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Battery drain

Discussion in 'General Tacoma Talk' started by Tmar04, Jun 28, 2025.

  1. Jun 28, 2025 at 12:39 PM
    #1
    Tmar04

    Tmar04 [OP] Well-Known Member

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    My Tacoma is old (2000) it has a battery drain when parked. Is there anything that needs to be energized 24/7 that I’m not aware of? Everything is operated pretty much manually but as soon as I switch off the engine, battery voltage drops from 14.0 to 12.7. Seems to take longer to start unless I leave charger on overnight. Thoughts?
     
  2. Jun 28, 2025 at 12:59 PM
    #2
    Dm93

    Dm93 Test Don't Guess

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    Your always gona have a few milliamps of draw because even on an older vehicle there's some stuff that has keep alive power to keep memory, time, etc, shouldn't be more than 50 milliamps (0.05A) though.

    Have you actually checked it for a battery draw?

    It's normal for the voltage to drop when you turn the engine off because the alternator is no longer running and a fully charged 12v lead acid battery is 12.6v.
     
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  3. Jun 28, 2025 at 1:19 PM
    #3
    Littles

    Littles Stupid is as stupid does.

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    How old is the battery? An old battery will start to loose voltage over time and eventually cranking amps.

    I just had a 5 year old AGM that I thought was experiencing symptoms of a parasitic draw, and then it couldn't turn the engine after charging overnight with 12.8 volts. Swapped over to my auxiliary which was purchased at the same time, but has seen a lot less use cranking the engine, and everything worked again.

    Any auto parts store should be able to load test it for you. Id put my money on old battery.
     
  4. Jun 28, 2025 at 1:26 PM
    #4
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Battery fine. 5 yr warranty and less than 1 yr old
     
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  5. Jun 28, 2025 at 1:30 PM
    #5
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Dm93. Thank you. I just thought fairly new battery would hold 13.0 v for a while. Ground lead sparks just barely enough to let you know there is a drain. But you have convinced me it’s prob normal. I’ll just keep charger handy. Great forum - great guys
     
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  6. Jun 28, 2025 at 1:36 PM
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    Littles

    Littles Stupid is as stupid does.

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    Agree. Probably normal. If you want some piece of mind and aren't familiar with the process @Dm93 was suggesting, disconnect the negative terminal and complete the circuit with a multimeter connected in-line and set to amps with the truck off and see if it's above 50 milliamps.
     
  7. Jun 28, 2025 at 1:37 PM
    #7
    Dm93

    Dm93 Test Don't Guess

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    I mean typically they will hold a slight surface charge above 12.6v for awhile but it's gona drop back to 12.6 after a bit.

    Just because a battery isn't that old doesn't mean it's good though, you could fully charge it and leave it unhooked overnight then check the voltage in the morning. If it's dropped well below 12.6v it likely has an internal short developing in one or more of the cells.
     
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  8. Jun 28, 2025 at 2:01 PM
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    4x4junkie

    4x4junkie Well-Known Member

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    If you decide to check it this way, also allow the truck to sit for around half-hour to 45 minutes or so without connecting/disconnecting anything, and all doors closed... Many vehicles post-mid-1990s or so have some circuits that need to "go to sleep" (so to say)... Before that happens, 100-200mA is typical, but afterward it should drop to around 15-30mA.
     
  9. Jun 28, 2025 at 2:08 PM
    #9
    Littles

    Littles Stupid is as stupid does.

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    Good suggestion. When I was searching for my parasitic draw at the in cab fuses, I also used a c-clamp to hold the door sensor closed on my access cab, since you kind of need to keep the driver side door open to access the fuse panel.
     
    4x4junkie[QUOTED] likes this.
  10. Jun 28, 2025 at 2:11 PM
    #10
    canuck guy

    canuck guy Well-Known Member

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    This is your answer.
     
  11. Jun 28, 2025 at 2:54 PM
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    b_r_o

    b_r_o Gnar doggy

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    There's nothing normal about having to pull out the trickle charger to get your truck started

    Just because the battery is a year old doesn't mean it's good. Simply put, asking a battery to start your car every morning is a battery test.. and it sounds like its failing that test.

    Tomorrow morning (or right now) put a multi-meter across the battery with the engine off. Should be 12.6 volts. See if the engine will start. During cranking if the voltage drops below 10.0 the battery is weak and needs to be replaced

    Or

    Turn the headlights on and walk away for 10-15 minutes. Come back and see if the battery voltage has dropped below 10. See if the engine starts. A good strong battery should still be able to start the truck even after sitting with the headlights on for 15 minutes

    These are 2 examples of a simple battery test anyone can do in their driveway
     
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  12. Jun 28, 2025 at 3:55 PM
    #12
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Again, my thanks to all you guys.i will do some testing tomorrow after church and report results.
     
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  13. Jun 30, 2025 at 6:17 AM
    #13
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Well,guess what? I checked battery voltage this morning after sitting all night properly hooked up in circuit and 12.77. So my worry was all for naught. But, you see, when you’re 86 you can get away with with it. All you guys were right. I am forever grateful.
     
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  14. Jul 6, 2025 at 11:08 AM
    #14
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Now is another problem. My veh is a 2000 prerunner. When I fill up with gas. About 1 second before pump shuts off, gas leaks out under truck. Every time, every pump, every station. A
    Mx there are smell of gas fumes when I fill up all around truck and in truck. If I knew what to order would help. Thanks to all.
     
  15. Jul 6, 2025 at 8:33 PM
    #15
    soundman98

    soundman98 Well-Known Member

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    that's going to be in the filler neck. there's the tank inlet, which goes to a rubber hose, which then connects to the gas cap/hose piece. i would check the gas cap/hose piece at the point it intersects with the hose for rust/rot
     
  16. Jul 7, 2025 at 3:27 PM
    #16
    Tmar04

    Tmar04 [OP] Well-Known Member

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  17. Jul 7, 2025 at 5:17 PM
    #17
    slater

    slater Well-Known Member

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    Need more info or a video while its cranking, so I can see your "taking longer to start"
    may have nothing to do with the battery....
    As stated, generally your battery car off will sit at 12.6 volts...
    Your battery car off shouldn't sit at 14.0 volts like you think.

    "bro" made a suggestion but didnt included a key element a VERY important piece of info....
    Disable the coil so the engine doesnt start.
    The battery shouldn't drop below 9.6 volts while cranking engine for 15 seconds.
    After 15 seconds of constant cranking of engine without engine actually starting, if voltage drops below 9.6 volts, battery is faulty....
    Thats how you correctly load test the battery without an actual tester.....

    Or just drive it to an auto parts store & borrow their battery tester for free...

    It may not be starting right away from other reasons like fuel pressure related issue, etc & you think its a battery issue...
     
    Last edited: Jul 7, 2025 at 5:27 PM
  18. Jul 8, 2025 at 8:07 AM
    #18
    Tmar04

    Tmar04 [OP] Well-Known Member

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    Thank you so much. Your suggestion made sense to me, a non mechanic. Again, my thanks
     
  19. Jul 8, 2025 at 8:07 AM
    #19
    Tmar04

    Tmar04 [OP] Well-Known Member

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    I was worrying for nothing
     

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