The meaning of watt hour rating for a battery generator

Battery Generator Portable Power Stations – Watt Hours (Wh)

Watt Hours. Referenced as Wh. Every battery generator (also known as portable power stations) has a number for watt hours (Wh). But what does it mean? How should you relate watt hours to what the battery generator can really do?

Well, I’m going to help you with that. I’ll keep it simple. And I will give you some examples.

Watt Hours as it relates to a battery generator (portable power station) is the CAPACITY of ENERGY that it can store for your use on devices, appliances, etc.

Once you get a general understanding of power consumption for the things you might plug into the battery generator, you’ll generally know how long the battery generator will keep it running. Based on its rating.

Jackery 240 Watt Hours

For example, the most popular and best selling battery generator is apparently the Jackery 240. It is inexpensive, and performs very well, given its specs. But, it is rated for 240 Wh. What does that mean?

Well, the best way to understand it is this… It will operate a 240 watt device for one hour. Or on the other extreme, it will operate a 10 watt device for 24 hours. Or any combination of device loads that add up to this number.

After that, the battery generator will need a recharge (via solar panels, or, plugging it in to a powered outlet). Actually, being more realistic, more like about 80% of that. But I’m not going to get all technical…

Jackery Explorer 240 — Watt Hour Examples

So, that’s not much available power in this example. But, people love this patricular battery generator. Why? Because for certain uses it’s absolutely fine and perfect. Although it won’t run your typical appliances, Jackery states the following general examples for what the Explorer 240 can do. The list exemplifies the ability to do one-each within the list (not all together).

I added the ‘watts’ column. Note: My laptop charger only draws about 100 watts. Not sure why they suggest only 2 charges (probably more like 3). But that’s just being picky (grin).

Phone 1024 Charges 
Camera 2410 Charges 
Drone 604 Charges 
Laptop 2002 Charges 
LED Light (800 lumen)1318 Hrs 
Fan 1615 Hrs 
Mini Fridge 604 Hrs 
midsize LED TV 683.5 Hrs 

So as you can see, it has its uses, even though it’s only rated at 240 Wh. Maybe for tent camping (powering LED lighting, recharging your phone, a little fan, etc..).

Everything depends on how much power any given device will draw from the battery generator. So that’s the key. Knowing this.

Battery Generator to run a CPAP

Here’s another example… Lets say you’re looking for a battery generator to run a CPAP overnight. First you need to find out how much power your CPAP draws. Averaged over the night. Apparently this also depends on what features you have on. I don’t have one, so I’m not sure.

However, doing some quick searches… Lets say the CPAP uses on average somewhere between 50 and 100 watts (I believe that’s about right for a typical CPAP machine). Well, lets also say that you want to run it long enough to get 7 hours of sleep.

100 x 7 = 700 watt hours (Wh)
50 x 7 = 350 watt hours (Wh)

Measure the Watt Hour Consumption

So, it depends on your machine. And the features you have turned on. Look up the specifications. Or, you might simply connect your own CPAP through the following meter to measure it overnight one time… Then you’ll know for sure.

P4460 Kill A Watt EZ Electricity Usage Monitor
(view on amzn)

[ Read: ‘Kill A Watt Meter’ — How to Measure Power Consumption (kWh) ]

Worst case (100 watt power consumption while turned on?) you’re going to need a bigger battery generator. Maybe something like the Jackery 1000. I recently referenced this model in the following article:

[ Read: Jackery versus Gas Powered Generator ]

On the other hand, maybe a battery generator like the Jackery Explorer 500 will work for your CPAP overnight, or long enough to get the sleep that you want. 500 watt hours.

Are you getting the idea how to figure out watt hours as it relates to battery generators?

Jackery 500
(view on amzn)

Jackery Explorer 240, the most popular battery generator.

Battery Generator For Appliances

Now lets get into the big stuff. What kind of watt hours are required to run some of your typical home appliances? What are we looking at here?

I measured some of my own appliances over a 24 hour period.

My 20 cubic foot refrigerator consumed 1,400 Wh.

My smallest chest freezer (7 cu’) only used 240 Wh. The medium size (11 cu’) used 600 Wh. My big chest freezer (16 cu’) I haven’t measured yet!

The clothes washer consumed 60 Wh per load. The gas dryer used 290 Wh per load.

My pellet stove, depending on its setting, ranged from 60, 80, to 100 watts per hour on average. Startup was about 350 watts for several minutes.

As you can see, in order to figure out what size battery generator you might be interested in… You need to discover what loads you plan to apply and what they are. And for how long.

WATTS x HOURS = Watt Hours

Biggest Capacity Battery Generator?

Here’s the biggest capacity battery generator (still classified as portable) that I could find while doing some searching.

The Goal Zero Yeti 6000X portable power station. It holds a capacity of 6,000 watt hours. It can supply a maximum of 2,000 watts at any one time. It’s big bucks.

But it illustrates what you’re paying for… battery CAPACITY (watt hours), and maximum watts output. And, to an extent, the brand reputation.

