POWER DRAIN ON BATTERY

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ozzinc
Posts: 33
Joined: Thu Jun 29, 2006 8:49 pm
Car: infiniti q45, datsun 240z

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on my 91 q45 something keeps draining the power out of the battery, the battery that I have is new and the alternator is also new, im wondering if there is a short somewhere, after about 8 to 10 hours I go to start the car and the battery is dead. any tips on solving this problem would be great.


maxnix
Posts: 22627
Joined: Mon Jul 22, 2002 8:11 pm
Car: 1995 Infiniti Q45
1995 Infiniti Q45t
2000 Infiniti Q45

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Here is an idea, try searching on drain. Qisguy has posted some helpful posts as has Q45tech.

pouncer11
Posts: 54
Joined: Wed Apr 09, 2008 8:10 am
Car: 1990 Q45
Contact:

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Did you hook up a stereo system recently or mess with the wiring at all/install something

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Rex
Posts: 16845
Joined: Sat Apr 05, 2003 6:50 pm
Car: None
Location: South of ATL
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Is there an after market alarm system?

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qsiguy
Posts: 1961
Joined: Sun Mar 20, 2005 8:12 pm
Car: 1994 Infiniti Q45 Turbo

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Here is a quote from an old post I did regarding amperage draws under various conditions on my '94 Q45. It should give you a good idea of where your car should be if it was not draining the battery. If you have more than about .05-.07 amps draw from your battery with everything off after a couple of minutes there is something draining the battery so start pulling fuses for various circuits to narrow it down. I give several examples in my testing on what to disconnect and it's effect. This assumes you know how to test the amperage at your battery and have the appropriate equipment. I'm not responsible for damages to your vehicle!

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OK, I have some baseline numbers from my '94 that's currently great in the electrical department. I pulled the negative terminal and installed my Fluke ammeter inline. Leads in the 10 amp terminals on the meter. You could use the positive as well, would make no difference. I just used the negative as it doesn't have all the other wires connected to it. Negative meter lead to B- and the meter positive lead to the negative battery cable. If you get these backwards you will just read negative amps, no big deal.

Upon connection the dome turned on and stayed on due to my aftermarket alarm until I armed and disarmed it. Then it turned off. Also, there are apparently some systems that operate for a couple minutes upon connection of power as the amps take about 1-2 minutes to stabilize at the low level.

Initial connection w/alarm disarmed, dome light on -> 3 amps, settled to 2.6 amps

Aftermarket alarm armed, dome light off -> .24 amps then settled to .066 amps after approx. 1 minute.

Alarm disarmed, dome light off -> .063 amps after 1 minute

Start pulling large fuses in under hood fuse compartment, unless noted I reinstalled the fuses prior to pulling the next fuse/relay"IGN SW" 30A fuse -> .056 amps"ENG CONT" 25A fuse -> no change"INJ" 25A fuse -> no change"COND FAN" 30A fuse -> no change"MAIN" 75A fuse -> .043 amps"MAIN" and "IGN SW" -> .035 amps*When "MAIN" reinstalled amps were at .5 amps 2 minutes then settled back to .063 indicating that a circuit was operating for a couple minutes upon power up, ECU?"Power window" fuse -> no change"Anti Skid" fuse -> no change"Blower Motor" -> no change

Small underhood fuses"Eng Cont" 10A fuse -> no change"Fog Lamp" 15A fuse -> no change"Room Lamp" 10A fuse -> no change (unless the dome light was on already)"Tail Lamp" 10A fuse -> no change"ALT (S)" 10A fuse -> no change"Hazard" 10A fuse -> no change"Horn" 15A fuse -> no change"Headlamp LH" fuse -> no change"Headlamp RH" fuse -> no change

Relays underhood in junction box (same box as above)"Anti Theft" -> no change"Cond Fan" -> no change"Cruise Cont" -> no change"Inhibit" -> no change"A/C" -> no change

MiscellaneousTrunk open w/trunk lamp on -> .4 amps (amps fluctuating +/-)Room lamp fuse out, door open -> .233 amps (might be alarm LED drawing)Room lamp fuse out, door open, park lights on -> 6.2 ampsHeadlights on -> Exceeded 10 amps, couldn't get accurate reading

This should give you a good start on tracing the amp draw. I didn't pull the two really large fuses next to the fuse/relay box (100A+) or the two black/white wires plugged in at the B+ terminal.

ozzinc
Posts: 33
Joined: Thu Jun 29, 2006 8:49 pm
Car: infiniti q45, datsun 240z

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when I purchased the car there was a aftermarket alarm installed, but I disconnected it, but what I will do is remove the fuses one at a timeand use my digital multi tester to try and narrow it down to the source thats draining the battery, and thanks for the info guys.


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