Making the 12V hot all the time

[OneOleMan]

I’d like the 12V plug in the luggage area of my 2012 Limited hot all the time. This would let me to keep my ARB Fridge/Freezer running 24/7 rather than just when the ignition is on.

Has anyone done a mod like this? Would it be wise to have an auxiliary battery installed for this purpose?

 

[Doc_Fry]

I would not recommend doing so. You are far safer and more flexible running your own lead from the battery. You can even run it switched.

I am doing this using a separate Fuse/Relay seperate from the factory system. You do not need to get this elaborate. You just need a run of 14Ga wire, more than enough for 30amps at this length. Fusing it at the connection near or at the battery then to a 12 volt outlet in the rear. You can use a switch to turn it on off at you own convenience. You will need to wire up a relay to do so. See 12volt.com for instruction how to. I got my fridge switch to fit the factory location from aironboard. You can also get the carling type switch from otrattw.com.

In the future it give you the flexibility to connect to a second battery and allows you to be safer and make it easier to troubleshoot as well as more robust that putting that toll on the factory circuit. I am running an Engel MT45 and will put up an install how to when I install my relay box here in the near future.

Now a second battery isolated from the main is definitely a need if you plan on running for extended oeriods of time without running the vehicle. I was able to run my fridge on medium setting for 3 days on a second battery. If you are running the vehicle everyday for a few hour a good main battery should saffice.

 

[jicko]

Making all 12V hot is easy, I took 2 "add-a-circuit" (cost ~$10), and just wire them together and just plug them into your driver's side fuse box. 5min of work, will make all 12V hot.

Now, this will NOT run your fridge. I have been trying this for the past week.

The factory wire gauge of wires off the 2 rear seats 12V outlet as well as the cargo 12V outlet from the battery are probably not sufficient enough to handle the instantaneous current draw of the starting of the compressor, hence, at the 12V outlet, the voltage dips lower than the "battery monitoring" voltage. The ARB fridge will NOT run.

For the ARB Fridge, you need to run your own wiring. (this seems to be the conclusion I am getting at).

You may still want to make all your 12V always on tho, here are the instructions:
http://www.toyota-4runner.org/5th-gen-t4rs/165542-warthog-build-adventure-thread-2.html#post1671397
http://www.toyota-4runner.org/5th-gen-t4rs/187467-jicko-build-thread-3.html#post1957923

 

[Titanpat57]

As Doc stated...the wiring is NOT a suitable size for continuous operation of your fridge. Run a new outlet with a good #10, or better yet a #8 to applicable rated socket, and you'll have an outlet that can handle up to 15 amps, should you decide to run something else from it.

Be sure to protect the wire from chaffing with wire loom, and secure it so it doesn't move all over. Also make sure the rear of your socket can't connect against anything metal.

The only thing I would run on the existing wire is a phone charger.

 

[Antman]

As Doc stated...the wiring is NOT a suitable size for continuous operation of your fridge. Run a new outlet with a good #10, or better yet a #8 to applicable rated socket, and you'll have an outlet that can handle up to 15 amps, should you decide to run something else from it.

Be sure to protect the wire from chaffing with wire loom, and secure it so it doesn't move all over. Also make sure the rear of your socket can't connect against anything metal.

The only thing I would run on the existing wire is a phone charger.

Who are you and what have you done with Titanpat?

 

[Doc_Fry]

Here is the actual chart to figure out the right gauge wire for you application

Amps
@ 12 Volts LENGTH OF WIRE
American Wire Gauge (AWG)
3' 5' 7' 10' 15' 20' 25' 30'
0 to 1 18 18 18 18 18 18
1.5 18 18 18 18 18 18 18
2 18 18 18 18 18 18 18
3 18 18 18 18 18 18 18
4 18 18 18 18 18 18 18
5 18 18 18 18 18 18 18
6 18 18 18 18 18 18 16
7 18 18 18 18 18 18 16
8 18 18 18 18 18 16 16
10 18 18 18 18 16 16 14
11 18 18 18 18 16 16 14
12 18 18 18 18 16 16 14
15 18 18 18 18 14 14 12
18 18 18 16 16 14 14 12
20 18 18 16 16 14 12 10
22 18 18 16 14 12 12 10
24 18 18 16 14 12 12 10
30 18 16 14 12 10 10 10


You are looking at usng 14ga or 12ga wiring for up to 30 amps in a 12volt application. More than enoigh for anything you could throw at it and the usual 12v relay is 30amps.

