# Check my Math. Please



## Fire-Man (Apr 30, 2005)

To start with I am just curious---Lets say I got a 5000 watt/10,000 watt surge inverter. I am plugged into 2 recp. pulling app 5000 watts off the 115 volt inverter. Am I drawing app 400 amps off the battery bank, with about 43 amps off the output of the inverter?? Never tried to figure it this way. Thanks


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## dademoss (May 2, 2015)

Yes.

http://www.ohmslawcalculator.com/ohms-law-calculator

5000 watts @ 115 volts = (43.5 amps) = 416.7 amps @ 12 volts.


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## Fire-Man (Apr 30, 2005)

dademoss said:


> Yes.
> 
> http://www.ohmslawcalculator.com/ohms-law-calculator
> 
> 5000 watts @ 115 volts = (43.5 amps) = 416.7 amps @ 12 volts.


 
Thanks. Ran into a post on FB where a Guy is looking for a 5000 watt or bigger inverter to hook up in his truck. I just wanted to make sure I was right before replying to him. I do not know his story but he is probably planning to hook to one battery or the cig lighter and run his house----LOL---I have a couple questions on his post he has not answered yet.


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## Steve_S (Feb 25, 2015)

Fire-Man said:


> I do not know his story but he is probably planning to hook to one battery or the cig lighter and run his house----LOL---I have a couple questions on his post he has not answered yet.


Boy oh Boy is he in for a surprise.... LMAO hopefully that is not his plan.


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## Gary in ohio (May 11, 2002)

Fire-Man said:


> To start with I am just curious---Lets say I got a 5000 watt/10,000 watt surge inverter. I am plugged into 2 recp. pulling app 5000 watts off the 115 volt inverter. Am I drawing app 400 amps off the battery bank, with about 43 amps off the output of the inverter?? Never tried to figure it this way. Thanks


If you have a 5Kw inverter and a 5k load then you have the wrong inverter.
If your using 12v to feed a 5k inverter then your really doing it wrong.
If your expecting 43 amps out of an inverter then your doing it wrong.

I would re-think how you plan to deliver the power.. Good exercise in math but not a real world practical use... 400amps is going to need better than a 0000 wire guage and 0000 is almost 1/2inch of solid copper.. You need to get your battery bank up to 48v or higher to make this work


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## Gary in ohio (May 11, 2002)

Fire-Man said:


> To start with I am just curious---Lets say I got a 5000 watt/10,000 watt surge inverter. I am plugged into 2 recp. pulling app 5000 watts off the 115 volt inverter. Am I drawing app 400 amps off the battery bank, with about 43 amps off the output of the inverter?? Never tried to figure it this way. Thanks


If you have a 5Kw inverter and a 5k load then you have the wrong inverter.
If your using 12v to feed a 5k inverter then your really doing it wrong.
If your expecting 43 amps out of an inverter then your doing it wrong.

I would re-think how you plan to deliver the power.. Good exercise in math but not a real world practical use... 400amps is going to need better than a 0000 wire guage and 0000 is almost 1/2inch of solid copper.. You need to get your battery bank up to 48v or higher to make this work


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## Fire-Man (Apr 30, 2005)

I am not the best at ALL this but I gave him some helpful Tips-----he was planning to run it on one battery with a isolator----LOL with a stock 85 amp alt. BUT one good thing is he was figuring his wattage wrong. He is planning to run 2---20some cf chest freezers and he was figuring about 4000 watts together-----I am sure he can get by with a lot less wattage. He has not replied back with the amp draw yet.


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## samson (Jan 21, 2017)

I can pull that much power but this is the approach ...

48 volt battery bank for 1.

And 240 volt load for 2.

So 5000 watts is about 22 amps at 240 and 105 amps at battery voltage.

I use Xantrex XW4548 for that.
8 Deka 8-D batteries (weighing in at 150 lbs each)

Do not use Fronius for inverters, write me back for the horrid failure and non-warranty history I am still dealing with.


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