Installation on the FRONT shell. Questions!

[rickst29]

When closed, the exposed area of Rear Shell of my 2619 is a little bit too short for mounting a pair of panels there. (They would both fit fine on a 3720.) And so, I am mounting on the front shell.

Edited 05/16/2019: Upgraded!

I now have 3 "flex" panels on top of the front shell. (Flex is less durable, but reduces weight for lifting the Shell.) They are wired in Series, at Vmp (maximum power) about 55 Volts, and Voc (PWM mode "disconnect") at about 63V. They are attached to the TM Shell using 3M "VHB" tape, thickness "RP25".

Along the Roof, and down the front street-side lift arm, I have some cheap plastic "wire channel" from Home Depot. At the bottom of the lift arm, there is a small half-loop to provide a bit of extra "flex" for raising and lowering the lift arm (exactly as TM builds half-loops into the original wiring which goes up along the lift arms).

From there, wire follows the battery "+" connection wire along the Street side of TM, but goes up the middle of the 2619 "lower box" face - and through holes, into the MPPT controller.

The MPPT Controller is an EP-Ever "3215BN", capable of up to 30A output current. It is matched to a "MT50" Controller. I have a battery temp Sensor as well, but will be selling that Sensor when I upgrade to Lithium LiFePO4 and move the battery inside the coach. (LiFePO4 batteries create no hydrogen gas, and work indoors.)

[LoveToCamp]

I mounted my panel on my front shell (2417).

I mounted just in front of the AC, and on the street side of the front vent. I ran the wires down the street side front lift arm. I used zip ties to hold the wires on the arm. I used a stick-on wire channel I got at Home Depot to hold the wires down the side of the front shell. I caulked the sides of the channel, so it won't blow off when the adhesive gets old and loses its strength (just like me!)

I then threaded the wires through holes in the undercarriage, then towards the center of the front frame. There are three holes there, so I put my solar wires through one of the holes. I ran my battery wires through another hole, just for support, before running all of them to my controller, which is mounted on the front of the lower box. It will be covered by the front shell while in transit.

Hope this helps. I haven't taken the photos off my phone, yet, so I can't quite show what I did.

[Bill]

Theory says that if part of a solar panel is shaded, the output of the panel is drastically reduced - way more than you would expect for the amount of shaded area. The air conditioner makes a big shadow. For this reason, the pro installers usually suggest installing the panels as far from the airco as possible.

Bill

[rickst29]

And that's why I reserved some extra distance for the "along the roof" portion. That doesn't include this distance between panels, because my MC4 connector wires from the junction box are adequate to reach my "Y" connectors (in between the panels) from a horizontal distance of over 1 foot each.

So, the panels can be separated lengthwise, from the mid-line of the shell, by a bit more than 2 feet. The "10 feet along the roof" allows the long wire segments to begin about 5 feet in front of the A/C unit, and that's near the end of each panel (not near the middle). Solar panels will lie forward from that point.

[rickst29]

Originally Posted by thewayneo

Hi--in your recent post you said: "40 feet per cable = one "extension cable" at 80 ft. That's an awfully long run - switching to MPPT (at twice the voltage, half the current) will be beneficial."

I've installed panels on previous RV's but due to weather, trees, deep valleys, ended up with a Honda 2000 (actually a pair). The gen saved my hide a couple times when in deep woods with a dead truck batt, so I'll always carry one no matter what. I remain interested in solar, but I really want 1 single panel around 200 watts, which are usually 24v not 12. In what I quoted from your post, are you saying that you are going to use 2 12's in series and the MPPT converts that down to 12v for the batteries? I can't find a description of a MPPT that clearly (to me anyway) says they do that, but maybe it's just a well known feature.

thanks for the info,
wayne

That's exactly right. A "Maximum Power Point" controller will take all of the input power at higher voltage, and convert it into more AMPS at lower voltage for the batteries (assuming that the batteries can accept all the current). They're somewhat more than 90% efficient at doing this job.

Example 1: A single "24V" panel, nominally 240 watts at maximum power, consisting of 31 Volts * 7.75 Amps. With MPPT, this will charge your battery at 14.4V, or maybe 13.7 or 13.8 (whatever you set for the different charge stages), but it will crank out as much as 16A on the battery charging circuit. (BTW, These are all real numbers for Renogy panels.)

Example 2: A single "12V" panel, nominally 100 watts at maximum power, typically running at about 18.9V * 5.3 Amps. With MPPT, if the entire 18.9 volts actually got to the controller, it would send about 7.3A on the battery circuit (at 13.6 volts).

A PWM controller can only cut the voltage, and send 13.6 Volts * 5.3 Amps (just 72 Watts, at "peak power" from the panels and a charging voltage of 13.6V). The rest is wasted. "PWM" rapidly turns on and off the Solar load, and runs it into capacitors, creating an "average" of 13.6V. During the short time periods when it disconnects from the Solar panel, the "excess" power is not being collected. (For 120VAC at home, an incandescent chandelier dimmer switch works the same way, except that you do not "pay" for utility power which you don't use.)