 

[Off_Gridder]

Here is the actual chart to figure out the right gauge wire for you application

Amps
@ 12 Volts LENGTH OF WIRE
American Wire Gauge (AWG)
3' 5' 7' 10' 15' 20' 25' 30'
0 to 1 18 18 18 18 18 18
1.5 18 18 18 18 18 18 18
2 18 18 18 18 18 18 18
3 18 18 18 18 18 18 18
4 18 18 18 18 18 18 18
5 18 18 18 18 18 18 18
6 18 18 18 18 18 18 16
7 18 18 18 18 18 18 16
8 18 18 18 18 18 16 16
10 18 18 18 18 16 16 14
11 18 18 18 18 16 16 14
12 18 18 18 18 16 16 14
15 18 18 18 18 14 14 12
18 18 18 16 16 14 14 12
20 18 18 16 16 14 12 10
22 18 18 16 14 12 12 10
24 18 18 16 14 12 12 10
30 18 16 14 12 10 10 10


You are looking at usng 14ga or 12ga wiring for up to 30 amps in a 12volt application. More than enoigh for anything you could throw at it and the usual 12v relay is 30amps.

Although those could be used as minimums for wire sizing, don't forget that the voltage drop can be significant when using smaller gauge wire. As your battery voltage gets lower, this can mean that your equipment (whatever it may be) isn't running in it's ideal voltage range or not at all.

As a simple example, if you plan to run 30 amps for 10 feet of wire using 14ga wire with a batt @ 12v, your equipment is only seeing 10.48v at the end of the 10 foot run. That's a 1.5v or 12.6% waste just because you wanted to save a bit on wire, EXCLUDING the losses from possibly using crappy connectors.

When you have that much wire loss, some equipment might not work at all once you get down to the last bit of juice in your battery, although you would have plenty without the voltage drop. If using an ARB fridge for example, that means your fridge will cut out way early to protect the battery just because of your wire size, not the "actual" battery voltage.

I have a business on the side installing off-grid alternative energy systems as well as building custom e-bikes and this is the most common issue I see in DIY systems, especially when connecting battery banks to inverters.

People often spend serious $$$ on getting the most efficient equipment, then loose all their efficiency gains (or worse risk fire) by running smaller wire gauges.

For any serious power requirements, or rewiring a central power plug I highly recommend:

-Using a voltage drop calculator to get clear figures on how much loss you are truly going to see and balance out your cost / benefit of going with bigger wire and your goals.
This one is nice:
Voltage Drop Calculator

-Wire everything straight to the battery. (with circuit protection obviously) Although people often are familiar with grounding to the chassis, its way less desirable than running both your positive and negative to the battery.

-Buy good connectors, the losses and risk of poor connection on some automotive connectors can be ridiculous. I am a big fan of Anderson Powerpoles for this type of installation. Don't be afraid to cut up your 12v cigarette lighter plugs to replace them.

 

[gunkl]

I'm with Doc on this one. Run a new cable direct to the battery. Fuse at the battery. Use high quality, correct amperage rated connectors and cables.
Because I tend towards over-engineering, I'd probably go with 12 AWG. 10 AWG is of course OK, but probably overkill for the length and constant current needed. Thanks Doc for actually posting the supporting gauge chart, there's a lot of questionable data floating around this place.

Here is the actual chart to figure out the right gauge wire for you application
[snip]
You are looking at usng 14ga or 12ga wiring for up to 30 amps in a 12volt application. More than enoigh for anything you could throw at it and the usual 12v relay is 30amps.

I would not recommend doing so. You are far safer and more flexible running your own lead from the battery. You can even run it switched.
[snip]

Use a good relay if you're going to do switched; don't use a 30amp rated switch (ugh) keep the switch wiring tidy by using appropriate small wire to run a signal to the relay, and keep the overall wiring clean by running the big gauge wire direct from battery/relay to load.

Making all 12V hot is easy, I took 2 "add-a-circuit" (cost ~$10), and just wire them together and just plug them into your driver's side fuse box. 5min of work, will make all 12V hot.

Now, this will NOT run your fridge. I have been trying this for the past week.
[snip]
For the ARB Fridge, you need to run your own wiring. (this seems to be the conclusion I am getting at).

Sorry to hear that didn't work out for you jicko; Warthog's power hack is.... ingenious, but well.. horrific frankly. There's no money saved in hacks that are highly likely to cause you grief in one form or another.

