My answer to How do you charge your laptop via USB?

Answer by Allen He:

You may feel your laptop like a useless box when it’s discharged and you don’t have an adapter with you. After all, not only do you not have a way to charge the battery in your laptop, you don’t even have a way to run your computer via a wall outlet. Particularly when the original charger that came with your laptop is broken, it becomes the real deal. But do not worry, we can show you alternative ways to charge your laptop without a charger.

Auto/Air Adapter
If you spend more time in your car than in an office because of your job specifications, then you will need this method mentioned below. But you can’t just wire the laptop directly to the car battery since their batteries have different voltages, sure, there are a myriad of ways to “hotwire” a laptop to a car battery however, in this case it’s better to be cautious as the laptop could become damaged.
The more efficient way of adapting the power from a car battery to charge or power a laptop is to use an inverter, such as TBS’ Powersine series PS600-12. These can be connected through the vehicles cigarette lighter or wired directly from the car battery and have the added benefit of being able to charge other devices such as audio/video equipment or even other mobile devices.

Solar Power
Another popular alternative to powering and charging laptops takes advantage of solar energy through the use of solar panels and battery kits. Unlike car battery alternatives, solar kits don’t rely on bulky power storage or large inverters to garner power, but harness the power of the sun.
Most of today’s solar technology has been refined to produce smaller, more efficient and flexible photovoltaic cells, making them ideal for adaptation into portable folding panels that are capable of harvesting enough energy to charge an 18V laptop.
Goal Zero Sherpa 100 Solar Kit is one of those devices that can not only charge a laptop but also store enough energy in a portable battery to recharge devices multiple times, in the case of the Sherpa 100, twice.

Portable wind turbines
Wind is another renewable energy source that can be harnessed to charge laptops and function much in the same fashion as solar but with a little more bulk and rigidity. They also harvest renewable energy and store it in battery form. Unlike their massive counterparts, however, they tend to use vertical-mounted blades utilizing more surface area in a smaller package.
Skajaquoda’s Trinity is one such charger that takes advantage of the vertical fan placement but places it in a small 12-inch package. When needed, the tripod-like legs are pulled from the tubular body and the blades pop out from the sides, making it ready to go. As the blades spin, they rotate an internal 15-W generator that produces power and stores it in an internal 15,000-mAh lithium-polymer battery.

As you see, a few alternatives are provided to get your laptop running again. Needless to say, before you use any alternative way to charge your laptop without original charger, you need to do a small research if it’s suitable for your specific device, some laptops can react very differently from your expectations!

How do you charge your laptop via USB?