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Battery Drain - What's The Normal Current Draw?


tiggrev
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My '92 SC400 has been draining a new battery after only about 3-4 days between drives, so I measured the nominal current draw (ignition off) at about 240 milliamperes. Seems rather high, but I don't know what the normal current should be ... usually it's around 20 to 40 ma for most cars.

I've pulled fuses one by one to track down what's loading the battery and found that the current drops to about 20 ma with the "Radio 01" fuse pulled (in the engine compartment). The radio, CD player, and power antenna are all working fine (with the fuse in place, of course), so I don't know where the problem might be. If I pull the "Radio 02" fuse in the driver's side kick panel, the nominal current draw doesn't change (stays at around 240 ma), so I suspect that the Radio 01 fuse is powering something else that's loading the battery.

Any ideas out there? What should the nominal current draw be for the SC400?

Thanks.

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My '92 SC400 has been draining a new battery after only about 3-4 days between drives, so I measured the nominal current draw (ignition off) at about 240 milliamperes. Seems rather high, but I don't know what the normal current should be ... usually it's around 20 to 40 ma for most cars.

I've pulled fuses one by one to track down what's loading the battery and found that the current drops to about 20 ma with the "Radio 01" fuse pulled (in the engine compartment). The radio, CD player, and power antenna are all working fine (with the fuse in place, of course), so I don't know where the problem might be. If I pull the "Radio 02" fuse in the driver's side kick panel, the nominal current draw doesn't change (stays at around 240 ma), so I suspect that the Radio 01 fuse is powering something else that's loading the battery.

Any ideas out there? What should the nominal current draw be for the SC400?

Thanks.

Normal current draw on most cars is .02-.05 amps ----.240 amps is excessive and definitely causing your battery draw .The "radio1" fuse is "hot all the time..It supplies voltage to the radio and amp only..I would isolate the the draw by unplugging your amp first. I would bet thats where your problem is.Have replaced many of them over the years.Come to think of it my SC needs one as well..But that one just sits in my garage..Anyway---Best of luck..

lexushead

Toyota Lexus Factory Cert. Master Tech

ASE/L1 Master

www.toyautoservice.com

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Normal current draw on most cars is .02-.05 amps ----.240 amps is excessive and definitely causing your battery draw .The "radio1" fuse is "hot all the time..It supplies voltage to the radio and amp only..I would isolate the the draw by unplugging your amp first. I would bet thats where your problem is.Have replaced many of them over the years.Come to think of it my SC needs one as well..But that one just sits in my garage..Anyway---Best of luck..

lexushead

Toyota Lexus Factory Cert. Master Tech

ASE/L1 Master

www.toyautoservice.com

Thanks, lexushead.

I originally tried tracking down the problem by sequentially unplugging the CD Changer, power antenna, and the amp (that's the box under the CD changer, right?). The current draw didn't change, so I guess that leaves the radio. For now, I've just removed the "Radio 01" fuse, but I sure miss the tunes.

How do I get access to the cable for the in-console radio? ... I'm a bit afraid to start pulling out panels. My '92 SC400 is in CHERRY condition and I'd hate to ding anything B)

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