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Discussion Starter · #1 ·
i'm not a newbie so dont tell me to search. i've been looking everywhere for the answer to my question and havent found it yet.

i'm running a PS2, screens, and a mini-fridge in my car. NO aftermarket sound system. i had a system a while back, and sold it. so all the monster cable and everything is still hanging in my trunk, and still wired to the battery. ALL my current electronics run to a 400 watt power inverter in my trunk, which is not plugged into anything. now, i was told that i should just run the inverter straight to the battery, and leave it on all the time, and wire in a master switch up near me, to turn on/off all the electronics whenever i want. i dont really want to do that for two reasons 1) i dont know how 2) it seems like a lot of work for a solution that doesnt seem all that great

now my question is where can i get anoter source of power. i was thinking a spare battery in the trunk, but i was told that has to run to your main battery so the alternator can charge it, which in turn will do me no good because it will still drain the main battery if i leave anything running while the car is off (like the mini-fridge)

the option i have been doing research on are bat caps, but i dont know anything about them. what they do or how they work, i have just heard them mentioned. i looked online at all kinds of farad capacitors, but they all talk about plugging into your amp and making your system sound better, but i dont have a system, so can i not use one of these?? is there a difference in a bat cap and farad cap?

or maybe antother option would be running the fridge (which only draws about 70 watts) to a fuse in the fuse box, and running everything else to the regular battery.

my ultimate goal is to be able to have the mini-fridge on as much as possible to keep the drinks cold.

i thought about an alternator upgrade also, but thats $500 which seems a bit high for a little extra power.

any suggestions?? sorry for the long post!
 

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1) Caps, Batcaps, Alternator Upgrade - scratch all that.
2) If you want to run fridge at all times, it will be wise to run a second battery to power it up. This way, the main battery will not discharge.
3) In order to achieve #2:
a) Second battery must be wired to the primary battery, so it will charge when the car is on.
b) A solenoid or a relay must disconnect the second battery whenever the keys are in "OFF" position to avoid discharging second battery.

Since you have the wiring done in the trunk from the sound system, it can be used for your new project.

One problem I have with it is if the mini fridge is eating up 70WT, that equals to approx 5.7 Amps @ 12V. With a battery charge of 70Amps/hr, the max it will last is 12 hours.

IMO, that whole deal is not worth it.
 

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wow, this is way too tricky for me. i say the fridge and the 2nd battery weigh too much and are slowing you down. ditch the fridge. get a cooler. and keep both hands on the wheel at all times :chill:

But in all seriousness, the fridge is a very cool idea (literally)!! I'm impressed by this idea! You'll have the ultimate road-trip vehicle with PS2 and an f'in fridge! Rock on buddy. Good luck! 8)
 

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Discussion Starter · #4 ·
the fridge only weighs about a pound. it is a cooler pretty much, its one of those hot and cold things. but it plugs in to your cigarette lighter or power outlet.

thats another option isnt it??

vlad, what about plugging the fridge into the cigaretter lighter? and leaving everything else to the power inverter and running that to the main battery??
 

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^^^^
That will work. You don't need an inverter to run the fridge.
Fridge will not work when the car is off, though. If you need to make it work, you would need to run it to the battery, or do the second battery setup.

The inverter is a separate issue. It only needs to be on when the car is on. To accomplish it, you will need to wire it to the battery power through a relay that would turn it on when the key is in the "ACC" position.


Do you need to run the fridge when the car is off?
 

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Discussion Starter · #6 ·
vlad_a said:
^^^^
That will work. You don't need an inverter to run the fridge.
Fridge will not work when the car is off, though. If you need to make it work, you would need to run it to the battery, or do the second battery setup.

The inverter is a separate issue. It only needs to be on when the car is on. To accomplish it, you will need to wire it to the battery power throuh a relay that would turn it on when the key is in the "ACC" position.


Do you need to run the fridge when the car is off?

i dont NEED to, and it is recommended that I dont, but thats the whole point of the fridge, to keep things cold. so i WANT to. if it cant be done, then this thread is useless because then i will just run everything to the main battery to be running while the car is on.

so my dilemma is HOW to get the fridge to run with the car off properly? if theres no smart way or safe way to do it, then i wont do it. i just wanted to ask the experts first.
 

