Output

voltage 12v and same for the car battery (some old land rovers were 24v and i think a few US cars are to)

current errr aint a clue, grab a multi meter, only a fiver at maplins

Usually 12v @ 10 amps (120 watts)

If the battery is good usually in the region of 3-400 amps for around 10 seconds.

Ed

Any half decent multimeter will measure current - that's why it's called a multimeter rather than say a voltmeter. But cheap ones may not be able to handle the 10 amps or so a lighter takes.

Engine running and system charging normally, 13.8V @ whatever rating fuse the makers put in the fuse box - could be 20A if they power interior lights and radio off the same circuit. As a 4x40w stereo will draw about 13A and the interior lights about 1A you would have about 6A to play with before the fuse blows. Turn the stereo and lights off and you can draw a bit more current. The wires to the lighter socket will not be rated for more current than the fuse rating so don't fit a bigger fuse or you could melt the insulation or in the worst case start a under dash fire.

Battery should have a label on it giving the rated capacity and peak cranking output. Rated capacity in AH = current x hours - usually over 10 or 20 hours, eg 60Ah on a 10 hour rating supposedly gives 6 amps for 10 hours but the voltage will be dropping off. Draw more than the peak cranking output or near this for more than a few seconds at a time or repeatedly without an adequate rest to dissipate the heat and the battery can warp plates or even explode.

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I wouldnt draw much more than 10amps continuous from the cigar lighter- the contacts within arent designed for heavy power transmission and get hot. Then melt.

Your question about how many amps from a typical battery.... Well if you were to dead short it you could pull around about 7-800amps from a ~ 60ah car battery.

The starter motor would draw around 200amps starting a warm engine, and around 500 amps starting a cold one. That is assuming a typical 2 litre 4 cylinder type engine.

With the medium size diesels we have around here - upto 6 litres at 12v using one or two 522 batterys which are each capable of suppling 1300amps you can see why proper fusing, insulation of connectors and being very careful to avoid other shorts is important.

Tim..

" Tim (Remove NOSPAM. Registry corupted, reformated HD and lost alot of stuff :(" <

car battery....

ps .... before either the plates buckle or they explode.

Don't try this at home children.

Tim..

Typically 12v and "up to 15A" - but I'd not go over 10A myself!

What kind of cigarettes did you have in mind?

A lead acid battery produces 2.1v per cell so it's 12.6v. Anything less and your battery is done for. When running the normal system voltage should be 13.8v.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!