Simple Portable Solar Advise Please

O

OutbacKamper

Senior Member
Joined
Jul 14, 2006
Messages
198
Location
Kelowna, BC, Canada
Hello;
I have searched for and read several other solar threads, but many of them are too technical for my very limited electrical/solar knowledge and involve more complex systems than I am looking for.

My 2013 Hawk has a single 12v deep cycle battery (new Optima blue top). I have a 3 way fridge, so my electrical power needs are low (led lights, occasional Fantastic fan and water pump use). I have no solar at the moment, but my camper came prewired for a portable solar panel. The pre-wire appears to consist of an exterior rear wall 2 conductor weatherproof plug and 2 wires coiled up in the battery compartment.

I would like to add a portable folding solar panel, with about 10-20 feet of wire so that the panel can by placed in the sun while the camper is in the shade. Here are my questions:

1) Does the factory wiring require a camper mounted controller, or can I buy a portable panel with a built in controller like this?:
61iktjM2pUL._SL1000_.jpg

https://www.amazon.ca/HQST-Polycrystalline-Foldable-Suitcase-Controller/dp/B01MS9E7L9/ref=sr_1_7?ie=UTF8&qid=1534183359&sr=8-7&keywords=foldable+solar+panel

2) If the panel with built in controller will work, can I simply attach the factory wires to the battery and plug in the portable panel, or is there more installation required?
3) I am considering a 100W panel - would that would work with the factory wiring?

Thanks for any input you may offer.
 
Hi ...I can try to help.

1) You most likely need a controller with any portable panel you buy, as I doubt FWC put a controller in your camper. Check that, but if not, then, yes, get a portable with a controller

2) That's a trickier question. You have to see how your external plug is wired. Can you see the back of the plug inside the battery compartment? If so, see where the red/black wires are attached. If the red wire is attached to the female side of the external SAE plug, then all is good. If not, and it's attached to the male side, then it's a Zamp brand SAE receptacle, and you have additional work to do. If it is a Zamp plug, then you will have to reverse the connections to the battery...i.e., red will have to go to negative, and black to positive. as the connections from the solar panel are coming into the receptacle the opposite way of the color scheme of the Zamp receptacle. Does that make sense?

3) Can you see what gauge wire you have coming out of that external plug? Most likely it's 12 gauge (12AWG). If so, that supports up to 20 amps, and for a run of 10-20 feet, which isn't excessively long, you'll be fine. Most 100W panels I've seen operate at about 5-6 amps in really sunny conditions. You can usually find the max voltage and amperage of the panel in the manufacturer's spec sheet.

Note that the particular plug you referenced from Amazon has alligator clips on the terminal wire ends coming from the controller. You can attach those directly to the positive and negative terminals on your battery, but since you said you'd prefer to use the external camper receptacle, you'll need a different cable from the controller to the external SAE port. You can find adapters for that on Amazon as well.
 
Hey Outback! Canadian Tire has a sale on right now for two Coleman 100w panels for $350 (sku 299-5777-2 200W is a nice amount of solar to have to support your single camper battery.

Otherwise, what Radar set is right on too.

Oh, I just notices that those Coleman units don't come with a controller though. ;-(
 
Don’t forget to run the wires thru a fuse to the battery. Otherwise, if there were a short across the wires plugged into that rear solar socket, it could get ugly quickly. The battery’s capacity could easily melt the wires and start a fire. Put the fuse close to the battery post

Paul
 
The other way to check and see how that external SAE plug/receptacle is wired is to use a voltmeter/multimeter. Hook the wires that are coiled up in your battery compartment to your battery the way the wires indicate, i.e., red to positive terminal, black to negative (what kind of connections do those wires have to the battery, BTW?), and touch the positive, red probe of the voltmeter to the male side of the receptacle, the black probe to the female side:

Attach0 (8).jpg

So, touch the red probe to the prong on the left side in this pic, the black to the shielded female side on the right. If you get a positive voltage reading, the SAE receptacle is a Zamp receptacle, and you'll have to reverse the connections going to the battery, if you buy any brand panel other than a Zamp panel. Zamp does this so that you'll buy their brand panels, which are fine quality, but pretty expensive. If the voltage reading is negative, you're golden.

