Need mathematical help??

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Jan 25, 2010 | 01:15 PM

#1 (permalink)

Crossfireone

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Joined: Jul 2007

Posts: 157

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From: S.W. Ohio

Need mathematical help??

Always wondered what the parasitic drain is on my Crossfire so since I'm installing a new battery thought I would take reading. I have a volt-ohm meter that has an amp. port so here's what figures I found. My amp reading is 0.05 A. The manual for this meter shows that 1ma = 0.001 ma. It mentions that a typical drain is 100 ma which allows for the clock&radio memory. Is there a formula that would tell me what my 0.05 A reading translates into for a VOLT draw that my car is putting on the battery with the key off & all known draws other than parasitic draw are off, in other words doors closed ,no alarm set, auto lock feature subdued, etc.?? Thank you

Jan 25, 2010 | 02:56 PM

#2 (permalink)

pizzaguy

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Joined: Jun 2009

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From: Fort Worth, Texas

Re: Need mathematical help??

Quote:

Originally Posted by Crossfireone

That fits within specs, nothing to worry about unless you plan to let the car sit for long periods of time (like over winter).

Quote:

Is there a formula that would tell me what my 0.05 A reading translates into for a VOLT draw that my car is putting on the battery with the key off & all known draws other than parasitic draw are off, in other words doors closed ,no alarm set, auto lock feature subdued, etc.?? Thank you[/i]

There is no such thing as "Volt draw". Your current draw is 50 millamps, you are within specifications.

Jan 25, 2010 | 03:02 PM

#3 (permalink)

GDC-SRT

Senior Member

Joined: Dec 2007

Posts: 1,366

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From: Mn

Re: Need mathematical help??

I believe Pizzaguy is right.

.05A
multiplied by 1000 ( one Milliamp)
Equals 50 milliamps

Jan 25, 2010 | 05:03 PM

#4 (permalink)

waldig

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Joined: Feb 2008

Posts: 4,508

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From: VA

Re: Need mathematical help??

1ma. or milliampere is 0.001 AMPS. Let say that the battery has 50 amphours of stored current, You could ideally support a 1 ma load for about 50,000 hours. Or Ideally 50 amps for one hour, but the higher the rate of drain the less you can get before the voltage ( Pressure or push) tapers off and falls below like 10 volts and your kaput.

The battery has self discharging characteristics which shorten that by a goodly amount, as a good battery will sit for a couple of months and still crank you up, beyond that your into the lucky region.

Woody