Is 150 OEM wiring OK for running a fridge?

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

I will echo amts post

from experience I would advise against using the starting battery to run anything while the car is not running.
Starting batteries are just not designed to do this.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

Sweetpea,

That sounds very inefficient. You are converting 12V to 240V to convert it back to 12V, when if you left it at 12V it would ruin the fridge.

The 240V socket in the back of the Prado has a 12V inverter behind it to convert the 12V from the alternator to 240V and a max of 100watts.

You would be better just plugging it into the 12V socket.

Regards

Aidan

Yes, there are inefficiencies doing it that way but the extra heat that it generates is insignificant.

There are two processes I am trying to maximize efficiency;

1. Keep the fridge and freezer working efficiently. That is; keep the correct temperature.

2. Maximize the charge going into the aux battery under the bonnet when the engine is running.

Everything thing else is way down the ladder of concerns.

1. I get regulated 12V when driving regardless what else is drawing current so the fridge keeps working.

2. The way it is installed means that when the alternator is providing output the highest voltage I can produce is across the aux battery thereby maximizing the charge. If I run the fridge off the aux battery whilst it is being charged it will reduce the volts across the battery and reduce the charge. It automatically switched to the fully charged aux battery when the engine is off.

Hence I meet my two main efficiency criteria.

I know I should spend $1300 or $1400 and buy a flash Engel or Waeco 60 lt fridge/freeze and wire it up as suggested but my $360 fridge and simple power supply has been over 20,000K of harsh and corrugated outback roads from Melbourne to Darwin and roundabout in the middle and it has not let me down.

I try and keep it simple and light. My Prado only has 3 doors and my camper fully loaded is less than 1000 kg.

YMMV.

S.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

I will echo amts post

from experience I would advise against using the starting battery to run anything while the car is not running.
Starting batteries are just not designed to do this.

What he said and what AMTS posted.

A standard 150 with its low system voltage is lucky to maintain 50% State of Charge on a good day. It is great for battery longevity and if you don't flatten it some other way is likely to be able to start the engine under computer control. If pushing the button doesn't start the engine you just call a flat top.

You don't have a huge margin of charge to start with so it is not too hard to forget the fridge overnight when it averages 3 amps for ten hours and your left with not enough charge.

And as AMTS says, deep discharge will decrease the life of the battery.

If you don't want to go the full dual battery you could consider getting one of the portable battery packs of the appropriate size for the fridge.

S.

[MYT150 Member Find all posts View Profile Close MYT150]

Yes, there are inefficiencies doing it that way but the extra heat that it generates is insignificant.

There are two processes I am trying to maximize efficiency;

1. Keep the fridge and freezer working efficiently. That is; keep the correct temperature.

2. Maximize the charge going into the aux battery under the bonnet when the engine is running.

Everything thing else is way down the ladder of concerns.

1. I get regulated 12V when driving regardless what else is drawing current so the fridge keeps working.

2. The way it is installed means that when the alternator is providing output the highest voltage I can produce is across the aux battery thereby maximizing the charge. If I run the fridge off the aux battery whilst it is being charged it will reduce the volts across the battery and reduce the charge. It automatically switched to the fully charged aux battery when the engine is off.

Hence I meet my two main efficiency criteria.

I know I should spend $1300 or $1400 and buy a flash Engel or Waeco 60 lt fridge/freeze and wire it up as suggested but my $360 fridge and simple power supply has been over 20,000K of harsh and corrugated outback roads from Melbourne to Darwin and roundabout in the middle and it has not let me down.

I try and keep it simple and light. My Prado only has 3 doors and my camper fully loaded is less than 1000 kg.

YMMV.

S.

You could do the same thing on 12v by having a relay, or two, that are activated/deactivated by the ignition to switch to the main battery with ignition and when the ignition is off take it from the second battery all going to the same socket.

Just a suggestion.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

You could do the same thing on 12v by having a relay, or two, that are activated/deactivated by the ignition to switch to the main battery with ignition and when the ignition is off take it from the second battery all going to the same socket.

Just a suggestion.

Yes, of course I could but that would mean another heavy run of wire from the main battery to the fridge.

As there was already a 240V socket right next to the fridge it saved me all that trouble and cost.

The 240v to 12v power supply was already there for power camping spots.

It works and comfortably meets all of my criteria for reliably keeping stuff frozen or cold.

I am not sure why so many are trying to convince me to do it a different way that is more complex, more expensive and offers no gain whatsoever.

I drive a highly unmodified 3 door SX so I already have a complex but at least I hitch the camper on and see a lot of this wondrous land.

And I keep saying YMMV.

S.

[150gxl Member Find all posts View Profile Close 150gxl]

Thanks to all who replied. The NOs' have it.

150GXL, your solution seems a good option. I will be towing a van so the 12v in the boot and Anderson plug would be the go.


