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I have an 04 hybrid. The car started to not maintain a charge in the 12 volt battery a couple months ago. We recently had the 12volt batter replaced and about 3 months later the battery died again. We took it to a shop and they found the battery to be defective and gave us another one. Since the car has gone a few weeks or a few days before the battery was dead again. The timing is random. We even had it towed once to the dealership to have them look at it. They were unable to find anything wrong with the car. the car is 100% stock. Ive only got a warning light or anomaly reading from the instrument cluster once. That happened the first time we changed the battery a couple months ago. We let the car sit dead for a couple weeks. When we started it the hybrid battery showed no voltage and the IMA light turned on. We took it around the block and the IMA light went out. Never saw it again. The trip to the dealer took place after and they found nothing. At first i thought the alternator might be bad. But the dealer didn't find a problem, the car is driven daily and it can last weeks. Quite honestly im stumped.. Any ideas of where to look?

 
Rep Power: 209

could be an intermitent problem not happening when they looked at it, my guess would still be the alternator

 
Rep Power: 517

A HYBRID has no alternator.


Intermittent drain after shutoff is more likely.

 
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This is my first Civic or Honda car for that matter. Do they have any parts that tend to be suspect to that kind of failure?

 
Rep Power: 517

There's not many common items I would look at on something like that.....
dome light left on
trunk light left on
ANYthing not original to the car
aftermarket radio/alarm/remote start
used and BHPH car lot GPS payment assurance systems.....



Better would be to actually diagnose, PROVE there is an excessive amount of current draining the battery by measuring with an ammeter, then determine where that draw may lie by isolating and narrowing down the entire car electrical system to a few individual circuits....

IOW you would track down a draw the same way it should be done on any other car.

 
Rep Power: 126

as ezone said, you need to check battery state first.. then check for a parasitic draw with ammeter/ multimeter..

take the negative batery cable and put it in series between the batery post and negative cable,,, key off at first you will have battery draw becaues of ECU's.. wait for 3 min till they go to sleep mode.. your meter has to be connected all the time, you will see draw go down when they go to sleep mode... if draw is bigger than 25 amps.. you have something draining your car batery over night.

alarm, aftermarket radio, short, something has changed because of some work.. ..

you can actually calculate lets say at 25 mili amps , and the rating of the battery 310cca, you can calculate how long your batery till it dies under that load..

 
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I was able to do some diagnosing on the car this afternoon. I also learned a couple of other things. I never drive this car. my wife is the one who uses it and she filled me in on a couple more possible symptoms today.

The at rest amp draw was 0.04a. From a flat battery jump start alternator producing 14volts.

Once started in at least 2 instances the hybrid battery level dash readout shows 0 bars.

On to occasions while driving all indicator lights in the instrument cluster illuminated. One the car was turned off and back on everything works as normal.

I dont know if this is normal but the hybrid battery meter showed full charge after only 1.5 miles of driving.

After the jump start the IMA light illuminates. Once some charge has been put into the battery bars and the car is cycled off/on the IMA light goes out.

At this point there is very little draw while parked and alarm set. When running the alternator is performing as it should. There are no aftermarket items installed in the car.

Any ideas?

 
Rep Power: 517

40mA draw is a little on the high side ---but not horrible.
Problem is, if there is an INTERMITTENT large drain, this did not catch it in the act.

Again, there is no alternator. The IMA system handles charging duties for the 12v battery.


If the 12v battery died or got real weak, the IMA system can 'forget' what the IMA battery state of charge was and reset its meter to zero. It can stay there until it learns the state of charge or has had time to recharge it. This could happen while driving normally, or sitting still and holding the engine RPM high enough to get the charging indicators going.

The electronics in the car are susceptible to voltage fluctuations and rely heavily on a constant, stable, reliable power source (good 12v battery).
If the 12v battery is weak, the electronics can "freak out".
If you try to jump start the car and have the key turned on when you connect the jumper cables, the electronics can again freak out due to the voltage surge.

This is not normal. I can explain away almost everything but this.
What codes can be found, and which system started the process?
You may need to read, document, and then erase all fault codes, then drive until this happens again, and read fault codes as soon as it happens or before turning the key off.
(A dealer level scanner may be needed if a cheap code reader does not give answers)


Allowing a car battery to go dead is very hard on it and can shorten its life expectancy dramatically. They are not designed to be run down.

 
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Thank you for all of that useful information. When it comes to hybrids of any make, I'm fairly in the dark.

The dead battery has only been a result of this stinking gremlin. I suspect its what killed the new battery I had in it the first time. The car will be fine for a random amount of time then go flat overnight. But that's the nature of an intermittent problem.

As far as codes are concerned, I'm told that the dash light thing happened before going to Honda for service. I can't swear to the fact that they hooked the computer up to it. But I would assume they would as part of a routine check. They reported no anomalies.

As far as i know its a bad ground or some relay is getting stuck open until the system drains.



Thank you all for contributing to help me find this problem. For now ill see if I cant get my hands on a code reader. Otherwise unless there are any more ideas I fear I might be stuck just waiting for whatever it is to finish breaking so it can be found.

 
Rep Power: 126

40 ma is still big draw.. how many amp per hour rating on your battery.. you can calculate with that load how long will it last ..

anything above 25 ma is significant.. i had 25ma on other car with aftermarket hack alarm that someone did...

but you said no aftermarket equipment..

 
Rep Power: 517

No, not without making sure we are gonna get paid for it.
Stuck closed. Contacts of a relay would stay stuck closed allowing the circuit to be completed and the load (system or device) to remain powered up when it should not be.


50mA is a general "industry standard" maximum draw figure.

Hondas in general are pretty good about staying right around or below 30mA, some I see drop as low as 5-10mA.

40 isn't really all that bad IMO, but a little higher than I expected....that's not enough to be a map light or anything real noticeable, so I suspected some aftermarket electronics somewhere.