George Laing notes that Nikon has announced a DC-powered charger for the D1, F100 and E3/E3s battery packs.
Called the MH-17 Quick Charger, it's designed to plug into an automobile cigarette lighter. A note to US dealers indicates that charge time is approximately 160 minutes for the D1's EN-4 pack, while the F100's MN-15 and the E3/E3s' EN-3 will take about 110 minutes. List price is US$320, with no word on the expected street price or when the product will ship.
A more versatile solution than a dedicated DC charger is an AC inverter. An AC inverter is a small DC to AC converter box that enables a range of AC-powered products to be powered and used simultaneously in the car, including multiple battery chargers, laptops and even television sets.
A popular and inexpensive brand of AC inverter for North American use is Statpower. The Statpower PROWatt 250 has been dangling from my cigarette lighter for almost five years now and has performed flawlessly. It enables multiple 110-120 volt devices to be powered at the same time (as long as all together they don't draw more than the maximum wattage capacity of the inverter). It should be well under US$150 in the US. There are several models to choose from, each with a different maximum operating power. Be sure to select the one that has somewhat more capacity than you'll think you need when all your favourite electronic devices are switched on. Email Statpower for information on pricing and distributors in your area, or call them directly at +1 604-420-1585.
For photographers requiring 220v output, you may wish to follow AP photographer Jerome Delay's recommendation for locating a "Java-enabled" inverter:
Just read about Nikon's fast car charger. Neat but expensive.You're right about the inverter. It's the most useful part of my kit. It's from Hama, 12V DC in, 220 AC out, 400Va output power, reference 45740, purchased at Amsterdam duty free for less than a 100 bucks. And it will make coffee.