# 12 volt power inverter size??



## killzoneq2 (Feb 18, 2007)

*What size (how many watts) 12 volt power inverter would I need to run this (Voltage @ 60 hz 115 Volts, Maximum Current Drawn 7.2 Amps) I need to run this 115v fan on my 12volt system on my compressor.*


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## naptown CR (Feb 20, 2009)

killzoneq2 said:


> *What size (how many watts) 12 volt power inverter would I need to run this (Voltage @ 60 hz 115 Volts, Maximum Current Drawn 7.2 Amps) I need to run this 115v fan on my 12volt system on my compressor.*


115 volts x 7.2 amps = 828 watts 
I would get a 1000 watt to allow for some wiggle room and so you don't burn it up.


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## 480sparky (Feb 1, 2009)

naptown CR said:


> 115 volts x 7.2 amps = 828 watts
> I would get a 1000 watt to allow for some wiggle room and so you don't burn it up.


 
And that would be 1000w run, not 1000w surge.


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## naptown CR (Feb 20, 2009)

/\ yeah what he said


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## Leo G (May 12, 2005)

Most all inverters have a 200% surge available


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## Electric_Light (Nov 25, 2007)

killzoneq2 said:


> *What size (how many watts) 12 volt power inverter would I need to run this (Voltage @ 60 hz 115 Volts, Maximum Current Drawn 7.2 Amps) I need to run this 115v fan on my 12volt system on my compressor.*


What was the point of shouting?

First of all, explain what this load is. Fan and compressor? 

So the load is rated at 828VA. Wattage is dependent on power factor. Surge rating needed depends on the type of motor. If it's an induction motor, the name plate should have a starting KVA rating.



naptown CR said:


> 115 volts x 7.2 amps = 828 watts
> I would get a 1000 watt to allow for some wiggle room and so you don't burn it up.


What is your basis for assuming this motor has a unity power factor?


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## Tinstaafl (Jan 6, 2008)

The parallel question to that which you need to consider, is how long you are going to be running that load. You'll need enough battery/alternator capacity to handle that.


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## Tinstaafl (Jan 6, 2008)

Electric_Light said:


> What is your basis for assuming this motor has a unity power factor?


No need to nit-pick. All of these devices have fudge factors, and we're not launching a moon shot. :thumbsup:


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## killzoneq2 (Feb 18, 2007)

I am going to be mounting this onto my compressor. It has two 1/4hp motors to run the fans. It will need to run for several hours at a time.


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## 480sparky (Feb 1, 2009)

Several hours?

Either get AAA or install a dual-battery system thruogh an isolation system.


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## killzoneq2 (Feb 18, 2007)

I will probably set up a dual battery.. If I do this will a 1000 watt work? Is there anything special I need to look at or features that the inverter should have?


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## 480sparky (Feb 1, 2009)

You won't need anything extremely high-tech (such as one with a pure sine wave for electronics), just one big enough to run the load.

But I gotta ask.... why does just this item need 120vac and nothing else? Is there never any normal power available?

I know running 100' of drop cord on every job is no fun, but this seems like an expensive solution.


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## killzoneq2 (Feb 18, 2007)

Thanks for your help guys..


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## killzoneq2 (Feb 18, 2007)

There is like 500 different brands of inverters out there...Hate to jump on one that is new for $80.00 if its only going to last a few months. Are these thing pretty much all the same? The price range varies quit a bit on I am assuming junk to quality inverters? What is a good brand name to look at? I am going to be doing mostly mobile services with no power supply available. I want to try to maintain this 100% self contained status if that makes any since.


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## 480sparky (Feb 1, 2009)

I would find a local RV/camper dealer and talk to their sales help. If they are of any size, they'll be selling these things all day long so they have some experience with them.

They'll also have the isolator kits and deep-cycle batteries.


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## Railman (Jan 19, 2008)

Wouldn't it make more sense to use a couple 12v radiator fans to cool your comp? They can be had for a few bucks from a salvage yard.
Joe


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## killzoneq2 (Feb 18, 2007)

I thought about that, but If I can throw an inverter on there, Its gonna save me lots of time and fab work..


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## AustinDB (Sep 11, 2006)

this is your business and if you're making money while the equipment is operational, the $80 option may leave you in the dust sooner than later. Look into Xantrex for RV quality inverters.

do you have a gas motor running the compressor? how about installing a generator head (the part of a generator that 'makes' the 120v) via belt drive to the motor running the air compressor. I'm not positive, but 'think' the drag of the gen. head will be nearly zero if there is no current draw, therefore the low current draw needed for these fans should not terribly effect the compressor's operation.


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## Railman (Jan 19, 2008)

Maybe a couple pf these?
https://www.surpluscenter.com/item.asp?UID=2468022709230721&item=16-1362&catname=electric
Joe


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## killzoneq2 (Feb 18, 2007)

Railman, That may be the answer!! I am going to check the CFM rating on the current fans and if it is comparable, and will bolt right up, I'm buying them..


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