Another Solar Question

[theresa p]

Hi All

I was told by Trillium Canada that a 50 watt system would be enough to keep a battery well enough for the dc fridge that comes with our trailers. Was curious to know if anyone has used a panel from "Sunforce" and what your thoughts on this or similar products.

Thanks

Dennis

Here is the link: http://www.costco.ca/Browse/Product.aspx?P...300&topnav=

[Bud Kennedy]

If the frig pulls 10 amps at 12 volts then you are using 120 watts per hour. 12 volts X 10 amps = 120 watts

From what I understand the frig will run continuously on 12 volts. ( my Dometic dosn't even have a thermostat when running on 12 volts ) so we are talking about 120wattsX24hrs=2,880 watt hours.

The 50 Watt solar panel at 100% sun provides 4 amps. 50watts/12volts=4amps
Therefore it can only provide in 8 hours of good sunlight, 4X8= 32 watt hours.

If you are using an inverter on a 120 volt frig, then due to losses in the inverter, you get less than if on 12 volts. In either case, the energy to keep the frig cold will amount to the same.

If you are boondocking for more than two days, the only way to have cold food is by propane unless you have a tractor trailer to mount all the solar panels on.

[theresa p]

Thanks Bud

The fridge is not that big at all and I am told by the manufacturer that the fridge would draw approx 24 amp hrs for the day so 1 amp per hr.

That is coming right from Nova Kool, so I am somewhat confused, if can replace at a modest 4amps per hr with a solar panel than 6 hrs a day should be enough should it not.

Dennis

[Bill F.]

Thanks Bud

The fridge is not that big at all and I am told by the manufacturer that the fridge would draw approx 24 amp hrs for the day so 1 amp per hr.

That is coming right from Nova Kool, so I am somewhat confused, if can replace at a modest 4amps per hr with a solar panel than 6 hrs a day should be enough should it not.

Dennis

Hi Dennis,
The old Trillium fridges were real power hogs but it looks like your modern one is much more efficient. As long as the sun shines every day you might be ok but that isn't realistic. This panel will only keep the fridge running and will not build any reserve capacity. One overcast day and you're in trouble. A bigger panel would keep the fridge running plus add reserve capacity to carry you through a day when the sun doesn't shine. Also you probably should be considering other requirements(lights, tv, furnace, etc.) Converting to LED lights before going solar is money well spent.
Bill

[Larry C Hanson]

Hi Everyone,

What they were probably talking about is that the 40W panel
would be enough to keep battery charged to power the
circuit board that controls the refrig on propane or electric
not to cool the fridge on 12V.

Larry H

[theresa p]

Thanks Bill and Larry

We don't use alot of extra power we do camp mostly outside but thinking of lights and maybe a radio if it is raining while boon docking isn't a bad thought.

And Larry no our fridge is only dc would like a three way or at least maybe a two way but haven't found one that small as of yet,,,,hahahahaha

Well we will take all into consideration, I am hearing that the controller might be as if not more important than the type of panel to be used and maybe even a larger one although Trillium Canada says they sell a 50 watt panel to do the job. I do believe they also sell these trailers with two 6 volt gell cell batteries as well.

Thanks again something to think about for sure......

Dennis

[Tim Ryce]

And Larry no our fridge is only dc would like a three way or at least maybe a two way but haven't found one that small as of yet,,,,hahahahaha

Hi Dennis,

The snipppet I've included above is the magical piece of info that was needed to accurately assess your power consumption. Seeing as your fridge is a DC-only system (and new-ish), it's likely a compressor-driven system, which operates on a different principle to the typical propane/AC 2-way or propane/AC/DC 3-way fridges; these multi-way fridges usually require a massive amount of heat, provided by propane flame or electric resistance. It's this electric resistance that is the reason for the high power draw.

In summary, I'd trust what you're hearing from your manufacturer!

~T

[Rick G]

Hi Dennis,

The snipppet I've included above is the magical piece of info that was needed to accurately assess your power consumption. Seeing as your fridge is a DC-only system (and new-ish), it's likely a compressor-driven system, which operates on a different principle to the typical propane/AC 2-way or propane/AC/DC 3-way fridges; these multi-way fridges usually require a massive amount of heat, provided by propane flame or electric resistance. It's this electric resistance that is the reason for the high power draw.

In summary, I'd trust what you're hearing from your manufacturer!

