I've had my PC680 for over 4 years. My 7 is not a daily driver and I live in Seattle (and don't drive it in the rain) so I go long stretches without starting the car.

For the first two years, it could go 2 or 3 weeks without a problem, then the times slowly came down...with the coler months making it a shorter interval. I actually just replaced it with a new one 3 weeks ago because it stopped taking a charge suddenly.

I have used a cheap charger for the past 3 years and it works fine (although, maybe it's possible the charger contributed to it's early demise...I think the marketing info says they are supposed to last 6 years :)

Overall, I've been very happy with the PC680. You can see my install info at:
http://www.micromanx.com/goble/rx7/batcrane.html

 

The alternator charges them just fine. It has a relatively constant rate. Your typical battery charger will put out 16-18 volts. That's too much for these batteries. They like 14.7 volts. They won't charge worth a **** at higher volts. (I've tried)

There's more info available at the Odyssey Factory website.

 

What does an algorythm have to do with charing a DC battery?

 

http://www.odysseybatteries.com/charging.htm