[SuperGeek]

The stock alternator on the 2008 model is 90A. For more info, see page 300 of the manual - use the link to the left for "451 smart forwto Owner's Manual".

There is no factory upgrade option, and I have no idea how much load is on the system as delivered; anyone here know or know how to measure?

I can imagine the load on a fully loaded Passion is already near the maximum, since the jump-start instructions specifically say to minimize load and not use headlights while the two cars are connected. Of course, I have all the options you mention and I can have all on at once without a problem. My voltage never drops below 13 volts running (12.6 V in "Off" position) , so by my understanding, the alternator's keeping up.

 

[SuperGeek]

I did notice that lag and dimming with my old 42Ah battery; mine started near a second and increased to 3 seconds. After sitting in the driveway for a weekend my battery was consistently showing 11.3 volts. With my 2.0 upgrade, I got it replaced with the 60+Ah battery last month, and I haven't had any issues. Cranks up in half the time, no dimming or lag.

If you have an '08 and haven't gotten your upgrade, talk to the dealer about that. Or just lift open your battery compartment and see if your battery says 42Ah on it. If your car doesn't qualify under the warranty battery replacement, a new battery is about $50-100. $150-200 if you go for an Optima red or yellow top... but those will last almost a decade.