KarenAnne

I hope this isn't a duplicate question. The car has been having this problem for awhile and I have the dim idea I may have asked about it before.

Every 2-3 months the battery goes dead. My brother, the previous, original owner of the car, tells me I don't drive it enough. I found the battery dead today. Last week I made two 15 mile trips. The week before I drove it 50 miles.

Does it really need more driving than that, and if so how much? My sister-in-law used to use it to commute to work so they were using it more often than I am.

The mechanic has checked it for a drain. It has twice had new batteries installed.

Getting annoyed :-)

Thanks for any clues,

Karen

Johnhav430

Is our assumption that the battery is good, because the car has gotten 2 replacements already?

With a fully charged battery I do think a car should be able to sit a month and no problem. A compromised battery all bets are off. And no, 50 miles a week would likely not be sufficient, if compromised. Just think, many of us used to drive 50 miles a day pre-pandemic.

There's also the inexplicable, maybe due to quality My wife's, and my buddy's mom's cars, both had dead batteries during the pandemic. After jumping, both batteries tested fine. With my wife, I just went to Costco and got a new battery. The old was 2 y.o. and no problems since. With my buddy, his mom took the car to Honda who could find nothing wrong with the car or the battery that went dead, no issues since. There is no scientific explanation why the batteries failed, and upon jumping, they pass load tests. My wife's car sat only 4 days. Buddy's mom, daily driven.

The cheapest option is to get a new battery, but if it were just replaced, that's not advisable, perhaps there's a parasitic drain.

Do you only drive every 2-3 mos--if the car sat 2-3 mos., you drove it 50 miles last week, that likely isn't long enough to fully charge it. Maybe you should plug it in with a battery tender? Or do you drive daily but very short distances?

You are perfectly fine to be annoyed, we're all ordinary people and don't need these problems lol

KarenAnne

Yes, I'm assuming the battery is good. The last time my brother told me which one to get, some super duper excellent battery,

I know how much I've been driving the car, because our Governor asked people to record things for contact tracing if necessary. Here it is since the beginning of September. This doesn't quite match what I said originally as I looked at my calendar more carefully: This is pretty typical usage. The car is not sitting unused for months.

Sept 5 miles, 10 miles, 2 miles
Sept 5 miles
Sept 20 miles, 15 miles, 10 miles
Sept 5 miles, 15 miles
Oct 40 miles, 30 miles
Oct 15 miles, 10 miles, 15 miles
Oct dead battery.

bradland

Have you checked the health of your alternator? It sounds like you keep replacing batteries when the real problem might be the alternator.
If the alternator isn't doing its job a new battery will get you by for a little while before it dies. Obviously using headlights, stereo, AC fans, etc., will drain it quicker but if you aren't driving much you've prob been getting by on battery power alone.

TominPT

As I have mentioned in several other "dead battery" threads, if you leave any door of the car not completely closed the interior lights stay on and the battery will be dead a few days later. You must be certain that all doors are completely closed when you park and leave the car for any period of time.

I speak from experience. Argh.
If you are being diligent about the doors, the alternator may be the likely culprit as Bradland points out,

KarenAnne

Thanks for the alernator suggestion. I will talk to the mechanic. I hope that's it, it would be nice to get this fixed.

I am pretty sure I am closing the doors okay, and I'm the only one in the car except for people putting pickup stuff like groceries in the back seat and I close that door.

Also the car has power door closers which I think avoid this problem.

KarenAnne

By the way, out of paranoia, when I leave the car in the garage, I always wait for the headlights to go out. Would they go out if a door were not completely closed? Of course, I might be missing their staying on when I park it elsewhere.

LS430Lexus

I have found that an AGM battery seems to minimize these issues. It costs a little more but is worth it in the long run. Also, make sure the trunk is closed. My failure to make sure it is completely closed has caused me to have a dead battery on occasion.

In my area, Auto Zone and Advance Auto will perform a pretty good free battery, starter and alternator check. They provide a print out of the results and it can be helpful in narrowing down the problem. Good luck.

CSA

My hunch is its your alternator coupled with infrequent short trips that don't do much to recharge the battery. After 17 years, it might be time for a new alternator. I just did mine on my 05. Most cars aren't still on the road after 15-17 years, so it's hard to complain.

AGM batteries are great, but they are not so great for old cars that sit.

If you don't have a AAA membership, it's worth considering. If I recall correctly, it's about $40 a year. With a phone call, they will come to you and check the battery and the alternator, give you a jump start if you need it, install a new battery if need it, put a spare on if you have a flat, etc.

