New Solar install feedback?

[Ductape]

Well, since we got a new DP to start the new year, I have to do solar again. We travel for about six month each year and boondock as much as possible. I want enough solar to handle routine loads and keep the batteries topped off, but have no objection to running the gen for heavy load times like electric cooking or if the weather is too cold and we run a lot of heat.

Due to limited space on the roof I don't plan for a 100% solar solution. On our previous coach we had 630W on the roof, which worked quite well and we rarely needed the genset unless camped in the trees. What I have space for (while maintaining easy walking on top) is 4x100 mono panels. Mono because they are narrower at 21".

For batteries, we have 600AH of Lifeline. For heavy charging, we have the Onan and a Magnum ME2012 which will charge 100A.

Given the space constraints, I basically plan for a system adequate for temperate conditions. Too much furnace and we'll need to run the genset for maybe an hour in the AM, and I'm OK with that.

Now down to specifics what do you think of this: Renogy 400W kit for $702

Last time I did this I purchased each part individually and went for maximum performance at any price. Doesn't seem like a worthy goal this time. I'm looking for reasonable performance, and something I won't shed tears over if we trade coaches again in a few years.

So... given all that, would you buy the kit, or separate components? Different controller? Different panels?

Thanks in advance for wading through this long winded post. 🙂

[Ductape]

Just a brief update on this thread after completing the installation. I did use the Renogy panels as the narrow width allowed installation alongside the a/c units without getting too close to a shadow. All in series just because it was easier to plug and play that way. #6 factory prewire down to the Renogy Rover 40 in the basement. I installed a switch on the down leads so I can isolate the panels from the controller.

So far I like the Rover 40, but no real chance to determine system performance until we leave home and put it to the test. The terminals will accept a number 6 wire, although the documentation says #10. I got the optional bluetooth module so that makes monitoring and adjustments easy to do with a phone. One feature I'm missing from prior experience with a Midnite controller is the ability to engage equalization with a button push. Seems like the Renogy is just time/calendar based. I've used EQ in the past to top charge the Lifelines when I had the time to sit and monitor the charge current. Looks the the process with the Rover will be slightly more involved, but I can just go in with the phone and up the float voltage to accomplish a top charge if no easier method is found.

As I sit here thinking about it, in the time it took me to step outside, open the basement, and push buttons on the Midnite I can make a voltage change from the recliner, so what am I whining about? 🙂

[epfd217]

Since the door is open for buying pieces, check the rest of Home Depot's prices. The Grape Solar 100w panels are only $97. You did mention width being an issue and they are 26" wide vs 21", but it would be a huge cost savings to grab four of those if it works.

[BFL13]

If the controller will be near the batteries at all, then #8 from it to the batts is fine for 25 amps. Pigtail to your #6 to the roof. #6 can be very long and not worry about loss at 25 amps. Wiring from individual panels collected to the #6 on the roof can be #10 or 12 (6.2 Isc).

You don't need MPPT and the 40a Grape is half or less of the Tracer cost. 12v panel cost is then the "issue" as usual.

If you went PWM that would mean you care about total panel amps (same as Isc value) and not much about voltage drop or panel heating loss of watts. So you would even be ok with #8 all the way.

If you had the Tri 2030 you could get its matching 30a controller, but if you have a 2025, the Grape is the one to get. Even a simple Solar30 would do the job you are looking at.

[Ductape]

Thanks, I need to dig into it more and confirm if the Renogy is really a Tracer or not. I can always buy the panels separately plus a Tracer and the cost is about the same.

[lawrosa]

2oldman wrote:

Ductape wrote:
Last coach was #10, this one is #6.

Ok. Now you need to make sure the controller's lugs will handle that size wire.

Renogy specs #8. And there are reported issues with lugs breaking.

tracer specs #6..

Last time I researchee anyway..

[lawrosa]

Ductape wrote:
@ Lawrosa, I absolutely would go with residential panels if I had the space. Did exactly that on the last coach; two big panels and a Midnite controller. Worked fantastic.

But this coach has too darn many things on the roof already. I would have to relocate factory installed roof penetrations to fit a couple of big panels, and that's not happening.

Not really too worried about the shade either. In my experience, we're either in the sun, or in the trees. 🙂

Really? OK....... 2 panels win in my book..

Its the same $$$ so it dont make sense. 400 watts 12 volt vs 540 watts 24 volts

4 panels 3.4 ft x 2.3 ft x4 = 31.28 sq ft

2 panels 5.4 x 3.3 = 24.82 sq ft

Edit: Oops is my math wrong?


4 panels 3.4 ft x 2.3 ft x4 = 31.28 sq ft

2 panels 5.4 x 3.3 = 35.64 sq ft

[BFL13]

2oldman wrote:

Ductape wrote:
Last coach was #10, this one is #6.

Ok. Now you need to make sure the controller's lugs will handle that size wire.

My Tracer will do #8 just right. You can use short little pieces of #8 in the controller and go to #6 or whatever from those "pigtails"

[2oldman]

Ductape wrote:
Last coach was #10, this one is #6.

Ok. Now you need to make sure the controller's lugs will handle that size wire.

[Ductape]

2oldman wrote:

Ductape wrote:
the coach is prewired with 10AWG from the roof which would handle parallel

Barely.

OK, I will have to eat those words. Just crawled into the basement to do my due diligence and Newmar has stepped up their game. Last coach was #10, this one is #6.

@ CA Traveller, I do recall seeing your install before, very nice! If I was looking for more performance I'd go down that road. Two things changed my thinking this time around:

-Spent ten days camping in the trees in NH last fall. My high performance solar system was useless.

-Worst of all was trading in the coach for this one. Hated seeing those panels and controller go with the coach. Kissed a big investment goodbye, but I wasn't going to leave holes in the roof. We did swap batteries and kept our AGM. And I'm the sort that trade may happen again in a few years, so...

[CA_Traveler]

Ductape wrote:
@ Lawrosa, I absolutely would go with residential panels if I had the space. Did exactly that on the last coach; two big panels and a Midnite controller. Worked fantastic.

But this coach has too darn many things on the roof already. I would have to relocate factory installed roof penetrations to fit a couple of big panels, and that's not happening.

I choose option 3 which was to mount the panels over the factory roof stuff and that worked out very well. Click.

[Ductape]

Don, the coach builders always cheap out on the size of the factory wiring down from the roof, so voltage drop is a concern. I'm not interested in pulling new wiring through the coach... so probably either series or series-parallel. So likely operating at 36 or 72 volts from the panels.

The controller does have remote temp sensing.
Controller page

My thinking on sourcing through HD is twofold.
Free shipping to the nearest store.
Easy returns if there's a problem. I'll open the box in the store and see if the panels are OK. I shudder to think about shipping panels.

[2oldman]

Ductape wrote:
the coach is prewired with 10AWG from the roof which would handle parallel

Barely.

[pianotuna]

Why use an MPPT controller with 12 volt panels? Is there a temperature compensation probe on the battery bank with the "kit" controller?

[BFL13]

I used three 100w with my Tracer MPPT 20 amper ok (should have had a 30 amper though) and it made no difference in amps to the battery whether series or parallel. (But I have fat wiring for both ways) I also got the same amps to the battery with the Solar 30 PWM controller when I swapped that in.