Need Fridge...can Solar keep up with an Electric Only Fridge???

[chowman2011]

Considering putting in an electric Only Fridge...based on having Solar tied in.

Any suggestions, comments on taking this route??

This is for My '77 Silver Streak "Refurbish".

Thanks,

Christopher

[moosetags]

Check out the Tundra and Nova Kool compressor refrigerators. Most are DC only and work with a solar charging system to multiple six volt batteries. We just ordered a truck camper with a 7.5 cubic foot Nova Kool. It is DC only and we plan to run it with a 95 watt solar system and two 6 volt batteries.

We don't have the truck camper yet, so I can't comment on how it operates. On other forums, these things have a good rep.

Brian

[chowman2011]

Looks like the type of set-up(fridge and solar) I am thinking about....

Nova Kool appears to be a popular item...price is higher than I had hoped for--technology based I am guessing??

Model rfu8220 Nova Kool

I'll have to think on that...in the longer run...it'd probably be a good choice...

And it goes on....

Thanks,
Christopher

[lewster]

I have been running an Engel top load refer/freezer on 12VDC for 3 years purely on solar. The charging system had 4 X 100 watt AM Solar panels charging 2 X Lifeline GPL-6CT 300 amp/hour golf cart batteries thru their HPV-30DR controller. The system never want off and performed flawlessly.

The NovaCool units and others like them use the same Danfoss compressor and typically operate at around 3-4 amps when on DC current. You should have no problems at all if you have a large enough battery bank and the solar panels to keep them happy!

[chowman2011]

Originally Posted by lewster

I have been running an Engel top load refer/freezer on 12VDC for 3 years purely on solar. The charging system had 4 X 100 watt AM Solar panels charging 2 X Lifeline GPL-6CT 300 amp/hour golf cart batteries thru their HPV-30DR controller. The system never want off and performed flawlessly.

The NovaCool units and others like them use the same Danfoss compressor and typically operate at around 3-4 amps when on DC current. You should have no problems at all if you have a large enough battery bank and the solar panels to keep them happy!

Thanks Lew! I'll have to look into them also--Engel.

Nice description of the solar products too...my other 'to-do' aspect...

And if I am limited to space for 3 panels?? I haven't actually measured--just a visual guesstimate...

Thanks,
Chistopher

[barts]

Originally Posted by chowman2011

Thanks Lew! I'll have to look into them also--Engel.

Nice description of the solar products too...my other 'to-do' aspect...

And if I am limited to space for 3 panels?? I haven't actually measured--just a visual guesstimate...

Thanks,
Chistopher

Rough rule of thumb from AM Solar - in warm months you get rated power 5 hours/day. If your fridge pull 3-4 amps, you'll need %duty cycle * 24/5 * 4 amps; in warm weather that (100%) you're looking at 19 amps peak output just for the fridge - 3 100W panels will do just over that. Some of these fridges are rated at 24 amp-hrs/day at 70F external temp; if you're someplace hot (100F interior temp is really easy) this goes up quickly.

So, I'd guess marginal for really hot places; prob. doable otherwise.

Note that one of the attractive things about the Danfoss is that
the compressor is available separately if you wish to a marine style
icebox; you can make them much more efficient by using space (insulation).

- Bart

[chowman2011]

Bart,
Good info to know! I'll have to think more on this subject.

So, refrig. and other electricity...I would probably need 4 panels? How about number of batteries? Big box on front; and I could utilize the storage(in bedroom area) for other batteries(yet there is that distance(wiring) factor)..

The Engels seem on the small side...fist thought...guess Iam used to the 27cu.ft. Home fridge ....

How about the typical 2 or 3 way fridge....thoughts on one of those as far as primarily power from Solar???

Thanks ALL,
Christopher

[Jammer]

Christopher

Remember that much depends on how much sun you get which is a function of 3 things:
- weather
- latitude
- time of year

Latitude and time of year affect day length and angle of incidence, and the presence of cloud cover reduces output to a fraction of rated power.

In Colorado you won't average nearly as much power as Lewster (in Florida), and probably somewhat less than Bart (in California). Spring and fall trips would be especially problematic due to the typical Colorado weather patterns (periods of clouds and rain almost every day) during these times and the shorter day length and reduced angle of incidence.

You will need around 50-100 amp hours of battery capacity per day on cloudy days for the fridge alone, so for a budgetary estimate, figure the maximum number of cloudy days in a row times 50 or 100 or whatever. In general it is difficult to get more than 400 amp hours of batteries in a typical Airstream-sized trailer due to weight, space, ventilation, and cost constraints.

It helps keep the battery size down to have a small generator and multistage converter to use to recharge the batteries in a pinch. Then you can size everything based on 2 cloudy days in a row and run the generator for an hour or two on those occasions when you get a 3rd.

It also helps matters to have a charge line from the tow vehicle, especially if you move around a lot. Even if it only ends up bringing 10 or 15 amps it will end up making a difference.

[chowman2011]

Originally Posted by Jammer

Christopher

Remember that much depends on how much sun you get which is a function of 3 things:
- weather
- latitude
- time of year

Latitude and time of year affect day length and angle of incidence, and the presence of cloud cover reduces output to a fraction of rated power.

In Colorado you won't average nearly as much power as Lewster (in Florida), and probably somewhat less than Bart (in California). Spring and fall trips would be especially problematic due to the typical Colorado weather patterns (periods of clouds and rain almost every day) during these times and the shorter day length and reduced angle of incidence.