~T

The Trillium website lists Nova Kool compressor fridges as their refrigerator, website here : http://www.novakool.com/products/sin...r1900_2600.htm

The Nova Kool website doesn't give power consumption for each model but claims that most fridges use less than 30 watts at 12V. Also, their compressor fridges are controlled by a thermostat, indicating that they do not run all the time, unlike older absorption fridges (like mine). So, if you have a smaller fridge, it is entirely possible that a 50 watt solar panel would keep you going for a few days at least, and might be enough to keep it going for long periods, depending on the outside temperature (how hard the fridge has to work), the thermostat setting, and the amount of sunshine you see. Sounds like a reaonsable approach to me.

Rick G

[theresa p]

Thanks all for your reply's will give us something to think about for sure.

Do you think that the controllers that come with said package will be adequate or should we look for an after market one to be on the safe side.

Dennis

[peterh]

Yea, a 50 watt panel could, theoretically power a 'fridge like the Nova Kool, but, in practice, it doesn't work that way.

Our Scamp 5er is set up for boondocking. With its 105 watts of roof-mount solar panels, all-LED lighting (only a few of which are on at any given time), large fresh tank, both a (no electricity required) Wave 3 heater as well as the standard Scamp furnace, electric water pump, propane 'fridge, and water heater we can and do camp for days without hookups. We also use our house battery to charge our laptop, cell phone, and camera batteries, and we have a 12-volt AM/FM/DVD/TV we occasionally use. Most of the time we use our electricity-free Wave 3 heater to keep our trailer warm and only turn to our furnace, which draws 2.8 Amps when it is running, to quickly heat up our trailer after we get home and when we're somewhere wet. (The Wave 3 puts a lot of moisture in the air, which fogs the windows and makes it damp inside in rainy or high-humidity climates.)

Most days our 105 watts of solar provide ample power to boondock without any compromises, other than not being able to use the microwave and having to manually water our drip coffee maker, but some compromise is necessary when camping in campground with lots of trees, on days when the skies are heavily overcast, and when we camp off-season.

This May, late in the month, we camped at 8000+ feet at the Grand Canyon North Rim, but even though the sun is both strong at 8000 feet and up long in May, we were coming up very slightly short because of all the trees. If we stayed much longer we could have balanced our power consumption by unplugging our AM/FM/DVD/TV, which has a parasitic power draw .13 Amps (1.5 watts/3 Amp-Hours a day) when its turned off but plugged in. If we depended on a Nova Kool 'fridge we would have needed to make other compromises, like not using our furnace to quickly warm our trailer and not using our laptop, and even then might have come up short, even though we were in Sunny Arizona.

There are many times when solar power can be a loosing battle. Camping in the even more heavily trees and very damp Olympic Rain Forest, where the trees catch almost all the sunlight and Wave 3 becomes an indoor rain maker. Camping off-season, in late-Fall or early-Spring when the sun's angle is low and the hours of sunlight short. Camping on heavily overcast days when solar panel efficiency is compromised by 75% . . . even a thin layer of clouds can reduce panel efficiency by 33%. During the dark winter months in the northern US, where we live, our solar-power trailer doesn't stand a chance and we're restricted to short stays or need hookups.

The take-away from all this should be that solar panels are part of an energy use strategy, but they aren't the whole strategy. Our power-use strategy includes selecting sunny campsites when the weather is cold, installing LED lights, choosing and using non-electric appliances like our propane-powered 'fridge and Wave-3 heater whenever possible, snuggling under a heavy down quilt at night, remembering that sometimes we have to turn off parasitic power draws like the entertainment console and be careful about using and charging our laptop and other devices.

A Nova Kool 'fridge does not fit with this strategy.

[Roy in TO]

Canadian Tire has 25% off on many solar / battery items this week.

An 80W Solar Panel can be had for $525 Canadian. Not sure if this is a good deal or not. Specs as follows:

•The 80W solar kit with sharp module has water white tempered glass, EVA laminate, plus an aluminum frame for extended outdoor use

•The bypass diodes minimize the power drop caused by shade

•Perfect for homes, boats, RVs, back-up and remote power use, 12V battery charging, and solar power stations, pumps and lighting equipment

•High efficiency polychristalline solar cells

•Easy to install and maintenance free

•Completely weatherproof

•Connect multiple panels for more power

•Includes: One 80W solar panel, wiring, brackets, screws and voltage tester

[Roy in TO]

Plus they have this battery on sale for $225, reg $300 Canadian.

12V Eliminator Renewable Energy Deep Cycle Battery
Product #11-1879-8
•Renewable energy deep cycle battery

•12V sealed AGM (Absorbed Glass Mat) deep cycle lead acid battery

•Designed to be used with Xantrex PowerHub 1800 (11-1877) or as part of any battery bank for a renewable energy system

•100 ah at 100 hour rate

I'd appreciate hearing any opinions on the quality and pricing of both the solar panel and battery.

[theresa p]

Thanks again to all who replied, still thinking about all the info....

Dennis