ARB Fridge power requirements, here's the numbers for you!

[flyinhawaiian01]

I've been meaning to do some quick tests to show what the actual requirements for an ARB fridge is when installed in a vehicle, finally found a few minutes to snap some photos and show what is required by these units.

Okay, here we go...

This is my ARB fridge and my test equipment, an Alinco power supply with ammeter:

This unit has been extremely reliable and accurate when comparing it to various equipment that I run off of it, mostly ham radio stuff and some R/C equipment.

For this test, I set the fridge to 0ºF, as you can see, it was at 27ºF for the test, so the unit was forced to turn the compressor on. Here's the full load:

Here's the voltage at specified load, ~13.0VDC:

Now, to simulate a lower voltage with a load on it, I've set it to 12VDC:

At 12.1VDC (or as close as I could get it), here's your current draw:

Now, it will run as much as it feels it needs to run, but once it hits the target temp, it will shut down completely, and drain is at 0 amps, basically just enough to keep the led display on and run its thermometer circuit.

These units will cycle on and off according to several things; ambient temp, amount of items placed in unit, target temp set for items and the amount of times the unit is opened. It is impossible to give a "one number covers all" prediction due to these variables, but with a general idea of current draw of no more than 6 amps and having it turn on for 10 minutes per hour for cooling, you're pulling ~1Ah from your battery!

Of course, a stock battery will not provide as much long-term current as a deep cycle AGM battery, as it is not built for deep cycles of charge-drain-charge-drain! This is why its recommended to upgrade the battery if you use an ARB fridge with the engine off for long periods of time. Its also why people see their stock batteries are dead after a few months of this type of current drain.

I've already run mine in my vehicle over a period of 4 days without starting the vehicle once. The fridge ran for 3 full days without issue, and the fourth day I noticed the warning light came on, meaning that the battery's voltage dropped below the threshold (which was set to "NED" which is medium setting for the ARB units). I then started the 4runner with no issues, and it did not require a jump start or battery charger to do so. It didn't even seem weak when it started, and because of this (and the fact that I have a jump pack with me at all times, especially if I'm going camping or wheeling), I've set the unit to the LOW setting, meaning that it can run the battery down even lower than before! Of course, I do have an Odyssey battery in my 4runner, as well as all my other vehicles, so I can run this in any of them without worrying too much about a dead battery.

So, there you have it! a MAX of 6 amps when its physically running the compressor at a minimum 12 volts, that really isn't much power consumption at all, especially when you realize that it doesn't constantly run 24/7!

My suggestions? Keep your AGM batteries topped off with a battery tender made for AGM batteries, especially if you're heading out for a long camping week or wheelin' trip.

Pack the ARB well and make sure to have it full, you'll have less fluctuation in temps if you have it fully packed, as the stuff in there will keep the temps level and regulated.

Don't keep opening the fridge! Leave it shut as much as possible to keep the cold air in!

Stop thinking that 2 AGM batteries and a full-on multi-battery charging circuit is necessary to run an ARB fridge! Unless you're in the desert for 2 or 3 days without ever starting your vehicle, and you head out there with no way to get a jump start from another vehicle or a jump pack, you'll be just fine with one good AGM battery and the stock charging system of the 4 runner!

Hard wire your 12VDC plug for the ARB directly to the battery using good 8AWG wiring at the very least. The smaller the wire gauge, as well as the longer the run, the more resistance the line will have, which equals more current required at the fridge, and that means you'll have more current used than necessary. Good wiring will almost eliminate this issue, so do it right and not worry about it!

:thumb:

 

[Jono.ful]

I'm always surprised these things have as little current draw as they do. 8awg would be a little overkill, as it is rated to 40 amps. since volt drop over a 20' or so run is going to be negligible, 10 or even 12 gauge would suffice, but there is nothing wrong with running 8. you're just going to spend more than you need to.

