fridges? 3 way or compressor

davmck · Member

fridges? 3 way or compressor

justcruisin01 · Guru

If you can keep the power up ok then the compressor is the way to go , particualy up north.

davmck · Member

thanks for the reply, yes we will be spending the first 12 months up north from weipa to darwin, i guess chasing power all the time can be an issue.

jimricho · Guru

Welcome to the forum Dave,

The obvious "upside" of 3-way fridges is the ability to run on gas for extended periods without "ground" or "shore" power (240v) available. Another consideration is that they are silent in operation, this may be a factor during the night inside the van. Many compressor fridges a fairly quiet in their operation however. There may other GN members who can comment from personal experience on this.

The "downside" is they are significantly less efficient than compressor fridges. They are slow to cool down to operating temperature and can be a problem in hot conditions. Litre for litre they draw several times the current of a compressor type.

The Waeco (compressor type) 140 litre upright draws 2.6 amphours per hour (32 degrees ambient, 12v operation, according to their blurb) making a battery/solar combination quite practical. This compares with 12-15 amps for a 3-way.

Compressor fridges are quite uncritical about being off-level and will perform better when travelling.

(I've almost convinced myself to buy one to replace my 3-way, I have higher priorities for my finances at this stage though....like booze, long lunches etc.)

Jim

-- Edited by jimricho on Sunday 7th of February 2010 08:08:42 PM

dave06 · Guru

yep Engel compressor for me, however "T" rated three ways aren't bad

original question was which is better well it's got to be compressor regardless of what brand!

jimricho · Guru

My reference to the Waeco above is neither a recommendation nor otherwise. It was just an easy source of data on the power consumption.

davmck · Member

thanks jim for the reply, after much concideration and many cans biggrin

, i have gone with a 190lt waeco with 2x fullriver 120ah batts and 3x 120w solar panels, also have a 1kva genny for backup so should be ok.
cheers
dave

Gary and Kerry · Guru

davmck wrote:

thanks jim for the reply, after much concideration and many cans, i have gone with a 190lt waeco with 2x fullriver 120ah batts and 3x 120w solar panels, also have a 1kva genny for backup so should be ok.
cheers
dave

WOW!!! thats one serious set up.
You shouldn't have any problems running your fridge and mostly anything else you want to run.

jimricho · Guru

davmck wrote:

thanks jim for the reply, after much concideration and many cans, i have gone with a 190lt waeco with 2x fullriver 120ah batts and 3x 120w solar panels, also have a 1kva genny for backup so should be ok.
cheers
dave

Looks like you have plenty of capacity. I doubt you'll need to fall back to the generator option. With that much charging capacity I wouldn't bother going to the trouble and expense of wiring a charging circuit from the tow vehicle.

One comment on the the two batteries however. I would suggest you wire in a changeover switch with one backing up the other rather than just hooking them up together in parallel. Battery suppliers will sometimes tell you that it's ok to just parallel two identical batteries but my personal experience has been that if you want to get the maximum life out of the batteries it's best not to do this.

A suitable switch can be purchased from marine accessory suppliers.

PS: I don't have any "hands on" experience with portable generators but it is my understanding that 12v output is not really suitable for battery charging. It is best to use the genny's 240 v to charge a battery via a charger.

-- Edited by jimricho on Tuesday 9th of February 2010 06:11:07 PM

davmck · Member

hi jim, the changover switch you refer to are they automatic, would be a pain if manual having to keep an eye on voltage levels, still having mixed thoughts about compressor type, have friends on the road full time and they say i will continue to have power problems, but in defence they say there 3 ways are useless on 12v, my wife has injections for health reasons which have to be kept at 2-6 deg, and can only get script every 6 months so cooling is pretty important.

Ron and Shirley · Senior Member

Davmck

In your situation the compressor fridge is the only way to go. With your proposed solar/battery system you will only rarely have power problems then you have the genny, via 240v, for a few hours to give you the boost you need. Alternatively you could head for an over-nighter in a Caravan Park.

Your power problems will only come when you get a number of days in a row of overcast (crappy) weather, and/or you use too many other appliances either via 12v or an inverter.