Johnhav430

I know with my uncle's Acura, dealer said can't find any issue. An indie found his bluetooth module was malfunctioning and had a parasitic drain, and since he doesn't talk and drive, he was OK with disabling it. In his case every 3 days car was dead.

Driving once in a while really charges the battery a lot less than one would think. I used to drive my garaged car around 1 time every 2-3 months. I drove it to work 26 miles, of which 15+ was 65 mph highway. Went to my car at lunch, listened to the stereo, and in about 5 minutes it went into battery saver mode. What I'm trying to illustrate was at that time, I figured the drive "reset" or made my current normal. I think a tender helps, but I'm not convinced they are a cure all--they go into green when the voltage is good. that's only V in v = ir. The older the battery is, the higher r is....

Honestly for us, from now on, any issues, just replace the battery under warranty at Costco. Again with my wife's nobody will ever know what happened, but new battery = good ever since, 2 y.o. battery...my Lexus is over 4 years old....

If you want to do an $85 experiment? Get a new battery and see. Worst case it goes dead with a new battery, and now you're 100% sure it's not the battery. Again, my wife's car was dead, and after jumping, battery passed load test. Same as buddy's mom. So I have no explanation on that one...both cars driven....

LSneewb

@KarenAnne Does your car have a remote start or aftermarket bluetooth ?

i928

You can get an automotive load battery tester to test your battery and alternator health. It is more convenient than go to auto store to get free test or mechanic shop to check.
If both battery and alternator is healthy. You can get a battery tender junior charger to charge battery as temporary workaround for a parasitic drain.

bradland

If your 430 has Nav you can check battery and alt. health FREE without opening the hood. There's a hidden (pseudo secret) menu accessible from the Nav screen.
Accessing it before starting the car shows battery output, start the car and you'll see how many volts the alternator is producing. It may not be as profound as an actual load tester but the price and convenience are great!

Johnhav430

From being on forums from across multiple brands over the years, there's a resistance to doing load testing and buying a tester. It's probably the $35 I guess or the inconvenience of dealing with an auto parts store (people blow that on other useless things all the time). I'll never know why, but some things are meant to be mysteries! I do think the battery tender will do what you say and accommodate for the drain.

Again, it also seems like horsepower, people dwell on voltage (R increases over time, so what happens to i?). google answered the question for me, as to why a battery tender can turn green, yet the battery it was on, cannot start a car. We're never the only person in the world who experiences something nowadays.

Also, as I learned during the pandemic, my wife's car, and my buddy's mom's cars, both died, with batteries that passed load tests, after being jumped and driven. Wife's car sat 4 days, buddy's mom's daily driven. Put in a new battery on wife's, no problem since. Friend's mom, did nothing except pay the dealer to say nothing wrong, no problem since. Something happened, but we'll likely never know what. I can say, that my wife's did have about 170 CCA less than a new battery. So now we get into what's a pass, and what's not. The new battery rated 730 did 900 at 65F. The old was still almost 730. 730 is 730, it starts a car. But it's lost some over a brand new. Another clue in my wife's? Airbag warning--that's never happened before with the other 3 batteries in the car's life that went dead.

If I were in the OPs case, I'd just go to Costco and get a $85 battery and throw it in. This will confirm if I have a more serious issue, as now I am 100% certain my battery is good. My hunch is there's a 50% or greater chance, the problem goes away. If it doesn't, I know it's not the battery and I know I have much more serious issues. I'm not out $85--I have a brand new battery to show for it. Otherwise, we're simply assuming the battery is good using subjective info. And we're perhaps using an assumption to decide we're not going to be spending $85 to know.

edit: Look at it this way--what if, I insist I want to know what happened with my wife's and my buddy's mom? Then, most likely, we'll have to test more than once, just like we'd test for COVID. I'd need my wife's old battery back, reinstall it, and test under various temperatures in the real world, and at minimum, to duplicate the car sitting 4 days. How does the expression go? Is the juice worth the squeeze?

jmdav89

I have tested my alternator with a Schmacher battery charger that requires that the car needs to rev to 2200 rpms for 2+ minutes to test the alternator charging capacity. What that tells me is that you need to be driving your car at speeds that will allow the alternator to charge the battery. If you drive around town at low speeds and start and stop this may not be enough to charge the battery sufficiently. Anyway getting the alternator tested is a good place to start. Your local RI Auto Zone parts store can do this test without taking it to a repair shop