 

[flyinhawaiian01]

Well, yes and no, actually. For 20+ feet @ 20A, you should run an 8AWG wire if you want to be at 3% or less in voltage drop. I say 20A because that is what an absolute maximum draw on a cig plug would be at (such as this type of cig jack HERE). While you may only use your plug in the back for your fridge, if you ever sell the vehicle, or if you ever let someone use your vehicle, and they plug something in that draws more than just the 6A required by your fridge, it would not be ideal for a 12AWG wire.

You could get away with 10AWG, but its almost the same price to just go 8AWG wire, and its easier to just find the right fuse holder that accepts 8AWG nice and tight.

I use this chart for double-checking load limits on wire every now and then, it helps to see a quick chart to confirm numbers when wiring up stuff in the vehicle.

So, while you're absolutely correct at 6-10A, 12AWG would be just fine, if you ever plan to do anything more with it, best to just get the 8AWG wiring kits available with the fuse and connectors.

 

[rigtec]

"...Well, yes and no, actually. For 20+ feet @ 20A, you should run an 8AWG wire if you want to be at 3% or less in voltage drop...'

Hi flyinhawaiian01,

I am very impressed with how your theoretical skills and passion to write and pass some of this insight on to others is developing exponentially! Good job! Rgds,

rigtec, cheers

 

[Jono.ful]

Well, yes and no, actually. For 20+ feet @ 20A, you should run an 8AWG wire if you want to be at 3% or less in voltage drop. I say 20A because that is what an absolute maximum draw on a cig plug would be at (such as this type of cig jack HERE). While you may only use your plug in the back for your fridge, if you ever sell the vehicle, or if you ever let someone use your vehicle, and they plug something in that draws more than just the 6A required by your fridge, it would not be ideal for a 12AWG wire.

You could get away with 10AWG, but its almost the same price to just go 8AWG wire, and its easier to just find the right fuse holder that accepts 8AWG nice and tight.

I use this chart for double-checking load limits on wire every now and then, it helps to see a quick chart to confirm numbers when wiring up stuff in the

So, while you're absolutely correct at 6-10A, 12AWG would be just fine, if you ever plan to do anything more with it, best to just get the 8AWG wiring kits available with the fuse and connectors.

yep, and 3" anti ballistic tank armor is a heluva lot stronger to use for skid plates as well. don't use a 40lb sledge hammer where a 16 oz hammer will do the job. as an electrician, I'm generally not in the habit of wiring things for "what if". you build things for the intended purpose - and to applicable code requirements (for voltage drop we're allowed 5%, not just 3%) - because no one is ever going to plug a 500hp motor into your average 15A household plug.

I can't speak to specifics in the american electrical code, but table 2 in the CEC is a much better resource for checking wire ampacity that your bluesea chart

 

[LawnDart]

Thanks, this makes me feel better about my decision to go with an Odyssey 31M battery only, for my fridge needs. My fridge will be turned off when not being used while in town, and generally when offroad we're not stuck at a campsite for more than a day.

 

[flyinhawaiian01]

yep, and 3" anti ballistic tank armor is a heluva lot stronger to use for skid plates as well. don't use a 40lb sledge hammer where a 16 oz hammer will do the job. as an electrician, I'm generally not in the habit of wiring things for "what if". you build things for the intended purpose - and to applicable code requirements (for voltage drop we're allowed 5%, not just 3%) - because no one is ever going to plug a 500hp motor into your average 15A household plug.

I can't speak to specifics in the american electrical code, but table 2 in the CEC is a much better resource for checking wire ampacity that your bluesea chart

Well, since you're an electrician, you should know that larger cables are required for dc loads, vs. an ac load. This is pretty basic electrical theory here.

As for your Canadian electrical code, that's based on ac, not dc loads. The marine chart I posted is standard specs for dc loads, and given that you should always overbuild rather than underbuild things, especially electrical, the chart is quite perfect for this scenario.

