Old battery and rate of parasitic drain on car all of a sudden

I have a 2006 Suzuki Forenza with original battery, so it’s been about 9.5 years now. Yesterday, I couldn’t start the car, and it made a few rapid clicks on trying to start it. I didn’t have time to deal with it so took a spare car to work. Came home to check/try the car and it had so little charge that dashboard lights, automatic door locks, etc. didn’t work, the warning indicator lights that light up on turning power on barely lit up. Seems like the battery was nearly discharged.

I’m attempting to have it charged with an external charger right now to check on the car later (and try to check for parasitic drain), have the battery tested, and bring the car to mechanic for a more thorough inspection (I’m not a car person).

I was just wondering though in the meantime:

  • did I get lucky to get nearly 10 years of life out of a car’s factory installed battery? and that it’s likely time for a new battery regardless of whether the battery still holds charge?

  • The car was working fine the previous day, I never had to jump start the car. Although I had trouble starting car once or twice in the past, but that just required waiting a bit and attempting to start car again - may have been warm weather related. It just failed yesterday, and I don’t recall leaving headlights on or things like that. I’m just wondering had my car been parasitically draining already and just hit a critical point yesterday (slow drain before but faster drain at some point like yesterday), or can parasitic drain just happen all of a sudden like fine one day, then some drain/short the next that kills the battery.

I think you can chalk it up to dead battery blues. 10 years is above norm, mine usually got replaced at 8 max. Daughter slow cranking 02 saturn, say 10 years old, 65 cca vs 800 cca (cold cranking amps) in the new battery.

Yes you got lucky getting that much time out of a battery and with winter coming on a new battery just makes sense. As for batteries working fine one day and not the next is not uncommon.

Go buy a lottery ticket!

That’s lucky!

I came home from work one day, shut the engine off, ran into the house to take a quick shower to go out for the night, and when I turned the key, nothing.

Opened the hood, checked the battery, no voltage!

The battery was five years old!


You’ve gotten twice the expected lifespan out of your battery. Just replace it.

That’s how old batteries fail. Work fine one minute and not at all the next. So much so that when a car is in the shop here, we test batteries that are between 3 and 7 years old. Batteries over 7 years old are recommended for replacement without testing, just because at that age a battery can test fine one day and bad the next.

The original battery in our Nissan lasted 7 years. We replaced it with a heavy duty Kirkland from Costco. That battery lasted 11 years at least till when we sold the car.

Thanks for the input. I guess it’s battery shopping time for me now.

With a new battery, should I still check the car (drain or short circuit, alternator, starter) just in case or chalk it up to old dying battery?

@daluu Can’t hurt to check for parasitic drain while the battery is out. An ammeter between the + terminal and the battery cable should show around 20 milli-amps or less depending on the car model. Expensive cars with lots of options draw more than a basic car.

@Mustangman, is that with negative terminal connected to car or battery entirely disconnected? I read online to test between the negative terminal and negative cable, and check for ~75 mA, greater than that indicates a possible drain. Or to test with a 12V test light (should not be brightly lit or on instead of amp check).

The battery in my truck is 12 years old and no signs of any problem. So it’s entirely possible a battery can last 10 years or even beyond. Truck isn’t used a lot, so that may have to do w/its long lifetime. Heat is what damages batteries fast I’m told. Is the area you live on the cool side? I’m assuming you don’t live in a climate like New Orleans or New Delhi.

When I’ve tested the “off” drain on my cars I disconnect the negative battery terminal and install an amp meter in series before reconnecting. Make sure everything is turned off when you do this, otherwise you can damage something, including the amp meter. On my Corolla with everything off I read less than 10 mA current draw. Newer cars have more electrical stuff going on, so 50 to 75 mA might be possible and still be within normal specs. My truck has an aftermarket radio and it reads around 25 mA as I recall. Remember to put things back the way they were before attempting to start the engine of course.

Your overall plan sounds good. If your battery load-tests ok, and there’s no indication of unusual current drains with everything off, it could be

  • battery connections and/or grounds are corroded
  • alternator isn’t working properly, so battery isn’t getting fully charged
  • the battery is coated with something conductive, like battery acid. That can discharge the battery, the current just runs along the surface from one post to the other. That won’t show up with a meter-test. Clean the outer surface of the battery and see if that helps.

Checking parasitic drain, give it some time. You may read a high number initially, perhaps over 100mA, but wait 10 minutes or so. Usually the processors go into a power down mode after some minutes and reduce the current significantly.

Start out with the meter on the highest range (usually 1 or 2 amps, as the 10 amp range has a separate connector) and change the range later as needed.

Actually, better to do this on the 10 or 20 amp range initially (with everything turned off) then repeat the test changing the connections to the lower range.

You can put the meter in series with either lead of the battery, makes no difference.

On third thought, I’d go buy some 1 ohm resistors. 1 watt or higher is fine. ebay has plenty.

put that in series with either battery lead and put the voltmeter across it, in the DCV mode. This will protect the meter from damage. Then use ohm’s law. 1 volt means 1 amp, 0.1 volt, 100 mV means 100 mA, etc. If the resistor has more than 1 volt across it, it will overheat, indicating you have way excess current drain.

I’d just buy a new battery and be done with it. 90% chance that’s the problem.

I agree - buy a new battery and don’t worry about parasitic drain unless it goes dead. Not at all likely.

Before disconnecting your battery, read your owners manual about what you need to do to keep your radio from losing its memory, or worse, needing a reset code to be keyed in before it will work again. I always write that radio code on the file folder where I keep other documents about the car, also in the back of my owners manual.

You are overthinking this, just replace the battery. The cahance that it is anything other than a worn out battery is very small and if something else is wrong you still needed the battery anyway.

@shanonia, radio can be messed up w/o power for some time? Or you mean it just looses it’s preset stations (that are like browser bookmarks on a computer/smartphone)? I don’t mind loosing the presets, sounds lame if the radio craps out and needs reprogramming to work. I’ve never heard of that before.

It’s a security feature to (they think) prevent the radio from being stolen.

When the power goes totally off the radio becomes dead until you enter the security code. See the manual.

You've gotten twice the expected lifespan out of your battery. Just replace it.

For ypu people who live in the south…but not for us who live in the north. 7-10 is the norm here, 3-5 in the southern states. I’ve had batteries last 12+ years.

If you bought the car new, there would have been a hang tag on the radio with the reset code printed on it. It may be among your papers or maybe in the glove compartment under the plastic spoons and straws. Otherwise contact the seller or a Subaru dealer. With proof of ownership they can probably obtain the code, maybe charging a small fee.

The longest lasting battery I ever had came in a new car I bought . It was a Delco with the green eye . That battery lasted 13 years . I tend to keep good vehicles a long time . I would say your battery has probably lived out its useful life . As mentioned before most parts places will test it for free .