Just another fridge question

Submitted: Friday, Dec 29, 2017 at 18:43
ThreadID: 136031 Views:3391 Replies:8 FollowUps:7
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Just got back from a week away and my 85ltr Waco just doesn’t seem to be coping. All trip the numbers on the fridge read 0 to -1c but the freezer just didn’t keep frozen and the fridge part was just cool at best. It’s running of two 90ah deep circle batteries and the gauge is always 12 to 12.5 wiring is good and running through an Anderson plug. The thing that really has me confused is when I’m driving the thing will freeze the whole freezer will have ice on the walls to the top with the batteries charging at 13.5 but parked over night the thing will almost defrost.
Any advice would really appreciated
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Reply By: Allan B (Sunshine Coast) - Friday, Dec 29, 2017 at 19:06

Friday, Dec 29, 2017 at 19:06
Hi Darryl,

Firstly I would question the fridge cutout (Battery Monitor) setting. This is the setting at which the fridge will shut down when the voltage (at the fridge) falls below the set value. It can normally be set at one of several levels. The "H" setting will shut the fridge down if the voltage falls below 11.8 volts. If your battery gauge can show a reading of "12v" then the voltage at the fridge may well be below 11.8v and the fridge will shut down until the voltage has risen above 12.6 volts.

While you are driving, the alternator will be maintaining the battery terminals above 12.6v and the fridge will continue to operate normally.

To be sure of the voltage being supplied to the fridge you really need to measure it with a reliable meter right at the Anderson plug while the engine is off.


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AnswerID: 615775

Reply By: Notso - Friday, Dec 29, 2017 at 19:14

Friday, Dec 29, 2017 at 19:14
As above. The fan will keep running so you'll think the compressor is too. Also if your 2 deep cycle batteries are only at 12 volts, they are in a fairly low state of charge so I'd be looking at your charging system as well.
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Follow Up By: Athol W1 - Friday, Dec 29, 2017 at 21:50

Friday, Dec 29, 2017 at 21:50
As per Notso, but also make sure that the compressor is running when checking the voltage by back probing the fridge side of the Anderson plug, or even better is where the wiring enters the fridge (a couple of pins pushed into the wire and measure the voltage across the pins). Also run the voltage cut out on LOW.

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Reply By: HKB Electronics - Saturday, Dec 30, 2017 at 12:23

Saturday, Dec 30, 2017 at 12:23
First off is it a compressor fridge?

If the fridge is directly connected to the deep cycle batteries and it runs ok when the cars running then it would appear you have an issue with your deep cycle batteries, the charging system, or a voltage drop as suggested above. Also the charge voltage of 13.5V is low, it would be worth checking why, could be your charging them directly off a low voltage alternator or car has an smart charge setup, could also be a DCDC charger in float charge mode or the batteries are deeply discharged?

The temperature readings your getting, where are you reading them from, I don't understand how the fridge can only be cool if the temperature is 0-1 Celsius are you measuring it with a thermometer?

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Follow Up By: RMD - Saturday, Dec 30, 2017 at 15:47

Saturday, Dec 30, 2017 at 15:47
The charge voltage of 13.5 is not just low, it is too low to charge the batteries and just enough to run a fridge anyway. Until the batteries are being charged at at least 14.4v the situation won't improve and probably will get worse due to stuffed batteries and still NO overnight reserve capacity in those batteries.
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Follow Up By: Alloy c/t - Saturday, Dec 30, 2017 at 19:20

Saturday, Dec 30, 2017 at 19:20
Why comment if you don't know the product ? Your first statement says it all 'is it a compressor fridge ?' ...... Waco do not make a fridge in 85lt that is NOT a compressor fridge .......
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Follow Up By: HKB Electronics - Saturday, Dec 30, 2017 at 21:07

Saturday, Dec 30, 2017 at 21:07
The symptoms cause and affect does not need to be model specific, the type of system though compressor or absorption does need to be considered as I like many others and unlike you apparently do not keep abreast of every model of fridge available on the Australian market so to save time I asked the question absorption or compressor and provide some information that might be useful for the OP which is more than what you have done!

PS Dometic/Waeco do make an 85ltr absorption fridge but it appears it is not available in Australia.

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Reply By: swampy - Saturday, Dec 30, 2017 at 14:10

Saturday, Dec 30, 2017 at 14:10
Compressor fridge ?

