thank you, kluber. Fortunately, the one thing I was up-to-speed on was that Zamp reverses polarity on their connectors. I did check the polarity with a voltmeter just to make sure it was in fact reversed....it was. Going to do exactly what you said, splice the SAE extension I have and reverse the polarity at the connection, in essence making my own SAE to Zamp adapter, solder the wires together and heat shrink the soldered connections.

 

[radarcontact]

That picture also proves that it's wired in parallel.

Good thing, right? To mix and match different wattages of panels.

 

[knoxswift]

Good thing, right? To mix and match different wattages of panels.

I find it interesting because I would say a good thing for PWM controllers but for MPPT it's really based on use case?
I have a PWM controller so I was happy to find it pre-wired in parallel.
But FWC has been using MPPTs for a few years now?

My understanding you can get better performance with an MPPT with high voltage and let the MPPT bring it down.
Where this would be contrary would be if you plan on alot of Shade where trying for high voltage would be hard due to shade?

 

[radarcontact]

Measure the voltage at the rear socket. If it is zero volts, it isn’t connected. If it is 12-15 volts, it is likely connected to the factory controller as it was in my 2014 Hawk. I plug in a portable panel without a controller at that rear socket.

Paul

Hey Paul, I have a question for you....sorry if it sounds like I'm an idiot.....but I used my neighbor's voltmeter to check the polarity of my Zamp rear plug. When I touched the exposed prong on the plug with the red probe, and the shielded prong with the black probe, I got a positive voltage.....is that what I should be seeing if the polarity on the plug is reversed? My head is spinning now, because when I spoke w/FW regarding my Hawk they couldn't definitively tell me how they wired those SAE plugs, and I saw a video on connecting to those plugs on YouTube that has confused me about using voltmeters and what to expect, etc. Thanks. Also wondering, if in fact the polarity IS reversed, can I switch it around with the wires behind the charge controller (i.e., the pic I posted above)?

 

[ntsqd]

I find it interesting because I would say a good thing for PWM controllers but for MPPT it's really based on use case?
I have a PWM controller so I was happy to find it pre-wired in parallel.
But FWC has been using MPPTs for a few years now?

My understanding you can get better performance with an MPPT with high voltage and let the MPPT bring it down.
Where this would be contrary would be if you plan on alot of Shade where trying for high voltage would be hard due to shade?

It isn't so much that the MPPT controllers work better this way (although that is probably true too), it is that with a controller that can handle a higher input voltage that you have less line loss for the same wattage. Recall: Volts X Amps = Watts (V*I = W) so if the volts increase the amps decrease at the same wattage. When the amps decrease there is less power lost to heat as a function of the wire's resistance. (V = I/R)
Said differently, with a higher voltage you can use a smaller wire because what drives the wire gauge choice is the amps it will need to conduct. With a 10 ga. wire size constraint due to the various connectors employed it makes sense to build the system to operate at a higher voltage.

 

[Vic Harder]

To add to ntsqd's point, notice that the power lines carrying electricity from the generating station to the substation are not super thick gauge... they are VERY high voltage, low current wires. Long distance = high voltage = more efficient.

 

[radarcontact]

Maybe someone out there can clear up some confusion for me....

Here's my wires coming from the panel, and the plug it's going into:



When I check the receptacle with a voltmeter, touching the red probe to the exposed prong on the left, and the black probe to the covered prong on the right, I'm getting a positive voltage reading of 14.5.

The wires that plug into that receptacle have the red wire plugging into the left side (i.e., the side with the exposed prong), and the black wire plugging into the right side.

My conclusion is that this Zamp plug is the correct polarity, and NOT reversed like many of them are.

Am I missing anything? I'm confused because when I talked with FW yesterday they couldn't give me an answer one way or the other on how my camper was wired.

Thanks.

 

[PaulT]

Hey Paul, I have a question for you....sorry if it sounds like I'm an idiot.....but I used my neighbor's voltmeter to check the polarity of my Zamp rear plug. When I touched the exposed prong on the plug with the red probe, and the shielded prong with the black probe, I got a positive voltage.....is that what I should be seeing if the polarity on the plug is reversed? My head is spinning now, because when I spoke w/FW regarding my Hawk they couldn't definitively tell me how they wired those SAE plugs, and I saw a video on connecting to those plugs on YouTube that has confused me about using voltmeters and what to expect, etc. Thanks. Also wondering, if in fact the polarity IS reversed, can I switch it around with the wires behind the charge controller (i.e., the pic I posted above)?

Rather than trying to understand what was done, just remember that you want to wire the portable panel’s positive wire to the rear socket’s positive wire. You are connecting the roof panel and the portable in parallel; that is, is positive to positive, negative to negative.

One of these may do what you need. https://www.amazon.com/RENOGY-MC4-to-SAE-Adaptor/dp/B01N1TALFY

One of these may work to reverse polarity of the rear socket.
https://www.amazon.com/CES-Gauge-Quick-Disconnect-Harness/dp/B0057ZQJ12

I made my own adapter cable similar to the first from one of the second plus MC4 connectors as I could not find a suitable adapter when I needed it.

Paul