PV panel recomendation needed

KJINTF

Hi

Hope to purchase very soon and install over the next seevarl weeks about 250 to 300wats of PV panels on the roof of my RV and need some help choosing the right ones. Existing system equipment consists of; Morningstar (MPPT 60, RD-1, TS-RM-2), TriMetric 2025-RV, WF8945-REP, 2 Costco 6V golf car batteries, no inverter and no plans for one, will use the generator when needed. My thoughts are leaning toward the Kyocera KD135 panels two of them in series for the higher voltage.
Need recommendation for the panels mounting hardware and anything else needed - Arizona Wind and Sun parts numbers would be great - preference is to mount the panels flat to the roof - no way am I going up there to tilt them.

Thanks for the help
Ken

BB.

Re: PV panel recomendation needed

None of us here work for/at/with NAWS--So we cannot really speak for them and their recommendations for hardware (other than the two admins--Rick and Windsun--but they spend most of their time in their real world store).

For RV Mounts, NAWS does have a page for them:

RV Solar Panel Mounts

One of the big issues will be getting / making up proper wiring and fuses / bus bars / electrical connectors / random bits of hardware... Do you have that stuff picked yet?

To give you an idea of what an RV/Trailer install may include--Here is a nice thread.

KJINTF

Re: PV panel recomendation needed

Hi again

Thanks for the quick response
No I have not picked all the hardware out just yet
Sugestions would be appreciated
I da have 50ft or more of 4awg stranded wire and end connectors that I plan on using for the installation, along with a few Bussmann 187 series switch / breakers.

Any additional suggestoions on the PV panels?

BB.

Re: PV panel recomendation needed

The Kyocera panels are a good choice. Two in series with a MorningStar 15amp MPPT charge controller is also a very nice combination.

You have a choice between Kyocera panel with a junction box or pig tails. If you choose the pigtails (cheaper panel), then get a male/female cable, cut in 1/2, and use to wire into your trailer wiring (cutting pigtails may void panel warranty). And you may want the pair of tools to service the MC4 locking connectors.

Choice for panels--Pick those that fit the area, are mono or poly crystalline panels (stay away from thin film) and look for a good $$$/Watt on your door step (shipping individual panels can be expensive--large panels may require truck shipment).

You have a very nice list of components--Don't see any problems/big issues...

Regarding your power usage--we always recommend changing out to LED/CFL lighting, and reducing power usage as much as practical. A pair of 135 watt solar panels does not generate that much energy--So conservation (and backup genset) is usually required.

Have you measured/estimated your Amp*Hour (at 12 volts) or Watt*Hour per day consumption and what you are expecting from the panels based on your location and season?

For example, assuming 4 hours a day average of sun (summer may give you more, winter less) for an off grid system supplying 12 VDC power:

• 2x 135 watts panels * 1/12 volt battery * 0.62 system derating * 4 hours of sun = 55.8 Amp*Hours of 12 volts per day

Is that roughly what you are expecting?

-Bill

KJINTF

Re: PV panel recomendation needed

Again THANKS for the quick response - and on a Saturday even better

I just placed an order on line at NAWS for two of the KD135 panels and will be cutting the pig tails off just as soon as they arrive. The price difference was HUGE between the old style box connector and the unwanted pig tails.

Why did the industry go with the MC4 pigtail connectors?

I have the Morningstart MPPT 60amp Tristar mostly because it has an Ethernet interface. The RV computer system has both serial 232/422 and Ethernet interfaces. I tend to prefer Enet interfaces. The system is wired for both Wifi and a 12 port IP router. Too bad the TriMetric 2025-RV does not offer Ethernet interface for configuration / firmware upgrades. The rigs Blue Ray player even has an Ethernet interface for firmware upgrades.

Earlier this year I replaced all the 1003 / 1141 / 1156 incandescent lamps with plug in LED replacements. I have found the biggest power hog to be the stereo / TV system 150watts / side (I Love my music and we camp way out in the back woods thus do not disturb others, hardly ever see others within miles). The TV system is a 31" LCD HDTV. A close second power hog is the forced air heating system blower motor. Yes I believe the power from two 135w panels should be enough but if not the 60amp MPPT controller has plenty of head room for a few more panels. Even better I have "acres" of open space on the top side the the rig. The Onana 4Kw genset is always a backup but I hate the noise.

Ken

dwh

Re: PV panel recomendation needed

KJINTF wrote: »

Hi Morningstar (MPPT 60, RD-1, TS-RM-2), TriMetric 2025-RV, WF8945-REP, 2 Costco 6V golf car batteries

All good except that's a lot more charge controller than you need for 2 or 3 7.5a PV modules.

As long as the PV voltage is high enough (the Kyocera is), there is no real charging advantage to using series to get higher voltage. The main advantage of series in that situation is that you can use smaller wire from the PV to the charge controller and save a couple bucks on copper.

But, there is also a disadvantage - important to consider for RVs. If you wire the PV in parallel, then if you get a bit of shade on a corner of a panel, it will only drop the output of that one panel. If you wire in series and get some shade, it will drop the output of the whole series string.

KJINTF

Re: PV panel recomendation needed

Thanks,

I do indeed understand the series parallel thing best to keep out of the shade or might have to start the genset or engine once in a while

I have ZERO space for large 8awg or even 6awg wires from the panels to the controller - plan on using 10awg wire. My biggest problem in the entire installation getting the wires down from the roof without being seen or in the way of other things.

The biggest draw for me of the MPPT 60amp controller was the Enet interface. Yes an overkill as far as current capabilities but the way they internally parallel three 20amp controllers to get the rated 60amp gives me some advantages regarding power consumption of the unit itself.

dwh

Re: PV panel recomendation needed

Rooftop fridge vent? Mine has a ton of room room behind/above the fridge to drop wires down.

BB.

Re: PV panel recomendation needed

The loads you have listed are quite a bit for an RV solar PV system... It would not hurt to throw a Kill-a-Watt meter on your AC loads and see what they consume per day...

-Bill

KJINTF

Re: PV panel recomendation needed

Thanks for the suggestion of the roof top "RV Refrig"
Too bad when I had the rig constructed I made sure the RF Refrig vented out the side too many issues with leaks in past rigs. Yes indeed it was a great place to run cables. The current refrig does have a temperature controlled DC fan to help the draft, might draw 700ma at best and only runs a few hours in very hot weather per day.

I am thinking of the Satellite dish mounting soon to be "hole" located in the front center of the rig. I do not have and have no intention of ever having a dish. Was thinking of possibly drilling out the marked template "hole" and passing the wires down to the entertainment system then through the floor to the eguipment compartment. Only a though right now once I get involed things will change as they always do

The AC loads in the system are not part of the PV solar system they include; Roof top air conditioning, Microwave oven, Toaster, etc, we use the small 75watt inverters to charge cell phone, computer, etc batteries.