On another power comment; those planning to run radio transceivers, you should always run the power to the battery; tapping off existing inside wiring is more likely to give you grief in the form of electrical noise.

 

[jicko]

Sorry to hear that didn't work out for you jicko; Warthog's power hack is.... ingenious, but well.. horrific frankly. There's no money saved in hacks that are highly likely to cause you grief in one form or another.

It wasn't about "saving money", it is about "KISS" when you can. It is 2 "add-a-circuit" and few minutes of my time. It is definitely a good attempt.

Now, it is proven that it won't work, I will just have to suck it up and run a wire, or I will install a 2nd battery @ the back, and run a battery maintainer in the cargo space.

 

[Doc_Fry]

Although those could be used as minimums for wire sizing, don't forget that the voltage drop can be significant when using smaller gauge wire. As your battery voltage gets lower, this can mean that your equipment (whatever it may be) isn't running in it's ideal voltage range or not at all.

As a simple example, if you plan to run 30 amps for 10 feet of wire using 14ga wire with a batt @ 12v, your equipment is only seeing 10.48v at the end of the 10 foot run. That's a 1.5v or 12.6% waste just because you wanted to save a bit on wire, EXCLUDING the losses from possibly using crappy connectors.

When you have that much wire loss, some equipment might not work at all once you get down to the last bit of juice in your battery, although you would have plenty without the voltage drop. If using an ARB fridge for example, that means your fridge will cut out way early to protect the battery just because of your wire size, not the "actual" battery voltage.

I have a business on the side installing off-grid alternative energy systems as well as building custom e-bikes and this is the most common issue I see in DIY systems, especially when connecting battery banks to inverters.

People often spend serious $$$ on getting the most efficient equipment, then loose all their efficiency gains (or worse risk fire) by running smaller wire gauges.

For any serious power requirements, or rewiring a central power plug I highly recommend:

-Using a voltage drop calculator to get clear figures on how much loss you are truly going to see and balance out your cost / benefit of going with bigger wire and your goals.
This one is nice:
Voltage Drop Calculator

-Wire everything straight to the battery. (with circuit protection obviously) Although people often are familiar with grounding to the chassis, its way less desirable than running both your positive and negative to the battery.

-Buy good connectors, the losses and risk of poor connection on some automotive connectors can be ridiculous. I am a big fan of Anderson Powerpoles for this type of installation. Don't be afraid to cut up your 12v cigarette lighter plugs to replace them.

Now although it os capable of doing so with the wire run that is rated as a maximum amperage that it is capable of. That does not mean that they will be running the maximum at all times. The equipment they intend to run at best will never go over 15amps. So, it dictates that you still will be within the limits of the wiring and very safe to do so.

In the application you speak of yes then you do get higher spikes and it does pay to run larger guage wire. Too many people waste money every year caught up in over doing it. Or which oxygen free wire is better etc. I do agree that there are drops when reaching the maximum length of the wire yet still within normal operating standards for the equipment being run. If the user chooses in the nd to go bigger then it is there decision. Is it needed? I dont believe so and the facts do support it. Use high quality compents.

Yes, if you are running switched I did say use a relay. I dont want that to get confused. You can see how to wire a relay at 12volt.com for this application with a switch. Again both Air On Board and OTRATTW have switches that will work for your situation. I am using a AOB switch for my Engel as i ran out of room for more OTRATTW, which are in my opinion a much higher quality switch.

I do appreciate your experience and could also throw in mine as a certified 12volt installer of days of old. I am not trying to start a war between what is and what isnt just posting what I beleive is needed and what has worked for me in the past without any issues at all using an Engel MT-45 and various other equipment since 2007 in my FJ on a second battery running it almost daily. Your mileage may vary.

 

[gunkl]

It wasn't about "saving money", it is about "KISS" when you can. It is 2 "add-a-circuit" and few minutes of my time. It is definitely a good attempt.

Now, it is proven that it won't work, I will just have to suck it up and run a wire, or I will install a 2nd battery @ the back, and run a battery maintainer in the cargo space.

"saving money" "saving time"
I live by DIRT-FT before KISS.
I'm confused by the KISS element of the second battery idea, but good luck to you, I'm looking forward to hearing how it works out. Second batteries are always one of those things I'd like to do, it'd be nice to know I had a backup to jump the vehicle with, but I've never seen it simple enough to be yet another system I want to deal with maintaining (or finding cargo room, carrying additional weight, etc)
I do know a guy that has a solar panel roof rack setup for camping out in the desert that is significant enough to keep both his primary and secondary vehicle batteries charged up during the day, so he can run a fridge and all his other stuff all night long (for.. questionable reasons.. but it's a cool setup!)

