Fridges

[RobertMartin]

HAS any tried one of the new fangled WAECO portable fridges on a yacht???
They tell me that they draw about 1.5 amp/hr and only need to work for 1/3rd (8hrs) of a day to stay cool...

Also, on another note, when a wind generator is producing say 2 amps, is that 2 amps an hour, a second a what?????

Gota love this Forum ))))

ta..

Bobby aka Seawolf..
Sail as if your free

 

[HenryB]

Seawolf,

I haven't tried one of the new fangles fridges but I have an older Waeco unit and it draws about 5 amps when it is running. My guess is that they quote an average current based in their assumption of it running 1/3 of the time - 5/3 is about 1.5 amps.

Regarding your generator query - if it produces 2 amps then that's its current output. If it keeps this up for an hour then its produced 2 amp hours of power, or for 24 hours it would produce 48 amp hours of power.

If you are hoping that a wind generator will replenish the power used by the fridge then get a big generator - from my experience you will be lucky to average more than 15-20% of its quoted maximum output.

Back to the fridge - if it draws (say) 5 amps and runs for 8 hours per day then it will consume 40 amp hours per day.

Hope this helps,

 

[Guest]

Amps is Amps

2 amps is just that. Amps are the of flow of current. Do you mean amp-hours? This is the continuous amps flowing consistantly for the number of hours. 2 amps for 1 hour = 2amp-hours, 2 amps for 2 hours = 4amp-hours.

Your figure 1.5amp/hour should give the same result as if 1.5 amps was continuous for one hour and could best be stated as consuming 1.5 amp-hours. It is an average use as the frig stops and starts. When it is running it will draw a greater current. It may say run continuously for half an hour drawing 3 amps and the next half hour be stopped, drawing zero amps Thus the average current used is 1.5 amps per hour [1.5amp/hr]

A better use of the term is using the continuous [averaged amp/hour rating] and working out the amp-hour use. your 1.5 amp/hour if operated over an 8 hour period would consume 8 x 1.5 amp-hours = 12 amp-hours. So to run this from your battery, the battery would need to have this reserve capacity at least. A 72 amp-hour battery would allow you to run your frig for 8 hours and have 60 amp-hours left. In fact you could run the thing for 48 hours before using up the whole battery. A bit like using petrol in the tank. Well so the theory goes. This is just a rough and ready means to estimate power consumption for battery minded persons. There are many more wrinkles to this theory and applied science and these forums are littered with threads extolling the merits of the writers theories.

Any way, what sort of yotty are you or are you a poofter who has to have ice in your gin and tonic [Or should that be gin/tonic or perhaps gin-tonic]. What ever is wrong with salt beef hard tack and navy rum.

Ahaaargh matey.

 

[RobertMartin]

Re: Amps is Amps

I want milk in my tea, can't stand black tea, foul stuff....
Thanks for your reply ))

Bobby aka Seawolf..
Sail as if your free

 

[RobertMartin]

Thanks for that, I got it..

How do you find the fridge, are you happy with it??? Would you buy one again or get a built in fridge e thingee...

))

Bobby aka Seawolf..
Sail as if your free

 

[billskip]

HI ..I dont have experiance of new fridge ..but was attracted by the adverts of low power consumption,,until I read the small print ..Maybe it says somewhere that the temp in the fridge is -x whith outside temp say +25 then you use average 1.5ah..if temp outside is 35+ as is in med the fridge will never switch off..therefor
using maybe 5ah..just a thought..

 

[LeonF]

I haven't bought one yet as at around 400quid I reckon a bag of ice in the cool box at a pound a time is more economical at the moment. However an old salt (is there any other kind?) at my club has bought the very model and swears by it.Make sure you have a battery management system or some such to control your power needs though. And what's wrong with uht milk ? I can't bear gin without ice- drink warm red instead.

L.A.R.Ferguson

 

[HaraldS]

I have three separate WAECO's built in, with 40 litres each. I think they all use the same type of Danfoss compressor (type 35) and they are quite efficient. The rest is a question of the quality of the isolation and the ambient temperature. The 1.5Ah/h is and average that WAECO quotes assuming 33% duty cycle (8hrs in 24hrs), which means when they kick in they draw three times that current: 4.5A. That seems about right as mine take just over 2A at 24V.

 

[jollyjacktar]

Increase efficiency

Problems with friges is that their efficiency is most directly related to cold loss by allowing the heat in. Ergo if you can reduce the loss of coldness then you improve the efficiency. Thus open the door less often and for shortest possible periods, use a chest type of frig rather than vertical door type [coldness flows out and falls], but even better increase the insulation of the chest. Double the insulation and half the heat loss and double the efficiency, rather like double glazing or insulating your house. I have found that I can make all these improvements in an onboard installation and then I only need to run a frig for a very short period of time, once a day. And yes Olaf I can chill my rum as well.