Again, yes, you can use 12AWG if you like, it would power the 6A load just fine at 20 feet. However, I would rather have a little larger wire to make sure that there are no issues if I plug something in that's a bit more, say a small air compressor or inverter!

Having said that, let's try something here...

Go ahead and calculate a 5% loss in voltage drop at 12.1V, which is standard resting voltage of an automotive battery. What does your voltage drop to at the plug? Yep, 11.5V, which is too low to power the ARB properly, and results in the unit shutting down because its not seeing enough voltage. If you turn it to the LO setting for voltage sensing, you can get it to power up, but your current now shoots up to almost 8A, and that will just deplete the battery that much faster.

So, at a 3% voltage drop with 8AWG wire, at 12.1V, your supply is at ~11.9V, which means less current draw and a more stable voltage at the fridge.

Electrical is not something I skimp on, or do the absolute minimum. We can argue this all day long, but the fact remains, slightly larger cables, while not absolutely necessary, are not worth the couple of dollars saved by cheapin' out.

 

[Antman]

Well, since you're an electrician, you should know that larger cables are required for dc loads, vs. an ac load. This is pretty basic electrical theory here.

As for your Canadian electrical code, that's based on ac, not dc loads. The marine chart I posted is standard specs for dc loads, and given that you should always overbuild rather than underbuild things, especially electrical, the chart is quite perfect for this scenario.

Again, yes, you can use 12AWG if you like, it would power the 6A load just fine at 20 feet. However, I would rather have a little larger wire to make sure that there are no issues if I plug something in that's a bit more, say a small air compressor or inverter!

Having said that, let's try something here...

Go ahead and calculate a 5% loss in voltage drop at 12.1V, which is standard resting voltage of an automotive battery. What does your voltage drop to at the plug? Yep, 11.5V, which is too low to power the ARB properly, and results in the unit shutting down because its not seeing enough voltage. If you turn it to the LO setting for voltage sensing, you can get it to power up, but your current now shoots up to almost 8A, and that will just deplete the battery that much faster.

So, at a 3% voltage drop with 8AWG wire, at 12.1V, your supply is at ~11.9V, which means less current draw and a more stable voltage at the fridge.

Electrical is not something I skimp on, or do the absolute minimum. We can argue this all day long, but the fact remains, slightly larger cables, while not absolutely necessary, are not worth the couple of dollars saved by cheapin' out.

^^^^Yup.

 

[Jono.ful]

Well, since you're an electrician, you should know that larger cables are required for dc loads, vs. an ac load. This is pretty basic electrical theory here.

As for your Canadian electrical code, that's based on ac, not dc loads. The marine chart I posted is standard specs for dc loads, and given that you should always overbuild rather than underbuild things, especially electrical, the chart is quite perfect for this scenario.

Again, yes, you can use 12AWG if you like, it would power the 6A load just fine at 20 feet. However, I would rather have a little larger wire to make sure that there are no issues if I plug something in that's a bit more, say a small air compressor or inverter!

Having said that, let's try something here...

Go ahead and calculate a 5% loss in voltage drop at 12.1V, which is standard resting voltage of an automotive battery. What does your voltage drop to at the plug? Yep, 11.5V, which is too low to power the ARB properly, and results in the unit shutting down because its not seeing enough voltage. If you turn it to the LO setting for voltage sensing, you can get it to power up, but your current now shoots up to almost 8A, and that will just deplete the battery that much faster.

So, at a 3% voltage drop with 8AWG wire, at 12.1V, your supply is at ~11.9V, which means less current draw and a more stable voltage at the fridge.

Electrical is not something I skimp on, or do the absolute minimum. We can argue this all day long, but the fact remains, slightly larger cables, while not absolutely necessary, are not worth the couple of dollars saved by cheapin' out.

