The Raon Digital Everun is one of the few UMPCs with a battery life that surpasses 5 hours.

No matter how incredibly powerful your laptop is or how many encyclopedias are stored in its harddisk, the moment it runs out of juice it amazingly transforms into an expensive doorstop. Mobility is more than the ability to lug the notebook around. Being untethered also means your system should be able to survive for a reasonable amount of time without charging.

The following machines all have exceptional battery life. However, in the bid for greater uptime, compromises had to be made. With the exception of the Lenovo ThinkPad X61s, these notebooks use slower but more energy-efficient processors. The Sony Vaio VGN-TZ18GN and Toshiba Portege R500 are based on the Core 2 Duo ultra-low voltage chip which chirps along at a leisurely 1.2GHz (compared with full-powered processors that range from 1.6GHz to 2.8GHz). The Sony Vaio-G118GN and Raon Digital Everun aren't even dual-core platforms with their Core Solo and AMD Geode processors, respectively. However, the core strength of these portables is that when their more powerful counterparts grind to a stop from lack of juice, the following mobiles will keep on pumping like the proverbial Energizer bunny.

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	1.	Sony Vaio VGN-TZ18GN (Core 2 Duo U7600 Processor 1.2GHz, 1GB RAM)   Outlook One of the first notebooks to incorporate a flash-based Solid State Drive (SSD), the Vaio TZ series features an impressive feature set like integrated Webcam, fingerprint sensor and an LED-backlit display. Despite its diminutive 11.1-inch chassis, it still manages to squeeze in a DVD Super Multi drive under the hood. Cheaper models without the SSD component are available as the Sony Vaio VGN-TZ17GN and the Sony Vaio VGN-TZ16GN. Standard battery : 11.5 hours Extended battery : 18 hours See full specs | Rate this
	2.	Sony Vaio VGN-G118GN (Core Solo U1500 Processor 1.33GHz, 1GB RAM)   CNET Asia rating: 8.7 out of 10 The good: Incredibly light; sturdy carbon-fiber body; great battery life. The bad: Only a core solo processor; tops out at 1.5GB of memory. The bottom line: Sony's latest business-centric Vaio is a wonder of sturdy construction, ultralight portability and enticing design. At the same time, it's not exactly an inexpensive number-crunching beast. Standard battery : 11.5 hours Extended battery : Not available Review | See full specs | Rate this
	3.	Toshiba Portege R500 (Core 2 Duo ULV U7600 Processor 1.2GHz, 1.5GB RAM)   First take The Portege R500 is Toshiba's newest premium notebook for the business crowd. Just how premium is it? Well, with a list price of S$3,999 (US$2,944.27), this puts the R500 out of reach for all but the highest executive. However, for a dual-core 12.1-inch ultraportable complete with integrated optical drive, there are few which can compete in its class. The Sony Vaio G series may be slightly more affordable at S$3,799 (US$2,797.02), but it has only a Core Solo processor. The HP Compaq 2510p comes closer with a Core 2 Duo chipset, but isn't as slim or light. Protected with Toshiba's EasyGuard features and possessing long battery life, the Portege R500 is great for frequent travelers. Standard battery : 11 hours Extended battery : Not available First take | See full specs | Rate this
	4.	Raon Digital Everun (AMD Geode LX900 processor, 512MB RAM)   First take When we first set eyes on the Everun, honestly, we weren't impressed. Looking like an ungainly, elongated Treo PDA-phone, we preferred the simplicity of the slate Asus R2H, slider Sony UX series and even the clamshell Kohjisha SA1F00 and Fujitsu LifeBook U1010. TrendsMobile, the distributor bringing the Everun to the Singapore market, passed us a pre-production unit over the weekend and though we still did not really go gaga over the design, we could appreciate its inner beauty. After all, with a battery life of close to 6 hours and a whole slew of upgrade options, the Everun has come closest to fulfilling the UMPC promise of mobile connectivity and all-day computing. Standard battery : 7 hours Extended battery : 12 hours First take | See full specs | Rate this
	5.	ThinkPad X61s (Core 2 Duo Processor L7300 1.4GHz, 1GB RAM)   CNET Asia rating: 8 out of 10 The good: Solid performance, thanks to the latest Core 2 Duo processor; extremely portable design; excellent keyboard; fingerprint reader; easy-to-use ThinkVantage utility; lengthy battery life with optional extended battery. The bad: Lacks built-in optical drive; standard-aspect display feels outdated. The bottom line: The ThinkPad X61s provides excellent dual-core performance in a lightweight, compact package that's still comfortable to use. Standard battery : 6 hours Extended battery : 10 hours Review | See full specs | Rate this

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