You will need around 50-100 amp hours of battery capacity per day on cloudy days for the fridge alone, so for a budgetary estimate, figure the maximum number of cloudy days in a row times 50 or 100 or whatever. In general it is difficult to get more than 400 amp hours of batteries in a typical Airstream-sized trailer due to weight, space, ventilation, and cost constraints.

It helps keep the battery size down to have a small generator and multistage converter to use to recharge the batteries in a pinch. Then you can size everything based on 2 cloudy days in a row and run the generator for an hour or two on those occasions when you get a 3rd.

It also helps matters to have a charge line from the tow vehicle, especially if you move around a lot. Even if it only ends up bringing 10 or 15 amps it will end up making a difference.

Great Info Jammer! Thanks

One of the reasons I moved to Colorado(from the midwest) IS the amount of sunlight throughout the year--just a thought.

As for the Solar aspect...
Right with You on the batteries, space considerations, inverter , tie-in to tow vehicle and having a backup generator(in a pinch)...

Those are some of the other major tasks to take care of with My '77 Silver Streak "Refurbish"...

Prev. Owner utilized Solar with this trailer for a period while building "off-grid" home...50+ft of heavy gauge cable(2 awg as I recall) came with the trailer(already tied into battery box wiring).

SO,
I am thinking 2 Great Batteries, 3 panels and the other necessaries to start for the Solar(I am new to the solar realm details)...

Thought: Do I have considerations w/ the already present converter that may need to be addressed??

Also considering a 'smaller' Dan Foss compressor type Fridge to start with--I do have Good Coolers if I need them

$600 to $800 seems better than $1400 to $1800 Just for the Fridge...

where that $800 to $1000 can be used for the Solar Set-up(haven't checked on pricing that yet)...

My , My...now getting into some bucks....

on that note--I look forward to seeing thoughts, experience , and suggestions in regards to these aspects!

Enjoy,
Christopher

[chowman2011]

Originally Posted by barts

Rough rule of thumb from AM Solar - in warm months you get rated power 5 hours/day. If your fridge pull 3-4 amps, you'll need %duty cycle * 24/5 * 4 amps; in warm weather that (100%) you're looking at 19 amps peak output just for the fridge - 3 100W panels will do just over that. Some of these fridges are rated at 24 amp-hrs/day at 70F external temp; if you're someplace hot (100F interior temp is really easy) this goes up quickly.

So, I'd guess marginal for really hot places; prob. doable otherwise.

Note that one of the attractive things about the Danfoss is that
the compressor is available separately if you wish to a marine style
icebox; you can make them much more efficient by using space (insulation).

- Bart

Hey Bart,

Am I understanding correctly? Building an icebox using a Dan Foss compressor?? I could, but not sure that is something I want to take on at this point...A unit that I can install and be using is a better match at this point.

Sounds like You are saying 3 100w panels is cutting it close?
THoughts??

Thanks,
Christopher

[Jammer]

Originally Posted by chowman2011

Thought: Do I have considerations w/ the already present converter that may need to be addressed??

It depends what you have and also depends what your expectations are.

I have flooded (wet cell) batteries, and a very average converter, which works out OK for me even though it has to run overnight to fully charge the batteries and in really cold weather will probably never fully charge them. In hot weather it overcharges the batteries a little and I just add water.

But I don't have a generator so the only time I use the converter is if I'm parked overnight someplace with electricity.

If I were boondocking and wanted to recharge from a generator I would get a better converter.

[wkerfoot]

The DanFoss refrigerator which I have in my Liner does not run constantly. It only draws when it is running. Also it cools much faster since it is pumping freon through the cooling panels.

Bill

Originally Posted by barts

Rough rule of thumb from AM Solar - in warm months you get rated power 5 hours/day. If your fridge pull 3-4 amps, you'll need %duty cycle * 24/5 * 4 amps; in warm weather that (100%) you're looking at 19 amps peak output just for the fridge - 3 100W panels will do just over that. Some of these fridges are rated at 24 amp-hrs/day at 70F external temp; if you're someplace hot (100F interior temp is really easy) this goes up quickly.

So, I'd guess marginal for really hot places; prob. doable otherwise.

Note that one of the attractive things about the Danfoss is that
the compressor is available separately if you wish to a marine style
icebox; you can make them much more efficient by using space (insulation).

- Bart

[chowman2011]

Bill,
I Appreciate Your Input! So far, it is noted that a Dan Foss compressor Refer Cools Quick...Has better stability(reliability) in a variety of situations...

Thinking this may be the route to go for the Fridge.

Cheers,
Christopher

[UAPachyderm]

If you are going solar only, I'd choose National Luna for the absolute best performance and the lowest draw. NL costs more than Engel (the other high quality, high efficiency fridge) but the performance of NL is unsurpassed. The NL 40 power consumption is 1.53 amp/hour average draw when set to freeze at 14 degrees in ambient temperature of 90 degrees. The largest NL 125 only draws 1.85 amp/hour in the same conditions.

Lewster is the solar genius and I respectfully defer to him. I'm just a dabbler and have learned a lot from Lew. I'm sure he could tell us what would be required to run the NL above. I'm guessing one 31 AGM would cool/freeze the NL for two or more days without over discharging. Shouldn't take much solar to sustain such small consumption.

An outside the box thought, you can install a second battery in your vehicle easily and affordably with an NL kit or an NL battery pack ... fridge won't need solar using this method.