Portable Solar and Monitor Location

[fudge_brownie]

I am taking a bit different approach to solar on my 21. For starters I will have it built "solar ready" so a roof top unit can be installed in the future. I do not care to have the unit on the roof for a variety of reasons not important here. Rather I will go with a portable unit made with two 40 watt panels that are hinged. I expect it will fold nicely and stow in the wardrobe cabinet.

I had just corresponded with Jim (CPAHarley) regarding the placement of the solar monitor. I believe Jim had one of the first 21’s with a solar panel. Jim's reply was: "I had them put the solar on the rear part of the "U" dinette so that it is visually seen from the front, if needed."

It appears there is some flexibility of where to locate the monitor; I am hoping someone else has ideas.

I was interested in the location of the solar monitor as I will have Escape install the wiring harness for a Trimetric TM2025-RV. This is a comparable unit to the Go Power that Escape uses. At the same time I will have Escape install a marine charger inlet. I will connect my portable solar panel via an extension cord (of various sizes) to the Escape with this inlet. The inlet will go near the outside 110 volt outlet, giving me access to the battery compartment.

Inside the battery compartment and near the battery boxes I will install the shunt and a Xantec C35 controller. I have chosen the Xantec because it allows adjustable charge rates, most battery manufacturers recommend charge rates of 14.7 volts, temperature compensated. The inexpensive controllers seem to be locked into a 14.1 volts charge rate. This is a good time to check the specs on your controller.

What I will have is a portable solution that I can connect quickly for those occasions that solar is needed. I will not have as much difficulty with sun angles, shade and worry getting a certain camp site. I will have my $110 of solar panels and extension cord at risk of theft. Since I believe I will need and use solar only about 30% of the time I do not feel the portability will be an issue.

[thoer]

Paul -- please keep us posted on what portable solar you end up buying, as I am considering one too.

[Donna D.]

I'm going to be doing something similar. With a 12 volt plug added to the rear of my 5er for charging the batteries (thanks for the idea Jim!). But I'm looking at purchasing one 160 watt solar panel... Just thinking. But a number of folks on the CasitaForum are looking at this one too: Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

They also offer a 100w suitcase model for $165: Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

[Brian B-P]

The photo suggests that the plan is to use a common NEMA 5-15 connector for the solar panel connection. If so, I suggest re-thinking that: the risk of connecting 120V AC to the input intended for solar panels may be small, but is not good. There are many connector types which would not be subject to this risk.

[fudge_brownie]

The use of this NEMA plug is common on water craft. It is a marine style plug and thus has the water tight characteristics necessary to be used on the outside of the trailer. It is also advertised for use on an RV. That is not to say it is correct, I am not familiar with the code that would cover this.

However, it is the male plug in the receptacle, certainly it could be mistaken for 110 but we do not commonly plug in the female end of an extension cord.

You have said there may be many connectors suited to this task. There certainly are, however, I have not found one that has the characteristics of surface mount on fiberglass, water tight, and a color that will match well on the outside of an Escape. Perhaps you could suggest an alternative.

[fudge_brownie]

Donna,
I have looked at that solar unit from solarblvd, I like the design with the hinges, protected corners and the stand. I seriously considered the unit. I am concerned that the model you cited it is just too big. From what I find, it seems having a panel at or over 60 watts is adequate for charging a single 12 volt or the dual 6 volt. Maybe look at the smaller 100 watt version of that panel.

Before I purchased I would be interested in the brand and model of the PWM controller. The final consideration is the design of the controller fastened to the solar panel; this means you will have limited range to move the panel away from your trailer. The recommended installation is to place the controller as close as possible to the batteries; here is where you may have some #8 AWG wiring or heavier. Usually the controller is mounted on or near the battery storage box, not out on the solar panel. I would like the wiring between the controller and battery no longer than a meter. Depending where the batteries will be on the new 5.0 I would guess you would need 3-4 meters of wiring to have the ability to stand and direct the panel to the sun. Not enough in my mind for those shady and forested campsites. On the other hand if the controller is not on the panel but next to the battery you have much greater range for the panel and wire gauge does not matter. I would guess 30+ meters.

Here is a link to what appears to be the same unit, they state the wire included is two meters.

I have not be able to find a foldable panel without the attached controller. For that reason, I will use two 40 watt panels from solarblvd and use a stainless steel hinge to fasten them together.

[thoer]

Paul - thanks for all the research you are doing on portable solar. As I said I am interested in doing the same - but in my case it will be an add on to our current 17b. I still like the idea of inputing into the existing 7 pin somehow. I might just look into making some sort of water resistant box to put a controller in.

Please keep us all updated as you make you panel decisions and how you like them once you get them.

[fudge_brownie]

Eric
Is the battery on the rear bumper on your 17? What about the Progressive controller and charger, under the rear dinette - driver side? If yes and yes the issue with using the 7 pin Bargman vehicle connector is the long wire run, unless you placed the solar controller closer to the battery. I can see why you are considering something like the marine charging inlet.

Can you put the solar controller in the Escape and run #8 AWG wire to the battery, keeping in mind that the distance should be 2 meters or less? This would eliminate the need for a water tight box.

In my testing I was trying to reduce the distance from the 7 pin Bargman, into the trailer and then out to the battery. I would guess 2-3 meters. I tried and still have in place a connector called an Anderson Power Pole from Powerwerx. The connectors are all 15 amp and you choose the silver connector size to crimp on depending on the wire gauge you are using. This has proven to be very dependable and I just let the end hand out of the battery box about six inches.

