Car dies but battery, altenator, starter, parasitic drain, etc test fine

subaru

#1

My coworker and I have been trying to find out what is wrong with her car. We’ve had help from o reileys, autozone, advanced, and a mechanically inclined family member with no results. It is an 05 subaru outback 3.0. She bought it 4 months ago. A week ago the battery died at red light. It tested bad and was replaced. Then yesterday it died at stop sign. Jumped it and died in 5 seconds. Before dying, car would not rev. Jumped it leaving cables on for 5 minutes since battery was almost drained. She made it half mile back to office and coasted into lot. Battery tested good but drained and was fully charged. Altenator tested 7 times to be certain. We bought a 10A multimeter (our town has no 20A). Tested for parasitic drain. No results. We took Altenator off and tested a couple more times. We took out non essential fuses to be safe. Nothing was left running. There was a phone charger that has been plugged in for the whole four months. She took it out for good measure. Starter tested good. 3 people said battery cables are good. They appear to be non corroded and tight imo as well. They checked fuel pump. All was well. She wants to go on vacation for the 4th but is scared to try. Mechanic friend said wait until it happens again, go to o reileys and demand them replace the battery as it has to be bad even if testing good. I’m not sure of this is the correct approach, but what else is there? One online mechanic said a voltage test on electrical system is next step but only a few select mechanics even know how to do it such as one that specializes in electrical wiring or something like that. Please share any knowledge. I have suggested she change cables out for good measure, kindly ask o rieleys to give another battery, and to buy a solar panel that goes in battery charger which keeps battery from draining as it is only 30 bucks and was suggested by someone online.


#2

@Dispatcher

Please don’t take this the wrong way, please

Do you know HOW to measure parasitic draw?

The leads are NOT hooked up to the meter the same way, versus measuring voltage

“No results” makes me wonder exactly what you mean

0.L which means out of range, in other words, you’ve got the wrong setting . . . ?

parasitic draw is within normal parameters . . . ?

no draw at all . . . which is unrealistic because even a perfect system will probably have at least 5 milliamps of draw . . . ?

speaking of the alternator . . . exactly HOW are you going about testing it?

What tools are you using?

a simple multimeter will not give you the whole picture


#3

Sorry if I was not clear enough. The multimeter tested .3 which according to the eric the car guy video was within normal. I did not help with test. The mechanically inclined guy and coworker did test following his knowledge and eric the car guy video which was most detailed video ever. It was a simple 20 buck multimeter which was best option in our town. Altenator was tested at 3 different stores a few times on car and a few times off. I read to have it tested many times so that is what we did. They just use the machine they have to test it. She is on way here now and just called to say it is losing power but she is trying to make it here so to be on standby in case she needs me.


#4

A friend of mine had the same car and problem. The trouble with the current draw was due to the CD player being jammed so I suggest you check that first.

Normal current draw on the battery with the car parked and things have gone into the sleep mode should be less than 30 milliamps, more like about 15 to 20 I believe.

Here is a link that may help you out:

http://www.aa1car.com/library/battery_runs_down.htm

If the car is dying on the road then something is wrong with the charging system. The alternator itself may be okay but there could be wiring problems to it. You should see around 14 volts at the battery while the engine is running around 1,500 RPM.


#5

@Dispatcher

“The multimeter tested .3 which according to the eric the car guy video was within normal.”

It would seem “eric the car guy” is WRONG

.3 means 0.3 amperes, which means 300 milliamperes

That is definitely WAY above normal parameters

The upper limit of normal parameters is generally recognized to be 50 milliamps

You have 6 times the normal parasitic draw

As such, the battery is getting drawn down every time it sits, and the alternator has to work pretty hard to restore it

The proper way to test a charging system is to bring the car somewhere and have them test everything as is, installed in the car

Same thing goes for batteries and starters

No offense to anybody that removes those components and brings them to a store for testing

Sounds to me like the charging system is NOT okay. Bring the whole car somewhere for testing. Not o’reilly or pep boys. You should pay a shop to diagnose and repair the problem


#6

In the main fuse box under the hood, Check SBF-1 fuse, 120 AMP to see if it’s blown.

