Please chime in? How much diesel are we talking about using Paintpollz's example?
to qualify my own example a little further, I don't own a laptop I have an iMac which I love but it is quite thirst for power and is the only thing I own which would require an inverter (I have already starting preparing to liveaboard and sold virtually all my material possessions to go towards the boat kitty).
because my computer is not portable an iPad would be useful anyway, as the only alternative (for internet) is a USB dongle or connection through mobile (cell) phone.
I just did a quick search and found this too ($198):
Pedal power generator ZSFD-1088 is a Brushless Alternator with Gearbox Which can give 50W output with 15-18rpm rotating speed. Because it can give powerful output with low speed, low torque and small size, it is widely used for Exercise Bike, Household Electric Appliance and other Portable charger etc.
The Specification of it is Below:
1. Electric Performance
(1)Rated Rotating Speed: 2000r/min (16RPM with Gearbox)
(2)Rated Current: ≥2500mA
(3)DC Voltage Output: 36-55V DC
(4)AC Voltage Output: 30-50V AC
(6)Line to Line Resistance: 5.8Ω±0.5Ω
2. Mechanical Behavior and Operating Characteristics
(1)Mechanical Noise: <60dB
(2)Output Characteristics: No-load output Voltage varies directly with the rotating speed
(3)Ratio of Speed: 1:125
(4)Weight (Approximate): 3.2kg
3. Dimension: 255mm(L)X120mm(W)X40mm(H)
4. Configuration is below:
The multifunctional powerbank includes a 12V internal battery and through the integrated inverter you can also select an ouput of 3V, 4.5V, 6V, 9V and 12V so it can almost always match your mobile devices for charging them.
Even an AC inverter is integrated in the powerbank so you can enjoy 220V power at max.100W. To complete the powerbank is equiped with an integrated flashlight, storage space or adapters etc and an integrated handle for easy carrying and transportation.
The Powerplus Gazelle is a heavyweight addition to the PowerPlus range, offering a truly versatile portable Eco Power solution. The Gazelle is pedal powered, or can be charged by optional car adapter or the included mains adapter. It offers a range of DC outputs along with a USB output and an amazing 230 Volt AC output for running mains applications such as TV's, Laptop computers, mains lighting, refrigerators etc. The main power bank when charged can be slid off it's stand and used anywhere any time to power any appliance up to 100 Watts. The Gazelle also has an integrated bright LED search light with 2 light settings.
Fully charged the Gazelle will shine its integrated 9 LED light for up to 85 hours, a 7 Watt Energy saving light bulb for 10 hours, a 14 inch TV for 1.5 hours, or a Laptop computer for an hour.
Size: 337 x 355 x 267mm