Running an Engel 57lt combi fridge, requirements

Most fridges will cut out when voltage hits a certain level, some have multiple settings, mine is set to cut fridge off at 11.3v I think.
10 to 11v will see just about any fridge cut out I am relatively sure.
Some have an emergency override so you can turn the fridge on again to keep food cold.
It is possible your cut off switch is faulty, or the fridge control electronics circuit board has gone haywire, this is common with use when 4WDn due to conditions, but especially vibrations.
I have a 100 amp hr battery and it will run my fridge (Techniice 45lt) for at least 3 days with no other input, but normally I tour daily and charge via alternator / voltage relay, and have a 100w flexi solar panel to charge if I want to stay long camp days here and here, or even a few days.
It isn't wise to let a battery discharge too much anyway, too often, it isn't good for any battery from what I have read.
Mine rarely goes down to 80%SOC the way I tour, only using the car charging.
My fridge draws between 1.45 and 1.65 or so, but older fridges are known to draw higher amps.
Often, battery voltage or faulty leads are the cause of fridges acting erratically, but reading your voltage reading above, I'd say either faulty battery or faulty fridge is the problem, not how much charge you can get into it so much.

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Hi Geoff,

If your auxiliary battery is a "90amh crank battery" then I take it that it is a battery designated as a 'Starter Battery' not a 'Deep Cycle Battery'.
A Starter Battery can be used in this duty but it it not designed to do so and will not do the job as well as a Deep Cycle Battery. It also will have a short life. It is designed to deliver high starter current for a short burst not to deliver current for lengthy periods.
A Deep Cycle Battery is designed for the purpose of lengthy periods and to be discharged down to about 50% of its rated capacity...... but NOT lower.

When you say "When I check the battery it still has charge, 10 to 11 volts." I'm afraid that you are very mistaken. A lead-acid battery is considered to be exhausted when its voltage falls to 12.0 volts. "10 to 11 volts" is grossly over-discharged and very harmful, permanently, to the battery.

If you are running your fridge at "about -5 degrees" this can be considered to be operating as a freezer and will accordingly be consuming a lot of power from the battery. It is not surprising that it is not coping. Running at 4.2 amps for 12 hours will consume 50Ah from your battery and that would be as much as you could drain from a fully charged 100Ah deep cycle battery in good condition. It is much more than your present 'cranker' can manage. You then need to be able to replace that drain promptly next morning.

You really need to obtain a Deep Cycle battery of the AGM (Absorbed Glass Mat) type of at least 100 AH (Ampere hours) and assess your charging and consumption. A blog by John (Members' John & Val) on Electricity for Camping may be of help to you in assessing your needs.

Only the very latest Engel has a low voltage cut out and you should be able to adjust it to AFAIR 10.5 or 11.5 volts.
Older fridges than this year's model will just keep on going until the battery is completely flat, and the compressor will work down to about 10 volts.
if your battery is reading between 10 and 11 volts remember that the fridge will pull down the volts when the compressor is operating and it will recover a bit when the compressor stops.
You can buy low voltage battery protectors from Engel who sell a fabulously expensive one at $75 or more, or there are lots on ebay or online sellers. I have one from ABR sidewinder.
it looks like you have killed your battery by letting it get too low.
Regards Philip A

hi
1st cranker battery . Please explain? - 90amh ?
A cranker batt eg century flooded type is rated in cold cranking amps
Eg a Century also has a RC reserve capacity
To get an "Ah" rating RC x .6 =Ah rating

In tough conditions 60lt fridge/freezer combo can draw around 60amps for a 24hr period .

At least a 100 -120 ah battery is recommended
For battery longevity max 50% discharge only

Have a LVD low volt disconnect fitted and set it at 12.0volt /50%

Remember if using solar the bigger the better
U need to replace the power as quickly as possible [allows for limited sun etc ]
At least 160w if not 200w

swamp

For the sake of battery longevity, I have always considered allowing the voltage to drop below about 12.2 volts is a BAD thing to do. Certainly I would NEVER allow any of my batteries to drop below 12 volts.

I run a 60 litre Engel off three 100a/h AGM batteries and have a pair of solar panels on the canopy roof as well as the ability to charge them via a Redarc isolator. I honestly couldn't even begin to try and tell you how long my three batteries would operate the Engel before they would drop down to (my self-appointed minimum voltage) 12.2 volts.....I've never seen my batteries drop below 12.7 volts. As soon as I park in my carport I hook-up the 240 volt cable to the truck, which takes over the running of the Engel as well as a hardwired 25 amp charger which keeps all FIVE of my truck batteries charged. I HATE flat batteries and I go to great lengths to ensure I never suffer from that problem.

Basically, what I'm trying to say is you need to either increase the size/type of battery you use or make arrangements to pump more charge into the one you already have.

Geoff, just a point for the uninitiated, you never mentioned what vehicle you own?
Some, like Toyota's FJ Cruiser and others have limited space for the larger batteries. Measure up and get advice.

I am more than happy with my Redarc BCDC charger/regulator 120W Solar and AGM Aux battery.

Back in the day it was two 120amp cranking batteries for the big diesel and a diode type isolator. Batteries were swapped over regularly but lasted about 3-4 years. Deep cycle batteries couldn't be charged by the vehicles alternator if they dropped to far. Technology has gone well past those former issues but bear in mind all batteries liked being kept topped up regularly.

Cheers

dad

Just to summarise and to bring home a few issues.
1/ 57 litres is a big fridge ....... that is a lot of capacity to cool no matter which way you slice it.
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2/ running a fridge as a freezer increases its power demand considerably ..... like 4 to 6 times the same machine would run as a fridge under the same circumstance.
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3/ an N70 90-100 is AH battery will barely support a 40 litre fridge run as a freezer reliably particularly if it is chilling down ..... overnight.
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4/ your battery may be buggered ....... if the battery is not new and you do not know how old it is, or what it has been doing, it may have nowhere near the stated capacity.
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5/ the battery may not be getting fully recharged ...... if the battery is being hammered...... and its a bit old ...... it may take 6 to 8 hours pluss to fully recharge ...... remember whatever is charging it, has to have sufficient to support the fridge AND recharge the battery
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6/ your solar panels ..... if they are running well ... will only produce their rated output .... In summer, between 11am and 3pm, with a clear sky when properly oriented and clean ....... OH and in a high solar radiation area (not victoria or tasmania)
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To sumarise the summary ........ all too often people are far too optomistic about power systems a fridges ...... like not just a bit ..... twice, 4 times or more too optomistic.
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My back of beer coaster calculations would say ...... you need 300 to 400AH of battery capacity and 240 pluss watts of well set up solar to support that fridge long term ....... if run as a freezer you will need vehicle or mains charging for reliability.

cheers

I'm no expert on the subject but learned a lot setting mine up this yr I think your going in the right direction fitting a decent sized agm battery and you already have 120w solar to help keep it topped up.
If you want to keep meat frozen safely you need the freezer to be -15 or colder to keep bacteria at bay but -5 may be ok for shorter periods of time you can do a search to see what the recommended fridge/freezer temps are to keep your food fresher and safe for longer periods. I have a Redarc bc/dc charger on mine so that takes care of charging the batteries correctly when driving and it controls the solar imput when parked up C-tec is another very popular type of charger.