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How to make the fridge always-on:

1) Do the second battery setup with relay or solenoid disconnecting it from the main power (first battery) when the car is off.
2) Connect fridge to the second battery.

Advantages:
1) Fridge is always on.
2) Main battery will not be drained.

Issues:
1) Will the fridge turn off when the second battery is discharged?
2) If the fridge does not turn off when the second battery is discharged, the second battery will end up deep-discharged, which will decrease its future capacity.
 

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Discussion Starter · #8 ·
to answer your question, no the fridge will not turn off when the second battery is discharged. but i would much rather run down the second battery and would not even mind replacing it every so often, as opposed to not being able to start my car one day probably when I am out in the middle of nowhere.

sounds like i will go with the second battery and relay setup. i suppose a local Car Toys or Tweeter could do this for me??
 

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^^^^
I don't see why not.

To confuse you even more, I have seen breakers that disconnect the battery when it is almost discharged.
 

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10secondIS said:
i'm not a newbie so dont tell me to search. i've been looking everywhere for the answer to my question and havent found it yet.

i'm running a PS2, screens, and a mini-fridge in my car. NO aftermarket sound system. i had a system a while back, and sold it. so all the monster cable and everything is still hanging in my trunk, and still wired to the battery. ALL my current electronics run to a 400 watt power inverter in my trunk, which is not plugged into anything. now, i was told that i should just run the inverter straight to the battery, and leave it on all the time, and wire in a master switch up near me, to turn on/off all the electronics whenever i want. i dont really want to do that for two reasons 1) i dont know how 2) it seems like a lot of work for a solution that doesnt seem all that great

now my question is where can i get anoter source of power. i was thinking a spare battery in the trunk, but i was told that has to run to your main battery so the alternator can charge it, which in turn will do me no good because it will still drain the main battery if i leave anything running while the car is off (like the mini-fridge)

the option i have been doing research on are bat caps, but i dont know anything about them. what they do or how they work, i have just heard them mentioned. i looked online at all kinds of farad capacitors, but they all talk about plugging into your amp and making your system sound better, but i dont have a system, so can i not use one of these?? is there a difference in a bat cap and farad cap?

or maybe antother option would be running the fridge (which only draws about 70 watts) to a fuse in the fuse box, and running everything else to the regular battery.

my ultimate goal is to be able to have the mini-fridge on as much as possible to keep the drinks cold.

i thought about an alternator upgrade also, but thats $500 which seems a bit high for a little extra power.

any suggestions?? sorry for the long post!
Will the frig be mounted into the ski pass? Just flip down the arm rest and have yourself a cold one.

I sawsome one on tv do that (either on Hi-Rev 2Rs or MTV). It looked pretty tricked out.
 

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Use a dual battery isolating relay.
Put a thermostat in the cooler/fridge to only require power when it hits the high temp of ?..
Use a standard bosh relay and wire it to the thermostat and to the 12V in of the cooler.

This will allow a 2nd battery to maintain the cooler only. The car will always start even if you leave it parked for extended periods of time.
The T-stat will supply power only when the cooler reaches a max high temp you choose, thus adding to the legth the car can be parked before the 2 nd battery faces discharge issues.
Use a deep cycle battery for the 2nd battery.
A Batcap can seriously help, but it will not have the capacity that a deep cycle battery would.
 

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Discussion Starter · #12 ·
lisnup65 said:
Use a dual battery isolating relay.
Put a thermostat in the cooler/fridge to only require power when it hits the high temp of ?..
Use a standard bosh relay and wire it to the thermostat and to the 12V in of the cooler.

This will allow a 2nd battery to maintain the cooler only. The car will always start even if you leave it parked for extended periods of time.
The T-stat will supply power only when the cooler reaches a max high temp you choose, thus adding to the legth the car can be parked before the 2 nd battery faces discharge issues.
Use a deep cycle battery for the 2nd battery.
A Batcap can seriously help, but it will not have the capacity that a deep cycle battery would.
sounds like a plan. thanks!!!


Peter Klim:

yup, mounted through the ski pass........looks sweet!
 

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dont forget that a mini fridge has cooling elements which build up condesation. Could pose a big problem if something goes wrong and it goes out after its at its cold setting, which would then drain the moisture into your trunk.


they have these cool things now, called blue ice, you put them in a freezer, then into a cooler, and voila! cold beverages.


good idea, but its an IS not an RV. more hassle than its worth i think.
 
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