ok, so since we're talking about specific loads i'll provide some details and hopefully someone can help me out, cause i'm not an electrician or even remotely electrical-minded and when i try to consider various specs and put it all together i find it kind of confusing.
i have a 2003 Toyota Camry Solara and first of all, it has 2 cigarette lighter sockets. the one on top is unmarked and is apparently just considered the 'cigarette lighter' in the car manual. the other is below it and is termed the 'power outlet', even though it appears to just be another cigarette lighter. all this time i've been using my phone charger through the top one, should i have been using the bottom one? and if i were to get an inverter, should i plug that only into the bottom one, or wouldn't the top one work just as well? i'm confused as to why i have 2 of them.
next, in the manual it has a notice "to prevent the fuse from being blown, do not use the electricity over the total vehicle capacity of 12V/120W." i was thinking about this one someone else linked to earlier in the thread:
http://www.amazon.com/Duracell-Mobile-Pocket-Inverter-100/dp/B000U0M7PG/ref=sr_1_10?s=automotive&ie=UTF8&qid=1277060596&sr=1-10
now that's rated 175W, but it says not to go over 120W in my manual, so obviously i don't want to use the full capacity of that inverter, right?
now as far as what i want to run...i want to charge a laptop battery and the laptop charger says it's 90W and input AC 100-240V, output DC 19.5V. so with the 90W i wouldn't be going over the 120. but what about the part where it says not to go over 12V? how am i supposed to do that if chargers require over 100V AC?
also, i'd like to charge a videocamera battery, that charger says input AC 110-240V and output 11V, doesn't say a word about wattage. then there's an external hard drive i'd possibly like to run just long enough to offload files, and that doesn't say a word about wattage or anything.
i'm just trying to figure out of any of these 3 things on their own are going to be a problem for the inverter and/or for my car's electrical capacity (definitely wouldn't try using more than one thing at the same time).