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Starter, alternator, or battery

Discussion in 'General' started by tiggen, Jun 2, 2023.

  1. tiggen

    tiggen Things are lookin' up.

    Car is 2012 Rx350. Mom drives infrequently. Battery is less than one yr old.

    She went to start it today, not enough battery to open doors. Put a meter on battery, it read 0.13 volts. (Maybe it read 10.13, which seems more likely, but it was dark in the garage.)

    AAA comes after I had gone, he jumped th car, ran some sort of diagnostic, and says it is the starter.

    My question: how does a "bad starter," which is apparently still good enough to start the car, drain a battery?

    And what part do I need to replace?
  2. ChemGuy

    ChemGuy Harden The F%@# Up!

    pull the batt and take to store to test it. Its probably that. If infrequent is like once a week or less I could it dying in a year.

    If they jumped it and starter worked then how can it be the starter?

    With all the electro-digicals in the starting system anymore (autostart, CAN bus, etc)...I wouldn't trust an on car 'diagnostic' saying the starter is bad...right after the car started. :rolleyes:
  3. tony 340

    tony 340 Well-Known Member

    +1 charge battery and test it before doing anything else. Age means nothing

    My corvette eats batteries after 2 weeks of sitting. Totally normal.

    Mom probably needs a new battery and a battery tender if it is sitting for long periods of time.
  4. R1M370

    R1M370 Dr. P Ness

    AAA guy probably meant the thing that starts the starter. :D
    YamahaRick likes this.
  5. USracer900

    USracer900 Well-Known Member

    My mom was the same way with her Accord. Went through 3 batteries because she doesn't drive often enough to keep it recharged. I bought her a battery tender but she has a hard time figuring out to connect the plug. Getting old sucks.

    But yeah, 99.9% it's the battery.
  6. tony 340

    tony 340 Well-Known Member

    Put a tender quick connect on the new battery and make it simple for her.

    Female brains do not think like yours do.
  7. Black46

    Black46 Well-Known Member

  8. Daniel06

    Daniel06 Well-Known Member

    If it sits outside you can also install a solar panel and adapt the battery tender to solar power or buy solar panel battery tender. It's always on the car then.
    Razr and StaccatoFan like this.
  9. pickled egg

    pickled egg There is no “try”

    Well lemme tell ya…

    I have personally had hands on a GM starter that had a parasitic draw through the starter solenoid, causing the battery to discharge within two days.

    Not a common issue, I’ve only seen it the one time but some customers at the parts store have seen it (often enough that step one of the diagnostics is to disconnect the high amperage wire from the starter to see if that cures the problem).

    But yeah, I wouldn’t take seriously anything the jump start boy had to say about potential problems…
    27 and long path/road like this.
  10. Sabre699

    Sabre699 Wait...hold my beer.

    I just disconnect the battery between usages as I only drive my 'vette a few times a month.
  11. beac83

    beac83 "My safeword is bananna"

    It may be the alternator or starter, but if the battery is showing 0.13 Volts, it is now bad and needs replaced. Once they get down to about 0.7-0.8 per cell or 4-5V total (12V batteries have 6 ~2.4 cells) then they are not likely to recover.

    Replace the battery and then troubleshoot to find the source of the actual problem.
  12. Dave Wolfe

    Dave Wolfe I know nuttin!

    We'd disconnect the batt on the jet I used to fly...
    Sabre699 likes this.
  13. Motofun352

    Motofun352 Well-Known Member

    I religiously keep my vette on a battery tender for the same reason. One week of being idle is enough to make it questionable. One time it started in the garage but I only drove it a few miles into town. Not enough to do any serious recharging and it then died in the store parking lot.
  14. Cooter!

    Cooter! Sarcasm level: Maximum

    Without diagnosis the AAA guy was totally guessing. Ignore him.
    Those little electronic meters the parts store people use are JUNK. The only way to load test a battery is to load test it with a high load.

