Just to clarify, we've drifted off-topic . . .
We have, Joe? The "topic" (which you already changed once) was, as far as I can see, safely running an AC device, such as an audio power amplifier, off of the vehicle's electrical system. A full discussion on this topic shouldn't be limited to just the accessory socket (ie: what used to be called the cigarette lighter back in the day.) Perhaps it's appropriate to - again - change the topic heading to reflect this? I'll leave that to you and PV1.
Here's a recap . . .
I inquired if running an 60 watt per channel stereo (combined total 120 watt) audio power amp from the accessory port, which is labeled to able to accommodate that exact wattage. I further inquired about two possible inverter choices. I was advised that, while the port is labeled such, the limitations of the interface meant that attempting to draw anything beyond around 5A would be risky.
It was then suggested that I might want to consider a separate tap from the 12V battery and terminate with Anderson connectors. I'm fine in pursuing this sort of modification and the talk turned to ("off topic?") the practical concerns of what gauge of wire to use and how this could accommodate a more powerful inverter that the 120 to 150W ones I originally envisioned.
Next, the conversation turned to the idea of running an far more powerful inverter, as it's been observed that the vehicle's traction battery is capable of supplying up to 900W when the car is turned on (ie: "Ready.") But, if I'm reading PV1 correctly, this is something that I could only do for 10 minute periods. That doesn't sound like something I'm particularly interested in trying.
I'm also questioning the value of the most recently linked item: the "cigarette lighter" plug with Anderson outputs. If the port itself is the compromising factor in safely accessing the 12V battery's fullest potential, it seems somewhat pointless to insist on passing through that port and onto a set of connectors that are more robust . The "a chain is only as strong as its weakest link" adage would seem to apply here.
So, yes, I suppose I'm wanting to focus on the "off topic" idea of, say, 12 gauge wire directly from the battery, inline fuses (or fuse,) the wires passing into the cabin and then terminating on 30A Anderson pins.
Questions I still have . . .
1) What's the procedure for attaching the wiring to the battery? What size lugs are on the i-MiEV's GS Yuasa's 12V/32Ah unit? Is it advisable to loosen the the bolts on the sides the the terminal clamps and inserting lugs through there? Or should I completely remove the terminal clamp/wire assemblies and slip larger lugs underneath there and reattach? From what I understand with any sort of modern computerized cars (i-MiEV included,) doing the latter would require a trip to the dealer to reset the dash warning light (if not something even more involved and expensive.)
2) Is it necessary to fuse both negative and positive wires? I'm assuming just the positive one would do the trick. With the above described battery/wiring scenario, is a 30A fuse (or fuses) recommended, or should it (they) be of a smaller value?
Final adage of this post "the only stupid question is the one that didn't get asked."