Goal Zero Yeti 6000X
(view on their amzn site)

Biggest battery generator?

I hope that you now understand how watt hours relate to battery generators and their ratings.


  1. While I may have been able to play Mozart’s Four Horn Concertos, electrical power was difficult for me to understand. My science minded DH explained it this way. Think of a damn. The water being held are the volts. The exit of water is the amps. It can be amped up by increasing the flow of water. Multiply these these two together and you have watts.
    Stay frosty.

    1. Not so.
      Amps are only *part* of the equation.
      10 amps, using a 12 volt battery system is 120 watts.
      10 amps, using a 48 volt battery system is 480 watts.
      10 amps, at 120 volts AC is 1200 watts.

      Watts, and watt-hours provide a more complete picture of consumption than amps alone.

      1. To figure amps, watts, and voltage for a device, use the PIE equation; P=IxE.


        If you know any two of the three, you can figure out the third.

        If you have a device that runs on 110V and draws 2 amps, you can figure its wattage P=IxE);
        2 Amps x 110 Volts=220 Watts

        If you know the wattage draw and amperage, you can figure out the voltage (E=P/I (you’re dividing here):

        If you know the wattage draw and the voltage, you can figure out the amperage (I=P/E (again, dividing)

  2. I built a CPAP battery box and will add pics and information tomorrow. I’ve been meaning to write a guest article on it. Just to busy with work. I have successfully run my CPAP with humidifier on a 100 amp hr gell cell battery for 3 days without a charge using a very low end inverter. Worth every penny to get a good nights sleep. To make it easier for the DW to handle I placed it in a rolling ice chest as she is to small to lift the battery and carry it in the house. Very simple set up and can them be moved to recharge the battery using a solar panel.

  3. It is all about the batteries. Watt hour capacity is a good measure but also compare the battery composition and how many times the batteries can be recharged.
    A quote found on the web “The cycle life of a Lithium iron phosphate (LiFePO4) battery is more than 4 to 5 times that of other lithium ion polymer batteries. The operating temperature range is wider and safer; however, the discharge platform is lower, the nominal voltage is only 3.2V, and the fully-charged voltage is 3.65V.”
    Both types of batteries are used by the different manufacturers.
    Study them well before you buy.

  4. Is a solar generator an option for running a microwave, single electric hot plate, plain drip coffee maker or crock pot (6 or 8 quart on either low or high for hours)? If a microwave says input 120V, 1800 watt single phase does this mean it needs at least an 1800 watt generator and it could run for the amount of minutes needed, usually less than an hour? Does anyone have experience using a solar generator for the appliances listed? If so, can you share your thoughts? Thanks.

    1. Rootbeer,

      The answers to your questions are mathematics. Every appliance is unique. One needs to run the numbers.

      With that said, the appliances you referenced (with exception to the microwave) are those which are typically “ON” for relatively long periods of time. A crock pot. Hot plate. Coffee Maker (a sort of hot plate).

      So, not only do you need to know the power-demand in Watts (e.g. lets say the hot plate demands 1,000 watts), but for how long (Watt-hours). That hot plate being ON for half an hour will not only require a generator capable of putting out 1,000 watts, but the battery generator also needs to provide enough energy for 500 Watt hours (in this example).

      A Microwave Oven. My home microwave (as an example) is 1,200 watts. So, a generator would need to be able to put out at least 1,200 watts. The Watt hours are minimal because a microwave “usually” isn’t ON for all that long…

      You need to know two things about every appliance (assuming they’re all typical 120 Volt appliances compatible with a given generator). The power demand (Watts), and for how long they will be “ON” (Watt-hours). Then, you will have a better ability to compare those loads with any given generator and its specifications.

      A battery generator can only provide “juice” until the battery runs down, requiring recharge. A gasoline generator will provide its rated power as long as you keep feeding it gas.

  5. If any of you have an electric golf cart, you may be interested in my latest project…

    I bought a cheap 1500 watt, 36v Chinese inverter from Amazon and installed that under the rear seat of my 36v Golf cart. I tied it to the batteries, which should store about 10,000 Wh (10kwh) of power. The inverter was only about $120 bucks, so if you already have a golf cart with good batteries – you have 95% of what you need. Even if you don’t have one, you can buy a used one with good batteries cheaper than the Goal Zero system cited in the article.

    It’s enough power to run fridge/freezers, lights, small appliances, tools, etc. It’s like a quiet generator on self-propelled wheels. It’s often easier to move my golf cart around than it is to stretch out a extension cord and put it away afterwards. My mitre saw does bogg down on startup, but it mostly works. You can buy inverters of different sizes, so you can go bigger or smaller depending on your needs.

    My one word of caution would be careful on how much you drain the batteries to avoid damaging them. Most golf carts are lead-acid and you can impact the lifespan of the batteries if you discharge more than 50% on a regular basis. So in my case, I’m sort of limited to 5000 Wh – unless its a really dire emergency.

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