I've done a search on Alternator issues, diode issues, parasitic drain issues, and the many anomalies others seem to have, but my one question here about the readings I'm getting for the Diode mode test does not seem to have been covered as specific as I would like to be with my question. I've itemized all the conditions and tests I've done, and then note my last two bullet points about the diode testing readings - I'm quite sure that's the problem, but as always, would like a second opinion.

My Crossfire SRT-6 is eating the battery when parked, overnight, one day. Nothing was left on, charged the battery, did it again. Quite sure it's a diode(s) in the Altenator, but that's quite surprising considering the car has only 36,000 miles on it.This suddenly started happening, there was no prior indications or recurring charging/engine idle, I have had no electronics/lighting acting wonky. No warning lights on the dash while running about the battery or charging.

Nothing is wrong with the battery, it's only a year old. The battery charges fine with a charger and holds a charge. I have both an old Sears Die-Hard 10-AMP charger with engine start for 'lead-acid bath' regular batteries, and an Optimate 6 Ampmatic Charger for AGM/Gel batteries. Just to be sure, I tested with another new battery I have. Both batteries test Voltage at 12.64 / 12.62 - so good on both counts.

All connections are good - California car, no corrosion or cracked wires, looks like new under the hood, never sees rain. Car is all stock as it left the showroom, except for a radio that was professionally installed years ago and a Sprintbooster installed - neither have any shorts or issues.

There is no parasitic drain or overloading draw/short circuits - that test reads at .024 . - (typographical error corrected)

Charging test with everything on (headlights/Air Conditioning /Dome Light): reads 14.42v / 14.45v

My multimeter is working fine/tests good, no issues.

HOWEVER - when I do the alternator Diode test, car off, and multimeter set as in the photos, I get the following:

With the black lead on the positive post / red lead on the alternator housing I get 205 as shown. (.205 volts)

With the red lead on the positive post and black lead on the alternator housing, it climbs through the range to max at '1.484 / 1.494' as shown.

I have not done an AC multimeter test on the alternator yet, merely ran out of time today, had another project to tackle elsewhere. But with the above result of 205 (.205 volts) as opposed to a range of 500 to 800 (0.5 to 0.8 volts), wouldn't one deduce that's suspect considering all else is working properly, especially with the battery draining in a single night?





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"especially with the battery draining in a single night"?
Have you disconnected the alarm siren? It causes battery drain from leaking internal batteries.

 

I have a suggestion. Find out which fuse is for the alarm in the under hood fuse box. On my 2006 base model it is #9. (Fuse for alarm siren, dome lights etc...)
Pull that fuse and run your test again and see if anything changes. I know they shouldn't effect each other, but who knows on these cars. The alarm siren is the number one suspect for parasitic drain on these cars.

 

Thank you, both good points - while I'm not suspecting a parasitic drain from any of the components regarding my amp-draw test results, and seeing what the diode test produced, I'll concede I did not run the parasitic/amp/voltage draw test in 'locked/security on' mode. I merely closed the door and waited about 30-minutes for shut-off processes/ECM-thinking to finish.

I should run the drain test again with that in consideration, and while there, I'll test the security siren batteries draw and pull that fuse as suspect - I hate the damned siren anyway, don't even need it. For the few times it's gone off when reconnecting the battery in the past several years, I couldn't get out the key fob and shut it off fast enough. Embarassing.

I would never park it in a place that thieves would try to get to it anyway. And no offense, I don't think the car-theft market is looking for 19 year-old Chryslers, SRT-6 or not, as a high profile get to flip on their list, whether for absconding it to Mexico or destructing it for parts. Just not enough market interest or value draw; they're too busy stealing Hellcats, Corvettes, Mustangs, BMWs, Mercedes, Toyota Camrys, Honda Civics - and KIAs or Hyundais ( those last two, purely for the joy-ride.)

I'm still hoping someone can comment on that .205 diode test result though. I ran it with another multimeter I have and got .205 again on one way, and it climbed to '1' (OL/Over Limit on that neter) the other way (what was 1.494 on the other meter).

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Someone like @pizzaguy or @zip439 would know a lot more about testing for drains than me.
Hopefully they'll see this and respond.
Hopefully they won't kick my butt for tagging them! LOL

 

So you have the alternator completely disconnected from the car's wiring when you get these readings?
If so, I'd say you have one or more leaky diodes in the alternator.

 

SPec is nothing more than .055 amp, if you are seeing .24 amp, you have a huge problem. TO BE CLEAR, this is a current reading with the meter in series with the battery ground lead, on the 10amp scale-is that correct?

 

DOH! Sorry, decimal point off - meant to type .024. Thanks for catching that, fully knew should not be more than .055, the reason I overlooked it. Was just typing to fast to note I cleared that test.

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No; not off the car, but that will be my next step seeing how everything points to having to replace it anyway. Seems removing it will be inevitable. I'm still going to test the siren batteries this weekend, regardless, before resting on the alternator diodes being the sole target. Who knows; it could be the diode(s) AND the siren batteries.

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