 

[charles_reed]

WAECO are certainly not new-fangled - they've been around for at least 40 years.

Like their major rival, ASU they are both Swedish, both using the same German Danfoss unit.

Of the two, the ASU Thermoprodukter is the more economical having some rather more sophisticated software.

As regards power usage the following all affect, very considerably, your no of amps drawn.

* Size of box - mine is about 21l.
* Efficiency of insulation - I use bewteen 100 and 400mm of closed cell foam with a reflective aluminium backing.
* How full the box is - I try and keep mine as full as possible, it reduces power consumption by cutting convection rates
* Whether the box is top or side opening - top opening cuts the loss of cold air spilling out.
* External ambient temperature - the hotter it is outside the more power you use.

The ASU is technically superior to the Waeco in having a larger holding plate and a smart controller which responds to system voltage rising above 13.5v to start a supercooling cycle to take the plate down to -10C. On this setting the compressor is pulling between 5.5 and 6.3 amps.
Between 12.1-13.4v the compressor comes on without the cooling fan or high speed compressor and draws about 3.5-4.0 amps and takes the plate down to 0C.
This can be modified by changing the strength of the solution in the holding plate and patching the temperature-control software.

My unit is fitted in the old ice-box with considerable additional insulation, which is probably superior to a free-standing unit. The compressor unit is ducted and air-cooled.
You can get a variety if water-cooled units as well as a free-standing unit very similar to the WAECO range.
In an ambient temperature of 18-28C my box pulls 40ah in every 24 hours - fed by a Ampair 8amp wind generator and 1 x 85 watt solar panel.
This is sufficient to avoid running the engine to recharge 215 ah of domestic battery. Before the addition of the solar panel the wind generator produced, in a 72 hour period, the equivalent of 40 amp hours, given that the area was more windy than the S Coast of the UK.
Under power, for any length of time it will freeze tonic water and weak beer.
You can prevent this by taking it off "Auto" and controlling the temperature as though it were a normal fridge.

My original Freon 12 ASU unit was replaced by the latest version 2 years ago (I only replaced the original becaase of the fan unit packing in and the perceived difficulty of getting Freon top-ups). I think the old unit was more efficient (very subjective), but it missed some of the bells and whistles of the newer one.

If you are interested, Thermoproduktor SA have a website at www.isotherm.com.
In this you'll find a reasonably objective 3rd party comparison with the WAECO - if you want to take the matter further I'd suggest dealing direct with them, they're UK distributor was So'wester.
Tel No 0046 480 15080
Address Box 715, Kalmar, 391 27, Sweden.

I have found their after-sales support superb and their products good (in marked and dismal comparison to the UK marine industry).

 

[colin_jones]

The portable fridges work fine on the boat ( when we were fitting her out) and in the car. I do not have exact consumption figures, but the system is certainly impressive. Several buddies also have them as a means or transporting food from home, in car, to boat. Good idea for a week ender.

I have a 60 litre Waeco main fridge for which the statistics are much as for a DIY cooling kit:-

35 watt compressor at 12 volts = 2.9 amps per hour when running flat out at 20 deg C, but they only need to run for about 20% of the time even for a box up to 100 litres. (29 litres = 1 cu foot) which is about half an amp an hour as long as the insulation is up to spec.

There are many false prices floating around (£400??) The cost of the kits works aout at about £280 - £320 - depending on how good you are at shopping aropund.

 

[Guest]

I have recently purchased a Waeco Coolmatic CB36 fridge. (£340) From www.marine-super-store.co.uk. (They are a member of the ybw shopping quay.)
When I originally checked out the price on the web site it was £240 but this was obviously a mistake. They phoned and said it should be £340 which I wasn't surprised at and was fair enough. However, if you are interested in a cheap fridge then I believe this price is still wrong. I suspect that the original price of £240 had the numbers transposed and should have read £420 not just a typo with the first digit. Everywhere else seems to be charging the £420 figure!
The service was excellent with delivery next day.

 

[Guest]

If your looking for the absolute bargain of a portable fridge then look no further than LIDL (The cheapo supermarket). I'm not kidding. I got a 100litre (plenty beers!) fridge which does its job adequately, especially if you give it a kick start with an ice pack. It draws about 2 amps and cuts off if the voltage of the battery drops below a certain level, and it cost a grand total of £69. It had to re-model the boat to make it fit but, hey I'm happy.

 

[steve]

Re: Amps is Amps

Try powdered skim milk. Believe me, you won't notice the difference.