Found the info again... SFC A50 is the generator I was thinking of... not for running your Airco.. but for keeping the battery up all the time.
here some basic info from their website:
The SFC A50 is a battery charger based on DMFC (Direct Methanol Fuel Cell) technology. Using Methanol as a fuel, this system offers much higher energy density than Pb-batteries, which are widely used today. The unit delivers up to 100Ah per day (1200Wh per day), operates almost quiet and is very environment friendly. The replacement of an empty fuel cartridge can be done in seconds compared to several hours needed for charging an empty Pb-battery. The SFC A50 is intended to operate in combination with a 12V
Pb battery. The battery can provide peak power as well as startup power for the SFC A50 while the SFC A50 offers a significant extension of energy density to the Pb battery.
The Smart Fuel Cell works as a battery charging unit. If the voltage at the connected battery drops below 12.5V for longer then 10 seconds, the SFC A50 automatically initiates the charging process. The charging process of the SFC A50 will be completed and the unit will switch to sand by mode when on of the following conditions occur:
Battery voltage is higher than 14.5V
Battery voltage is over 14V and charging current is less than 1A
Battery has been charged for six hours and the voltage is higher then 12.5V
Complete Data Monitoring Interface includes Live access to SFC A50 internal system parameters e.g. stack voltage, stack current, temperatures. Delivers all necessary information for evaluation, testing and system integration.
Remote battery charger for 12 Volt
Pb-batteries whenever solar power, grid power or combustion engine driven generators are not an appropriate solution. Works well with solar for a hybrid solution.
Power: 50W (continuous)
Voltage: 10,5 - 14,5V DC
Ambient Temperature: -20 C to +40 C, -4 F to +104 F
Storage Temperature: +1 C to +45 C
Humidity: 20% - 90%
Fuel Methanol Consumption: 1,3l Methanol/kWh at continuous operation
Noise Emission: less than 40dB(A) at 1m distance during operation
Dimensions: (WxHxD) 380mm x 260mm x 150mm
Weight: App. 6kg (without fuel cartridge)
Electrical Interface: 12V
DC output including sense wire to automatically charge 12V
Here's a situation almost every RV aficionado is certainly well familiar with: on a holiday journey there is a beautiful spot beckoning to linger longer than originally planned - but the on-board batteries have almost completely run down. Unfortunately, the most scenic locations are not connected to the power grid. This is where the SFC A50 comes in, representing an attractive alternative to conventional power supply systems.
Reliable power supply throughout the entire winter season
Even if solar cells fail to do the trick in the dark winter season, you can count on the SFC A50 to provide adequate power. The fuel cell is capable of feeding a daily 100 Ah to the battery and delivers an output of 50 watt. With only a single five-liter methanol fuel cartridge the SFC A50 will deliver electricity for a five to ten day period - depending on the season and personal consumption. In this way, RVs can operate independently - without the unpleasant exhaust and noise of a generator. Moreover, the fuel cell can be reloaded in only a few seconds.
Thanks to its own thermal discharge the capacity of the battery increases. Especially in the wintertime, this ensures a one hundred percent availability of on-board electricity. With its mobile, clean and silent power generation, the fuel cell offers a far more comfortable alternative to generators or solar cell systems.
The unit weighs around seven kilograms and is about the size of a briefcase.
Thanks to the compact dimensions and light weight the unit can be easily retrofitted and integrated into vehicle interiors. Power supply is fully automatic due to the charge controller: whenever battery voltage drops below a certain level, the SFC A50 is activated and recharges the battery. A remote control unit is available as an accessory for easy operation from anywhere inside the vehicle.
Clean and silent power generation by methanol
Also available in a lightweight weatherproof box...
and here an article on fuel-cell integration in a trailer: Fuel Cell Works Supplemental News Page
and here some other, portable models..
EFOY - Energy for you
US dealer: Sandpiper Technologies Video Cameras and Surveillance Systems: Home Page