    Wanna play technician? Okie Dokie, here ya go:
    Charge the battery with a REAL (10 amp+) charger. None of those Tender things will work for this. No charger? The auto store should do it for you.
    Let it rest a few hours and test voltage. Should be 12.5+. If it's less, (like 12.0V) it is bad, get a new one.
    Watch the meter and start the car. Should not dip below 9.6V. Both a bad battery OR a bad starter can cause this. 90% its a bad/weak battery but you'll need an amp meter to find out 100% if its the starter.
    Now that its running, rev to 2500-3500 RPM and the meter should be between 13.5-14.7. That is your charging system working. Any less and you need a repair there. Hint: before you tourette and buy a new alternator, a non-op charging system could be as simple as a fuse.
    Bonus check: Set the meter to 10A and don't forget to swap the leads to the right holes of the meter. Car off, charged battery, disconnect the (-) and put the meter leads between the battery terminal and the cable end. Direction doesn't matter and no you won't get shocked. Wait a minute for things like dome lights etc to stay off and read the meter, should be .3 amps (.003 at that scale) or less. That is the amount of electrons the car is sucking out of the battery while sitting. A high draw means dead battery soon. The factory is pretty good about that so is there anything aftermarket in it?

    Theres a few reasons this will keep happening to a infrequently used car. It's REALLY hard on cars to just sit:(
    1) Parasitic draw is lethal to batteries, regardless of age. A good quality Tender thing (1 amp, not .5 amp) is a good start, but put it on a lamp timer to only be on about 8 hours a day.
    2) Starting a car with a weak (or just jumped) battery is hard on the starter, causes a much higher and extended draw than normal.
    3) Once this dead-battery car is running, the alternator has to go full field to try and charge it up. They aren't meant to do that job, and revving it up or ripping down the highway to charge it will get that sucker literally RED hot. If you have no other choice, letting it just idle as long as you can is the easiest on parts.

    Remember, a little mechanical empathy will save you time, trouble, and money:)
  15. long path/road

    long path/road let's think about this!..??

    damn !!! Hazard county.. Folks... love it !! anyone can scream new battery by hoping things happen.. I was like that with a girlfriend once... will say .. I checked the schematics ..and yup loose wire somewhere/ or a wire just taking all the energy connection to a hot ...the melt down..started.. damn cash drainer....
  16. Venom51

    Venom51 John Deere Equipment Expert - Not really

    All of that is good. Don't forget that most of the new junk has a demand based charging system. It will not turn on the output from the alternator unless there is enough draw to demand it.
    Triple X and long path/road like this.
  17. tiggen

    tiggen Things are lookin' up.

    Thank you, sir! It appears all is well. Will know for sure when/ if the car starts this morning, but according to your post it "passed" all the tests.
  18. 27

    27 Well-Known Member

    Since were on about batteries... wth happened to them? I had a Duralast in a shop truck for 14 yrs! My Ford Superduty ones went 10yrs, a prius went 12 yrs...

    When I bought the semi the generator had a 12 yo Napa/Balkamp in it, still fine...

    I replaced every battery in the semi.... the 24v system, the house system, the hydraulic gate back up system, both chassis and house batteries in the diesel pusher....couple thousand bucks a decade ago... nearly all of them failed before the warranty ran out... two had catastrophic failures melting plates together and melting the bottoms out... those were Napa commercial.... I tried others after...

    I know they’re all built to fail but it’s ridiculous... there are only a few manufacturers Johnson Controls, AC/Delco, can’t remember who all but most just build them for others...

    anyone know of a good manufacturer?
  19. Mechdziner714

    Mechdziner714 More Gas Less Brakes

    I have had good luck using an OptiMate4+ battery charger to revive dead really low voltage batteries.
    27 likes this.
  20. 27

    27 Well-Known Member

    on the serviceable ones, like deep cycle, I’ve had luck putting new acid in them.... 5 gal is like $50 and goes along ways if the plates or ok

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