From the first post.....here's an example of a cable adapter you can use for the solar controller to your external SAE plug/receptacle:

https://www.amazon.com/Terminal-Wiring-Harness-Disconnect-Extension/dp/B07BKZ89TS/ref=sr_1_fkmr2_2?s=automotive&ie=UTF8&qid=1534253450&sr=1-2-fkmr2&keywords=sae+to+o+ring+12+gauge

You'll probably have to snip those loop connectors off the ends in order to attach them to the solar controller. This particular connector has a built-in inline fuse, like Paul suggested (although this fuse would be external to the battery compartment. I think it would accomplish the same objective, but maybe Paul can elaborate further). It's 16 gauge wire, so it can handle the amperage from your 100W panel fine. If you go to two 100W panels, as Vic suggested, I would probably upgrade the connector to a thicker gauge, as this one has a 10A fuse, and, with two 100W panels you'd be over amperage at max capacity (though I believe the 16 gauge would be fine for up to 13 amps....if you put a 12.5A fuse in there you should be OK w/ 2 panels). BTW, that connection (solar panel to SAE connector) is another place where you could potentially reverse the polarity of your wires. If you have a Zamp plug and you didn't want to reverse them at the battery for some reason, you could reverse them coming out of the solar controller. Your choice.

If you look at the write-up on Amazon for the HQST panel you said you wanted, they have a spec sheet there with the voltage and amperage at optimum. Listed optimum voltage is 17.8V, and optimum amperage is 5.68A.
 
Thanks for the replies everyone. I will be doing some traveling until early September, so I will not be posting much for a while. Once I return I intend to investigate further and will post with updates of my portable solar progress.
 
Good detailed instruction radarcontact, but your write up still confused me a bit. I have a 2016 Grandby with rear wall ZampSolar SAE plug. I tested as in your write up. I have 160 watts on the roof and ZampSolar controller. I want to use my Renogy portable 100 watts to plug in the rear wall plug if I am parked in the shade. I used the included spare SAE plug with bare wire at the end of 20” wire and crimped on MC4 plugs. I just wired the plugs positive to positive, negative to negative wires. Why all the confusing language about reversing polarities, etc.
my main question is whether it is ok to use my Renogy 100 watts portable with controller and plug into the rear wall plug, which I believe is wired into the onboard ZampSolar controller, or do I need to bypass the controller on my Renogy.
I use my portable on my travel trailer directly to the batteries so rather not bypass the controller every time I need to use on the Grandby. Would having the voltage going thru two different controllers in line damage anything?
 
muttmaster said:
Good detailed instruction radarcontact, but your write up still confused me a bit. I have a 2016 Grandby with rear wall ZampSolar SAE plug. I tested as in your write up. I have 160 watts on the roof and ZampSolar controller. I want to use my Renogy portable 100 watts to plug in the rear wall plug if I am parked in the shade. I used the included spare SAE plug with bare wire at the end of 20” wire and crimped on MC4 plugs. I just wired the plugs positive to positive, negative to negative wires. Why all the confusing language about reversing polarities, etc.
my main question is whether it is ok to use my Renogy 100 watts portable with controller and plug into the rear wall plug, which I believe is wired into the onboard ZampSolar controller, or do I need to bypass the controller on my Renogy.
I use my portable on my travel trailer directly to the batteries so rather not bypass the controller every time I need to use on the Grandby. Would having the voltage going thru two different controllers in line damage anything?
Click to expand...
Radarcontact's cautions are right on. He is saying that you can't just wire positive to positive, etc.. without checking that the connector is in fact wired that way. SOME of the ZAMP's are wired in reverse! So check it with a multi meter before plugging it in.
 
I used test light to check polarity at the Rear SAE plug and used multimeter as radarcontact suggested. SOME ZAmp plugs may have reversed polarity, but mine was “correct” I called tech at ZAmp, and he said there is no standard as to which side is set pos or beg and they do the reverse for safety reasons? Anyway, can I use my Renogy with controller and plug in the rear SAE that goes to my onboard ZAmp controller? Can’t wait to install another Trimetric setup as I did in my older Grandby per your instruction Vic thanks.
 
I would be guessing, but ... I suspect the wires from your rear facing portable connector are wired directly to the battery. If so, then you can just plug in the portable and use their controller.

I that guess is wrong - and the portable connector goes to the on board controller, then you will need to bypass the controller on your Renogy portable unit.
 
I will check the back of the ZAmp controller to see if the rear SAE plug connect there. If it goes to the battery directly, they will be best for me as I would have to bypass the Portable’s controller. What damage can if really cause if juice from one portable panel goes thru two different controllers ? Best not to? I guess, has anyone done that or seen the effects? I can’t be the only solar novice that have that question.
 