Any way , check volt with multimeter at fridge in the first up in the morning .
As mentioned earlier ,does the onboard low volt cut out have a delay [the better LV cutouts do ].
If the cut out is an issue get a Projecta LV cut out [has a delay ] .
Set the onboard unit set at 10.5 v [renders it ineffective basically]

Carrying out these simple checks will get u in the right direction .
AnswerID: 615786

Reply By: The Bantam - Sunday, Dec 31, 2017 at 11:55

Sunday, Dec 31, 2017 at 11:55
This is an ongoing ever repeating issue with caravans and others that travel with fridges.

Lets have a bit of a reality check.

As soon as you say the word "FREEZER" you are talking about a high demand device.
Nothing you can do will change that.

AND if your housekeeping and other management are absolutely top shelf, you will increase the demand of your fridge/freezer considerably. ..... the fridge motor may well running CONtinuously.

Forget any average demand figures the manufacturers publish, they are always very optomistic.

Unless you ABSOLUTELY MUST have a freezzer ... don't ..... if the unit will run as 100% fridge do so. it will reduce your demand considerably.

THEN we get to battery charging ...... people WILL NOT face up to the facts ..... batteries take a significant time to charge ...... the older they get and the harder their life has been the slower they charge.

Unless you have a full days drive ..... I mean 8 hours pluss drive time, you have no hope of fully recharging a deeply cycled battery in a day .... no matter the charge voltage, the available charge current or the charge device or the size of the battery ........ regardless of how you measure "fully charged".

Time and time again, people are running fridges that are TOO BIG, off batteries that are too small, with insufficient recharge capacity and insufficient charge time.

AND ... AND ... if you say the word "FREEZER" it all gets 4 to 6 times worse all round.

A couple of real world examples.

I have a couple of 30ish litre Waecos

If I run one as a fridge and the other as a freezer ...... and this is 2 day prechilled with minimial opening ...... in summer the freezer is flat out lasting over night in summer off a 90 AH battery ....... the fridge 2 maybee 3 days easy.

I have at least a dozen battery chargers here from 1 amp to 30 amps and charge a variety of batteries from 4 to 200AH regularly.

how long a battery takes to charge depends on the condition of the battery and the depth of charge.

I Have had neglected/ abused batteries take 2 and 3 days to charge sufficient for the multistage chargers to drop back to trickle ....... the same battery in good health on the same charger may take 6 to 8 hours to come back form 1/2 charged.

I am currently running my portable fridges in the house as freezers, because the house freezer in on the fritz and the parts won't be available till everybody crawls out from under their Christmass rock.

Adding a quantity of unfrozen ice packs to one of them and it takes 3 to 4 hours to return to -15. .... this is running on mains

the message is all of this takes time and a lot more energy than most people want to believe ...... a big portable fridge is not necessarily a good idea.

AND portable Freezer is not as easy as many people think

AnswerID: 615831

Follow Up By: Member - Racey - Monday, Jan 01, 2018 at 09:52

Monday, Jan 01, 2018 at 09:52
Spot on Bantam
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Follow Up By: Member - McLaren3030 - Monday, Jan 01, 2018 at 13:26

Monday, Jan 01, 2018 at 13:26
Well put Bantam. My Caravan has a 170 Ltr. Dometic Fridge & Combination Freezer. I run 2 x 160 Amph batteries, with 2 x 200 Watt roof mounted Solar Panels. To date, (touch wood) I have not experienced any problems with either the Freezer or Fridge, even sitting stationary for 6 days in 35+ degree heat.


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Reply By: Member - shano s - Monday, Jan 01, 2018 at 18:06

Monday, Jan 01, 2018 at 18:06
definately got thermo probs.
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Reply By: Von Helga - Thursday, Jan 11, 2018 at 10:02

Thursday, Jan 11, 2018 at 10:02
Similar problem with a Nat Luna Fridge Freezer.
On checking specs I found that they run harder when the temp is set above -9 Deg C.

Appreciate that -18 Deg C would be best but apart from ice cream everything else remains Frozen at -9 Deg C.

So I have decided to work the batteries a little less harder and use the freezer at -9 Deg C particularly when solar production is marginal. oh and add ice-cream to the diet when we are in a CP.

All the other advice here would be relevant also.
AnswerID: 616020

Follow Up By: Allan B (Sunshine Coast) - Thursday, Jan 11, 2018 at 10:08

Thursday, Jan 11, 2018 at 10:08
I think you mean.... "they run harder when the temp is set BELOW -9 Deg".

"-18 Deg C" is BELOW "-9 Deg C" on the temperature scale.


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Reply By: Von Helga - Thursday, Jan 11, 2018 at 10:13

Thursday, Jan 11, 2018 at 10:13
Of course Allan
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