why does my car keep eating batteries

[Whitecrystal1]

In my 95 Bonnie I replaced the battery around 8 months ago with a cheap $50.00 Werker battery from Batteries Plus. I'm thinking this is their house brand. After using it for around a month it started dying overnight. I went back to the store and they told me that the battery was fine and there must be something in the car drawling it down. So I left and disconnecting the battery at night to see, it still died and needed to be jumped. After going back to Batteries Plus a second time they replaced the battery with another new one. That was maybe 7 months or so... and all was good until 2 weeks ago when it started doing the same thing. I couldn't get the battery to even take a charge this time. So, and I know this might not have been the best decision bought a new battery for the 94 and swapped the battery that was in it into the 95. It's a Diehard battery, I don't know how old it is but it seemed to be ok until now. This morning it was dead. I didn't try to jump it and haven't tried to charge it either because I had to work and didn't have time to fool with it. Is this just coincidence that this battery went bad (not sure the age) or maybe because of a problem with the car. When I installed it I check the voltage when running and it was right around 14 volts and the voltage gauge on the dash always stays around 14 unless I have the defrost on, then it drops to 12 << not verified by actual meter, just reading the dash.

What do I need to check?

Thanks

[Jrs3800]

If it drops to a dead 12v with the rear defrost on, then the alternator is not putting out what it should be.. Once you hit 12v you are pulling down the battery..

When was the alternator last replaced and was it a Palladium( spelling ?)

[Whitecrystal1]

Alternator is original. The voltage has always dropped when using rear defrost < I forgot to mention, this is only at ideal not when moving or pressing on the gas.

[Jrs3800]

Its just strange you mention how fast the var eats batteries..

My 91 Bonneville had an Everstart Maxx for 7 years... Currently that Battery is in the SSE to crank it up and move it from time to time.. It still holds a charge and starts the car...lol

The Alternator in the 91 LE puts out 14v just about all of the time.. Stays in the upper 13's under load as well..

My 95 is the same as yours.. It has drops in voltage.. Longest i think I have kept a battery in it has been 4 years..

I am not sure whats eating your batteries unless the Alt is not putting out the amperage it should be.. I am almost at a loss... I'd almost think the Alternator is tired.. Has it been tested as well?

[Whitecrystal1]

I haven't tested it yet but that's kinda what I'm thinking too, just that usually when I've had one fail in the past it always caused all kinda of wacky things to happen; gauges and other stuff to go crazy.

Before this started happening Batteries would last 3-4 years in it. I have always been proud that the alternator has been hanging in there. With my Grand Ams (2) and Suburban, they all seem to need batteries and alternators at the same time.

Does the alt. need pulled to get tested?

[Mechanical Mike]

I'd check the draw on the battery with everything turned off. You need a mutimeter with a 10 amp or higher range. Disconnect a battery cable from the battery and connect the meter between the cable & battery. Some years will show a high reading until the PCM goes into power saving mode so see what the reading is after 1 minute. Should be less than 1/10 of an amp.

PS - The alt can be checked while on the car.

[GoldenBullet]

arent our cars known for eating alternators?

[Skippy1827]

Yes, when my alternator went bad in my 98, my lights on the dash blinked and went dim... I put the biggest alternator in I could find for my 98 and it worked a long time....it still is...I know who has my Bonnie.. My bet is alternator

[00Beast]

Definitely have the alternator load tested. Advance does it for free, not sure about anywhere else.

[Bugsi]

And check your battery cables for corrosion, especially the positive cable where it attaches at the battery. The cables are known for corroding, I've had this happen in 5 different Pontiacs, even when only a few years old. It can be difficult or impossible to tell from inspecting the cable's battery connector, the only reliable way to check it is to run a vertical slit in the insulation down the length of the cable and peel back the insulation so you can inspect the copper strands. If it's okay you can push the insulation back up and wrap the slit portion in electrical tape. I can't stress how common a problem this is, for me it's been a more common failure than the alternator failing. Symptoms included: Not starting, lights dimming with defrosters or turn signals, etc. Definitely check the cables. If you have a bad cable the best bet is getting a factory replacement cable. Next best bed would be a good condition original from a donor vehicle. (Junkyard).

[Whitecrystal1]

Yes, when my alternator went bad in my 98, my lights on the dash blinked and went dim... I put the biggest alternator in I could find for my 98 and it worked a long time....it still is...I know who has my Bonnie.. My bet is Not alternator

Mine does have the 140 alternator in it.

And check your battery cables for corrosion, especially the positive cable where it attaches at the battery. The cables are known for corroding, I've had this happen in 5 different Pontiacs, even when only a few years old. It can be difficult or impossible to tell from inspecting the cable's battery connector, the only reliable way to check it is to run a vertical slit in the insulation down the length of the cable and peel back the insulation so you can inspect the copper strands. If it's okay you can push the insulation back up and wrap the slit portion in electrical tape. I can't stress how common a problem this is, for me it's been a more common failure than the alternator failing. Symptoms included: Not starting, lights dimming with defrosters or turn signals, etc. Definitely check the cables. If you have a bad cable the best bet is getting a factory replacement cable. Next best bed would be a good condition original from a donor vehicle. (Junkyard).

