Compressor fridge vs 3-way

Submitted: Wednesday, Jan 25, 2006 at 13:11
ThreadID: 30095 Views:4300 Replies:9 FollowUps:9
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Have done a search of the forum but still don't have enough info to make a decision. After trying out an old York for a couple of years and finding we liked caravanning we decided to bite the bullet and buy a new van. Looking seriously at a 16ft Majestic. However it has been suggested to me that a 12 volt compressor refrigerator is a better choice than a 3 way fridge. The van will have a 100 amp/hr battery and a 60w solar panel, and there will be an Anderson plug on the Rodeo to charge while driving. Fridge size 150 to 190 litre. Not intending camping for long periods away from parks, but need to be able to camp without power for a couple of days occasionally. I need to know things such as -
What brands are there and how much power do they draw?
How long would this battery last with a compressor fridge and a few lights?
Do I need a bigger battery OR a bigger solar panel?
I could use a small generator to recharge the battery if it gets low - space and weight are not a problem with the Rodeo, and the generator could come in useful at home as we get floodbound at times.
Have been told the 3-way can struggle at times, they need more maintenance, but are quieter.
Sorry for all the questions but I won't get any answers if I don't ask.

PS most travelling woild be done in the cooler months of the year.

Don
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Reply By: desert - Wednesday, Jan 25, 2006 at 13:46

Wednesday, Jan 25, 2006 at 13:46
Engel make an up-right, as I'm sure lots of other company's do too. Phone around.You'd need a 90W solar panel to be covered, and a geny is always good for quick charging, or when the sun is clouded out. How long does the battery last? Depends on: ambient temp; how much bleep in the fridge;how many times you open the bastard;and how cold you enjoy the stuff! No short answer.
AnswerID: 150798

Reply By: Gerry - Wednesday, Jan 25, 2006 at 13:48

Wednesday, Jan 25, 2006 at 13:48
Hi,
Several members of our 4WD club have off road vans, most (but not all) with 3 way fridges. I can tell you that anything over 30 degrees, especially if it lasts more than a day or two, will cause the fridge temperature to rise unacceptably. Over the recent hot spell, most of us were looking at temperature in excess of 20 degrees in the fridge (in one case it rose to 27). Those with compressor fridges, while temperatures went up slightly, were still quite acceptable. Several of us are very seriously contemplating changing over and one has already done so. While one large (N70) battery will do it, two are better. From experience, 120 to 180 watts of solar panel will give you hassle free operation, providing you manage to get sunshine on them.
Hope that helps
Gerry
AnswerID: 150800

Follow Up By: Mad Dog (Australia) - Wednesday, Jan 25, 2006 at 13:59

Wednesday, Jan 25, 2006 at 13:59
Gota agree with that, in summer the 3 ways give nothing but heartache and warm beer, had enough of them in the vans I used to have, never again.
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FollowupID: 404344

Reply By: Darian (SA) - Wednesday, Jan 25, 2006 at 14:46

Wednesday, Jan 25, 2006 at 14:46
Yep - mild climate the 3 ways are good - when it gets opressively hot for days on end (and outback travel often does) they struggle. The compressor version would be good with your large deep cycle battery, and for a couple of days I'd guess, if other appliances were used minimally (there is a calculation for all this). The generator idea (presume you are talking inverter tech gennies) completes the picture - all situations are then covered IMO - charge the batteries, provide quaity AC for any appliance and use it round the home too ......... as in the case here in Adelaide, the mains power goes off so regularly that people expect it ...... a much reviled pollie (hmmm.... came from Roachies current home base) flogged the power utility off overseas a few years back (after promising not to, of coiurse) and life has never been the same since. The current power supply mob use chinese fuses made from wood and they blow as soon as more than 3 houses in any suburb turn on the kettle.....sigh.......I'm ok now.
AnswerID: 150818

Reply By: revhead307 - Wednesday, Jan 25, 2006 at 14:57

Wednesday, Jan 25, 2006 at 14:57
I have an OLD chescold 3 way, as a beer fridge in the shed..where it runs off 240V.
In Yalgoo...it often hits 40-50 degrees in the shed...which used to render the fridge useless.

