Fridge is running down my battery

Submitted: Friday, Feb 27, 2015 at 20:02
ThreadID: 111261 Views:4506 Replies:8 FollowUps:8
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Hi all,

My problem is I am by no means a sparky so I think I may have done something wrong. What I have set up is in the back of the ute in a canopy, I run a primus mammoth 65 litre fridge. The issue is that parked at work, in full sun, the fridge draws the battery down so low that it shows ERR1 which the tech tell me means is generally consistent with lack of power to support the fridge.

As it is running on the back of a ute it is running in hotter conditions than if it were running elsewhere, therefore I assume it will use considerably more power in this application. It also runs out of power when I park it in the open at 2pm and return to it at midnight, the tech says that running out of power during the night tells him I may also have a power supply problem to the fridge.

Can I check the math and set up with this knowledgeable group before I spend a lot of money I don't have.

Specs are: average current draw for the fridge 4.6 A power input 55W, compressor is a SECOP BD50F. Fridge is set to cut out at 10.2 volts. Average Consumption: 0.89A/h
The battery is a 130 aH AGM which is fully charged each night using a Microprocessor controlled battery charger. When driving the battery is maintained by the redarc BCDC125-LV in car charger which is located in the back of the ute also. Twin core 8 B&S cable is run back to the battery/alternator under the hood in accordance with the wiring diagram and 6 B&S from the battery to the merit plug (<2metres) the fridge connect to that by the 2 metre long cord.

Assuming hot conditions in the back of the ute what would the effect be on the aH usage with the fridge shutting down at 10.2 Volts.

Any help would be appreciated.
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Reply By: noggins - Friday, Feb 27, 2015 at 20:17

Friday, Feb 27, 2015 at 20:17
As for the reason why your fridge is running the battery flat I couldn't even guess
What temp do you have it set at ?
Remember the further below zero you set it the more power it uses.
The hotter in the tub the harder it has to work.
( best temp for a Really Chilled Beer is -2 , soft drink that has no alcohol content +2 or slightly above, will stop it from exploding / freezing )

As an aside on fridges in the back of the ute ,
I bought one of those solar fridge fans and pop riveted it to the 140W solar one on the canopy roof , ran the lead down into the canopy and attached the fan to where the air is drawn into the fridge giving it a slightly forced air flow over the condenser coils of the "Chinese Fridge" I often use as a freezer.

I did the same with my 35 ltr Engel that lived in the canopy of the ute before I changed it to inside the cabin, The result was certainly a drop in used power but as I had no way of measuring the actual figures I cant give the data here.

AnswerID: 546689

Reply By: HKB Electronics - Friday, Feb 27, 2015 at 20:21

Friday, Feb 27, 2015 at 20:21
Are you sure your figures are correct, less than 1A average consumption is
very low for a fridge that size?

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AnswerID: 546690

Follow Up By: Neil.w59 - Friday, Feb 27, 2015 at 20:23

Friday, Feb 27, 2015 at 20:23
that is the quoted figure... but I am also having doubts. Assuming a fully charged battery for it to be brought down to 10.2 volts what sort of draw is that suggesting?
FollowupID: 834467

Reply By: Les - PK Ranger - Friday, Feb 27, 2015 at 21:26

Friday, Feb 27, 2015 at 21:26
Yes, I would have thought you'd be drawing closer to just under 2 amps with that size.
That said, there is an issue for sure.

Assuming the battery is ok, it should run the fridge for days, my 100 amp hr AGM runs my 45lt for at least 3 days (haven't had to try it beyond that), goes down to about 30% battery charge according to the Arkpak gauge.
But I rarely don't get it to charge fully each day while driving / touring.

When you open the canopy rear door when it's hot weather, is it obviously VERY hot in there ?
If so, you probably need to try keeping it cooler.
- Add a whirly vent, auto type . . . or, not sure a battery operated exhaust fan is a good idea (may add to the issues), but possibly a solar powered one.
- Solar film the windows with a dark even slightly reflective tint (good for security from prying eyes too.

Other than that, can you add a solar panel or two to the roof and take advantage of the sun to support the battery a bit ?
If you have panel(s) on top on a frame on a roof rack, it will also shade the canopy.

