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You have probably seen portable solar chargers that recharge mobile phones and tablets, and they work just fine. But can a solar panel run a computer? If you’re going to rely on solar energy and you’ll be using a computer for work, knowing the power consumption of computers is a must. Fortunately, that’s what this guide is for.
A 300 watt solar panel can run a laptop for up to two hours. A computer equipped with speakers, printer and router will require 400 watts or more of solar power.
How Many Solar Panels are Needed to Run a Computer?
There are many types of computers and usage varies from person to person. On average, a desktop computer uses 150W-200W, but if we add a printer, router and speakers, it could reach 300W. To run a 300 watt computer for 8 hours a day, 2400 watts of solar power is required.
A 300 watt solar panel like the DOKIO Solar Panel Kit can produce up to 1500 watts with 5 hours of sunlight. You need two of these to generate 3000 watts, enough to run a computer for 8 hours. You will also need a battery to store solar power o you use the computer when the sun goes down.
Solar panels are not 100% efficient, so a 250W panel might produce about 200W an hour. You need 3 x 250W solar panels to run a 300W computer.
The formula is:
250W solar panel = 200W per hour
200W x 6 hours of sunlight = 1000W
3 250W solar panels = 3000W
If a 250W solar panel can produce 1000 watts, three of these can generate 3000 watts, greater than the 2400 watts requirement of our computer.
It does not have to be a 250W solar panel. It can be any combination as long as the total watts is greater than 2400W. In fact we recommend 3000W minimum in case there are cloudy days and the panels can’t produce enough energy.
Solar Panel Requirements of Computer Peripherals
For your reference this is the average consumption of computers, various peripherals and how many solar panels are needed. Again these are for general considerations only. Computer specifications vary so check the instructions or manufacturer website.
|Computer / Peripheral||Solar Panels Needed|
|Average Desktop Computer||150W-200W|
|Desktop Computer with Peripherals (printer, modem, speakers)||300W|
Solar Panel Requirements of Custom Built Computers
Custom PC builds often use more power than all in one units because they are customized. This is especially true for gaming because of the hardware. Expect to use more solar power if you plan to run a gaming PC on solar.
|Custom PC Build Type||Solar Panels Needed|
If you’re going to build a PC you’ll have to figure out the power usage of each component. Total it, add some headroom and you’ll know what solar panel size is needed. PC components have vastly varying specs, but here’s a general guideline.
- Motherboard: 30W-180W
- Power Supply: 130-700W+
- SSD: 1W-3W
- Case Fans; 0.5W-5W
- RAM: 2-6W
- HDD: 0.7-7w
- GPU: 30W-400W+
- CPU: 50W-175W
How to Install a Solar Powered Computer
You’ll need solar panels, batteries, a charge controller and an inverter. A solar panel kit includes the panels, charge controller, cables and connectors. The inverter and battery are (usually) sold separately. We have a solar installation guide here, but this is a quick overview of the steps.
- Install the solar panels on the rooftop, ground or RV.
- Link the panel connectors to the charge controller.
- Plug the charge controller to the battery.
- Connect the inverter to the battery.
- Connect the computer cable to the inverter.
Some solar systems may have a different sequencing order, i.e., connect the controller to the battery first before the solar panel. Refer to your solar panel kit installation instructions for particulars. if you’re buying the parts individually, make sure the cables, wires and connectors are appropriate for your system.
Give the solar panels time to charge. This can take a few hours or several days depending on the weather. When the system is charged, turn your computer on and it will run on solar power. You can keep using the computer as long as there’s power in the PV modules.
The inverter capacity must match or exceed the computer requirements. if your system needs 500 watts, get a 500 or 1000 watt inverter. A good choice is the Maxpart 1000W Power inverter which can be used in homes, RVs or trucks.
How Many Batteries are Needed to Run a Solar Powered Computer?