It is not water proof nor sealed so there is some risk of water getting into the connector, it would really have to be hanging in a puddle of water. It water gets that high you are going to have more problems than a wet connector.

Also, some of the solar controllers are sealed units, they can withstand being out in the elements, particularly if this is on a portable unit that will only be used occasionally. The Morningstar Sunguard that I have been using is such a beast.

[thoer]

Paul - yes, I have twin 6V on the rear bumper and the OEM charger under the seat. What confuses me about the wire run and sizes, is that while driving, the OEM wire is carrying the charging current to the batteries from my Tacoma's alternator. Why the need for heavier wire with the solar as opposed to the alternator?

[Donna D.]

Originally Posted by fudge_brownie

Donna,
I have looked at that solar unit from solarblvd, I like the design with the hinges, protected corners and the stand. I seriously considered the unit.

I can't offer more than what I posted. Perhaps you should join the CasitaForum and join in on the solar thread? After all, folks that own all molded towables are more a like than different and owners are looking for the same things... no matter the brand or size.

[SeldomSeen]

Originally Posted by thoer

Why the need for heavier wire with the solar as opposed to the alternator?

This question of wire size comes down to basic electrical theory. Larger wires will loose less voltage over a long distance than smaller wires. I have seen that with my 2013 Ford F-150 and my Escape 19 running down the highway all day that the dual 6 volt batteries never fully charge. ( according to the specific gravity of the batteries)

This is at least partially accounted for by losses created by the undersized "charge" conductor on the truck. Bigger wire might help here as well because the batteries will not charge correctly if the correct voltage is not applied. By the way the on board charger in the Escape never fully charges the batteries either, which I think is also related to low voltage.

I think the best solar info on the web is Handy Bob, even if you disagree with some of his ideas. HandyBob's Blog « Making off grid RV electrical systems work He's a full timer in a big rig that never uses a generator.

[thoer]

Seldom - I understand about wire sizing and voltage drop. I was assuming that the tow and trailer have large enough gauge wire to carry sufficient charging voltages, but I guess that assumptions may be incorrect. Do you know what gauge wire Escape uses for that run? (I am trying to track down what Toyota uses on the Tacoma)

Our Tacoma with the tow package has a 130 amp alternator and seems to completely top off our dual 6 volt batteries during our drives according to my Equus 3721 Battery and Charging System Monitor. (Also so does our OEM charger according to that monitor)

[Jubal]

From Carmanah- GoPower solar systems that Escape TT installs:
We use a 10'gauge wire for panel installation. If you have any technical questions please email ahillis@carmanah.com or call 1-800-667-6527 ext. 8329
Our 2012 Tundra (with towing package) with a 170A alternator uses 10 guage wire for the charging circuit to the 7 blade trailer harness connector.

[fudge_brownie]

I have not examined my wire gauges but Jubal, the previous poster, replied to a past question about gauge and said that Escape uses either #8 AWG or #10 AWG. In Jubal's case he said they used one of each on the live and ground wire from the Bargman 7 pin connector to the Progressive controller. He replaced the 10 gauge wire with a 8 gauge.

My understanding you can examine the connector on the battery side of the wire to match the color code with the AWG of the wire. There are different views if you have dual 6 volts, the wire between the batteries could be between #8 AWG and #2 AWG. This is somewhat dependent on what you are running. For instance those with an inverter would be using the smaller number but thicker wire.

[Jubal]

Do not rely on the connector size to determine the wire size. Escape attached 8 guage wire to the 6V batteries with 10/12 yellow guage connectors. The wire guage is usually printed on the wire insulation.
The gauge of the wire that connects the two 6V batteries in series should at least be the same gauge as the largest wires that connect the batteries to the converter or inverter.

[thoer]

I just checked and the wires connect to my dual 6v are 10 gauge, so I am assuming that the run thru the trailer from the 7 pin is most like also only 10.

So, given the 17' length of our trailer with a hypothetical 80 watt solar panel, outputting into one of the controllers that outputs 14.1 our voltage drop over the trailer length would be 0.23v resulting in 13.87v according to Voltage Drop Calculator

Then there will be more voltage drop depending on length and gauge of the wire to the panel. So it looks like Paul's method of putting the plug in connector right at the batteries is what I am going to consider.

[SeldomSeen]

I believe that the correct voltages required for different charge cycles are shown here for the Interstate GC2-XHD-UTL that Escape installed in my 19. Just multiply by 2 for the 12v value.

[SeldomSeen]

Now for the battery charging voltages, once again...

[jamie beers]

Sorry for my ignorance - newbie here - talking out loud when I should be listening.... But Seldom's chart would seem to indicate that Eric is not really going to be getting much of a charge to his battery?

[thoer]

Originally Posted by jamie beers

Sorry for my ignorance - newbie here - talking out loud when I should be listening.... But Seldom's chart would seem to indicate that Eric is not really going to be getting much of a charge to his battery?

No ingnorance at all, you are right. If I ran that setup thru the 7 pin plug like I was hoping to do, the voltage drop would make it hardly worthwhile apparently. And looking at those Interstate recommendations, those voltage seem quite a bit higher than most chargers and controllers put out.