Dead battery, I'm stuck. Will a battery just go from 12.5 to 1.5 in two hours??

[Muse]

Literally stuck right now.
- -
Edit: Please read the next post before (or instead of) the following.
- -
Yesterday, I went for a 7 mile drive, came home and was working on some stuff around the house and the alarm went off. I think, "shit, is someone fucking with my car?" It was in the driveway. I go out there and don't see anybody. I press the button on the remote that's supposed to stop the alarm. It also normally activates it and locks the doors, or deactivates it, at the same time unlocking the doors. The remote would do nothing, the alarm kept going. After maybe a minute, the alarm stopped, but I don't think it had anything to do with my pressing the remote's big button.

Right now, ~18 hours after this happened, the doors are locked, I presume the alarm is activated, and the remote does nothing. I have a spare remote, and that one's also having no effect. I don't want to use the key to open the door because the alarm will go off. There's a way to deactivate the alarm, but I don't remember it. I think I have to use the "easy valet" switch inside the car (I don't remember where it is), in conjunction with the igniiton key, I'll have to study the manual.

The car's a 1997 Mazda 626LX, and I'm pretty sure the alarm was installed when my dad bought it. The car's been mine since my dad died in 2000. I called Omega (who own Crime Guard) in 2000 and asked them about the alarm because I didn't have the manuals. They said I had one of two possible models, and they sent me instructions for both: 533i and 328i. They said the two models, the feature set, was nearly identical.They said I could look under the dash on the driver's side and find out which I have, but I was never able to determine it. Couldn't figure it out from the manuals either, the user's manual and the installation manuals.

Omega are closed for the weekend, so I won't be able to call them and get a person on the phone until Monday morning. I was hoping to use the car today. Something like this happened over a year ago, and the remote wouldn't work, it stopped happening a few days later, mysteriously. I don't know what's at play here. I think the battery has a decent charge on it. Ideas?

 

[Muse]

I drove the car like 7 miles yesterday, and shortly afterward the alarm goes off while the car's sitting in the driveway and the alarm won't respond to the remote. I don't want to set off the alarm and don't attempt to do anything about it until this morning. This morning I am prepared to turn off the alarm and open the car using the keys. The alarm doesn't sound, open the hood, test the battery, there's less than 1.5 volts on it! Why would the battery die just like that? It's old, probably about 84 months old. But just die? Should I just bring the dead battery to Kragen and get another? Is there some way I can test for a short or something?

 

[The Boston Dangler]

the battery is good for 5 years, you're on year 7.

 

[Muse]

the battery is good for 5 years, you're on year 7.

Yup, I figured it was due, but to just go belly up like this, is it possible? It wasn't showing signs. I don't use the car much, but after a 7 mile drive into the hills and back I figure it would have a good charge on it. Could it just die sitting in the drive way a couple of hours later? I hope that's the case, it's the best case scenario right now. I can throw the dead battery in the basket of my bike and pedal over to Kragen (or elsewhere) and get a new battery...

 

[The Boston Dangler]

how do you know it wasn't showing signs of failure if you don't check the voltage manually on a regular basis? if you jump start your car without a battery in it, you can read exactly what the charging system is putting out.

 

[wirednuts]

agreed. just because it didnt show any signs doesnt mean it wasnt degraded. all a battery really has to do is start the engine. if it does that, it appears the battery is fine... but once it hits that level where it cant crank anymore, it appears like complete junk.

 

[Muse]

So, should I just buy a new battery, put it in and see what happens? Or should I do some testing? I suppose my alternator could have gone bad all of a sudden, but seems unlikely. Or it could be a combination.

Around 15 months ago I had alarm problems and thought the battery was bad and brought the car to Kragen, it was still in warranty, but barely. It had about 5% left on the warranty (they'd credit me 5% of what the battery cost). They tested it and said it was still good, they wouldn't sell me another battery. I'm going to remove it and bring it to them on my bike now...

 

[The Boston Dangler]

So, should I just buy a new battery, put it in and see what happens? Or should I do some testing? I suppose my alternator could have gone bad all of a sudden, but seems unlikely. Or it could be a combination.

