2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Amp draw with car off

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Old May 3, 2007 | 09:38 AM
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Amp draw with car off

My car is pulling 0.27 amps with everything off and the key out. Does this sound to high for memory circuits?

If the car sits for 4-5 days it drains the battery enough to where i have to jump the car.
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Old May 3, 2007 | 10:12 AM
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yes, memory circuits shouldn't drain the car after even weeks.
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Old May 3, 2007 | 10:52 AM
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If the battery was suspect they might. I realize the condition is not normal. Im curious if the battery is going bad or if there is indeed some kind of parasitic short.
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Old May 3, 2007 | 10:52 AM
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That's actually about right for normal...


-Ted
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Old May 3, 2007 | 11:02 AM
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If I'm not mistaken (perish the thought), that's 270 milliamps, which is about a factor of 10 higher than spec for dark current draw. Connect a multimeter in series with the positive battery cable and start pulling fuses to isolate the source of the excessive draw.
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Old May 3, 2007 | 12:24 PM
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I cant seem to find the spec in the FSM for dark current draw. Which is the reason I asked.

Ive heard some cars are normal at 20-60 mA and others are as high as 500 under normal conditions.

So, im not sure what to think.
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Old May 3, 2007 | 12:53 PM
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Go48 gives good advice. I would suspect dark current should be no higher than 50ma for your car. A multimeter must be set on the Amps scale to troubleshoot your problem. You need an ammeter.
Disconnect a battery terminal and put an ammeter in series between the battery and cable. Start with a high scale on the ammeter to protect the meter. Work your way down the range scale until meter reads aprox mid scale. Now start pulling fuses. The ammeter reading (current) will decrease when you pull the guilty circuit fuse. If there are multi devices on this fuse you have to someway disconnect each device until you have isolated the problem. RX7MAVEN
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Old May 4, 2007 | 06:37 PM
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Originally Posted by RockLobster
I cant seem to find the spec in the FSM for dark current draw. Which is the reason I asked.

Ive heard some cars are normal at 20-60 mA and others are as high as 500 under normal conditions.

So, im not sure what to think.
Yeah, I looked in the FSM before I posted and couldn't find it either. But the FSM for the RX-8 says 20 mA "backup current", so I suspect the FC would be somewhere near that. Certainly, 270 mA is higher than it should be. If you do the numbers, 0.27 x 24 (hrs) x 5 (days) you get a usage of about 32 amp hours. That is a very big drain! Particularly if the battery is a bit on the weak side to start.
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Old May 21, 2007 | 02:22 PM
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Battery was junk. I replaced it and have not had an issue since.
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Old May 22, 2007 | 01:39 AM
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If you still have the same 0.27A draw, then you still have a problem. That'll still flatten a new battery, it'll just take longer.
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Old May 22, 2007 | 06:13 PM
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Nobody has stated the correct amp draw yet
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Old May 22, 2007 | 06:32 PM
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ROT = 50 ma max
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Old May 30, 2007 | 09:39 AM
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Ive got a number of aftermarket devices pulling memory current and the more ive talked to people the less I am worried about it. From what I hear older computer controlled cars (like ours) pull a lot more anyway than newer cars.
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Old May 31, 2007 | 12:59 AM
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Originally Posted by RockLobster
Ive got a number of aftermarket devices pulling memory current and the more ive talked to people the less I am worried about it.
What aftermarket devices are these? Electronic memory requires tiny amounts of current, but what you've measured is about six times more than what should be expected.
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