After being hit by Hurricane Irene last week, I happened to loose power for literally one week so rather than rely completely on batteries and being a nomad, I used my Cobra 400 watt power inverter (wired directly to my car battery such that I can keep it powered even without the key on accessory) on and off to power a small emergency lamp, charge my laptop battery, power my modem, and other small items like a mini-fan.
For the most part this was limited to maybe five hours tops per day and I usually would idle my engine every hour for a few minutes to make sure the battery got a boost again, and while I never had anything fail, I wanted to ask if the drain/charge cycle from the power inverter could've caused any wear on the battery, and also if it's okay to idle your engine to power an inverter.
The reason for the latter question is because I heard that in the winter it's best to not let the engine idle to warm up as it allows carbon to build up, however wouldn't Seafoam or a similar cleaner in the intake fix that? I also heard that the idling affects the oxygen content in the fuel, but don't most modern cars have sensors to compensate?
Also, my final question is how long you need to idle your car for the battery to get a good charge. I heard from my father who is an Electrical Engineer that car batteries are designed for a burst of power rather than a steady stream (like in Marine batteries) so it's never ideal to have an inverter running without the engine -- but if the battery is designed to burst output, does that mean it would have a rapid/instant recharge once you crank the engine?
Thanks very much in advance for any insights,