How car jump starters work?

I would like to know how those commercially available jump starters provide hundreds of cranking amperes to start cars?

Simply, what is the electronics behind this?

Here is an example jump starter:

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Any explanation / hint would be very much appreciated.

Thanks, Mike

Reply to
siliconmike
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** Another Groper ......

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** It weighs 20 pounds .

It comes with a charger.....

Hint , hint ????

........ Phil

Reply to
Phil Allison

They have a battery inside of them! A brick-sized battery can easily provide

100 amps for a little while (typically it'd be something like a 12V, 2Ah battery, which will provide 100A for about 1 minute... and that's only if the car's battery is completely dead).

I've never taken one apart, but I believe it's just some simple charging circuit and probably a good-sized Schottky diode to prevent incorrect hookup.

Reply to
Joel Kolstad

"Joel Kolstad"

** From the size and weight ( 21 pounds) of the unit, SLA battery of about 18 AH is more likely.

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At circa $31 it comes well within the cost too.

....... Phil

Reply to
Phil Allison

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Hint - a well charged battery, for the few seconds till the motor starts (or NOT). Won't work if your original battery developed a short!

Stanislaw Slack user from Ulladulla.

Reply to
Stanislaw Flatto

The battery is connected directly to the outside world on the alligator clips; you connect it up wrong, you fry...

The complexity of the charge circuit depends on the product model. Some of them have a simple LED state-of-charge indicator and these models tend to have slightly more complex charge circuits. These products are designed to be plugged into AC longterm, and as such they are float charge circuits - typically an adjustable regulator (TO-220 package, like an LM317) and a current-limiting resistor.

Reply to
zwsdotcom

A diode can't prevent incorrect hookup.

Reply to
John - KD5YI

Four can.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Or some variation of....

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or

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...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

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