[DML] Re: tracking down a power drain

["twinenginedmc12" <twinenginedmc12@xxxxxxxxxxxxxxxxx>]

Hi Andy.

There may or may not be something wrong with the amplifier. Lots of devices chew up standby current.  If they specify a standby current in the user's manual, you can compare it to what yours draws to see whether it's excessive.  

That current draw, 0.05A, would typically not be enough to deplete a new charged battery in 5-6 days.  But repeated exposure to overdraining will degrade a battery relatively quickly compared to a battery without such a drain.  If you multiply the parasitic current an Amperes times the time in hours, and make sure that the product of those two numbers is only a small fraction of the battery storage capacity specified on the label in Ampere*hours (Ah), say 1/10 for example, battery longevity and charge retention will improve.  The lower the parasitic drain, the better.

Let the battery drain and sit discharged, and it won't last long, and will hold a smaller and smaller charge over time.  It seems plausible that's what's going on here.

Rick.


--- In dmcnews@xxxxxxxxxxxxxxx, Soma576@... wrote:
>
> Hi Group,
>  
> I'm trying to determine why my battery is too drained to start the car  
> after 5 to 6 days of sitting.  By inserting a digital multimeter in-line  with 
> my battery, I determined that my Lockzilla draws about .01 A while sitting  
> (drops to zero when Lockzilla is disconnected).  In addition, I have a  
> stereo system with an amplifier.  The amplifier, when isolated, seems to be  
> drawing about .03 - .04 A with the key out of the ignition.  The draw is  
> constant even when I remove the remote and speaker leads from it.  The amp  is 
> not on as per the LED's on it, but it is definitely pulling some power.   When 
> I disconnect this amp and the Lockzilla, my DMM fluctuates between 0.00 and 
>  0.01A (I can't find that last half-amp by pulling fuses, maybe the meter 
> is a  little off) and when both are plugged back in it reads about 0.05 A.   
> Is this enough juice to drain a battery in less than a week?  I have not  
> put a meter on the battery to read the voltage after it sits for a week so I  
> don't know how low it's getting, but certainly low enough to not turn  over.
>  
> I know it's not exactly DeLorean related, but the amp is a JL Audio 250/1  
> monoblock amp for a subwoofer.  The instructions don't give a resting draw,  
> so I'm wondering if that is typical?  Seems a little high, so aside from an 
>  internal problem with the amp, what else could go wrong with it?
>  
> Andy
>




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