Is your second battery in the engine bay? and what type of battery did you go for?

thanks,

Puddock.

Hi Puddock,

We used a Supercharge Allrounder MRV70, on the advice of the installers, saying good "bang for buck" with these.
Confirming also that the heavy wiring was used for the 12v plug in the boot, looped up from the Anderson plug.

Our fridge at the time was a Waeco 60l unit but now that our van has an outside fridge and inside fridge, we went down to
A 40l unit. (Gave the 60 to the kids and it's still going strong at 10yrs old).

EDIT Yes, the second battery is in the engine bay where the EuroSpec cars have it standard.
The redarc sits just behind the original battery.

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

Yes, of course I could but that would mean another heavy run of wire from the main battery to the fridge.

As there was already a 240V socket right next to the fridge it saved me all that trouble and cost.

The 240v to 12v power supply was already there for power camping spots.

It works and comfortably meets all of my criteria for reliably keeping stuff frozen or cold.

I am not sure why so many are trying to convince me to do it a different way that is more complex, more expensive and offers no gain whatsoever.

I drive a highly unmodified 3 door SX so I already have a complex but at least I hitch the camper on and see a lot of this wondrous land.

And I keep saying YMMV.

S.

I used to do the exact same thing run the fridge in the back off a 240V -12V power supply and never had a problem.
When we arrived at our campsite i would take the fridge out and run it from the caravan battery / solar system.
This suited the way we were camping staying in one place from 3 days upto a week or more.
now we tend to only stay 1 -2 days and move on and see more of OZ.
This is when i decided dual battery and leave the fridge in the car was the better option for me.
I can run the Fridge as a freezer for 3 days without starting the car.
As what you are doing works for you and worked for me previously, stay with what you have.

[Puddock Junior Member Find all posts View Profile Close Puddock]

I asked the original question so...

Just came back from 3 weeks / 2000 klms around New England area. FWIW I had no time to do anything wiring wise with the new Prado before we left.

I chilled our full 50 CFX to -18c before we left and plugged into the rear seat 12v outlet while we were on the move and 240 v when we stopped. Zero problems. Came home with food still frozen.

[Guest Close Guest]

You drove 2000km and didn't eat any of the food?

Given your scenario, the starting temp of the fridge would have kept things properly frozen if the fridge wasn't opened and new items thrown in at ambient temp; and even if the low voltage cutout was activated for a little while.

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

Just came back from 3 weeks / 2000 klms around New England area. .

3 weeks to do 2000K do you drive slow or was it all offroad?

[InnerCityBoy Junior Member Find all posts View Profile Close InnerCityBoy]

I used to do the exact same thing run the fridge in the back off a 240V -12V power supply and never had a problem ...
now we tend to only stay 1 -2 days and move on and see more of OZ.
This is when i decided dual battery and leave the fridge in the car was the better option for me.

Am on the same journey as you Fred63. I still run the fridge off the inverter (or 12V from the middle console) when driving to allow the dual battery to fully charge ... then plug the fridge in to the second battery in the car when I stop overnight ... or to the trailer battery if stopping longer. That said my small Engel only draws between 1.5 and 3 amps, I might be more reluctant to run a larger fridge through the built-in wiring.

[Benny's Tuff* 150 Lurker Find all posts View Profile Close Benny's Tuff* 150]

I intend on buying a new 80L Engel at Easter whilst in Brisbane. Then drive home to the country (22hrs) and setup a DBS for my first trip out of home in July (as I won't have time before I go). Anyone know if I could run the Engel through the 12V-220V socket in rear just for the trip home only? I would consider prechilling it before I let Brisbane. From memory, it only draws 4.2A and I believe it still has original main battery.

Thoughts?
Ben

[InnerCityBoy Junior Member Find all posts View Profile Close InnerCityBoy]

Anyone know if I could run the Engel through the 12V-220V socket in rear just for the trip home only? I would consider prechilling it before I let Brisbane. From memory, it only draws 4.2A and I believe it still has original main battery.

I've run my Engel (draws 2.8-3.0 amps) through both the factory 12V socket in the centre console and the 100W factory inverter in the back on several camping trips with no issue. Haven't run it off the starter battery overnight though, if that's what you're asking. Hope that helps.

[nanbar Senior Member Find all posts View Profile Close nanbar]

I asked the original question so...

Just came back from 3 weeks / 2000 klms around New England area. FWIW I had no time to do anything wiring wise with the new Prado before we left.

I chilled our full 50 CFX to -18c before we left and plugged into the rear seat 12v outlet while we were on the move and 240 v when we stopped. Zero problems. Came home with food still frozen.

Isnt the 240v outlet off when ignition off when your stopped? Do you leave the accessories on overnight to run jt?

[Guest Close Guest]

Isnt the 240v outlet off when ignition off when your stopped? Do you leave the accessories on overnight to run jt?

I think by 240V, he meant at a campsite or some other lodging place that had a socket.