What Size Inverter do I Need? [with Examples]
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Power inverters will let you charge any of your AC devices or power any appliances directly from your DC battery or Solar Panels. They come in many different sizes and could be Rugged, Hybrid, or Inverter-Charger combinations.
Some power inverters are optimized for specific needs, like Solar (extra energy can go back to the utility while giving your credit for your bills), and could be used on RVs, Trucks, Automotive, Boats, Vans, etc.
So, how do you size your brand-new inverter? Sizing an inverter is very simple, as long as you know how much power do you exactly need. If you think that at some point you will be plugging in more devices, consider that as well and add to your amount.
This means that once you know your total usage in watts (at the same exact time), you will be able to find a perfect inverter solution for yourself. You can generally find this information on the back of your appliance or equipment and if they give you Amps instead of Watts, here is a formula to help you out:
Amps x Volts (usually 110v-120v in USA) = Watts
The size of the inverter that you need greatly depends on the anticipated usage. All the devices that you plan to run at the same time have to be added and then pick the inverter closest for that size (about 20% up).
Inverters generally have two types of watt ratings, and they are:
- Continuous power
- Peak power (which is usually twice the size)
Make sure that the power size that you are looking for is:
And it will be in:
It is also important to note how much battery power you have available to you:
Here are some examples of what is the proper way to size your inverter based on your power consumption:
Inverter size (+20%) and round up
** Don’t forget! You don’t size your inverter but adding all devices you will use during the day, but all that you will use at the SAME TIME!
Now, let’s go over common inverter sizes and what are they useful for:
250 watt Power Inverter
A power inverter is a very handy device that will turn your 12-volt DC current (that is coming from your battery or solar) into 110/120-volt AC (what most household appliances run on). In a car or a truck (cabin), you will be able to plug your inverter directly into the cigarette lighter port (assuming you have appropriate cables).
How much power this will give you? Car DC ports are 15-amp fused, which means they will only be able to give you around 180 watts (15 amps x 12 volts). With a 250-watt inverter, you are right on target and you will be able to use it to its full potential!
In most cases, it will allow you to run your laptop and charge some phones (this is what we usually want them for anyway, right?). If you need to power something larger, make sure that you check the wattage that the device requires (if several, combine their wattage).
Inverters of this size (250 watts) usually come with 1-2 outlets and some USB ports. This is a great tool to have in your car!
Having a 300-watt inverter is very useful on the road and it works, pretty much like an outlet extension in our house (meaning, that it has multiple ports to use for different devices). You probably would like this type of inverter also to have a cigarette lighter cable and several USB ports to accommodate different electronics.
Since Power inverters provide two types of ratings (both in watts), it could be confusing at times. Basically, what you are looking for is 300 watts of continuous power. The Peak (or surge) power of these types of inverters is usually 600 watts and is meant to be available only for few seconds (since a lot of appliances have a high initial surge of power demand).
- Through a cigarette lighter receptacle. Very useful on the road.
- Directly to the battery. A great option for camping!
When you connect your 400-watt inverter into the car’s lighter port, you will be able to enjoy about 140-170 watts of power (12 volts x 15 amps). “Magic” happens when you connect your inverter directly! This way inverter will give you its full power!
Also, make sure you size your load properly before attempting to use an inverter unless you want to keep on changing fuses. This means that you need to combine all the wattage of the equipment that you are planning to use (at the same time) and put 20% on top of it.
If it fits your inverter, then, size of 400-watts is right for you, if not, get a bigger inverter or step down on your load. You can run either one large device or several smaller devices at the same time as long as they don’t go over 320 watts combined.
If you are serious about having power on the go, then a 500-watt inverter is right for you! This neat little device will bring you household AC power into your car, truck, van, and camping site!
500-watt inverters often come with multiple outlets and USB ports. Upper-scale devices will also have a battery cut-off feature and even display if you are running low on battery! If you have a car adapter, you can plug your inverter into the cigarette lighter socket (max 180 watts) or take it camping (use battery cables for maximum power).
Don’t forget that you need to make sure that you choose 500-watt of “continuous” power, because this is the power that your inverter will be able to constantly supply you with. The “peak or surge” rating will only last for a few seconds and is useful for devices with high startup surges.
600 watt Power Inverter
With a 600-watt inverter, you will be able to enjoy a cup of coffee with toast in the morning while camping! 600-watts may not sound like much, but it easily powers small to medium size appliances and power tools.
For example, this particular toaster oven (paid link) from Amazon is only 500-watts and it comes with a coffee-maker combo:
“Now, you can take your home-office or workshop on the road with you, just make sure that you have the right amount of battery power to accommodate it!”