We have around 180w of solar panels feeding through a Plasmatronic PL20 regulator to a 200Amphr battery. Our main 12v use, besides lights and some phone battery charging, is the 115L Vitrifrigo 12v fridge, which has been fantastic compared to the 3-way that we had in our old wind-up Campertrailer. Boy did that fridge struggle in the tropics, which is why we did not even consider a 3-way when we had our van built.

Initially I did keep an eye on our power use, which seems to average out for us at around 40Amphr per day, and battery "State of Charge" etc etc. Now we only look occasionally at the battery monitor and as long as the battery voltage is above 12.3v I am happy. We find that on overcast Victorian days by late afternoon our battery is back up to float (13.8v) and on bright sunny days the float voltage is easily achieved by lunchtime. We carry a genny as a back-up, but to date we have not had to use it in anger.

We have the van wired up to an Anderson plug so that the battery could be charged from the vehicle. However we have not had the vehicle wired up as yet as we find our solar system manages to cope.

IMHO a 3-way fridge on 12v is for when you are going from A to B and you have your vehicle wired up, via an Anderson plug, to run the fridge from the vehicle whilst in motion.

-- Edited by Ron and Shirley on Thursday 11th of February 2010 11:03:41 AM

davmck · Member

thanks ron for your reply, we to are getting a goldstream, will be built early april, what lenght is yours, suspension etc and have you been happy with it, our previous van was a trakmaster so i hope ive made the right decision
cheers
david.

Ron and Shirley · Senior Member

Hi David

Our Goldstream 15.5 Cutaway Pop-top is heavily optioned up from the base model, particularly with regard to 12v.

See http://tinyurl.com/ygtdrrh for details of our van.

To date we have had no issues of any description with the van, nor the Goldstream Link off-road we had for 8 years previously. We are very happy Goldstream customers that are very comfortable in the bush.

jimricho · Guru

davmck wrote:

hi jim, the changover switch you refer to are they automatic, would be a pain if manual having to keep an eye on voltage levels, still having mixed thoughts about compressor type, have friends on the road full time and they say i will continue to have power problems, but in defence they say there 3 ways are useless on 12v, my wife has injections for health reasons which have to be kept at 2-6 deg, and can only get script every 6 months so cooling is pretty important.

Hi David, Ron and Shirley have covered the issues well, but in essence I would not rely on a 3way to keep critical medical supplies in the temperature range you indicate while travelling. You've probably worked out that I have a 3way installed in my rig, incidentally a Goldstream Goldcrown, and I'm going on personal experience. This is despite having a voltage booster installed so I'm getting the full DC voltage to the fridge.

I also have a Bushman (Engel type) installed in the tow vehicle and I use this to store temperature critical food such as meat when on the move.

Regarding the switch, it is not automatic so you will need to keep an eye on the voltage from time to time. In view of the amount of charging capacity you have I don't think this will be too much of a pain. A bit like checking your fuel gauge from time to time in your vehicle to make sure you don't run out.

The switch is a 4 position unit so you can select battery 1, battery 2, both batteries, all batteries off. The switch is a "make before break" one, that is there is no drop out when switching positions. Using the both position will parallel the batteries and while this is not recommended its occasional use when charging should not be a problem should the need arise.

This is an example of the type of switch....

battery switch.jpg

For more information click on this Bias Boating link,

Also Bainbridge Technologies for voltage monitor and low voltage cutout info. Baintech products can be purchased through Battery World outlets.

Edit to correct typo and to check links

-- Edited by jimricho on Thursday 11th of February 2010 07:59:36 PM

jimricho · Guru

A further comment on operating 3 ways on 12v DC.....

A little while back I did a static test on my 3 way on DC (ie the van was parked and level, not on the move) over a two day period and I found the fridge performed as well as it does when on 240v. The fridge performs no where near this well when on the move so this leads me to believe it's the constant movement that interferes with the operation.

The voltage booster was in circuit and a power supply was used to simulate the battery. The voltage at the fridge terminals was 14 volts both when simulated for the test and when on the move.

Another bloody edit, why don't I get it right the first time?????

-- Edited by jimricho on Thursday 11th of February 2010 08:13:34 PM

DeBe · Guru

You are quite right Jim, when I worked on a Cray boat it had a 3 way fridge onit running on gas worked good when at anchor in callm water, when out at sea & rolling it would defrost. Also back in the 80s we lived in a 32ft bedford Motor home the 3way fridge in that would defrost when traveling & it to was running on Gas. Daryl