Can a 100 watt solar panel power a laptop? I am asked this question quite a lot. So I thought I would give a full answer in this post. The idea of running a laptop with a solar panel is very attractive.
Being able to power it at the beach, the park, on vacation and weekends away. Using it indefinitely off-grid and not running out of juice. Especially if you need to keep in contact for business purposes would be a dream come true.
With an internet dongle and unlimited power you could use it anywhere in the world when the sun was shining. Is this vision of laptop utopia possible? Let’s explore the possibilities and see.
Can A 100 Watt Solar Panel Power A Laptop?
“You cannot directly plug a 100 watt solar panel into a laptop to power it. It is possible to design your own system DIY style to power a laptop. As well as the 100w solar panel and a battery you would need a solar charge controller. Also a fuse, an inverter, wiring and AC power out connection to the laptop. This would be the safest DIY way to directly power a laptop using a 100w solar panel.”
There are videos on YouTube showing solar panels directly powering laptops using a buck-boost converter module. (Source: Wikipedia). This method doesn’t include a solar charge controller, battery, or inverter. I am unsure if this is as safe a DIY way of doing it as the method I described above.
If anybody knows the answer please let me know in the comments section at the end of the post.
Both of the above described methods are messy and difficult to deploy on the go. In reality I believe the majority of readers are probably not into DIY. And are looking for a simple easy to use ready made solution for a solar panel to charge their laptop.
Can You Charge A Laptop With A 100 Watt Portable Solar Charger?
You can charge a laptop battery directly with a 100 watt solar panel called a portable solar charger. This method will extend a laptop running time when off-grid. These solar panels are usually soft fold-ups made from industrial strength polymers.
They have multiple solar panels sewn into them that make up their final wattage output. Housing a controller unit with USB and 18V DC output ports. The units are lightweight and fold down to the size of a briefcase so can be easily transported.
A laptop requires a minimum of 15V to over 20V to charge it depending on the make and model. (You can find this information on the back of the laptops adapter.) Portable solar chargers usually have a DC output of 18V.
If the voltage of the charger is higher than the laptop voltage your battery will get damaged. If the voltage of the charger is lower than the laptop it will not charge properly.
Fortunately the controller unit I mentioned earlier should automatically detect the laptop’s voltage. This means the unit will adjust the voltage to suit your laptop. When buying a solar charger you should always check that it has this automatic protection. Look for chargers that have something like iSolar Technology incorporated.
Unfortunately if the laptop requires more than 18V to charge it will not charge properly. This is because the voltages have to match exactly. While this will not damage the laptop it may leave you feeling frustrated and disappointed. So always check the laptop voltage..
The number of amps required are also shown on the back of the laptops adapter. Again this figure can vary but solar chargers produce between 3 and 5 amps. You need to be aware that for the charger to produce the maximum 5 amps it will need direct sunlight.
On average the best sunlight will be captured for about 4 hours per day when the sun is directly overhead. This is assuming you have the solar charger rolled out flat on the ground. During this time you should achieve 5A of charging power.
You can try hanging it up facing the sun to achieve the best power output. But this will require you to adjust its position to follow the sun during the day. But remember the sun is weaker in the morning and late afternoon/evening
This means you may not generate enough amps to effectively charge and power the laptop at these times.
Solar chargers come with a connector cable which fits into the DC output port in the controller. This is great but the end that connects to your laptop might not be compatible with the input port.
Lots of manufacturers provide different connector ends for different laptop makes and models.
It is wise to make sure the provided ends will fit your laptop input port. If not you will have to source one from an electrical store or the internet.
Can You Charge A Laptop With A 100 Watt Portable Solar Charger and Power Bank?
Using a solar charger to directly charge a laptop battery can also cause a problem called reverse polarity. This is when instead of charging the laptop battery it discharges it which can cause damage. This can happen when there is no sunlight and the panel stops charging the laptop.
Most 100w solar chargers have a built in diode to prevent this happening. So you might want to check if the solar charger has one. There are problems with charging laptops directly with portable solar chargers. But you can alleviate all of them by charging a power bank instead of the laptop.
Charging A Power Bank Instead Of The Laptop Battery
A far safer way of keeping your laptop power going is to charge it with a power bank. Because of all the safety features it has you can safely charge your laptop battery with it. This also means you don’t have to worry about voltage and amp changes.
A great example of this is the ALLPOWERS 154Wh 41600mAh Power Bank. It takes 5-6 hours to fully recharge from 0 to100% under full sunlight conditions. It can be charged from a household wall socket. This means you can take it out already charged and use the charger to top it up.
It has enough capacity to recharge a laptop twice. It would be like having 2 extra laptop batteries with you. Yet it weighs around 3lbs and would fit into a pack along with your laptop.
If you have an expensive laptop I would consider charging it this way for off-grid use.
Can You Charge A Laptop With A 100 Watt Portable Solar Panel and Portable Power Station?
By far the best way to charge and power your laptop on the go is with a 100 watt solar suitcase, like the Renogy Eclipse and a portable power station. It just takes all the messing around out of it. Because you can simply plug your laptop into the AC output port without using any other connectors.
A great example is the EcoFlow River 600w 576Wh Max Portable Power Station. Perfect for keeping laptops charged it has a built in solar controller and 600w inverter.
It has 10 output ports:
- 3 x Sine-Wave AC ports
- 2 x USB-A
- 1 x USB fast charging
- 1 x USB-C
- 1 x DC Cig
- 2 x DC 5521 13V3A
It will recharge from an AC wall outlet in 1.6 Hours. A car cig port in 6.5 hours and a solar panel in 4.8 to 9.6 hours depending on available sunlight.
But the best part is the River Max has two 288Wh batteries which are detachable from each other. This means you can make it lighter by using only one of the batteries for short trips or days out. As well as charging your laptop. It will also charge smartphones and power appliances under a 600w power rating.
My Closing Thoughts
There is much more to charging a laptop with a 100 watt solar panel than first appears. The DIY methods I mentioned at the beginning of the post are messy and require electrical knowledge. They are fine to use if you are looking to keep your laptop powered up at home. During an emergency or power outage but as a portable solution I am not so sure.
Using a solar charger can be a good idea from a portability point of view. It can be a bit of a nuisance matching adaptors and there is the 18V limitation to consider. But if your laptop is rated at under 18V it is a good cost effective solution. As long as the charger incorporates the right safety features.
If your laptop is rated at over 18V your best solution will be to use a power bank or portable solar power station. In the end it will all boil down to your budget and how protective you are of your very expensive laptop.
For further reading check out my ALLPOWERS 100w Solar Charger Review
I hope you enjoyed this post and have found it helpful. If you have any questions about 100 watt solar panels charging a laptop. Or want to leave your own personal thoughts, please feel free to leave a comment below.