Whoa! Once again, need to do the math: in crude terms, 960W/12A = 80A! Accounting for inverter inefficiencies, you could easily be attempting to draw 100A at 12v to power that small "8A" chainsaw.
To safely handle 100A, formally you need something like #2AWG wire, depending on insulation, and serious mechanical attachments to both the battery and inverter. For these short lengths and intermittent duty I think you could get away with #4AWG or #6AWG.
Why would we want to stress our dc-dc converter?
Quoting from the above referenced link, I had written:"So, back on topic and to answer the original question regarding our i-MiEV as an energy source: even though it could provide much more power, I personally wouldn't want to draw more than about 100W out of an inverter hooked up to our i-MiEV 12v battery (the car in READY), especially nowadays as our OBC/dc-dc is proving to be iffy."
For the last couple of years I've been successfully using corded electric chain saws doing some serious work around my property (remember, I'm in the hills in a fire danger zone and must keep things clear). What I have is a 48v "power plant" mounted on a little red wagon consisting of Headway 12Ah LiFePO4 cells in two nicely-packaged 4P8S configuration modules in series and an inexpensive 2500W 48vdc --> 120vac square-wave inverter. Even with this setup, the inverter occasionally cuts out under a seriously-heavy load.
If you want to use 12v as a source fed by the i-MiEV, I would use a separate huge 12v battery and feed it from the i-MiEV through a small resistor to limit the instantaneous current being sucked out of the car, and don't forget the car needs to be in READY.
That said, knowing now what we know about the fragility of our OBC/dc-dc, I wouldn't mess with the i-MiEV's 12v battery any more
Suggest we continue this discussion on this thread:http://myimiev.com/forum/viewtopic.php?f=9&t=4251