Tip & How-To about Electronics - Others

# What size of inverter do I need?

The correct size of inverter is an easy calculation and important to ensure long life from the inverter and the life of the appliances getting there power from the inverter. To calculate you take the volts and multiply by the amps which equals the wattage. Every appliance has a tag which must state the volts and amps. Locate the tag to find the information. Here is an example.

Under Counter Refrigerator 1.3 amps (120 volts x 1.3 amps = 156 watts)
Microwave (120 volts x 10 amps = 1200 watts)
Alarm Clock Radio (120 volts x .03 amps = 3.6watts)
TV (120 volts x .6 amps = 72 watts)

You now add all the watts together, since the above list could likely be running at the same time. There is a combine wattage of 1431.6 watts. In this example you would need at least a 1500 watt inverter. However given some unknown variables personally I would get a 2500 watt inverter. Less stress on the inverter, will lengthen the life of the inverter. Had the total been 1,000 watts a 1,500 watt inverter would suffice.

You must also remember that your alternator on your vehicle must be able to keep up with the power demand of not only your vehicle needs but your inverter needs as well.

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## Related Questions:

### 3000 watt eliminator with OLP and LUP CODES any Ideas

Assuming you have a 12VDC In 120V AC out 3000W inverter.
LUP indicates battery voltage is low, so firstly make sure:

1. You 12V battery is good, it's large enough a minimum of 75AH and probably much larger is recommended and it's fully charged.
2. Verify you are using the correct size copper wires from battery to the Inverter DC INPUT(s). If you keep wire short the wire size can be smaller, but if the DC input wires are longer then you will need to use thicker copper wires.

At MAx load you would be taking 250 AMP from battery, so for a 5% Volatge drop of .6 V for a 10 ft length of cables from battery to Inverter you would need to use a 1AWG copper cable.

http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=0.4066&voltage=12&phase=dc&noofconductor=1&distance=10&distanceunit=feet&eres=125&x=37&y=8

OLP is a overload condition, which means you may have to many high powered AC powered things connected to the Inverters AC outlets or maybe something that has large start up surge, ie devices large electric motors.

Or it could be all due to a faulty Inverter.

Oct 22, 2016 | Eliminator Electronics - Others

You may get Memory Error when you try to access an archived variables. From the other hand Memory Error message is displayed if there is not enough free RAM to access the archived variables. For correcting Memory Error message use the 2ND then MEM to check RAM free size and 2ND then VAR-LINK to determine the size of the archived variables that you want to access. As the third step for correcting this problem deleting unnecessary variable from RAM and archiving large variables or programs. By the definition, the RAM free size must be larger than the archived variables

Feb 23, 2012 | Texas Instruments TI-89 Calculator

### i have a camper trailer with 100amp battery and was wondering up to what size inverter i can run iwill be using 60ltr fridge (not running it overnight) a tv and computor

Before you get too carried away, are you aware that no matter what size inverter you are running, you need enough battery capacity to convert to AC (hydro) . 1 x 100 amp battery will not last very long under that load. Do you have plans, or storage space for a few more batteries? How/what are your plans for charging those batteries after usage, such as plugging the trailer in or an external charger, or perhaps solar panels?All that needs to be considered. Look at appliances you plan on running and get the watts, or amps required reading of tags, then it will be easier to calculate for you, and recommend possible solutions.

Aug 05, 2011 | Electronics - Others

### Will you be able to give an easy index Ton/SQF for A/C capacity to be installed in South Florida? Thansks.

I have a couple of sites I can share with you. These are quick, easy, basic calculators to give you a general idea. Because of the conditions in South Florida - High Temperatures & High Humidity, you can expect better results from a professional analysis as proper sizing is critical for satisfactory operation.

This is for whole house air conditioning sizing:
http://www.northernac.com/newcalc.htm

This is for a room air conditioner:
http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/air-conditioners/sizing-worksheet/index.htm
or
http://www.goodhousekeeping.com/home/air-conditioner-calculator

I hope you find this information helpful.
Good Luck! :-)

Mar 08, 2010 | Heating & Cooling

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