200W Solar Power for 2A

[Reef95]

I'm adding solar panels my '03 Chevorlet Astro, I purchased 400W. They haven't arrived yet but I looked over the specs, again, and it looks like they are much larger than I expected.

So! I'm returning them once they arrive (unless they are a good size.)

I'm purchasing 200W (2 100's) Renogy Eclipse panels, which are 16 inches smaller than the 2 200's listed above.

I'm looking to power a compressor freezer (~0.74a average) 24 hours and a diesel heater (0.7a average) possibly 24 hours during winter and a MaxxAir Deluxe fan during hot summers (0.23a - 0.48a average) 8 hours a day.

I've tried calculating my usage a few times and I THINK 200W will suffice for 2A. 

400W would be fantastic but they're so large..

I'm sure this question is brought up often. I just want to be 100% sure before hitting the road..

Won't be chasing the sun, going to stay in the midwest USA (Minnesota).

Will also have my batteries hooked up to my vehicles alternator if I can figure out how to.

 

[1shemp]

Is the freezer 12 or 120 volt?

 

[Trebor English]

I'm sure this question is brought up often. I just want to be 100% sure before hitting the road.

There is  no 100%.  There will be a week of rain or an equipment issue [font=Tahoma, Verdana, Arial, sans-serif]at some point.  [/font]

 

[maki2]

If you go to some of the various websites you will fine calculators to help you determine how much solar you need.

You will be asked to input how much power you will be consuming from the various appliances and electronics.
You will also be asked your geographic location. Location and time of year is critical information that is part of determining how much solar you need.

The whole area of the USA and some other countries has been put into calculations that take into account the angle of the sun at various times of the year and also calculated for the averaging of sunlight based on typical weather patterns during the year. For instance on the Pacific Coast in the summer months the mornings are overcast with fog even though there is zero chance of rain. So that does limit the number of high output solar hours during the days during those particular months of the year. This means that locations do matter so what someone in Arizona might need for panels and battery storage will be quite different for what someone in NW Washington state needs for panel sizes and battery storage.

I am limited by the size of the roof on my nomadic dwelling space and the only way around that is to have supplementary portable panels to deploy to gain more solar power.

 

[Almost There]

I run a Whynter 65 Qt 12V unit as a deep freeze and I think the power usage you forecast is way, way off.

I also run the identical unit as a fridge and I can tell you that the freezer uses somewhere in the neighborhood of 5 times the power that the fridge does./ Keeping the freezer at  0F (optimal temp for long term food storage) and the fridge at 40 F is two different ball games entirely.

I have 4 Trojan T105RE 6 volt batteries for a total of 450 a/h of power. I use the same Renogy Eclipse panels you're contemplating - absolutely great panels BTW, I highly recommend them!

The 200 W of solar in the winter in AZ do not keep up with the power usage. I supplement them every second day with at least 2 hours of generator time powering a 50 amp battery charger. My panels are portable and are therefore tilted toward the sun giving them more efficiency than if they were flat on the roof of the van. I can also keep them cleaner as portables!

The amount of sun in the summer in the midwest is probably slightly less more than what I get on winter days in AZ but you'll get more cloudy/rainy days that I would.

 

[jonyjoe303]

The maxair if that is a roof vent, it probably uses more power, my roof vent at full power uses a little over 3 amps. A 12 volt fridge set to 40 degrees uses about 26 amps in a 24 hour period. 

200 watts of solar with mppt controller will give you about 10 amps. I max out at 12 amps from my 240 watt panel lying flat on the roof in summer, in winter it goes down to about 10 amps. 

Maybe instead of 2x100 panels get a larger 240 watt or higher single panel and install like mine. One big panel will be easier to install. I have the small astrovan as you can see in picture I could have added a larger panel with room to spare. Sometimes 2 or 3 extra amps make all the difference. If I could do it all over again I would have never added roof vents, the panel would be flushed with the roof.


Heres a picture of my 240 watt panel on my 86 astrovan

 

[Gypsy Freedom]

i run the most efficient chest freezer out there. the national luna, wins every comparison hands down, except purchase price... ouch

for the last several weeks it has been the only load on the system, and i am not going in and out of it much
my charge controller is data logging and i can see that , now, in november on the coast of oregon with day time hi temps in the 60's on a warm day and generally low 40's at night. my batteries are requiring an average of .8kwh per day to to run the freezer all night, all day AND recharge the batteries to float each day. when measured at the freezer, it "uses" less but the inefficiency of charging batteries makes a difference so i dont even look at consumption. i only look at how much power i have to generate to get my batteries back to full each day.

my batteries are lead acid, so if you had lithium, your efficiency would be higher and daily power required from the panels would be less for the same consumption

in warmer weather it will significantly increase the consumption

if you use the freezer to freeze stuff instead of just storing already frozen stuff the consumption will go up as well

but hopefully this gives you some real world data to base your thinking on

200 watts flat mounted at this time of year in Minnesota is going to be hard pressed to make .5 kwh on a sunny day

now if you can tilt them, you might get close

i forget the thread but i posted measured output of a few panels just yesterday for this time of year at 42 degrees north. you might check it out. but flat panels i am seeing around 40% of rated output peak but with tilt they are getting up around 70% giver or take. add in the short days and that really limit the amount you can produce on a sunny day.

during the summers, you will be making more power as the sun is higher but with higher temps, the freezer will be working much harder.

i dont have the data from last summer to compare, but in the past i have runn the freezer comfortably with 470 watts flat mounted on my minivan at the time. i think you will be pushing it to run a freezer with only 200 on the roof from what i have seen. i think you might get away with a smaller 12v fridge on 200 watts. many do