If you are serious about using inverter-powered devices, a good set of batteries (which are NOT your car battery) is absolutely necessary. The inverter will work at its highest efficiency if it’s not too far from your battery location and you are using the thickest cable you can get away with.
1000 watt Inverter
You can use a 1000-watt power inverter to power small appliances like a microwave to some power tools that will not require more than this amount when used at the same time. They are generally used in Recreational Vehicles (RVs), campers, trucks, boats, and as a part of a small solar setup.
It is a good size inverter to keep in the back of your truck, in case you will need some power tools or lights to use. Not to mention, you never know when there is a surprise birthday party or BBQ that you get to attend.
1500 watt Power Inverter
Whether you looking for a backup solution in case of power outages or running a small home office off-grid, a 1500-watt inverter may be just the right device for you! Powering office equipment, power tools in your shop, all kinds of amenities while camping should be no problem at all, as long as you size your wattage properly.
A rule-of-thumb for sizing your 1500-watt power inverter is to combine the wattage of all the devices you are planning to use at the same time (don’t forget basic necessities, like lights) and give yourself 20% headroom.
2000 watt Inverter
2000-watt inverters, are still portable devices that will give you plenty of AC power for your shop, home, camping, and recreation needs. These devices are commonly used on the road (RVs, trucks, or boats) and they are big enough for medium solar applications.
2000-watt inverters are perfect for pretty much anything! Whether you are building something out there in a wild and need power tools or simply just want to be comfortable in your RV, this inverter size can surely do the job (as long as you calculate your needs properly).
3000w Power Inverter
The maximum load of your 3000w inverter should be about 2400-watts combined. This means that the size of the inverter is capable of running quite large appliances or a few smaller devices at the same time.
Running a microwave oven, small refrigerator, heater, portable A/C, coffee-maker, etc, should not be a problem as long as you do not go over maximum wattage (3000-watts minus 20%). If you do not see wattage on your appliance label, you can simply multiply amps by volts.
Charging your phones and tablets should not be a problem as well and now you can even filter your inverters by different features and specifications that may be of interest to you. Anything from inverter having “AC Terminal Blocks”, for example, to the length of the warranty, tech support, etc.
4000w Power Inverter
This powerful 4000-watt inverter should be able to take care of your heavy-duty electricity needs. Anything from the small air conditioner, heater, hairdryer, refrigerator, and so on, should be able to run comfortably as long as you properly size your load.
You can run your shop or construction equipment, water pump, solar setup. The inverter of this size (4000 watts) is also perfect as a home or office power backup system.
Don’t forget that inverters have something called surge (or peak) current, which is also rated in watts. It is usually double the inverter size and it will last for only a few seconds (which is fine for most equipment surges).
5000 watt Power Inverter
This industrial-size inverter can power up practically any household appliance as long as you don’t go over 5000-watts (minus 20%, to be on the safe side). If you want to become totally energy-independent, all you need is a solar panel setup (or wind turbines) and an inverter like this.
High-quality 5000-watt inverters will generally have some kind of certification. UL-listed devices will have this type of label:
This label is for ETL-listed devices.:
In order to get a label like that, the equipment has to go through a series of tests and pass them. Most reliable inverters are made with technology that outputs Pure Sine Wave (which is similar to the one that is coming from utilities).
Power inverters of such sizes are usually called “industrial” are commonly used for very large loads. Don’t forget that doesn’t matter how large the inverter is, quality is what counts.
High-quality 7000-watt inverter systems will have some kind of certification attached to them (UL-listed, for example). It may not seem much, but if you have high-level production, spending just a little more for a product that is already tested out and certified is invaluable.
An ETL certification is similar to UL. If you are looking to save money, at least look for videos where somebody actually tested a product.
If you need large loads of power, this device may be right for you! 8000 watts of continuous power (and usually 16000w peak power) is capable of handling all kinds of off-grid and backup applications.
Here is an example of using an 8000-watt inverter in the shop:
This inverter is relatively inexpensive and it works!
10000 watt Power Inverter
If you have heavy-duty applications or running a remote construction site, you need this inverter! You can use a 10000-watt power inverter in your shop, home, remote job sites, RV, boat, or truck, and a lot of power will be available to you as long as you have good-sized batteries.
The 10000-watt inverter can be used to backup your whole house in case of a blackout or get you completely off the grid with solar panels and wind turbines. If remote living or traveling is your thing, you can install one of these in your cabin or an RV and have all the power you need!
Of course, this industrial-size inverter is also meant for very large applications and this is why preference would definitely toward the sine wave system. If you still would like to try out the “modified wave” version (the price tag is definitely much lower), just make sure your equipment is compatible.
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