Where could I buy an external laptop battery adapter from?

Having an external laptop battery adapter is so useful for you can just bring your laptop anywhere and anytime you want. So I found this External Battery Charger 12VDC Cigarette Lighter Adapter for Laptop in Black color for $43.95. This 12VDC Cigarette Lighter Adapter can be used in conjunction with one of the following external battery chargers: Dell Latitude & Inspiron Series Laptop Battery External Charger [PLT-8402WP]. HP F4812A, F4809A, F4098A Laptop Battery External Charger [PLT-4809WP]. Toshiba Satellite 1900/1905 Series & Acer Aspire 1400 Series Laptop Battery External Charger [PLT-1900WP]. It has a warranty of 6 months. Capacity: Output: 16.5v/0.8A DC.

If you got Compaq Presario then you will need this External Laptop Battery Charger for Compaq Presario R3000, R4000, X6000 / HP Pavilion zv5000,zx5000,zv6000, zd7000, zd8000 / HP Compaq Business Notebook NX9100, NX9105, NX9110, NX9600 Series for $80.00. It has an Input Voltage of 100 ~ 240V AC 0.16~0.52A 50/60Hz and Output Voltage of +17.5V DC / 1.5A. It has 6 months Limited Warranty and available in black color.

Check this one if you have an Asus Netbook. This is called Battery Charger (External/Standalone) for Asus NetBook EEEPC 900A 901 1000 PL23-901 and Eee PC 1000HE 1000H 1000HD 1000HA 1200 Series Notebook Laptop Li-ion Battery for $49.00. Charger Specs:12.0 V 3.0A which is brand new with 12 months warranty. Its Input Voltage is 100 ~ 240V AC 1A 50/60Hz  and Output Voltage is +8.4V DC with Output Charging Current of 1.0A. It is available in black color. This is for use with: ASUSEEEPC Notebook battery part numbers: AL23-901 AL24-1000 AL22-703 900A PL23-901 1000HE Series laptop battery. This battery charger can replace the regular AC adapter for your laptop. It is also an external/standalone charger which can charge your battery outside of your laptop.