Around 15 months ago I had alarm problems and thought the battery was bad and brought the car to Kragen, it was still in warranty, but barely. It had about 5% left on the warranty (they'd credit me 5% of what the battery cost). They tested it and said it was still good, they wouldn't sell me another battery. I'm going to remove it and bring it to them on my bike now...

a bad battery with no load can still give a good voltage. load testing a battery is potentially very dangerous.

is that kind of depreciating warranty typical? sounds pretty worthless to me

 

[Muse]

I called O'Reilly (formerly Kragen, I guess) and they tell me I can bring in the battery, test it, and they'll tell me if the battery died or if there's a short in the car somewhere. He said they'll know from testing it the answer to that question.

 

[Muse]

a bad battery with no load can still give a good voltage. load testing a battery is potentially very dangerous.

is that kind of depreciating warranty typical? sounds pretty worthless to me

The O'Reilly guy on the phone said they have one choice in a battery, $99.99, $110.35 with tax, comes with 2 year replacement warranty, 6 years prorating warranty. Guess I'll go for it, hope their testing is for real and right.

 

[soccerballtux]

wow, used to be much cheaper back before these hybrids.

 

[Muse]

the battery is good for 5 years, you're on year 7.

Yeah, but when O'Reilly put it on the charger they found that it took a charge. I had to wait in line, someone was already using the charger. 2 hours later I had a charged battery. I'm about to put it in the car, take it back and have them test the alternator. If it's bad, I'll buy a remanufactured one from them, take it home and hope I can swap it with the bad one. I have no idea if it's a piece of cake or a nightmare. I have some basic tools, have never done more on a car than changing the oil and filters and batteries.

wow, used to be much cheaper back before these hybrids.

Apparently batteries have become alot more expensive the last few years. Probably the metal inside. The rebuilt alternator (if that's what's needed) will cost about the same after I bring back the bad one and get about a $45-50 charge back for it (i.e. around $100 after the credit, don't know if they charge state tax, suppose they do). If it isn't the alternator I guess there's a short. I have no idea how to deal with that, suppose I'd have to take it to a shop.

 

[Muse]

Are you ready for this? I get the battery home in my bike basket, install it in the car and drive back to O'Reilly's. The guy (assistant manager with a big open end box wrench tatooed on his arm) comes out to the lot to test my alternator (I told him I did not see the light on indicating that the battery wasn't charging) and casually observes that the parking lights were on. Doh! Sometimes I think I'm an idiot! He has me crank up the engine and turn on a bunch of stuff (radio, heater fan, lights), says the alternator's cranking great, "you're golden!"

 

[The Boston Dangler]

at least you got a new battery for your trouble

 

[LTC8K6]

If you did not get a new battery, you should.

 

[Muse]

at least you got a new battery for your trouble

Nope, but they did put a hell of a charge on the old one. After driving it home (drove the ~3.5 miles home with it in the car), I measured the voltage with a cheap multimeter and it said 13.19v!

That faceplant pretty much sums up how I feel about this!

If you did not get a new battery, you should.

I was kind of thinking this 15 months ago when I went into the same O'Reilly's and asked for a credit on the prorated warranty on my current battery, which I thought didn't hold a decent charge. They put it on their machine and said they couldn't/wouldn't sell me a new battery because my current one was good. I believe the warranty has run out now, but they're telling me that the battery's OK, so what can I do? Fact is, 1/2 the year I don't drive the car except maybe every 6 weeks on average. That's the current pattern, could change, of course. During that period I keep a little float charger on it. As long as I manage to keep a decent charge on it, everything seems OK. However, put a drain on the battery (as I found out this weekend) and it goes dead pretty quick. I remember a AAA emergency towing vehicle driver telling me some years ago that a good battery should be able to withstand leaving the headlights on for a good 45 minutes (maybe he said an hour) without losing the ability to start the car. Here I had the parking lights on for maybe a couple of hours and the alarm went off and the remote wouldn't stop it. The battery's weak. I guess I'll just keep using it until it's obviously inadequate or O'Reilly's finally says "you have to replace your battery!"