You raise good points, I'm not disputing that. And you are certainly right, DC loads require different calculations for some equipment in some circumstances. Do me a favour though, go out and pull the 12v in the back of your truck and tell me what gauge wire is run to it. Betcha your truck it's not 8awg, and it runs your fridge just fine. Under certain circumstances, yes that arb unit can pull more than 6 amps, and if you want to build your rig for absolutely every eventuality, that's your prerogative. In the long run, you absolutely will spend more than you need to to accomplish the job. And yes, that amount will likely be tens or maybe hundreds, but not likely thousands. This is just an academic discussion. You can build your truck how you see fit, and I will do the same :hatsoff:

 

[tigger]

You raise good points, I'm not disputing that. And you are certainly right, DC loads require different calculations for some equipment in some circumstances. Do me a favour though, go out and pull the 12v in the back of your truck and tell me what gauge wire is run to it. Betcha your truck it's not 8awg, and it runs your fridge just fine. Under certain circumstances, yes that arb unit can pull more than 6 amps, and if you want to build your rig for absolutely every eventuality, that's your prerogative. In the long run, you absolutely will spend more than you need to to accomplish the job. And yes, that amount will likely be tens or maybe hundreds, but not likely thousands. This is just an academic discussion. You can build your truck how you see fit, and I will do the same :hatsoff:

Actually it won't power the fridge effectively as several members have run into. Toyota never intended for portable fridges to be ran from that port. I believe the gauge is 16 and it insufficient to run a larger fridge at full capacity. One member couldn't even get his to cool below 45 degrees with the stock wiring. Once he upgraded to 8 gauge wiring, the fridge ran fine. ARB even recommends running larger wiring directly to the port from the battery.

 

[FordyceCreek]

I have to admit my results have been less then stellar. The original metal ARB Fridge could go maybe 2.5 days and still be able to start the car under reasonable temps. The newer plastic unit rarely makes it a day. Obviously if you are in the mountains, and its cool these times can be extended quite a bit, especially shutting the unit off at night. To get 4 days it would have to be some real high mountain conservative cooling action for sure.

 

[chmura]

Awesome. I just purchased a NorthStar Group 31M for my 4Runner to run my ARB fridge.

What battery tender does everyone use to charge their AGM batteries and keep them topped off? A month ago [MENTION=65614]Antman[/MENTION] gave two Amazon links but I can't find that post now. Care to share again [MENTION=65614]Antman[/MENTION].

 

[flyinhawaiian01]

I use this model:

Keyline Charger

So far it works perfectly for all my agm batteries. I throw each vehicle on the charger every once in a while, moreso the '87 truck since I rarely drive the garage queen.

Doesn't take much to charge them up either. I usually throw a battery on the charger on a friday afternoon, and before the wife leaves for work on Monday, I pull it off. That's usually good for a month or two before I feel the need to do it again.

Been doing this with all of my agm batteries for the past 16 years, I finally had my last Optima yellow top die on me about 8 months ago, that was the first yellow top I bought back in 2000, so I got more than my money's worth out of that battery!

 

[e60ral]

i don't understand why anyone would go through the effort for this but use 12ga.

it makes sense for a manufacturer to not overbuild things because just cents per vehicle adds up to real numbers, but for a single owner doing a vehicle mod doing the bare minimum doesn't make sense when just a few more bucks buys you flexibility

 

[familymopar]

Actually it won't power the fridge effectively as several members have run into. Toyota never intended for portable fridges to be ran from that port. I believe the gauge is 16 and it insufficient to run a larger fridge at full capacity. One member couldn't even get his to cool below 45 degrees with the stock wiring. Once he upgraded to 8 gauge wiring, the fridge ran fine. ARB even recommends running larger wiring directly to the port from the battery.

You might be talking about me here, and whether you are or not, this is precisely my experience. The stock 12v port is simply ineffective. Had I been unable or unwilling to run the wires for a new port I would have returned the fridge. The 8 gauge wire straight to the battery made all the difference in the world. And is what ARB recommends.

 

[TRDPRORUNNER]

ARB Wiring Kit for 50qt fridge - request for help, please!

Hello all "ARB Fridge" owners...

