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car battery(how many amps?)

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

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.
 
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.
 
John Sorensen said:
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.

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 :D
 
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
 
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.
 
What is everyone worried about? 60 Joules is a piddling amount of energy.
A middling size flashgun puts out more than that :roll:
 
spuffock said:
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.
 
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
 
well what i'm trying to do is learn
and the way i do that is, i make something interesting

i just got done with a 2 wheel balancing thing(that was hard!)

before that i made a motor

**broken link removed**

now i am making a solenoid metal tosser
so far it chucks that thing 15ft

**broken link removed**


thanks for all the help
 
also i was thinking of useing an IGBT to switch it on and off

i'm useing a mosfet now
but the coil is .6 ohms
+ .1 or so for the wire's

so with a 18v drill battery i'm only pulling 25amps max?
 
Just on a practical note, I have had the fortune ( maybe misfortune? ) of seeing just what 2 decent sized car batteries are capable of doing under these conditions. I have installed many hydraulic systems on commercial vehicles, and sometimes repair work gets interesting:

Take 1 hydraulic pump connected via 2 AWG cable ( about 6 mm conductor dia )
Add 1 defective 2500psi hydraulic ram.

result: rapid fusing of said 2 AWG cable at the connection lug, 2 very hot batteries, 1 never to be found battery cap, and oh yes, and one really nice bang.

the cable is rated to safely carry 175 amps, no idea what current it took to vaporize it, but copper melts just over 1000 C
 
OK I ordered 20 - IRF1404 mosfets

continuos current 202amps
power dissipation 333wats
Rds(on) .004ohm

so i'm going to connect the battery's to 5 feet of 20g wire (= .05ohms)
with them
:twisted:
 
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