So even with a "12V" panel or parallel array, an MPPT controller can accept and convert more power from Solar into useful Volts * Amps ( = Watts) than a PWM controller can. It's because all of those "12V" panels run at much more than 13.6, or even 14.4 Volts. My 18.9V panels are a bit high, but not greatly out of line with others.
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But PWM controllers cost about $20 -- while MPPT controllers start at a couple of hundred. Still, I am going to buy MPPT: I intend to buy the new Rogue, after the designer finishes shaking out design bugs and begins to deliver in quantity. Until then, my "200 Watts" is really, really no more than 140 watts - before consideration of any power losses along the Solar to Controller cable, and those will be greatly reduced when I put my panels in Series.
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Two "12V" panels in Series is a lot like one "24V" panel alone, except that they cost more - they've got duplicate junction boxes, MC4 connector cords, aluminum frames, and backing sheets. My Maximum Power Voltage will be 37.8V instead of 18.9V, and my amperage will be the same as one panel alone (5.3A). I-squared-R power losses will go down - by a square root factor. (That's why power plants run AC wires at extremely high voltages, e.g., 512KV.) But, if the fridge, or air cleaner, and/or batteries can make use of the additional 60 watts, it's like getting more than half of another panel -- and without new wiring or increased weight on the roof. It will "unleash" my current panels.

My last reply w/photos to this thread got erased by the server so I will try again.
I mounted my 2 panels on the front shell of our 3124 using Liquid Nails (recommended by RV Solar Electric) to attach the 4" wide 1/8" aluminum stock to the roof of the TM. The panels are attached with pop rivets to the aluminum stock.
Our 3124 is an older model and the AC is mounted above the bed so avoiding it is not a problem.
I ran the wiring down the right front of the upper shell and across the bottom to the half way point where it heads out to the controller mounted on the inside of the V just before the hitch. When the shell is up the feed wire heads almost straight down to the controller and when the shell is down the wire nestles between the propane tanks.\
From the controller the power goes to a custom battery tray I had made that fits between the frame just behind the propane tanks. From there the power heads to the battery inside the kitchen cabinet although now I only use 2 batteries, one in the tray and one inside the TM. I have found that 2 Lifeline gel batteries supply all the power we need.
I prefer not to have a control panel read out in the TM. I just use the TM's battery gauge or a multi meter to see what the charge is.
Nothing fancy, but it has worked well for 13 years.

[rickst29]

Looks very good, and certainly shortens the wire runs by a great deal. But because of the MPPT upgrade (in a couple of months), I will want to set up with the Charge controller on the inside - if left outside, it could be too "tempting" for certain types of people.

[rickst29]

I installed yesterday; it took about 5 hours. For "extra safety" in high-wind conditions from the front (towing), I added another pair of mounts towards the front of the panels -- Each panel has 4 mounting holes along each side, and I'm using #1 front, #2 front next one empty, and the two ends. I used VHB tape type "R32", a new version which they claim to be "even better".

They are lengthwise on the front shell, a bit in front of the overhead lights (and skylight) along the middle. However, I put them close to the edges for two reasons: (1) By leaving a big gap along the middle of the roof; and (2) the edges, with all of that vertical wall structure underneath, are stronger and stiffer than the middle.

I went down the "street side" front lift. But with the cable hiding the black cables from view as they go down the shell, it's barely visible at all - and there are a couple of useful holes, down in the frame, which could be used by a door-side installation. If I was doing it again, I'd bring the cable down on the door side.

The last photo shows a big surprise: In 80% morning shade, 8:40 AM PDT (which is really like 7:40 AM, as far as the sun is concerned), and halfway under a tree, it already runs! (Green light.) Not much current, certainly, but the voltage is high enough to run "bulk" charge at 14.5V.
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I'll end with a summary of the two Ebay sellers, 'Renogy' versus 'WindyNation', as I see it, now that I've finished. I've not installed a WIndyNation kit, but I think that it is a slightly better choice:

1: Renogy has 100.0% approval, Windy has "only" 99.8%. Advantage Renogy, but very slight.

2. They both sell "100 watt" panels, but Windy's panels have about 5% more current (at 5% less excess voltage). Unless you have MPPT (which makes very little sense in a 200-400 Watt system), Windy's kit will outperform Renogy's. Advantage WIndy.

3. Renogy supplies only a 20 ft extension cable, which makes only 10 foot "plus" and "minus" cables after you cut it in half. That's not enough for a TM front shell install! WIndy provides 40 feet, which seems to be just enough for a front shell installation. Both cables are only 12 AWG, so, if you want 10 AWG, then you're ignoring the kit cable and buying another separately - no difference. But if you're going to use the kit-supplied 12-AWG, this is a big advantage to Windy.

4. Renogy's kits cost slightly less. Advantage Renogy.
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Summary: Either of these vendors seems to be great. But if you're willing to use 12-AWG cables, then WIndy wins.

New Edit, 5/16/2019: Picture shows my the PWM Controller from my "kit", which did not work well. I strongly recommend MPPT, in particular the EP-Solar "BNxxxxx" Charge Controllers, for all TM Solar installations of 200W and higher.