My battery recently went completely dead after sitting for 1 week. It was in the car when I bought it 10 years ago so I installed a new battery. The same thing is happening again. I disconnected the new battery and fully charged it, then reconnected it. 24 hours later, I disconnected it and it took 2.5 hours to fully charge it again. Any ideas what could be draining it all of a sudden? I never had an issue before when not starting the car for 2 or 3 weeks. It is always parked indoors and unlocked.
Battery draining when parked in 91
- Thread starter TMac
- Start date
Hey Terry, I would check any aftermarket alarm or stereo system, if these are installed in your car.
Bram
Bram
Hi Bram. Hope all is well with you. No aftermarket alarm or stereo and I pulled the stereo fuse to rule that out.
It is unlikely; but, make sure that your new battery is not a dud or that the alternator has not failed. An automotive electrical service can load test the battery for you. Inspection of the voltmeter when the car is running will confirm whether it is working correctly - should be around 14.8 volts when running. If the alternator is good and you don't want to have your battery load tested, you can check to seek what the parasitic current is when the car is off. Remove the ground cable on the battery and connect an ammeter in between the battery negative post and the ground cable to measure the parasitic current. I have never measured mine; but, based on the rated amp hours of the battery and how long mine can last when parked (> 2 weeks) I expect that the normal parasitic current is less than 50 milliamps. If your parasitic current is in that range then your battery is bad or you have a charging system problem. If your parasitic current is significantly above 50 milliamps then you have an electrical problem.
If it does appear that you have an abnormally high parasitic current, start pulling fuses to see if you can isolate the source of the draw. The only legit parasitic loads that I can think of are the clock, the radio keep alive presets, the security system, (the keyless radio if you have retrofitted OEM keyless), and the keep alive for the ECU, ABS, TCS, SRS, EPS (if you have it) - anything with stored error codes.
If it does appear that you have an abnormally high parasitic current, start pulling fuses to see if you can isolate the source of the draw. The only legit parasitic loads that I can think of are the clock, the radio keep alive presets, the security system, (the keyless radio if you have retrofitted OEM keyless), and the keep alive for the ECU, ABS, TCS, SRS, EPS (if you have it) - anything with stored error codes.
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Current draw
Check your trunk light to see if it's on when the trunk is closed. You can do this with a smart phone video. Check the the glove box as well. If they check out OK, disconnect the alt and see if the draw disappears. Jerry
Check your trunk light to see if it's on when the trunk is closed. You can do this with a smart phone video. Check the the glove box as well. If they check out OK, disconnect the alt and see if the draw disappears. Jerry
For some reason, the fuse panel in my drivers footwell does not have a sticker identifying the fuses - would someone be so kind to identify them for me?
That changed with the model years. You should find a diagram describing the fuse function and size in your owner's manual.
My manual says to refer to the fuse box label attached to the inside of the door (which is missing). It's a 91 Canadian model.
Life is more complicated.
Go here and down load a .pdf of the 1991 service manual
1991 Honda / Acura NSX Service Manual 2.0 (nsxprime.com)
Go to page 23-49 to find the fuse box layout with the fuse number; but, not the size or the function. Then you have to go to page 23-52 & 23-53 to find out the size and function of the fuse.
Go here and down load a .pdf of the 1991 service manual
1991 Honda / Acura NSX Service Manual 2.0 (nsxprime.com)
Go to page 23-49 to find the fuse box layout with the fuse number; but, not the size or the function. Then you have to go to page 23-52 & 23-53 to find out the size and function of the fuse.
Thanks Old Guy - I already had the manual but can't figure out page 23-52. I was hoping someone could list what fuses 1 to 8 are for. Maybe someone could send me a photo of their fuse box cover at [email protected]
I know (guess) you already fixed your issue but I will give my tips from personal experienced anyway, for other that stumbles in here.
Don’t leave the key in the ignition, as I did, even turned off.
It flattened my battery within two weeks.
Afterwards I did a quick check and it drained 160 mA with the key in, and 20 mA with the key out.
Don’t leave the key in the ignition, as I did, even turned off.
It flattened my battery within two weeks.
Afterwards I did a quick check and it drained 160 mA with the key in, and 20 mA with the key out.
That's a great tip. I wasn't aware of this.
I had a similar problem, battery died overnight after a car show. Once I got it properly jump started I noticed the brake lights stayed on after I turned the car off. Thanks to GooGoo, it turned out to be a broken small plastic brake light switch/stop on the brake pedal mechanism. EZ fix, although squeezing my ol' body under the dash, on my back and reaching up was not the fun part. But I could see the location of the missing part and I was determined to get it in there. It's a common Honda part #46505-SA5-000 .
https://www.youtube.com/watch?v=Ek1peFgk4LA&t=80s
https://www.youtube.com/watch?v=Ek1peFgk4LA&t=80s
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