How Big Should My Solar Generator Be?

Before purchasing a solar generator, you need to know what size will suit your needs. 

There are so many different capacities on the market to choose from, knowing which one is right for you can be quite overwhelming. 

Take Bluetti for example, we already sell around 9 different solar generators, all with different capacities. 

So, how do you know which size solar generator is right for you? 

In this article, we will explain how to size a solar generator based on your electrical needs. 

Differences in solar generator capacity 

Are you looking for 300Wh of power or perhaps a 2000Wh generator? 

What do these numbers even mean? 

Understanding whether you have a solar generator with a large capacity or small capacity is quite easy. 

Look for the number ending off with a Wh. 

The higher that number, the more capacity your solar generator has. 

Wh stands for Watt Hours - We will go into a little more detail here later on in the article. 

For now, just know that a solar generator marked 2000Wh has much more capacity than a 500Wh generator for example. 

Solar generators with larger capacities are also notably bigger than their lower capacity cousins. 

The reason for this? 

Simple, the higher the capacity, the larger the internal battery, therefore the bigger the solar generator. 

How big should my solar generator be?

To begin figuring out what size solar generator you need, first think about the task you would like it to perform. 

By that I mean what will its application be, how much appliances do you need powered and for how long? 

The more appliances you need powered, the bigger the generator will have to be. 

This is pretty standard among most things in life, nothing changes here with solar generators. 

The reason sizing a generator to suit your exact needs can seem complicated, is usually due to the variety of things people want powered. 

There is no "one size fits all" solution here. 

Your best bet will be figuring out "more or less" the exact amount of power you require based on the exact amount of appliances you use. 

Don't worry about small appliances

If you plan on powering small appliances like phones and cameras with your solar generator, do not worry so much about getting the capacity exactly right. 

In these scenarios you are affectively looking for a large power bank, and in this case a 500Wh solar generator will offer you many efficient charges at full capacity. 

How to know the working times for my device?

(Working time = 500Wh (capacity) * 0.85 / operating wattage of your device)

For reference, assuming the power consumption of your device is 60W (might be a Laptop ), working time will be 500Wh * 0.85 / 60w = 7 hours (roughly calculated) .

So if you own a laptop that draws 60 watts, you would be able to run it for 7 hours on a 500Wh solar generator. 

The formula stated above holds true for most of the solar generators here at Bluetti.

Further on in the article we will provide you with a table outlining the different run times based on your solar generators capacity. 

Why the wattage is important?

As you can see by the formula we gave you above, figuring out what size generator is right for you really all depends on how much watts each appliance you plan to run is drawing. 

Remember, as important the total Wh of your generator are, the amount of watts it can handle is just as important. 

Usually all solar generators will have two ratings:

  • Wh - Watt Hours
  • W - Watts

Watt hours indicated how much capacity your solar generator is capable of storing and the watts reading indicates what type of inverter it has built in to it. 

Remember, all solar generators store DC electricity, but all your appliance use AC electricity. Therefore, before your generator can power your device, it needs to convert its DC electricity to AC electricity. 

It does this by using the built-in pure sine wave inverter. Just like batteries, inverters also have a max limit they can handle. 

Inverters are rated by the wattage they can handle. 

So if your solar generator is rated 500Wh/300W really what its saying is the built-in battery can store 500Wh and the built-in inverter can power devices rated 300 watts and below. 

Therefore, it is VERY important that you know which appliances you want to power before buying your solar generator. 

Make a list of your appliances 

I want you to go ahead and make a list of the appliances you need powered and for how long. make a table like this: 

Appliances   Wattage Usage Time
Cell Phone  20 2
Laptop 60 3
Fan  35 5
Drill 1200 1


By making a list like this you can clearly see what size solar generator would best suit your needs. Also make a note on how many appliances you plan to power simultaneously, you want to always make sure that the combined wattage doesn't go over the preferred generators max wattage rating. 

In our example above, right off the bat we can see that in order to use our cordless drill, we will need a solar generator with a higher wattage rating than 1200 watts. However, if we were only wanting to power say the fan, laptop, phone, and vacuum cleaner, we could get away with a smaller solar generator of say 500Wh/300W. 

However, if we were only wanting to power say the fan, laptop and phone, we could get away with a smaller solar generator of say 500Wh/300W. 

How long would it last? 

Well for that we need to apply our formula: 

(Working time = 500Wh * 0.85 / operating wattage of your device)

Let's assume we want too run all appliances simultaneously. The combined wattage rating would be: 105 watts. 

Therefore, 500Wh * 0.85 / 105 = 4 hour running time. 

Run Times of Different Appliances 

Below we thought to create a simple table which outlines various different sized solar generators and how long they would each run all sorts of appliances. 

500Wh/300W Solar Generator

(Please note this assumes you run each appliance independently of each other)

 Appliance Run Time
Laptop (60 Watts) 7 Hours
Drone (50 Watts) 8.5 Hours
Phone (20 Watts) 21 Hours
LED Lamp (30 Watts) 14 Hours
Cordless Drill (1200 Watts) N/A


1500Wh/1000W Solar Generator

(Please note this assumes you run each appliance independently of each other)

 Run Time
Laptop (60 Watts) 21 Hours
Drone (50 Watts) 25,5 Hours
Phone (20 Watts) 63 Hours
LED Lamp (30 Watts)
42 Hours
Cordless Drill (1200 Watts) N/A


2000Wh/2000W Solar Generator

(Please note this assumes you run each appliance independently of each other)

 Run Time
Laptop (60 Watts) 28 hours
Drone (50 Watts) 34 Hours
Phone (20 Watts) 85 Hours
LED Lamp (30 Watts)
56 Hours
Cordless Drill (1200 Watts) 1.4 Hours


Final Thoughts 

Please note, we supplied the total amount of hours possible to run each appliance, this assumes you run the appliances entirely off the solar generator. 

In actual fact you would need to figure out how many hours each device (not requiring constant power) takes to recharge. 

For example a phone may take 2 hours to fully charge, that means a 2000Wh generator could recharge a phone 42 times before being completed depleted.

Here is the formula for thew above: 

Run Time / Charge Time = Total recharges possible.