Hey all,
I suddenly am having a fairly impressive battery drain problem with my 4Runner. All was well until I got it smogged last Wednesday. Then I came out to a dead car. Got it jumped, and then it died again overnight. Took the battery to O'Rielly's to get it tested and the fellow told me it was fine. Plugged it back in yesterday, and now it's so dead that the key fob doesn't even work. I haven't had any issues starting until now. So this leads me to believe I have a drain somewhere. I know my passenger front door lock is a little wonky but I'm not sure that is killing the battery, as it hasn't been a problem before. I haven't the foggiest idea how to start diagnosing this problem. Where do y'all suggest I begin?
Pull a battery cable off and measure amps then pull fuses until its zero. Once zero, you found the circuit with the drain.
That really sounds like a battery to me. Unfortunately.
But also, a good drain can flatten and then ruin a good battery too.
That fast sounds like a near dead battery to me as well.
Not saying you don't have a parasitic drain, but that quick a die is indicative of a rickety battery.
As for parasitic drain, an interior light being left on is a very common cause. Especially if you've a kid that sits in the rear seat.
Ranger50 wrote:
Pull a battery cable off and measure amps then pull fuses until its zero. Once zero, you found the circuit with the drain.
Let me preface this questionby saying I'm have little experience working with electrical systems. I should be measuring amps with my tester from the disconcerted cable to the opposite battery terminal right?
foxtrapper wrote:
That fast sounds like a near dead battery to me as well.
Not saying you don't have a parasitic drain, but that quick a die is indicative of a rickety battery.
As for parasitic drain, an interior light being left on is a very common cause. Especially if you've a kid that sits in the rear seat.
No kids so I'm safe on that front.
In reply to thatsnowinnebago:
Between the disconnected cable and the post that cable was on. If you want to measure amps, it's inline. Volts are measured across terminals.
No dome lights on, right? Friend of mine had that happen when his kids played with the switches in the back of the Camry.
Ranger50 wrote:
In reply to thatsnowinnebago:
Between the disconnected cable and the post that cable was on. If you want to measure amps, it's inline. Volts are measured across terminals.
Gotcha, thanks. Glad I asked.
Well I checked the amps across the negative terminal and cable from my battery and got 0.00 on my multimeter on the 10a setting and 45.x on the 200ma setting, regardless of which blade fuse I pulled. There's four square ones I couldn't get out. I didn't try too hard as I didn't want to break them. They're the ones shown on the lid below as J/B, Heater, AM2, and AM1. Does those reading make sense?
Double check the grounds. That amount is about right for a flaky ground.
In reply to Ranger50:
Would that take a fully charged battery down to zero overnight?
45 milliamps should not drain a battery overnight. 10 hours would be 0.45 amp hours on a 20 or 40 amp hour battery. I'm thinking bad battery. Leave it disconnected, charge it fully, let it sit overnight disconnected, hook it up. Is it dead?
In reply to Dr. Hess:
I don't have a charger so I jumped my battery with my work truck, then drove around for like 15 mins. I then disconnected the battery and tested it. Voltage was at 12.4v. Checked it again 2.5 hrs later and saw that it had dropped to 7.5v. That seems rather suspect to me.
Also, the small draw I mentioned earlier was likely my iPod that I forgot was plugged in in my glovebox. Oops.
If the battery goes from 12.4 volts to 7.5 volts in 2-1/2 hours with nothing connected to it, the battery is bad.
Most of the FLAPS that check my batteries say they are fine when they are not. Apparently, they don't know how to do a proper load test.
I like it when I see them do the test on a running car. I've seen this more than once!
In reply to foxtrapper:
So this is why our test machine will literally say "TURN OFF THE ENGINE!" if you hook it up to the battery while the car is running. (I'm one of them idiots with the red shirt that doesn't know anything)
foxtrapper wrote:
If the battery goes from 12.4 volts to 7.5 volts in 2-1/2 hours with nothing connected to it, the battery is bad.
yep, but let me expand a little:
anytime a car battery measures 7.5 volts with nothing connected it is bad.
Robbie wrote:
foxtrapper wrote:
If the battery goes from 12.4 volts to 7.5 volts in 2-1/2 hours with nothing connected to it, the battery is bad.
yep, but let me expand a little:
*anytime* a car battery measures 7.5 volts with nothing connected it is bad.
Ha, fair enough. Thanks everyone.
Once you get a good battery in there check the alternator output. I wouldn't be surprised if it's only putting out enough voltage to switch off the idiot light.
In reply to HappyAndy:
I get like 14v when the car's on. My handy-dandy HAM radio has a voltage display.
Agree with battery diagnosis.
On my Opel GT I had a battery that wouldn't hold a charge overnight and I disconnect the battery when parked in my garage so I knew it was the battery. Went to buy a new one and the store tested my old battery and said it was good. Told them it won't hold a charge more than a couple hours and I want a new one. Installed a new battery and haven't had any issues since.
In reply to thatsnowinnebago:
Flaky batteries can't be trusted to give a reliable reading, and the test should be taken on the battery itself.