This fuse allows the alternator to charge the battery.

Tester


#7

First I would be suspect of the true condition of the battery cables and the terminals at the battery. They may look fine, but have enough corrosion to block the flow of electricity.

I would pull the terminals and use a post cleaner to clean the inside of the terminals and the posts. When you tighten them back up, you should not be able to twist them while on the posts.
Also you should peal back about 1/2 inch of insulation at the terminal end and see if those cables are excessively corroded. Excessive corrosion…replace…they are junk.

Charge the battery on a charger before attempting to start it again. A heavy draw from the alternator to charge a dead…jumped battery could overload the alternator and damage it.

My next step would be to measure battery voltage at the battery. One reading for engine off, and what voltage the battery reads once the engine is running. The battery should read 12.5 volts with the engine off and with the engine running the battery should read about 14 volts.
If the voltage is the same while the engine is off and when it’s running then there is a charging problem.

My next step would be to test the voltage at the stud at the back of the alternator with the engine running. This wire will be bigger than the others and attached with a nut…separate from the other wires. Use caution that you do not accidentally ground that stud when doing this test . If that stud reads a higher voltage (14volts ) while the engine is running…then it is the wire that runs from the alternator to the battery where your problem is. This wire carries voltage to charge the battery and sometimes they are a fusible link, meaning that they act as a fuse and burn out to protect critical components.

Your auto parts store will be able to look up if it is a fusible link and set you up with what you need.

Yosemite


#8

It was within normal
Maybe I got the number wrong
I trust that the guy who tested it knew it to be normal. He was bus mechanic for a few years. So he is mechanic inclined. So for now assume normal. I didn’t first offer details on that because all I knew is that it was normal range to his standards and to the vid we found. Sorry about that.


#9

Concur w/ @db4690, 0.3 amps parasitic draw (with everything turned off and all the computers had a chance to go to sleep) is too much. So the cause of that has to be discovered as it is likely part of the problem. It should be 0.050 amps or less. But at 0.3 amps draw it would take 50-100 hours with the engine not running to drain the battery, so that might not be the entire explanation if the car is driven at least 5-10 miles on a daily basis.

Since OP seems to know how to use the meter in amp mode, OP could try using it in voltage mode and read the voltage at the battery posts. It should read around 12.6 volts with the engine off and the car has been sitting overnight. When the engine is then started and idling it should read 13.5 to 15 volts. Right after starting the engine it will read higher, then gradually the voltage will get lower, but usually won’t go less than 13-13.5 volts with the engine running. If that voltage at the battery seems to never go down even after running the engine for 15-30 minutes, there’s probably some device in the car using a lot of electrical power when the engine is running.


#10

@Dispatcher

Maybe you didn’t misunderstand the bus mechanic

I’ve met a few mechanics over the years, who were gravely misinformed, as to what constitutes acceptable parasitic draw

For example, a guy I’m working with right now . . . who is in almost all other respects a genius . . . insists that 500 milliamps is acceptable parasitic draw. I’m not sure where he got his information

I once tried to explain in a non-confrontational manner, that he was misinformed. But he wasn’t “open to suggestion” . . . so I never brought it up again

I don’t watch “eric the car guy” videos. And as such, I can’t judge him. But if he indeed said 300 milliamps was okay, then he was wrong. Pretty simple

IMO 300 milliamps is a substantial draw, and will damage the battery over time. And as I said, the alternator will be working hard every morning, to rejuvenate the battery

And as was already pointed out, if you bring the alternator to a store to be tested, you can’t test the wiring. That’s why you test the entire system intact, installed, not just one component on the bench.

I suspect the charging voltage at idle is considerably less than the 14V one would expect for a typical vehicle. It’s probably more like 12.6V, which would be in line with a system that is not charging at all. And that’s what it sounds like, based on your described symptoms


#11

I hesitate to get involved in this one because everything seems to be so off the wall in how things were done.