So i got a couple of computer fans...wired them up to a 12v adaptor, and placed them so they suck over the fins.

now the fridge keeps the beer cold in all conditions...makes a HUGE difference.

I even use it for day trips in the car...and the fans have enabled it to work efficiently where it struggled before.

Rev

AnswerID: 150823

Follow Up By: Nav 8 - Wednesday, Jan 25, 2006 at 16:09

Wednesday, Jan 25, 2006 at 16:09
Yep,did that with my caravan 3 way fridge, a couple of 12v fans from Dick Smith an no more problems in the heat.
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FollowupID: 404362

Follow Up By: Gerry - Wednesday, Jan 25, 2006 at 17:14

Wednesday, Jan 25, 2006 at 17:14
I agree it makes a difference, but certainly hasn't fixed the problem with ours.
Gerry
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FollowupID: 404371

Follow Up By: Nav 8 - Wednesday, Jan 25, 2006 at 17:24

Wednesday, Jan 25, 2006 at 17:24
Gerry,, Did you use the little $20 ones or the larger $40 units?
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FollowupID: 404373

Follow Up By: Keith_A (Qld) - Wednesday, Jan 25, 2006 at 20:27

Wednesday, Jan 25, 2006 at 20:27
Completely worked for us. One fan on the inside to cirulate the cold air; one fan on the outside to suck (or blow) air away from the fins to remove the heat. (fan close to fins).
I wired a $5 thermostat from Jaycar - (normally off) from the battery to the two fans. The thermostat is screwed to the fridge exhaust.
Fans only come on when temp on exhaust triggers thermostat.
Ice in freezer even on hot days. Try it - brilliant.
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FollowupID: 404405

Follow Up By: Member - David 0- Thursday, Jan 26, 2006 at 10:17

Thursday, Jan 26, 2006 at 10:17
I did the same. I also cover the windows of the four-wheel drive when carrying the three-way in the back. Mine works perfectly well in hot weather. In my view the 3 way is better for longer stays where power use is a problem. You can use them on gas.

Compressor fridges are best performers but for a long stay when using on 12 V you need solar panels to keep the battery charged. In a van, if I didn't intend to be away from civilisation for a long period, I would be happy with a 3 way.
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FollowupID: 404586

Reply By: Nav 8 - Wednesday, Jan 25, 2006 at 16:28

Wednesday, Jan 25, 2006 at 16:28
Gday Don,,,With regard to solar panels from experience, I have two 80 watt panels and two N70ZZ batteries, The whole system works great if you have plenty of sun but park under a tree or get an overcast day and you have to get out the back up Genset. Remember solar only works during daylight hours, your fridge works 24 Hrs a day also out of daylight you will only get full charge from about 10 AM to around 3 PM. depending on time of year. As you say you are traveling in the cooler months, in the north is not too bad but down south you will need a generator for back up. I am not saying solar is no good, its great its just not the be all and end all of power supply it has its limits. When all else fails the good old generator wont . Enjoy your travels,,, Regards Nav.
AnswerID: 150844

Reply By: flaminbeads - Wednesday, Jan 25, 2006 at 20:25

Wednesday, Jan 25, 2006 at 20:25
Thanks folks for all the responses. Of course answers always lead to more questions. ie
What is a N70 or N70zz battery?
What is or who makes an "inverter tech gennie"?

As I said I am looking at a Majestic van - should I get the battery and panels installed by the manufacturer (Battery pack mounted in boot $800.00
40 watt solar panel including regulator ect. $600.00) or should I get it installed after market and if so what sizes, how much and from whom?

