Laptop power inverter - car inverter
A more common solution for powering a laptop - although less efficient - is the AC power inverter or car inverter. It generates AC mains from DC power (ie: a car battery) in ranges from 150 up-to about 1500 Watts. It's usually a generic device not specially made for laptops. Input voltages vary from 12 to 24 volts DC or even higher for professional AC inverters.
The laptop AC power adapter in turn converts AC mains back to DC again. The double conversion process is quite a waste or energy. Say both devices have a conversion efficiency of 80%. The DC-AC-DC conversion results in a whooping 36 % loss of power.
Power inverter quality ratings
The power rating of AC power inverters is usually advertised as inflated and overrated. Small boxes capable of delivering 1500 watts of AC power sounds too good to be true. As always reality proves otherwise. Delivering 1000 Watts of real AC power requires quite a bit more and usually finds it's way in a significant higher price.
Important electrical characteristics for power inverters or car inverters are:
- Peak power duration (specified for Inductive and Resistant load)
- Cut-of power rating (When does it trip and auto-switch off)
- Output wave form (Square, Trapezium or Sine wave)
- Input power range (12V, 24 V or auto-ranging)
- Auto-switch off on low battery
- Low power standby mode and low power sensitivity adjustment
- Reverse polarity protection
For powering a laptop only - there are many relatively cheap power inverters on the market. If the power inverter should also power a desktop computer, audio, video equipment it's better to resort to the more expensive pure sinewave power inverters.
Quality power inverters
The marine industry is known to produce high quality and dependable AC power inverters. A top brand is the Phoenix inverter made by Victron Energy recognizable by it's bright blue metal casing. This company has a very long track record - power inverters do not get any better than this. Even on the second hand market Victron Energy power inverters are hard to get. Once you have one, you keep it.
At the other end of the price spectrum but with relatively good ratings
The Machine is equiped with a 500 Watt Alessi pure-sine wave AC power inverter produced by TBS electronics as pictured below.
|TBS Powersine 600W 24V Pure Sinewave power inverter - also known as Alessi|
Back to the Alternative laptop power overview.