Try this. Charge the battery for a few hours. Touch the probes of the VOM to the battery terminals. You should see 12.6 - 12.8 volts on a decent battery.

With the probes attached crank the engine over. You should not see the voltage reading drop below about 10.5 on a good battery.

And yes I’m aware of inductance battery testers which are, in my opinion, near worthless. A load test is the way to go.

Also in agreement with that .3 parasitic draw being way too high.


#12

I wonder if there is some misinterpretation? I pulled up an Eric guy video about parasitic draw and it sounded different than what was presented.

The video I saw showed a car with a 3.something amp draw which was correctly stated to be way too high and it was also stated that 50 Milliamperes was more like it.

On another note, the Eric video also showed him stating that you need a VOM with at least a minimum 200 Milliamperes scale. That kind of nulls the idea of finding a draw of anything less than 200 MAs.

With the car in question the problem was the interior light switch was left on. Presenting the bill to a customer figured at 100 an hour will go over like a ton of bricks for telling them something like this after going through the motions.


#13

ok4450: “you need a VOM with at least a minimum 200 Milliamperes scale. That kind of nulls the idea of finding a draw of anything less than 200 MAs.” ??

You can read 50 mA easily on a 200 mA scale.

PS, mA is correct. MA is mega-amp.


#14

I seem to remember seeing some of those “Eric the Car Guy” Utube vdo’s before and thought they were pretty informative. I don’t remember seeing him state anything that was completely incorrect. Ambiguous a little maybe at times, skips some parts to avoid the vdo taking too long or being boring, but over all pretty accurate.

Vdo’s and magazine articles about car repair and restoration, it depends on what style you like. Some folks might prefer just to see the finished result, some photos of the shiny restored car with specs on what engine, carb, and transmission were used to fix it up. Compared to that, I prefer an article that focuses on how to restore a single, simple part, like a door handle or antenna bezel, something that can’t be sourced from the junkyard so has to be made up from scratch or maybe by bending/re-machining/hammering on a door handle from a different car to get it into the matching shape.


#15

So the car is mine… and I just want it fixed. Brief sum up: ABS Light came on died in the middle atlanta. Battery tested bad. Bought a new one. Tested alternator behind battery came up passed. Starter also passed. 4 days later same thing. Charged battery took alternator off vehicle bench test 7 times all passed. Started parasitic drain passed. Not the issue. Cleaned terminals well that already appeared good. Same thing happened again next day. Replaced battery as covered on warranty, thought maybe bad batch battery. Was not the issue. Sent car to a wiring mechanic. He checked wiring, checked alternator and was stumped. We put new alternator in, still same problem. The alternator does not appear to be charging battery. THIS IS A CHARGING ISSUE!

Battery is reading 12.84V
Starter is reading 11.69 in 718mS
Drain test is reading .14 A

Alternator 13.49V NO LOAD
13.42V LOADED

Ripple Test 76mV

Everyone seems stumped. Anyone else dealt with an issue like this? I may be a female but thankfully I am not dumb neither is my co-worker that originally posted. I am open to all suggestions… but yes I do know how to do some test and when I don’t I have no problem asking the correct way.


#16

need more details.

“Battery is reading 12.84V” ? under what conditions? engine running or not?
“in 718mS” ? what does this mean?
“13.42V LOADED” ? loaded with what? A good alternator driving a partially discharged battery should read above 14 volts.

“Drain test is reading .14 A” This is somewhat high, but may be OK short term. IE, don’t leave the car for more than a few days.


#17

You need to clarify something, each time the engine has stalled it was because the battery went dead while driving, then the battery was replaced or recharged before the engine would crank over again? How long was the engine running before each failure?


#18
Battery is reading 12.84V
That's a good reading when the engine is off and the car has been sitting overnight, or at least a few hours. My Corolla's reads 12.6 V, so if that measurement is when the engine is off, there's no proof of a battery problem. The only way to test the battery is something called a "load test" but I expect if you've got a nearly new battery there's little point in doing a load test, the battery probably isn't likely the problem.
Starter is reading 11.69 in 718mS

I’m guessing this is data printed from some kind of machine the shop has that automatically tests the battery, charging, and starting systems. And this particular measurement is made at the battery when the starter is cranking the car. So it is sort of a poor man’s battery load test. In any event, that looks to be ok, if I’m interpreting it correctly. Again confirming the battery is not the problem.