 

[gunkl]

I do appreciate your experience and could also throw in mine as a certified 12volt installer of days of old. I am not trying to start a war between what is and what isnt just posting what I beleive is needed and what has worked for me in the past without any issues at all using an Engel MT-45 and various other equipment since 2007 in my FJ on a second battery running it almost daily. Your mileage may vary.

I'm not sure it's unique to this forum, but I've run across several mod experts that are very sensitive about anyone posting contradicting information or additional detail regarding the method of modifications, especially electrical.

I don't really understand why those individuals are easily offended and/or dismissive of such responses, this is, after all, a forum. I'm here to learn from everyone's experience, and listen to all angles of attack/knowledge, and then choose my path based on the best information available for what I need.

Then again, I'm just a newbie with <100 posts, so I guess I'm deserving of the instant slam I get for doubting an expert of many years with over 5,000 posts.

Ok, leisure time over, time to go back to professional life, where I might just happen to work daily with electronics outside of my toyota

 

[jicko]

I'm confused by the KISS element of the second battery idea, but good luck to you, I'm looking forward to hearing how it works out. Second batteries are always one of those things I'd like to do, it'd be nice to know I had a backup to jump the vehicle with, but I've never seen it simple enough to be yet another system I want to deal with maintaining (or finding cargo room, carrying additional weight, etc)

Check this out:
Installed dedicated battery for ARB fridge - Toyota FJ Cruiser Forum

This is not the typical dual battery with an isolator type system. This is what I meant by a "simple" secondary battery with a battery maintainer, rather than a direct hook up to the main battery and get charged with the car alternator. The separation of this is better.

 

[gunkl]

Check this out:
This is not the typical dual battery with an isolator type system. This is what I meant by a "simple" secondary battery with a battery maintainer, rather than a direct hook up to the main battery and get charged with the car alternator. The separation of this is better.

Yeap, nope, I wouldn't waste my time on that one. Again, too much work. Better off doing a battery isolator.

There are too many variables in his work, he gets merit for creativity and minimalism, but too many scenarios of running out of juice because he had to drive the vehicle for X hours to charge the battery the next day before the next night. I will often go camping and not move the vehicle for days. (Not always, but often)

Not to mention you'd need to use a deep cycle battery, and you'd still wear it out pretty quick. Using a deep cycle is even more critical when you're using a relatively undersized battery for the application.

Then again, on the KISS front, I seem to do fine camping with a good quality ice chest filled with ice and food. If I'm going for an extended trip, I carry extra ice in another chest, or I just plan to get some. At $5/bag, you can get 180 bags of ice for the cost of a $900 refrigerator. that's a lot of camping.

 

[Doc_Fry]

Yeap, nope, I wouldn't waste my time on that one. Again, too much work. Better off doing a battery isolator.

There are too many variables in his work, he gets merit for creativity and minimalism, but too many scenarios of running out of juice because he had to drive the vehicle for X hours to charge the battery the next day before the next night. I will often go camping and not move the vehicle for days. (Not always, but often)

Not to mention you'd need to use a deep cycle battery, and you'd still wear it out pretty quick. Using a deep cycle is even more critical when you're using a relatively undersized battery for the application.

Then again, on the KISS front, I seem to do fine camping with a good quality ice chest filled with ice and food. If I'm going for an extended trip, I carry extra ice in another chest, or I just plan to get some. At $5/bag, you can get 180 bags of ice for the cost of a $900 refrigerator. that's a lot of camping.

But whe camping I can have soggy free food and even Ice Cream a few days later with my steaks! Sushi! You name it! Now I myself do carry a cooler and well the better coolers are well almost as expensive as the fridge. IE Yeti 75 or even the yeti , think it is the 50.

 

[Titanpat57]

Although those could be used as minimums for wire sizing, don't forget that the voltage drop can be significant when using smaller gauge wire. As your battery voltage gets lower, this can mean that your equipment (whatever it may be) isn't running in it's ideal voltage range or not at all.

As a simple example, if you plan to run 30 amps for 10 feet of wire using 14ga wire with a batt @ 12v, your equipment is only seeing 10.48v at the end of the 10 foot run. That's a 1.5v or 12.6% waste just because you wanted to save a bit on wire, EXCLUDING the losses from possibly using crappy connectors.

