2016 Solar Prepped Coach - Solar Installation

[C.Martin]

More in series will give you more volts in the line to the charge controller...and less amps. It is actually the reason I did pairs instead of all parallel...to keep the amps low enough for the 6awg wire.

You can still do sets of two with the Victron. And I've never heard of this problem with a Morningstar, but I haven't read the specs on their controller recently.

[Sbrownstein]

Originally Posted by Rvlegaleagle

So back to square 1 I guess. Maybe they will fix it now that the cat is out of the bag sort of speak?

Glad it came out now though because instead of 3 sets of 2 panels in series it is now going to be 2 sets of 3 panels in series. Hope a 6ga wire will still work to the solar charge controller.

From what I can see they spec'd 24 volts minimum for charging 12 volts (actually more like 13.6 for bulk). If you have decent panels (100 watts or more) I don't see how you could go below that with 2 panels in series at any reasonable output current.

They aren't going to "fix it" they are going to change the manual...

[Sbrownstein]

Originally Posted by Itinerant1

Real world experience with the pt100. Starlight installed my system. 500ah 12v lithium batteries (GBS)
8 CTI 160 watt panels (1,280)_ 2 in series, 4 sets parallel to combiner box, Magnum PT100 controller, Magnum 3012 hybrid inverter, ME-ARC 50.
2 panels in series would 36voc. It's been 21 months operating now and haven't had any issues. 80a max is the most that I've seen. Here some data from the beginning of the year.

Nothing like real world data. Can't find much wrong with it. Even at 90 watts you seem to be getting 90 watts into the batteries.

It is not the voltage that drops when the sun goes away...as you show...it is the current!

Can't ask much more than that from an MPPT controller!

[C.Martin]

True...performance is superb. I guess the only question is really...will a high freq. just be a nuisance code? or does it result in long term damage to the controller. In otherwords...will it appreciably shorten the service life of the controller, if so...how much? I think great performance is what we're looking for...and an acceptable service life for the part.

[Itinerant1]

That's a good question, is it shortening the life of the controller. It seems not to hurt it's performance. In this past year while I wait for the coffee to brew in the morning I record data from the contoller for the past day.
This is from the past year boondocking no hookups in these states AZ, UT, WY, ID, MT, ND, SD, NV for 6,105 miles. This is what the system has harvested since the beginning of the year by month. Panels lay flat, no tilting.

Month ____ KWH_____ Ah to batteries
January___87.3______6,360
February__101.4_____7,410
March____136.5_____9,950
April______166.8____12,210
May______167.6____12,260
June_____164.2_____12,030
July______174.6____12,770
August___152.1_____11,150
September_108.0____7,920
October___ 90.0_____6,540
November _84.3_____6,200
December _94.5_____6,710
Total __1,527.3kwh___111,510ah
On/Work hours 4,214.4
*Harvest Total – Displays the total amount of energy in kilowatt hours (shown as KWH) delivered to the batteries.
*AH to Batt – Displays the total amp-hours (AH) delivered from the PT array to the DC system.
*On/Work Time – Displays the number of hours of active production by the PV array.

* Highest daily kwh haversted was on July 21st of 7.4 (740ah) in Idaho outside of Yellowstone National Park.

* Lowest daily kwh harvested was on September 15th of 0.2 (20ah) in North Dakota outside of Theodore Roosevelt National Park. Heavy overcast skies with rain.

In the past year the Honda EU2000i genterator has been used 7 times for 2 hours each time which charges at 100ah rate from the Magnum 3012 inverter/ charger into the battery bank and 3 times for 3 hours each when we ran the air conditioner before heading to higher elevation. Some of these run times where just to exercise the generator.

[C.Martin]

Wow!!! Thanks for posting. You have harvested sun very , very well!!!

Twenty three hours on the generator???... You have to use it more just to drop you generator cost per KWh to cover the purchase price. I guess you could sublet generator time to neighbors without solar

Again...thanks for sharing your actual results. It sure beats the pencil and paper guestimates...we work with planning out a system.

I stay plugged in most of the time...so I kick into float pretty early most days. I believe my highest daily yield was 5.0kWH. Your 7.4kWH is an amazing daily yield...

[Itinerant1]

I'm sure folks read threads from a lot of us and think it cost a lot of money. Which it can. Some are quite happy with hold over solar...enough to put some charge back in the batteries or cut generator time down.
While others want to get away from the rv parks and off the beaten trail some. So I'll add these last numbers.