AnswerID: 546693

Reply By: Crusier 91 - Friday, Feb 27, 2015 at 22:14

Friday, Feb 27, 2015 at 22:14
set up in the rear should a better option than under the hood, less heat.
From what you have mentioned, my guess is your battery is on the way out. You should be smelling rotten egg gas from your battery very soon.
AnswerID: 546696

Follow Up By: oldtrack123 - Friday, Feb 27, 2015 at 23:10

Friday, Feb 27, 2015 at 23:10
The fridge could well be running continuously drawing 4.6A with high ambient temps in the canopy
To make matters worse pulling the battery down to 10.v is dead flat & I would suspect your battery has already sufferred permanent loss of capacity[no longer anything like 130Ahr]
It may fully charge by the charger ,but that only means it has been fully chargedito whatever capacity it still has[130Ahrs down ???Ahrs
I suggest you:
Find a means of encreasing the air flow through the
canopy so it does not rise much above 40C inside

Set the low voltage cut out in the fridge to Max voltage or get a low voltage cut out fitted @the battery ,that cuts out around 12V.

Improve the air flow over the fridge condensor.[external fan/s]

If possible ,encrease the insulation of the fridge ,including the lid but do not restrict ANY air vents.[ the more insulation the less the compressor has to work]

Then either get your battery CAPACITY checked or buy a new one


FollowupID: 834477

Reply By: Batt's - Saturday, Feb 28, 2015 at 03:12

Saturday, Feb 28, 2015 at 03:12
I've been researching solar exhaust fans lately to fit to the roof of my alloy canopy and will also be adding a vent somewhere down low to help draw in cooler air.
AnswerID: 546705

Follow Up By: Neil.w59 - Saturday, Feb 28, 2015 at 10:08

Saturday, Feb 28, 2015 at 10:08
thanks all for this information. The ute canopy windows are all tinted and I fitted two computer fans to the front sliding windows which draw bugger all.

First step is to check the battery then,
follow that with check the wiring ,
finally look at fitting a solar panel to assist.

I am interested in those exhaust solar fans you are looking at reviews I have heard haven;t been too good.

FollowupID: 834479

Follow Up By: Batt's - Saturday, Feb 28, 2015 at 15:02

Saturday, Feb 28, 2015 at 15:02
I've been looking at these types there's a lot of different brands to choose from
FollowupID: 834492

Reply By: get outmore - Saturday, Feb 28, 2015 at 10:13

Saturday, Feb 28, 2015 at 10:13
is the battery stuffed? maybe get it load tested
AnswerID: 546712

Reply By: River Swaggie - Saturday, Feb 28, 2015 at 12:29

Saturday, Feb 28, 2015 at 12:29

You didn't mention if you have anything in the fridge, if it's empty it will go through the amps, food, liquids actually keeps and maintains the cold...

Ive had my Evakool Rf 60 litre under a black tarp on a Ute in 40 odd degree day and it froze stuff on number 5 and it goes to 10, you sure it's not an insulation issue or the unit has enough gas....

I'd change the merit plug to a 50 amp Anderson...

Could be the battery....

AnswerID: 546723

Follow Up By: Neil.w59 - Saturday, Feb 28, 2015 at 12:46

Saturday, Feb 28, 2015 at 12:46
thanks, I had considered that. I have a shorter lead which has a cigarette plug on it so might convert that to an Anderson plug.

As for the fridge the freezer section is full of ice bricks and the fridge is half full at the moment but have the same problems when it is full.

The fridge is still under warranty but I want to check the issue isn't of my making first.
FollowupID: 834484

Follow Up By: River Swaggie - Saturday, Feb 28, 2015 at 18:09

Saturday, Feb 28, 2015 at 18:09
You could always try one of these to keep an eye on things...

Volt meter, amps etc..
FollowupID: 834512

Follow Up By: Neil.w59 - Saturday, Feb 28, 2015 at 18:15

Saturday, Feb 28, 2015 at 18:15
will think about that. Especially if I have to buy a new battery.
FollowupID: 834513

Follow Up By: Zippo - Sunday, Mar 01, 2015 at 16:54

Sunday, Mar 01, 2015 at 16:54
Swaggie, the cables on that meter don't look heavy enough for their quoted 50A continuous rating. May not affect the O/P and his case, but may indeed be an issue for others depending on their application.
FollowupID: 834575

Reply By: nickb - Sunday, Mar 01, 2015 at 15:31

Sunday, Mar 01, 2015 at 15:31
Even if the fridge worked at max power for 8hrs it would only used about 50A so your battery should supply that easy if it is good condition and fully charged.

What charger are you using at home? To fully charge a 120Ahr battery from flat would take a long time.

As others have said running the battery to 10.2v is no good. Lowest voltage should be around 12.0V for max battery life. I also agree that the battery may be cactus.
AnswerID: 546776

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