I checked the Zamp controller onboard and found wire from the rear plug is connected to bus that is connected to the back of the controller. The bus is also connected to roof top panel I assume and the batteries. I better ask FWC for advise on how to use my portable.
 
"Simple" and "solar" shouldn't be used in the the same phrase! :oops: They should be though...

Plenty of good 150-230W panels on the market with integrated controller. Just be mindful of the stowed form factor and weight. A 180W Zamp portable weighs 34# and closed dimensions are 39.5“ x 21.5" x 3".

An external SAE plug wired to a high quality circuit break is a must to protect the circuit and eliminate a potential fire hazard. Matching the circuit break amperage equal to the controller amperage is a safe rule of thumb.

Most reputable portable panels will be fused between the panel and embedded/installed controller.
 
I dunno about this Advmoto18. If there is a fuse, it's purpose is to protect the wire and prevent fires. To do that, the fuse should be located at the power source, so at the panel, not at the controller end.

FYI, I don' t have any on my roof, nor do I have any at the far end of 100' of cable for my portables.
 
Vic...

Renogy recommends fusing between the panel and the controller and the controller and the battery bank. The fuse between the controller and battery bank should be equal to the controller amperage.

Is a fuse between the panel(s) and controller required? No, but, it doesn't hurt as it is only another layer of protection.

Rather then fuses, I used Blue Seas marine circuit breakers. Panel to controller side CB is equal to max output of all panels.

I have a CB between my roof panel and controller; just before the controller. Another CB just inside the camper shell from the external SAE port from my portable panel.

I probably over-fuse and CB my electrical schemes most likely due to my aviation background. I don't like fire! Lost a pilot buddy on the Swiss Air flight that crashed off Nova Scotia 2 decades ago due to an electrical fire in the cockpit.

Fuses and CBs are cheap insurance IMO.
 
rubberlegs said:
Hey y'all, I'm thinking of jumping into the solar bandwagon. Our battery goes down to near 60% or even 50% after a night of pleasant camping. What do you think about the recommendation on this website? Agree with their assessment? https://campaddict.com/portable-solar-panels/
Click to expand...
I have an older Zamp 80 watt, and it does a good job. Renogy has a good reputation as well. No info on the other.

I think you would do well with Zamp or Renogy, possibly the third.

Why not go with an onboard system? You could keep the batteries topped off when ever the camper is outside.
 
I agree with WanderingSagebrush.... go for a permanent install rather than portable, unless there is a good reason to go portable? Like you have a canoe on the roof, park in the shade, or some other reason.

Before you can size the panels correctly, we need to know how many AH of battery you have. Typically you would need to get at least the same or up to 2x as many watts as AH. I have 250AH, and 465 watts of solar.
 
We have the standard 89 Ah battery that came with our Fleet, and seem to use 30-50% in a night (based on measuring with a voltmeter occasionally). I think portable is better for us because of two reasons: we can park in the shade, and it's simpler to retrofit on the camper -- just plug it in. I figured I could put it on top if we are in the sun, and maybe it's less chance of being stolen while we are out hiking. But I've not figured out how to put it up there -- I tried standing on a tire and holding the edge of the roof today (roof down of course) and it's not a great handhold!

I had "electric car range anxiety" type feelings about our battery usage, so hope the solar mitigates that.

Then the other subject is how much. I saw on this website (https://www.specialized.net/solar/zamp-solar-systems/how-to-size-your-rv.html) that somewhere around 100W is about right, which kinda surprised me. But after calculating a few numbers it seems about right. I like the 90W Zamp portable if money is no object (https://www.zampsolar.com/90watt-long-portable) due to size, weight, durability, plug and play with the new camper.

Then there's the fun factor about solar. Already have solar for our house which has worked well for several years, and almost paid for. Even looked up the solar insolation data for several areas we'd camp (e.g. https://solarenergylocal.com/states/colorado/colorado-springs/) and I think there's enough if we park all day. If we don't park all day, the alternator works great but I've noticed it takes a couple hours to recover from overnight usage.

A calculation:

Say we use 45 Ah per day. That's (45 Ah) * (12V) = 540 Wh
Insolation is 3 kWh/m2-day in February.
90W panel is 27"x30". Thus:

(3 kWh/m2-day) * (27 in) * (30 in) / (1550 in2/m2) = 1500 Wh, almost 3x what we'd need. Ergo 90W is a good size, which is about the same as the battery Ah rating as you suggested.
 
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