Using 30%tax credit, plus
Dispersed camping
2016 (4/16 - 12/31) 200 days
2017 (1/1 - 12/31) 365 days
Consecutive days dispersed camping as of December 31, 2017 starting 12/23/16 - 373 days, still going.

Using previous 2 years of rving (fulltiming) prior to solar install (4/13/16), RV park cost averaged to $25.00 a day.
443 days of dispersed camping needed for return on solar.

When and if we get tired of being on the road we can pull the system off the 5th wheel and move it to a cabin. Sorry to hi jack your thread, just like to put real #s with experience for folks just starting to put their tow in the water.

[C.Martin]

No hijacking here. The intent of the thread was to share my installation with those contemplating Solar in a “Solar Prepped” 2016 Newmar Coach. Where to find the wire...and how big you can go with 6 awg prewire.

Everything else added to this thread is gravy...and well worth the exploration.

I can count the number of people I now know on one hand that can say they spent 365 days in a year dispersed camping. Oh wait...maybe one finger. Yeah...that would be you, my friend. Your experience is a wealth of information.

I can say I’ve dry camped for six whole days straight. Hmmm. I’m thinking 365 trumps that by a safe margin.

If you have a blog...I’m sure many would find your experiences as required reading. If you don’t have a blog...we can just hope you eventually want to document your experiences.

Solar is a pretty cool tool to have in the arsenal. Like you said...some just want to get a little extension on battery life...and others want to cut the service cord requirement completely. My original goal was to be able to abandon the coach somewhere, if I needed to, without a shore power connection...and when I return not find my batteries drained completely, and the food in my fridge growing mold and stinking.

My total install, no labor cost involved, and no Lithium upgrade, was $5502.08...or $3851.46 after tax credit applied. The cheapest Campground we’ve been to was $28 per night. So 138 nights would cover the cost of our solar install. We never expected to recoup that cost here in Florida...but when we retire and head out west...we will be doing a lot of dispersed camping. I am really happy to have the Solar...and really happy I did all the crawling around when I was 58 instead of seeing what it feels like when I’m 65... Can’t wait to do more dispersed camping...

[ghaynes754]

The Hybrid is a fit if you want to run an air conditioner while on battery/solar power. It will mix the two pulling from the solar and then adding in additional pull from the batteries.

If this is the planned usage then makes sense to use Lithiums. Worst case would be where the the AC is running, clouds shade the solar panels. The DC amps for a 15K AC is about 125ah. That is easily handled by Lithiums, not so well handled for AGMS, for for an hour or more.

[Dav L]

Maybe there is a thread on this, but curious...is there any selling back to the Grid when you are already charged? Any tax / energy credits available like on a "home" solar system?

[cruzbill]

Dav L, Short answer, no selling excess kwh to the grid. And yes, solar for your RV qualifies for the fed 30% tax credit (until it doesn't)


As for off-grid AC google FitRV and Gonewiththewynns

Not practical unless you dump $4-6k on lithium.

I haven't won the lotto, yet!

[Dav L]

re: selling back to the grid - 90% of the time my RV is parked at the house, next to the barn. I have toyed with putting solar grid on the roof of my barn in the past. If those "same" solar cells were on the RV, then I would get the dual benefit of mobile energy.

I have casually keyed into the advancements of elon's residential shingle solar cells...hoping they are cost effective by the time the Barn needs a new roof.

Since selling back is something Detroit Edison supports...why would they care if the cells were on top of the RV?

If they didn't care...what would the wiring ramifications be? Same RV is landline connected to the Barn 220v / 50A.

My next door neighbor installed a home solar system. I was very surprised when she said it cost $25K. There was a substantial amount of electronics mounted on her house wall, plus a Gazebo built with the solar cells on top that are 400 feet away from the electronics. Looked more expensive than $25K.

[cruzbill]

We have 7kw of solar panels on our roof. We get less than 4 cents/kwh, if we make more than we use. Other fees ($10/mo) eat up any credits. Its called Net Metering and it should work in your favor, but our utility has changed the rules over time. A home PV setup usually runs at 300vdc or higher, you don't want that voltage on your RV!

[C.Martin]

Selling back Solar would require a grid tie Inverter...the complete installation would need to be permitted and inspected...meet all NEC code requirements. I do not think most of our RV Solar installs jump all those hurdles.

You might put them on the roof of your house or barn...grid tie them...so you use utility electric at night, and Solar during the day...and just plug your coach into an outlet on the house system...same, same. You just can’t pull away with all those panels.