hi all

can a car battery put out 500 amps for under 10ms?

thanks for the help

 

There's two ways to find out...

j.

 

so doe's that mean asking in an electronics forum is not a way? :?


anyway i don't know those 2 way

so can someone please help me with this

thanks

 

Short answer, yes, depending on the CCA specification of the battery.

Most (if not all) automobile batteries will provide a CCA (Cold Cranking Amps) specification. The CCA is a measure of the current a battery can deliver at 0 degrees Farenheit for 30 seconds without dropping the voltage below 7.2 volts. So if your battery in question has a CCA measure greater than 500CCA, then you will be able to deliver at least 500 amps for under 10mS. Presumably, the CCA measure will rise (slightly) when the temperature rises as well.

 

ok good deal
thats what i needed to know


thanks for the help

 

The two ways are to "look it up" (research) or "try it."

There's not a whole lot of legitimate uses for 6 kW for 10mS, so I assume you're trying to do something destructive (and not just trying to start a car).

j.

 

Actually it depends on your voltagre criteria is. If you ran a jumper cable from one side to the other, you might get 1500 amps but only 1 volt output. Cold Cranking Amps is the load which will drag the battery voltage down to 10.5 (or the mfg can choose their own voltage for the test) at a given temp. You can get more current if you can live with 9V or whatever.

Anyways, 500 amps is similar to starting a large engine. I measured current going to the starter for a big Rotax 582 two stroke and it was around 300 amps to start and 100 to keep it cranking if I recall correctly. So 500 is probably not unusual for starting a truck.

 

oh man i hate that

i have been surfing the internet all weekend!
so i did look it up

when i asked here i got more info in 10 min then all weekend online

as for trying it i didn't want to buy a $50 battery if it would not work

thanks to the rest of you that gave me the answers i needed

 

OK, you got your answer now but you also got me curious what you are trying to do with 500 Amps for 10 milli seconds.
Its not a trifle amount of energy to play around with so, what's the secret :wink:
Klaus

 

u know that big bang everyone heard yesterday.... lol

 

For a little more serious approach, a lead acid battery has an EXTREMELY LOW internal impedance, along with most rechargable batteries it will happily supply enough current to destroy itself.

500A certainly sounds possible, particularly if you buy a heavy duty battery, but like everyone else - I'd like to know why you feel a need for this amount of current?. Bear in mind, it's got a good chance of destroying the battery, and probably whatever else you connect to it, also what are you planning for connecting it? - you will need short, extremely thick, wires to avoid limiting the current through the wires.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

What is everyone worried about? 60 Joules is a piddling amount of energy.
A middling size flashgun puts out more than that :roll:

 

I don't think so, a flash gun is a lot smaller - we used to use a home made strobe for disco's back in the 70's - I seem to remember it was about 10-20 Joules, far bigger and brighter than flashguns (and far bigger than most commercially available disco strobes).

But that's not really the problem, I suspect switching 500A ON and OFF in 10mS is somewhat more troublesome!.

But as we still don't have a clue as to why he asked the question, it's hard to know how it might be approached.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

I'm not worried - it is only at 12V, and that voltage will collapse as well quite quickly.

One thing I am concerned abt was to do with summing my chem teacher told me once.

12V lead-acid batteries have a low ESR (as N.Goodwin stated) which means it can chuck out alot of amps (teacher stated closing on 1000A into a decent short, new acid, clean rods and fully charged).

Now he then stated if you use chunky wire and short out a car battery it will dump all that nice power into itself and heat up bloody quickly and well the thing abt lead-acid batteries is well they are filled will ACID - figure out what happens if it goes BANG!!!!

I really wouldn't want a face full of boiling sulphuric acid

 

It took me longer to type this message than to find this link.

http://hypertextbook.com/facts/2001/MelissaNg.shtml

j.