Drain test is reading .14 A

I’m assuming this to be the parasitic drain, the amount of current being drawn when the engine is turned off and everything else is turned off and the computers have gone to sleep. You prior indicated this was 0.3 A. 0.14 A is a little high, we usually look for less than 0.05 A here, but the overage wouldn’t cause the car to die when you are driving it. I don’t think that’s the issue causing your engine to stall, but might be a clue to the actual problem.

Alternator 13.49V NO LOAD 13.42V LOADED Ripple Test 76mV

Assuming this is with the engine running, comparing the voltage at the battery with the headlights on vs the headlights off. Those both look a little low, but might be ok if the battery was almost 100% charged at the time the test was done. If this test were done after the car had been parked overnight I’d expect it to read in the 14 -15 volt range, and slowly drop to the 13.5 volt range as the engine idled and the battery recharged. But I think this test was probably done when the car had just been driven. So those measurements don’t indicate a problem. The ripple voltage looks ok too.

The alternator does not appear to be charging battery. THIS IS A CHARGING ISSUE!

The measurements above indicates the alternator is in fact charging the battery. Why? Because the charging voltage of 13.49 volts is more than the battery voltage of 12.84V. If the alternator wasn’t charging the battery the 13.49 volt value would be 12.49. So the battery must be being charged by the alternator.


I can tell you are frustrated with this problem OP, and you have a right to be. You depend on your car to get you where you need to go, and safely.

hmmm … well, what would I do if it happened to my own Corolla? Battery is ok, alternator is fine at least when testing in the driveway, and likewise parasitic drain , although a little high, isn’t the culprit to the battery draining and the car dying while driving it. My theory is something happens while driving that causes the alternator to stop charging, or a big current drain starts somewhere in the car’s systems. But that all only happens when driving, not idling in the driveway or garage. I guess what I’d do is connect a volt meter to the battery and put that meter where I could see it as I drove the car. It should always read above 13 volts as I’m driving the car. I expect if you did this you’d discover that in certain circumstances it was reading less than 13 volts while driving One idea, . ask your mechanic if he can install a volt meter temporarily in the car so you can watch it as you drive, looking for anything unusual happening.

Best of luck, let us know what you find.


#19

I assume the 13.49 volts reading was taken at the battery. You don’t state what the RPMs of the engine were at the time of the test. The reading should be taken while running around 1,500 RPM. You should see more like 14 volts hopefully as 13.5 is slightly low.

The .140 milliamp draw is not good. In my last post I told you where to look for the problem. Check the CD player.

As far as the car dying on you while driving it I have to suspect the battery isn’t causing the problem. There could be a problem with a connection to the power bus that makes it seem like the battery is dead. If the flashers don’t work when this trouble happens then either the battery is low or there is a bad connection to it in the panel under the hood.


#20

I had a similar issue the other day. One of the battery clamps was bad. I had it tested at Autozone to eliminate the simple things. The alternator tester showed a failed alternator when the ground clamp was put on the negative battery post. The alternator tested good when the ground clamp was placed on part of the engine itself. I think it was part of the intake manifold if I remember. So, it showed all was well and that the alternator was functioning when tested on something directly attached to the alternator itself (engine) but that there was an alternator problem when tested at the battery. This eliminated the positive cable since it was never touched. The negative battery clamp looked a tad iffy so I changed it. They are cheap so who cares? Anyway the problem was fixed by this simple work.

The test showed that the alternator was working but not charging the battery before I changed the battery clamp. I could drive it around all day and it worked fine as long as I didn’t turn it off. Voltage was around 14 on the engine but lower at the battery. Again, check all the major ground points and fuses that are applicable to this situation. The voltage was basically the same all around once the new clamp was installed.