jray3 wrote:Another downside of genset use is the risk of excessive amps into the battery during regen, though not a big risk given our 33 kW max regen.
I agree with you about the diesel genset. Bad choice of fuels in my opinion.
For a generator based range extender you need something purpose built to output DC regulated to around 360 volts or a bit less. Set up this way it couldn't overcharge the pack and too many regen amps would not be an issue because amps from the generator would drop as the cars motor regens, upping the apparent battery voltage. Most of the power from the generator would go straight to the motor controller over the top of the battery. Putting little stress or heat into the battery (less than driving without it). The systems shouldn't even see it for the most part since the i measures power in and out of the battery pack, at the battery pack. You would likely see some astronomical RR figures after a conventional recharge. But other than that it shouldn't effect the systems.
Then the question becomes how long does one want to cruise on the highway anyway. I prefer about 350 miles max in a day and would do 500 if needed. So at 500 miles that's about 8 hours time behind the wheel if you can average 65mph or 70mph. To my mind that is a worst case scenario (power consumption wise) to design around. It simplifies things if you actually do use the battery during the trip. Very slowly, but depending on it for some of the power. An educated guess 11Kw or 12Kw output would be just about right for a DC genset.