 

[SpatiallyAware]

At 7 years old your battery is on its last legs. Technically, the battery should run your parking lights for 4-5 hours and then start the engine with no problem.

Those test stations are frequently wrong. I've had numerous situations where a known bad battery and/or alternator tested good and vice versa.


I would go ahead and replace the battery. You might try going to autozone, advance, etc until one of their stations tests it as bad.

 

[Ferzerp]

They put it on their machine and said they couldn't/wouldn't sell me a new battery because my current one was good.

I was unaware that one needed a prescription from a weird machine in order to purchase a battery.

Walk in, say "I want to buy a new battery of type X"
Purchase battery.
Leave.

You don't have to take their advice.

 

[LTC8K6]

The battery is old enough to be replaced already, plus you have been totally discharging it, which is bad for it. I would not trust that battery any further than a drive to get a new one.

 

[Muse]

I was unaware that one needed a prescription from a weird machine in order to purchase a battery.

Walk in, say "I want to buy a new battery of type X"
Purchase battery.
Leave.

You don't have to take their advice.

I believe it costs me over $10 more if I don't give them my replaced battery. That's basically the reason.

 

[SpatiallyAware]

I believe it costs me over $10 more if I don't give them my replaced battery. That's basically the reason.

What's a bigger PITA, $10 or trying to get a jump from someone when you're stranded away from home?

 

[SilthDraeth]

I believe it costs me over $10 more if I don't give them my replaced battery. That's basically the reason.

Drive down there, unhook your battery, buy new battery, give them old battery.

Old battery is for the core charge. You can even buy new, put it in at home and then take back the old with receipt and get core charge refunded.

You can do this with a brand new battery, or an old battery. You don't need them to test it first.

 

[Bad Dude]

So what did you do? I am in no way an expert mechanic but I will give some advice. Every one here is trying to help but it all base on their experience rather than scientific proof. I have seen a basic battery last 10 years. Most good battery will give you 7 years. Most cheap gives you 4 years and any thing in between gives you 5 years. With those figures in mind, you need to take into consideration a few things. For one extreme changes in temperatures. Next, how your car treat your battery? How often you let the battery drain down. Let's get to the good part, how to know or make an educated guess when your battery might be going. You can do this yourself with a cheap multimeter.
1) Load test the battery, though this method is not accurate, it tells you the battery cranking ability. Grab the voltmeter, put on the battery. It should read 12V, overnight you should have 12.3V, right after you drove on the freeway for while and just shut off the car, it should read 12.7V-12.9V. Now keep the voltmeter on the battery, ask some one to crank your car. Right before the car starts, check to see how low the voltage drops. It should not get below 10V. If it does, then your car should not start and the battery is bad. Now crank the car and let it starts. While keeping the voltmeter on, you should have 14.3 or higher but should not exceed 16V at any time. CAUTION, any time you see the voltage at 16V and you have the voltmeter on properly, turn the car off immediately. Replace your alternator. If you have a Denso, replace the regulator and the brush kit if you have over 150000 miles. Now load the system while car is running, the voltage could drop to 13.7V then it should recover back to 14V or above. Now, you can check the tightness of the belt by checking the voltage fluctuation when revving the car up. If it's more than a 1V change, then your belt need adjustment. You could check the battery regularly and your alternator health. Keep an eye on dimming lights at night, if you don't have a big amp in the car. This is only roughly estimate the life span of you battery system. I hope this helps. By the way, Costco has a great battery for only $68.

 

[LTC8K6]

At ~7 years of age, he needs a new battery anyway...

 

[Muse]

So what did you do? ...

...I hope this helps. By the way, Costco has a great battery for only $68.

Nothing yet. Partly because of my usage pattern lately... I've been taking the car up into the hills ~3x/week, around 10 mile round trip. Other than that my next trip will probably be to Costco, also around 10 miles round trip, but not into the hills. I'll see if they have a battery that is appropriate for my car (1997 Mazda 626LX). Hopefully, if they do, I'll just buy it right there and change the battery in the lot and give them the old one. If $68, I'll be happy. Is it a pretty decent battery?