When you have that much wire loss, some equipment might not work at all once you get down to the last bit of juice in your battery, although you would have plenty without the voltage drop. If using an ARB fridge for example, that means your fridge will cut out way early to protect the battery just because of your wire size, not the "actual" battery voltage.

I have a business on the side installing off-grid alternative energy systems as well as building custom e-bikes and this is the most common issue I see in DIY systems, especially when connecting battery banks to inverters.

People often spend serious $$$ on getting the most efficient equipment, then loose all their efficiency gains (or worse risk fire) by running smaller wire gauges.

For any serious power requirements, or rewiring a central power plug I highly recommend:

-Using a voltage drop calculator to get clear figures on how much loss you are truly going to see and balance out your cost / benefit of going with bigger wire and your goals.
This one is nice:
Voltage Drop Calculator

-Wire everything straight to the battery. (with circuit protection obviously) Although people often are familiar with grounding to the chassis, its way less desirable than running both your positive and negative to the battery.

-Buy good connectors, the losses and risk of poor connection on some automotive connectors can be ridiculous. I am a big fan of Anderson Powerpoles for this type of installation. Don't be afraid to cut up your 12v cigarette lighter plugs to replace them.

I like the way you think....

May I also suggest the Red/Black wire from McMaster-Carr...awesome quality

 

[jicko]

[MENTION=117975]Doc_Fry[/MENTION] I agree with you. I am going the ARB Fridge route. Just cuz I can... LOL

[MENTION=121437]gunkl[/MENTION] The fact is.... I've received my ARB Fridge early this week. I've received my Odyssey 31M-PC2150 yesterday... and I am going camping this weekend

SOLUTION? I am just going to charge up my PC2150, and let it run for the weekend..... 100AH battery, it will power up my fridge for 48hrs without issue..... I will figure out a solution later..... optimal? Nah.... but.... I CAN....

By the way, I will be doing assorted fresh cut sashimi (I will be bringing my sashimi knife), ice-cold premium sake from japan, sitting by a camp fire, in the middle of no-where in Anza Borrego desert this weekend.....

 

[enkrypt3d]

not sure why everyone is so paranoid of running a frig 24/7? Might need a 2nd battery but with the ARB like I have, it will shut off before it drains the battery off of the 12v cigarette lighter plug in the back. It works great for my last road trip! Why would you need 15A on this dedicated circuit when the 12v works just fine?

 

[gunkl]

ffffffuuuuu i'm doing it wrong, ive only been able to have ice cream at the camp store or at a gas station to the next place, and sushi.. never..

damn i love sushi

*checks wallet*
*doesnt buy refrigerator*
*eats more sushi*

But whe camping I can have soggy free food and even Ice Cream a few days later with my steaks! Sushi! You name it! Now I myself do carry a cooler and well the better coolers are well almost as expensive as the fridge. IE Yeti 75 or even the yeti , think it is the 50.

[MENTION=121437]gunkl[/MENTION] The fact is.... I've received my ARB Fridge early this week. I've received my Odyssey 31M-PC2150 yesterday... and I am going camping this weekend

SOLUTION? I am just going to charge up my PC2150, and let it fun for the weekend..... 100AH battery, it will power up my fridge for 48hrs without issue..... I will figure out a solution later..... optimal? Nah.... but.... I CAN....

By the way, I will be doing assorted fresh cut sashimi (I will be bringing my sashimi knife), ice-cold premium sake from japan, sitting by a camp fire, in the middle of no-where in Anza Borrego desert this weekend.....

awesome jicko, good times sure to be had

 

[gunkl]

not sure why everyone is so paranoid of running a frig 24/7? Might need a 2nd battery but with the ARB like I have, it will shut off before it drains the battery off of the 12v cigarette lighter plug in the back. It works great for my last road trip! Why would you need 15A on this dedicated circuit when the 12v works just fine?

sounds like some folks are getting refrigerators that won't start the compressor on the 12v socket in the back of the truck-- the factory wiring doesn't have good enough instantaneous (startup) load capability. Also, they want the fridge to run when the vehicle is off-- those sockets are switched with vehicle power, so they've done mods to make them permanently on, but still had the current problem.

If these refrigerators have auto-shutoff (wow, smart, problems solved, who would figure they'd do that for an automotive application) that's pretty much a no-brainer for me, I'd just run cable from the battery up front all the way to the back and add a full time socket, all done.

Which ARB model do you have? *checks wallet*