I cleaned the cables a while back and they still look good but I never cut the insulation back.

I just had the battery tested and it was bad, so I went ahead and bought a red top. I checked the voltages while running and it was 14.20 with nothing running and 14.13 with the ac on. I am going to get the alternator tested at the end of the week when I have more time just to make sure. Could the alternator be overcharging the battery intermittently?

[Bugsi]

Could the alternator be overcharging the battery intermittently?

Yes, that's what happens when one or more of the rectifier diodes shorts out. Alternators are also subject to brush and bearing wear, but those make more obvious noises and such. But if you were buying cheap batteries, you could have just had a cell going bad, and then the normal charging from the alternator would act like overcharging the remaining cells in the battery. I've owned many cars, and many more car batteries. I've learned that it pays off to buy a good battery. For the last ten years or so I've been buying the Sears DieHard Gold batteries for our two cars (Bonneville and Grand Prix GT), and I only had to replace one, after I stripped out the battery terminal threads. :-(

[Whitecrystal1]

Update

This morning I went out to go to work and battery was dead, really dead lol. Now when I started this thread I went ahead and replaced the battery with a Red Top (7 months ago). I was able to get the car to start but not without putting it on a hot charge for 30 mins. It wouldn't jump from the battery charger without charging some first. I think I may know what the problem is but I'm not positive yet. I am disabling the compressor to see if that is running too much and killing it. I do hear it run on occasions just sitting.

[olblueeyesbonne]

My dad was having his air compressor (suspension) run in his 89 Olds 98 and always draining the battery. Disconnecting it turned out to be the temporary/cheap fix, but not ideal for hauling 5-600 lbs of papers for work in the trunk/back seat. I did at least install a sway-bar since it didn't come with one from the factory.

On my 99 SSEi I was having a problem from right when I started driving the car in January 07 until about 1 month ago where it would need a jump if left parked for 5-8+ hrs. I had a few spells of 2-3 months and even one 6 month stint with no jumps needed. It came back about 6 weeks ago and was to the point I would run the car, shut it off and instantly it was dead.
I pulled the radio out to test a factory one and noticed I had a couple wires mixed up in the Pioneer wiring adapter -BOSE power wire was hooked to the continuous power, as was the Infinity Basslink power lead, and the power antenna was hooked up wrong.
I also had a dead power antenna (bent and wouldn't come down all the way and eventually broke the cord). I changed that at the same time and now I notice it seems to have a little higher voltage while the car is running, but whenever I hit the brakes the whole electrical system sees a 2v drop in current.

[bobfather99]

And check your battery cables for corrosion, especially the positive cable where it attaches at the battery. The cables are known for corroding, I've had this happen in 5 different Pontiacs, even when only a few years old. It can be difficult or impossible to tell from inspecting the cable's battery connector, the only reliable way to check it is to run a vertical slit in the insulation down the length of the cable and peel back the insulation so you can inspect the copper strands. If it's okay you can push the insulation back up and wrap the slit portion in electrical tape. I can't stress how common a problem this is, for me it's been a more common failure than the alternator failing. Symptoms included: Not starting, lights dimming with defrosters or turn signals, etc. Definitely check the cables. If you have a bad cable the best bet is getting a factory replacement cable. Next best bed would be a good condition original from a donor vehicle. (Junkyard).

Had a similar issue with low voltage, the fix was a new cable from the alt to the positive terminal at the battery. The old cable was corroded badly.
Id much rather replace a $5 cable than an alt for way more money!!!!

[Bugsi]

Had a similar issue with low voltage, the fix was a new cable from the alt to the positive terminal at the battery. The old cable was corroded badly.

Yep, that was the case on my car, and my wife's car, and my wife's previous car, and my two previous cars. All Pontiacs.

[TUFFBONNEVILLE]

also the alternator brushes could stick and drain your battery
ive had that happen to me once every morning the battery would be dead in a 86 parisienne

[1993SSEi]

Back in 1997, the original owner of mine had a similar problem. Batteries kept getting replaced every four months.

The Dealer tracked the fault down to a Short with the Air pump for rear suspension. As a 'Temporary Fix' the tech disconnected the electrical lead to the Pump and the battery drain stopped. Then after a few months there's a receipt for Air Pump replacement and Battery drain issue never re-occurred.

Maybe try this same scenario?

[Whitecrystal1]

Back in 1997, the original owner of mine had a similar problem. Batteries kept getting replaced every four months.

The Dealer tracked the fault down to a Short with the Air pump for rear suspension. As a 'Temporary Fix' the tech disconnected the electrical lead to the Pump and the battery drain stopped. Then after a few months there's a receipt for Air Pump replacement and Battery drain issue never re-occurred.

Maybe try this same scenario?

I disconnect the pump the other day and so far so good. I guess the only way I'll really know is if I don't have any more issues with it later. I am still using the same Optima battery that I replaced about 7 months ago, I just had to charge it when it died the other day. I'm thinking the pump should be tied into the ignition and not to the battery so that it won't run when the ignition is off... if this is the real issue here I may end up rewiring the pump so it won't run unless the ignition is on.