Really appreciate the good write-ups here on the ARB & related info. Was wondering if any of you might share some info on exactly how you installed the ARB wiring kit. Had the fridge for a year but have only used twice so far on stock 12v port. Bought the wiring kit and want to install it myself if possible. Wiring in vehicles is not my forte, but I'm decent at wiring other things like equipment racks, soldering, etc. Just haven't ever run wiring from engine through the firewall into the back. Also, did any of you use the supplied 12v socket that came with the kit or did you just rewire to the existing stock port? Again, please forgive my lack of "auto wiring" experience. Just want to do it right and learn something along the way. If any of you wouldn't mind sharing your wiring plan with possible pics that would be incredible. Otherwise, I may have to hire someone and the quotes have been crazy high! Thanks in advance for any help guys.

*Edited for clarification and updates... I have read all the related posts on the wiring that I could but my main issue is how to get the thicker ARB wiring through the firewall. The grommet for the other wiring is soooo snug that I can't seem to gain ANY ground here. What's the secret please? Once through, I feel confident in running it to the back under scuff plates, carpet, etc. Just losing the battle breaching the wall into the cab. Thanks guys.

 

[flyinhawaiian01]

Not sure which grommet you're using at the firewall, nor do I know whether the ARB cable is running both hot and ground or not, but the grommet I used is a standalone grommet next to the brake booster.

If you need clarification, I can take a photo tomorrow on how I did mine, but there should be several posts with pics around here of that grommet. Maybe someone else can point you to one of those photos.

Once its in the foot well area, its just a matter of snapping off door sill plates and running it to the rear.

And I went ahead and used the stock 12v outlet with my own wiring. It works just fine, but you'll need to modify the plug on the back where the wiring is. I've done this with most every vehicle I've owned, so far I haven't blown anything up yet or set them on fire!!!

 

[LawnDart]

Been working on this. I didn't see a reason to go through the vehicle. So we're following the pre-existing loom we created for the rear CBI bumper rigid dually lights.

We're coming out from under the vehicle through one of the grommets under the vehicle, and installing the ARB outlet in that rear right tray over the right rear wheel. We're doing an on/off switch just for some added peace of mind to prevent any phantom draw when not using the fridge.

 

[Jhalko]

Hello all "ARB Fridge" owners...

Really appreciate the good write-ups here on the ARB & related info. Was wondering if any of you might share some info on exactly how you installed the ARB wiring kit. Had the fridge for a year but have only used twice so far on stock 12v port. Bought the wiring kit and want to install it myself if possible. Wiring in vehicles is not my forte, but I'm decent at wiring other things like equipment racks, soldering, etc. Just haven't ever run wiring from engine through the firewall into the back. Also, did any of you use the supplied 12v socket that came with the kit or did you just rewire to the existing stock port? Again, please forgive my lack of "auto wiring" experience. Just want to do it right and learn something along the way. If any of you wouldn't mind sharing your wiring plan with possible pics that would be incredible. Otherwise, I may have to hire someone and the quotes have been crazy high! Thanks in advance for any help guys.

*Edited for clarification and updates... I have read all the related posts on the wiring that I could but my main issue is how to get the thicker ARB wiring through the firewall. The grommet for the other wiring is soooo snug that I can't seem to gain ANY ground here. What's the secret please? Once through, I feel confident in running it to the back under scuff plates, carpet, etc. Just losing the battle breaching the wall into the cab. Thanks guys.

I just cut a larger hole, search around for the proper way to do it. Once you are through the ARB wires are easy to run. Just PM if you need any info or pics. I did this like a month ago. Also I used a blue sea 12v outlet to flush mount.

 

[tigger]

There is a large gromet with a cable bundle going through it. The gromet is about 3" across so there is plenty of room. Just take an exacto knife and cut a small X on one side. Then push the cable through, then pull it from the inside. Really simple. Make sure the fuse is near the battery (within 18").

I ran down the driver side and mounted a new port.