The key to successful charging is current limiting. The reason batteries cause it to barf is because they can put out a ton of current as the 770 essentially connects them directly to the Li-ion battery in pulses. It measures that current going in and too much will force it to stop to avoid destroying things. You need something like a resistor to limit the current. The problem with a resistor is you automatically turn part of your power into heat, and to charge it in a reasonable amount of time you need a fair amount of current, thus producing a lot of heat (For 6V alkalines).
Off hand I seem to recall the voltage it drops to when pulsing is about 4.2V; 6 - 4.2V = 1.8V of difference. Assume you use a 4.7 ohm resistor, 1.8/4.7 = .382 amps, for about .69 watts. That's a fair amount of heat for a resistor in an enclosed space. Assuming your batteries were immortal and stayed at 6V the whole time it's going to take roughly 4.3 hours for a full charge (Assuming a 91% charging efficiency). If you wanted to be clever you could use a 3V flashlight bulb as a resistor, and then watch the pulsing current draw.
Questions? Standard disclaimer applies: Don't Try This at Home. May turn your 770 into a pool of smoldering magma, explode, or sterilize you at a distance of 50 feet. Please don't play around with this unless you're willing to chance ruining your 770!!!

Larry

You know, I actually understood some of those words.

So, if I used an emergency charger that only takes 3 AAAs (4.5 volts), It 'd charge Nokillo better?

For that guy who bought the extra batteries -- just one would, it seems to me, give you eight(!) hours online. Have you done that?

I would still be a little concerned about too much current... I'm unsure of the internal resistance presented by the charging circuitry and battery. It may be a very fine line between not enough and too much. I tried using a 5V source and had a terrible time getting it to work. I would just suggest going the 4 AA (or AAA) route with a 3V (or 2.5V) flashlight bulb in series (i.e. cut one of the power wires and attach either end to the bulb).

I actually tried that today with 4 AA NiMH batteries and it seems to work fine. No idea how long it will take to complete a charge but it seems to be blinking along happily. It goes from roughly 5.2V to 4.1V each time it pulses and should be drawing about 400 mA per pulse. The bulb is essentially a constant-current regulator so selecting a bulb rated at .5A (500 mA) or less is probably wise. It should be stamped on the bulb or specified on the package if you were to go to Walmart or some place.

Larry

Energizer has recently released "Energizer Energi To Go Cell Phone Charger for Most Nokia Phones" in the US. I'm not sure if they are actually available yet (Best Buy lists them back ordered for $19.99). It has two lithium AA bateries in a small device with "intelligent power management". Has anyone tried this with a 770?