I live in northern NSW but will be picking up the caravan from Melbourne so any installer between here and Adelaide would do (going there after pickup)

I saw an Evakool 190l on the web. Any comments on these units?

Thanks again
Don
AnswerID: 150873

Follow Up By: Nav 8 - Wednesday, Jan 25, 2006 at 21:13

Wednesday, Jan 25, 2006 at 21:13
The N70ZZ battery is a standard heavy duty battery generaly used in a diesel 4x4 as a starting battery. I use these batteries rather than the deep cycle type so I can fast charge them with the genset and also they are connected to my vehicle and charged by that when I travel. When the batteries are down and I get full sun the 10 Amp meter on the solar goes off the scale. Deep cycle batteries dont like that treatment and probably not too good for the ones I have either but I have POWER. Am running two 80 Watt panels.,,, Nav.
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FollowupID: 404416

Follow Up By: flaminbeads - Wednesday, Jan 25, 2006 at 22:52

Wednesday, Jan 25, 2006 at 22:52
Nav, are you saying that a deep cycle battery won't be charged by the vehicle when travelling??
Thanks
Don
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FollowupID: 404465

Follow Up By: Nav 8 - Thursday, Jan 26, 2006 at 11:54

Thursday, Jan 26, 2006 at 11:54
No, but a deep cycle battery should be charged slowly at low amps, if you look up deep cycle batteries on this forum it should give you all the details you need. A quick explanation is deep cycle means the battery can be discharged down to about 70% and recharged slowly. A starting battery should be only discharged to about 20% but can be recharged quickly eg higher amps. The alternator on a 4x4 will put out about 35 Amps mabe more depending on how much charge is in the batteries. This is governed by the regulator that senses the voltage or pressure of the batteries,eg lower the charge the more amps the batteries will accept,as the pressure or voltage rises so the amps drop back. For this reason I use the standard battery as they are cheaper and still do the job. I am sure ther are people on this forum who do use deep cycle quite successfully but as crackles points out below each setup needs to be taylored to individual needs. Nav.
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FollowupID: 404608

Reply By: Crackles - Wednesday, Jan 25, 2006 at 20:43

Wednesday, Jan 25, 2006 at 20:43
Stick with a 3 way fridge for the van & fit a small fan in the back to aid ventalation in the heat. Our van has a similar battery & solar panel to run the lights, stove hood & inverter & copes well with that but adding a big compressor fridge would require at least doubling your present system to be able to reliably run for a few days.
My educated guess on run time for your setup with a 150 l compressor fridge would be between 24 hours (hot day/in shade) to 4 days (cold day/full sun)
This is worked on the belief that your panel in ideal sun would still only be putting in about half the average daily required power.
Solar systems are very unique to each individual's requirements & you'd be far better speaking with a solar retailer to ensure it can sustain the loads you intend to use.
Cheers Craig...........
AnswerID: 150878

Reply By: Morgan VIC - Thursday, Jan 26, 2006 at 11:11

Thursday, Jan 26, 2006 at 11:11
if you want the RIGHT information about caravan fridges and batteries then go and ask the gentleman on the Senior Travellers forum who is involved with them all the time.
http://groups.msn.com/seniortravelers/messages.msnw
AnswerID: 151038

Reply By: Member - Collyn R (WA) - Thursday, Jan 26, 2006 at 13:21

Thursday, Jan 26, 2006 at 13:21
Fridge consumption is very dependent on ambient temperature and fridge temperature setting.

For almost any fridge, energy consumption increases by 5% for every 1 degree C rise in ambient temperature and every 1 degree fall in internal temperature. (For fridge optimum temp inside is 4 degrees C.)

There is thus a huge difference in draw between say Ballarat - and my home town of Broome.

For reliable running from solar almost anywhere you need 180 watts.

!00 Ah will provide typical 18-hours without excess battery damage. More than that you'll be buying new batteries each year.
Trust this helps
Collyn Rivers
AnswerID: 151076

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