Solar panels can run computers as long as there’s sunlight. When the sun goes down that’s where batteries come in. The battery (or batteries, depending on your setup) stores power for later use. So if it’s raining or late at night, you can still run your computer.
The question now is how many batteries will you need?
Solar battery capacity is measured in amp hours (ah). They are available in different voltage levels like 12V, 25,V, 36V, 48V and so on. To find out how many you’ll need for a solar powered computer, use this formula.
Amp hours x volts = watts
Watts / volts = amps
If your computer uses 300W an hour (2400 for 8 hours a day), you need at least a 12V 25ah capacity battery (300 / 12 = 25).
25ah is the minimum requirement, and it means you’ll completely drain the battery down to zero. It’s better to use only half the battery capacity to prolong its life cycle though, so get a 50ah capacity instead. If your computer needs 600W / 50ah, get a 100ah battery, and so on.
Which Battery to Buy?
There’s a lot of debate which to buy, lithium ion, gel, AGM or flooded batteries. But we recommend lithium ion batteries. They offer superior performance, longer life cycle, longer depth of discharge and just a better investment overall. Just like you want to have the best power banks same with batteries.
Lithium ion batteries can store more energy than flooded or AGM and charge up 75% faster. You can drain lithium batteries to zero, and it can handle 5000+ full charging.
The ideal setup for a 300W computer? 3 x 250W solar panels, a 12V, 50ah battery, a 600W inverter and a 20A charge controller. The controller size depends on the solar system’s amps and voltage rating. If it is 14A, you need a 14A or higher controller. 20A to 30A provides more than enough plus gives you some cushion for power surges.
How to Calculate Computer Power Usage
There are two ways to measure computer power use, one easy and one hard. The hard way is to add up the total watt usage of each component 9computer, printer, modem etc.). The easier way is to buy a Kill-A-Watt meter. Connect your computer surge protector to the Kill-A-Watt, plug it into a wall outlet and it’s ready.
Use your computer and its peripherals as you usually do. After a week or two, the meter should give you an idea of the computer’s watt usage. This will tell you how many solar panels you will need and what size.
The video card and processor are the biggest energy hogs. These consume more power than the other components. Overclocking – common in gaming PCs- will require even more solar power. Our solar panel recommendations here leave room for future expansion, which is why it seems high. It’s better to set up a bigger solar power system now than wait when you need to upgrade.
Considerations For Running PCs on Solar Power
Throughout this guide we have used the ‘typical” desktop computer. That is, a home / office PC for typing, spreadsheets, web browsing and email. As shown in the chart above, gaming PCs need way more power and you have to double or triple the solar panels and batteries required.
Gaming PCs are designed to run for hours, so the solar panel / battery capacity must be able to keep up. A top of the line gaming PC consumes more than 800W an hour so a standard solar system won’t be enough.
You’ll save power with a laptop. If you use the computer for basic office related tasks, web browsing and watching videos, a laptop can handle it fine. Unlike desktop computers, you can charge a laptop quickly with portable solar chargers.
Large computer monitors use up a lot of watts. LED backlit monitors are more energy efficient and will save power. SSD also consumes less power than standard hard drives. On the other hand, high performance video cards require plenty of power.
How to Cut Down Computer Power Consumption
- Turn the PC off or put it in sleep or hibernation mode if you won’t be using it for more than half an hour. That will reduce its solar power use.
- Use energy efficient computers. If possible, use a laptop rather than a desktop.
- Gaming PCs should be run on electricity, batteries or solar generators. The only exception is if you have a powerful solar power system, say 3000W or more.
- Turn off the printer, modem and other peripherals when not in use.
- Turn off the computer when you’re done for the day. Do not leave it in standby mode because it still consumes power.
- Laptops need less solar power than desktops.
Computers have become a part of our daily lives, and for many people, so has solar power. It’s not surprising therefore to want to use them both. Fortunately it’s now possible and even practical. Just know that if you want to live off the grid or get a taste of solar power, you don’t have to give up your computer.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.