Solar plan

[azrving]

i read all of the posts of the solar installs and try to read everything that comes through. I didn't buy a trimetric or anything else to measure my use but some suggest matching it to the battery amp hours. I have 4 gc 2 Sams club batteries so about 400 ah. One online calculator said I was around 55 amp hours a day so it would seem that I could go 4 days but that's not true. It's more like 2 days and obviously depends on several factors.

Factors like how cold is it, how much water I pump from a 6 gallon jug on the ground and through my winterizing valve into the fresh tank, number of hours of 40 inch led tv which draws 6.7 amps. I have looked at the other heating options and could only really go with the cat platinum vented but have nowhere to mount it. I like my furnace as it does a great job, it just sucks 5 amps.

I understand how to cut down on energy use in several areas but I dont want to conserve, I dont want a wool hat in bed, I dont want extra bedding, I want to be just as comfortable in the RV as I am at home. The main reason I leave the north is to escape the cold, not to go camping or compromise on comfort. Not sounding snobbish just saying that everyone does it differently. I have wondered why I see people walking around inside big rigs with a flashlight only????

So far I have done it with 4 cheap batteries, an PD 4655, a Quick Charge brand battery charger 50 amp and a mega watt 30A 15.5 v power supply. I have had extremely short generator run times. probably because of hitting them with 105 amps and doing 15 volt top charges.

So right now I made it through the winter and I'm in the process of watching the batteries. I'm not worried about them but I am amazed at what they have done for me. I figure they should last 4 years for $350.00 so if they only last a year and a half that's fine. That's a $225 penalty for what I put them through. No big deal or I wouldn't have spent $3,000 on diesel fuel.

One thing you guys had mentioned is the generator noise out in the desert. I have never been out there and always pretty much woods camped so far. My Honda is in an insulated cabinet in back of my truck and is very quiet but when I visited west Texas I found out what you mean about the noise. It's a whole different game out in the wide open areas.

So it's time for solar. I dont plan on inverting to the heavy stuff. I always start any measurements with one question and that is do you EVER want to run the AC? I do, so I'm going to have the Honda 3000 with me. I will just push the remote start button for the Honda to run the the micro, hair dryer or toaster.

I'm thinking about 3 160 watt panels or 4 120 watt, a Morningstar PWM 45 Tristar. I would like to do this one time and do it right. I think I would be around $1,500 or so. On top of that price I may go to Trojan's or Crowns if my turds are shaky after running them this summer.

What am I messing up on? I like the idea of connecting straight to the panel box instead of those mc type connectors?? I have a crimp tool for all the connections. I also have a bit of 6 gauge on hand and will buy whatever is needed. I think I can make a combiner box and go thought the frig vent with Home D components. The controller will be within a few feet of the batteries. I have blue seas switches that let me separate banks for equalizing and charge either or both banks from either charger.

I dont want to have to go up there to tilt but I will make them tilt-able just in case.








Less chance of shadows?


If I use 4 panels they would probably be more like 22 inches wide I believe.


Thanks for your help and all the excellent reading you have provided. I made it through the winter because of you guys.

[Shadow_Catcher]

One of the things not talked about is the use of high voltage panels and an MPPT controller. We have a large teardrop (I know kind of an oxymoron)with a single 185W panel that puts out usable current from sun up to sun down and even with partial shade puts out 35V. We power a Waeco refrigerator freezer 19" TV/DVD XM radio lots of LED lights... I have an Espar diesel heater (lower power draw.

[azrving]

Westend, Thanks, I have never worked with MC4. I had this impression of light weight quirkiness or funny ends. I did notice a forum comment about people voiding their warr by cutting the mc4 on the panel

I like the sound of being over 400 watts as being in good shape. Like I said in my first ramblings, I dont want to do this over and I absolutely dont want to be sitting there thinking it's just a little too small. It's not a issue if I charge on the genny at times but.....

[azrving]

Smkettner, I was on the roof again and I see what you mean. 24 volt panels are cheap but the shipping calculator wasn't right. I think I need to register to get accurate shipping quotes. I understand that going up in voltage reduces current and the wiring can be smaller but are there draw backs to those large 24 volt panels? I haven't researched 24 vs 12. It's just fine with me if I never have to tilt. Like the kids on that commercial say "More is better". I like the thought of 690 watts. 🙂


Four 65"x40" panels



Any pros or cons?

[westend]

I think once you get around 300W and if you have the roof real estate, the 24V nominal panels and MPPT start making a lot of sense. I know there are a lot of MPPT-haters on the Forum and most, for their own use, PMW works well. That doesn't make using the larger modules and MPPT a bad choice. Yes, a good MPPT controller costs more but module prices are lower/watt and most of the better controllers have excellent functionality.

