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I recently purchased an IS350. The car was purchased as a pleasure car and I only drive it once or twice a week.

If the car sits for more than a couple of days, the battery is usually dead.

I have verified that the alternator is pushing above 14v and delivers adequate amperage for charging

The battery (less than a month old), when charged, passes a carbon pile load test to >400CCA

I have checked to ensure the dome lights, trunk lamp and all exterior lights go out as designed.

I have seen that others have had similar issues but never saw any resolutions.

The only operation that I have not performed is a parasitic load test as I haven't found the proper procedure and specs for an "acceptable" at rest load.

Is this an issue IS350s are prone to, can anyone offer any insight/experience with an identical issue.
 

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I recently purchased an IS350. The car was purchased as a pleasure car and I only drive it once or twice a week.

If the car sits for more than a couple of days, the battery is usually dead.

I have verified that the alternator is pushing above 14v and delivers adequate amperage for charging

The battery (less than a month old), when charged, passes a carbon pile load test to >400CCA

I have checked to ensure the dome lights, trunk lamp and all exterior lights go out as designed.

I have seen that others have had similar issues but never saw any resolutions.

The only operation that I have not performed is a parasitic load test as I haven't found the proper procedure and specs for an "acceptable" at rest load.

Is this an issue IS350s are prone to, can anyone offer any insight/experience with an identical issue.
What was your parasitic draw value? Should be less than 50mA after 5 miinutes. Another aspect is your alternator. even tho it may beputting out 14 volts, you may have some diode problems, introducing AC ripple to the output. Bad grounding can cause bad charging as well. Here is an extensive DIY i created awhile ago that will cover all aspects. Let me know...this should help.

http://my.is/forums/f221/diy-charging-system-full-diagnostic-alternator-battery-426000/
 

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Yes best bet is have Autozone, Oreilly's, or other automotive store check the alternator. It is more than likely the diode in the alternator. They will be able to tell you.
 

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Yes best bet is have Autozone, Oreilly's, or other automotive store check the alternator. It is more than likely the diode in the alternator. They will be able to tell you.
Unfortunately the free tests or the tests they do while the car is running will not be able to detect AC ripple or diode breakdown, only DC alternator output and status of the battery. The only way of testing besides using a meter is with a bench test, so the OP would have to physically pull the alternator out. The OP has found the alt to be able to produce proper DC voltage but the alternator still may have a failing regulator/diode pack. Best bet is to use a digital voltmeter/ampmeter and perform the tests I have provided in the DIY.
 

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Do you have any aftermarket electrical components (amp, LCD monitors, etc)?

Do you have an Optima battery?

Check for parasitic draw. Excessive draw killed 2 batteries in <2 years.
 

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Hmm autozone has a diode test In car
I have never had autozone do a charging system diagnostic, only pep boys, napa, and advance auto. All of their on board testers check DC alternator voltage output, load test on the battery, and status of the battery. they could not test for AC ripple or diode pack leakage. Maybe autozone has that capability so i cant vouch for them. I know they would not be able to check parasitic diode leakage and if they test for AC ripple, they would not get an accurate reading because that test needs to be done directly on the alternator + terminal(reading AC ripple at the battery wont be true because the battery will act as a buffer).
 

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I just know they said diode was dead when they ran the test was just putting it out there this was on my 02 toyota 4 runner.
 

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I had my charging system tested at Autozone a couple months ago. The guy only hooked up to the battery and ground, let his scanner do it's thing, and told me everything was fine...but it wasn't. The tests Jason mentioned were easy. I think the hardest part was figuring out how to use my digital multimeter haha.
 

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Check all your aftermarket stuff installed. it could be causing the battery to die.
Exactly. That's why I suggest a parasitic draw test as mentioned earlier and in my DIY, which will narrow down the issue to its source. As a total, it should never exceed 50-70mA after 5 minute, otherwise there will be a battery drain issue. This needs to be done with the alternator too.
 

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Did you perform any of the simple tests I have provided in the DIY link? I hate it when people by battery after battery or alternator and realize an underlying issue such as high parasitic draw(not sayin your case). A less than 1 amp parasitic draw would kill the battery in less than 24 hrs. Meter tests will give you peace of mind if checked when you have issues.
 
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