RV/Camper Solar Needs

dano

Putting together a Solar System for my 24'Class C MoHo.
Weekend / Extended week long Camp Trips here in SW.
Cant find much more than 500-750Wh / 40-50Ah Daily Load
Batteries: (2) Interstate GC2-6V/220Ah / 100Ah-150Ah Discharge (2-3Days without Charge)
Looking at:
1. (2) Kyocera 140W/8A-MultiChrystal x 3-5hrs/Day = 50-80Ah/Day
2. (2) ET 95/5A-MonoChrystal x 3-5hrs/Day = 30-50Ah/Day
3. SunSaver Duo/Remote Meter Controller

Anybody have experience with these Little RV Solar Systems....advice on MultiChrystal/MonoChrystal Panels - Controllers

Hey see you at Camp :cool:

dano

EagleOne

Re: RV/Camper Solar Needs

Hello Dano -

I am pretty new to solar myself, but I have a 'system' in the range that you are talking about. I have (2) Kyocera 315W panels and a MorningStar TS-MPPT60 charge controller. I kind of setup my system backwards - meaning 'how much can I do with what I've got'. If you really do only have a daily need of 40 - 50 Ah, then by my experience you will have no problems recharging that amount with 500-750W of panels. I have 630W, and I can get more than that on a rainy/cloudy day here in the Seattle area, albeit with long (is it summer yet?) days.

I think you will have more of a challenge trying to find open roof space for that much panel. I am lucky in that my 'RV' is really a step van and my roof is 7'6"+ by 21' with nothing sticking up to cause shading. I also have noticed that 50 Ah goes by pretty quick, but I have enough battery to make it as long as I have a decent weather outlook within the next couple of days. Today was partly cloudy with rain and sun and I was still able to get over 250 Ah. I actually was getting up to 725W peak for a minute or so! I guess that is the 'edge effect' that I have seen people refer to.

I have no experience with PWM controllers, but I would recommend at least looking into an MPPT controller to take advantage of the daylight/sunlight when you need it. I know that other forum members are vastly more knowledgable than me (and also more helpful), and I think they will say that 500W-750W of panel will do just fine with 220Ah of battery. I didn't look at the specs on those batteries, but I assume that you will wire them in series for a 12V system. Although 150Ah discharge might be a little much, I saw that you wrote 'here in SW' so I am under the impression that you are in the SW United States. I would think that would be better for you as compared to the 'NW' where I live except when our days are 12+ hours long and the temps don't hit 70F and the skies are clear and bright.

I would also think that 50Ah per day with 500W+ of panel would be a cinch (based on my LIMITED experience), but I am a little confused about your list of 1/2/3 above. If my math is correct, you are looking at 470W, but the panels are rated differently. Others here might chime in about a 'mismatch' among the panels. I hope they do - as I have no experience with differing panels and PWM controllers.

I wish you luck. It sounds like we might have similar needs/wants in that we only plan on really using the system for a few days every now-and-then, not full time 'real' use.

- Chris J.

icarus

Re: RV/Camper Solar Needs

Just a quick though. RV applications come with much lower efficiency net, largely because they re seldom if ever ideal aimed.

The rule of thumb for an off grid battery base system is (my rule) take the name plate rating of the PV, divide in half to account for all cumulative sytem loses, then multiply that by 4 to account for average hours of good sun, per day.

So a 100 watt panel might look like this. 100/2=50*4=200 watt/hours. for an RV, I would cut that in half again.

Tony

BB.

Re: RV/Camper Solar Needs

Dano,

I assume you are somewhere in the southwest (NW Arizona?)... Using Las Vegas (assuming you are camping in the region) for PV Watts with panels having zero degree tilt (laying flat):

Month Solar Radiation (kWh/m 2/day)
1 3.05
2 4.08
3 5.33
4 6.94
5 7.94
6 8.35
7 8.10
8 7.23
9 6.21
10 4.67
11 3.46
12 2.79
Year 5.69

So, depending on time of year, and if you tilt your panels or lay them flat, you can certainly get a lot of sun... First equation assumes you use an inverter for 120 VAC power, the second assumes no inverter on a 12 volt battery bank:

• 2*140 watts * 0.52 overall system eff * 5.33 hours of sun for summer camping = 776 Watt*Hours minimum per day (March-Sept)
• 2*140 watts * 0.61 overall system eff * * 1/12.5 volt battery * 5.33 hours of sun for summer camping = 73 Amp*Hours minimum per day (March-Sept)

In general, I think mono-poly panels (with glass top) will last longer than thin film/plastic topped panels.

Mono vs Poly crystalline panels--Usually, first choice is based on $$$/Watt ($2/watt or less these days). Mono panels are slightly more efficient and you may get more of them on your limited roof space (you need to fit the panels and check the price and see if it is worth it to you).

Otherwise, cost of shipping/insurance/packaging for a couple panels can dramatically affect panel pricing... So make sure you cost the panels (and other equipment) at your front door.

There are are lots of equipment that we like to recommend... But much of it depends on the overall size/needs of your system (total panel wattage, array voltages, battery bank voltage, AH rating of battery bank, need AC power or not, etc.).

So, what are you looking for/at for power needs, batteries, and panels?

-Bill

dano

Re: RV/Camper Solar Needs

Thanks ALL for your Response and Help on this Little Solar RV Project
Live here in Kingman AZ...and YES Solar Panels will be laying Flat on Roof
Building a Solar System for Low Maintenance Cruising/Camping...No Hair Curlers or Resistance Loads
Not going OFF the Grid just yet......stop in at the Casinos and Parks for Services. Do have a 4000W Generator for Electrical Emergencies.

1. Electrical Load: 500-750Wh or 40-50Ah/Day at 12V. No Plans for big AC Inverter yet. Have portable 400W Invertor for Laptop and TV/DVD Player
Load is Lights-4A, Water Pump-4A, Furnace-5A, Laptop-8A, TV-5A and Stereo-4A
2. Batteries: Have (2) Interstate GC2-6V/220Ah. 100Ah-150Ah/12V Storage at 50-75% Discharge (2-3Days without Charge)
3. Panels: Looking at these Options
a.(2) Kyocera 140W/8A-MultiChrystal x 3-5hrs/Day = 50-80Ah/Day
or
b.(2) ET 95W/5A-MonoChrystal x 3-5hrs/Day = 30-50Ah/Da
4. Controller-Looking at: SunSaver 25A Duo/Remote Meter Controller

Question is Pick on Panels and Controller for Mobile Use and Load

thx

dano

willardj

Re: RV/Camper Solar Needs

The thing I have learned in my short time of doing this is. Buy the biggest ones you can fit in your space. Its better to have more than enough than not enough. There is lots of very good deals out there now on panels.