I hate to be the bearer of bad news, guys, but the previously reported 1.5-hour runtime of the Willcom D4‘s standard battery is not limited to WWAN-only conditions. Nope. Exactly as stated on the official product page and in keeping with what I’ve always believed (it just makes no sense for Sharp/Willcom to publish the lowest possible battery estimate on their marketing materials), the D4 with its standard battery calls it a day within 1.5 hours under all conditions.
I’ll do more thorough and varied testing before I publish my full review, but based on my usage of the D4 so far (limited as it is at this point), I can confirm that you won’t spend much more than an hour online via wi-fi (Bluetooth off, screen set at mid-brightness) before you’re looking for an outlet.
I want to be utterly dismayed and furious with this pathetic battery life (from Menlow, the most efficient x86 computing platform around, no less!), but it’s difficult to be when Sharp/Willcom has always been upfront about this. Contrary to the 5- to 6-hour battery life listed on the DFJ product page, Sharp/Willcom has never suggested that the D4’s operating time was anything more than 1.5 hours. It’s an atrocious and embarrassing figure, to be sure, but why be upset over something that was always out in the open? I don’t feel tricked, ripped off, or misled because I got exactly what Sharp/Willcom said I would get.
It’s also worth noting that the D4 is supposed to be a Japan-only UMPC. I suspect that if it was ever officially released in the US, which is unlikely to ever happen, Sharp would probably include the 4.5-hour extended battery as a standard accessory. This is what Fujitsu did when they brought the LifeBook U1010 (bundled with 2-cell battery) to the US as the U810 (bundled with 4-cell battery), so it’s a reasonable possibility.
Another reason I’m not regretting my purchase at all is that I bought the D4 during Willcom’s launch promotion, which means I’m getting the extended battery (2880mAh) for free! Although it makes the device thicker and weighs an extra 4 ounces, I think it’s absolutely worth it. With the standard battery installed, the D4 is actually only 1 pound so a bump up to 1.25 pounds still keeps it really light.