I'd suggest to use lengths of MC4 to a combiner box and then use heavier cables to the controller. The MC4 wire is built to be out in the weather and connection is seamless.

IME, with anything around 400 W on the roof or greater, your batteries should be full before nightfall. It would take a big energy use to get them low enough that they couldn't be replenished if you have adequate sun.

[azrving]

12thgenusa wrote:
Sounds like your usage is more like 100 Ah per day. Looks like a nice amount of solar that would let you do anything you would like short of AC.

Have you found panels 22" wide?

I have looked at 22 inch panels on AM Solar but they are pricey for 135 watts. $350

135

[azrving]

2oldman wrote:
You may get early am or late pm shadows from the a/c cowling, but we all live with that. I use 2 Honda 2ks for my air.

rjxj wrote:
On top of that price I may go to Trojan's or Crowns if my turds are shaky after running them this summer.

I have NO idea what that means!

I mean that I may have to replace my sams club gc2's. The test isn't over yet but I think I have been pretty hard on them.

[12thgenusa]

Sounds like your usage is more like 100 Ah per day. Looks like a nice amount of solar that would let you do anything you would like short of AC.

Have you found panels 22" wide?

[2oldman]

You may get early am or late pm shadows from the a/c cowling, but we all live with that. I use 2 Honda 2ks for my air.

rjxj wrote:
On top of that price I may go to Trojan's or Crowns if my turds are shaky after running them this summer.

I have NO idea what that means!

[time2roll]

That roof could looks like it could be set up just like mine for 600 to 750 watts and MPPT controller.

3x 230 watt panels at SolarBLVD $450.

Morningstar 45a MPPT $470 or 60a $600 so $920 to $1,050 + mounting and some wire.
Well under $1,500 for pick-up and self install.

[Golden_HVAC]

I like the bottom picture with 4 panels. I have a total of 415 rated watts, and my Tri-Metric would read -120 AH in the morning in January, and I could fill the batteries by sundown.

My RV used 35 Ah daily to run just the CO, propane detectors and refrigerator. The water pump is insignificant, as it can pump 2 GPM for a hour and empty a 120 gallon tank with 7 amp hours.

I liked watching a bunch of TV, and had a direct TV receiver, and ran a 19" tube set. Now I have a flat screen, both used about 80 watts.

I agree that the microwave should be run from a generator, as mine went bad because I ran it on my Trace 1500 watt MSW inverter for about 5 minutes, it never cooked as well on shore power again!

While possible to run the A/C from a 2KW pure sine inverter, it would take about 800 watts of solar to do it! I do not have that much free area on the roof.

SunElec.com they sell aluminum frame solar panels in the $1 - $2 per rated watt price range. Make sure that you are getting panels with a frame, or you will have noplace to mount them.

I cut 6" long 2" angle aluminum (Home Depot) with 3 holes 3/16" for #10 screws into the roof (with rubber roof sealant that helps hold it down, even if the screws where to be removed) and a 5/16" hole for a 1/4-20 bolt into the solar panel frame. A Nylon locknut will discourage any would be theft.

Home Depot also sells grey Romex rated for direct burial, and exposure to sunlight. #10 wire can handle about 12 amps, so if you are running 7 amp panels, I have two on one run, but it would offer less voltage loss to have one panel per wire run. I ran the wires down my refrigerator vent to the controller.

Some MPPT controllers can handle 48 volts (or more) input, so you might be able to string up 4 panels in a row, and the controller can take in 75 - 100 VDC and put out 12 VDC to the battery at much higher amperage. Then one run of #10 wire will handle more than enough amperage.

I would recommend a pair of 20 amp controllers PWM (they are only about $25 - $35 each) and #10 wire connection for each pair of 100 - 150 watt panels). That would probably be a lot less expensive to install than a MPPT controller and less expensive wiring. The money saved could pay for one of those 150 watt panels at a place like SunElec.com

I debated a lot about installing the Trimetric. I ended up buying it because the wife said so. For the cost back in 1997, $375, I would have been able to purchase another 75 watt solar panel. But the wife said so. The Trimetric does not add more amp hours to the battery, just monitors it very accurately. It was nice to know how full the battery actually was. Back in 1999, the 120 watt panels where $429, now it is much less.

So the MPPT controllers are to expensive to be worth the extra 10% in power that they claim to put into the battery. The Trimetric is also a expensive accessory that is not going to add any amp hours.

Good luck!

Fred.