Hot Rods My car keeps killing batteries, why?

My car keeps killing batteries. I get a new one. The car runs great. It charges at 14.5 when running. If I let it sit a few days there is a slight drain on the battery somewhere I haven't located yet. But no big deal. I just disconnect the cable and replace it when I want to drive the car. But within a few months I'll go to start it ( it takes a while to start -cranking a bit) and it will drain the battery down . Put it on a charger and it won't get past 11 volts. The charger says it's fully charge but it won't even turn the car over .

Any ideas? I replaced both positive and negative cables.

 

"a few months" might have something to do with it. Drive the car every week, you'll be fine.

Batteries don't like sitting. If you are going to let it sit anyways, might try an optima, they seem to hold a charge a long time when sitting (disconnected). lotsa money though.

Then again, there might be some other problem, like you have a crappy charger, or something else is wrong with the electric system, etc.

 

Try a battery tender.

 

Aftermarket radio with digital display? Clock with a quartz movement added? Car alarm? All these take current even when the car is not running. In the car dealerships we call this "lot rot". We replace a lot of batteries because of that.

The Battery Tender is a good idea, batteries even when disconnected will self discharge IIRC about 6% per month.

 

Do you have a kill switch,I had basically the same problem and finally tracked it back to the kill switch,It was wired to where the radio memory was constantly on and within a week it drained the battery. HRP

 

my 61 Dodge sits for quite a bit between drives. it always has enough charge to start the car, and it is a hard starting M-Fer. my last battery lasted 8 years. "sitting" for a few months does not kill a battery, a slow drain while sitting kills it.

 

should start and run it for atleast a half hour a month and not at a idle either , so the alternator kicks in and fully tops it off with a nice healthly charge ( on some , at idle if the battery is low sometimes the alt will turn off and just pull juice or not turn on at all unless its flashed with 12 v its a "battery save feature" I never understood ) , a battery that is not fully recharged when stored will slowly die in a few months even unhooked , then they sulphate and short out . nothing but replacement brings them back at that point ( the Epsom salts treatment only prolongs it for a month or 2 or kills it outright )

on my O/t car that sits for extended periods I hook the charger up to it every 1-2 months and give it a long and low 2 Amp top off charge to keep it up . or take it for a hour drive down the interstate .. but I know what the battery draw is on it ( ECM and Alarm )

 

Irony of a battery killing car: "The alarm kills it...maybe if I were to allow it to get stolen, I could just forget about it."

 

but knowing my luck the guy would drive it around and keeping it charged ...

 

I do remember I had a 70's O/T gm that would drain battery dead if it hadn't been started in 2 weeks , we did the remove all the lights and I put my brother in law in the trunk to check that one , ( best 5 minutes of quiet I ever had with him around ) pulled fuses to no avail . only to find out it was the internal voltage regulator or the diode trio was kaput it kept the the field coil slightly charged up , we found it when I leaned on it and it was warm and the motor was not run in several hours . and when I pulled the battery lead on the back it sparked ( no juice being fed thru the plug as it was undone ) . new alternator and no more dead batteries .

 

I have seen that a few times. Fresh out of the box, too.

 

Then to add to the regulator story, mine kept the radio on and turn signals operable with the ignition shut off.
It finally went to full failure mode and overcharged and cooked my truck battery---on the day I picked up my Model A beginnings.

 

Something I learned about battery's draining over time. Take a 12 volt bulb with two wires coming out of it. Disconnect the ground cable at the battery, And connect one wire from the light to the battery ground post and the other to the ground cable. If there is a drain on the battery the light will be lit. Disconnect stuff (fuses etc) when the bulb goes out you've found your drain. My drain was the alternator. Took it to the alternator rebuilding guy and he fixed it right up.
It killed the first battery within a year. I was trying all kinds of stuff before I heard that trick.

 

Batteries can sit around OK, IF they are charged up. Batteries self-discharge, even if disconnected. Hot weather speeds this process, like most chemical reactions. They like to swap electrons too now and then, and put through their paces.

The problems start when the charge level reaches about 80%, as sulfation starts to get heavy, and is not reversed by the normal charging process, it becomes permanent and loses current capacity. Trying to charge a sulfated battery has been described as like trying to wash your hands wearing rubber gloves. Supposedly about 85% of battery failures are because of early sulfation. Heat, and vibration, are what kills batteries. Stationary lead-acid batteries can last 20+ years. Short trips leave a battery only partially charged. It pays to keep up on battery and charging system maintenance, make sure there are no "phantom loads" drawing it down, and keep batteries on a tender or charge them thoroughly every month or so.

 

Well it was being used everyday rather than sitting long periods of time but the last battery I replaced was installed when the car was built in late 2001 and I pulled it "just in case" in late 2015 (checked the built date of battery and the car; original!) . That battery is still holding a charge but I didn't want to be surprised down the road.

 

I like truck 64 reply, but I keep thinking about your comment on charging at 14.5 , if that is only for a short time after start ok, but if you are saying 14.5 all the time, you are over charging and at risk of serious damage. A full charge on a good battery is about 13.2 , 2.2 volts per cell, six cells on 12 volt battery

 

when I drove to work ( 20-30 miles one way ) never had a battery problems , the first battery in my then new O/t DD lasted 9 years ( AC Delco ) . then I bought my rig and started work from the house, my DDs battery only lasted 1-3 years and ussually died when it got super cold as it never got driven enough. right now the battery is out of it as I am doing some work on it and its going to be down for 2 or more months , I put it on the charger ( 2 amp slow feed) and it was down a little .

as for the alternators with internals going bad , happened to me more than once , had one the car wouldn't shut down if the heater fan was on , but if you turned the headlights, stepped on the brakes or the a/c compressor cycled on it shut off , learned to have my foot on th ebrake when I turned it off till I figured out what was back feeding ( the Trak Auto alternator ) . trak autos motto "we teach you to trak down the problem we caused with our cheap parts ..."

 

I had vehicles I only drove in the winter and others in the summer. The original batteries lasted 6 to 10 years. Replacements didn't last 2 years.

 

If it always charges at 14.5 volts when running there may be something wrong with the regulator, or internal regulatior, diodes. I had an ot pickup that boiled the battery out due to over charging. Seems like something like a diode in the alternator may be failing. What does the water level look like when it will only charges to 11 volts?

 

Today's OT vehicles have tires built to last to X.
I'm dismayed to see batteries in need of replacement within a two year cycle. This is without knowing how that vehicle is used. I'm talking about new vehicles, assembly line disposables.
From what I've learned recently, the aftermarket battery lead/acid battery life is typically less than 4 years. Pick a brand.
The higher priced and longer warranty batteries will typically last longer. This also depends on what the vehicle is made of.
On the other side..I could fuss about a battery on a tractor that had a disconnect between the plates and the post, when my Dad had me take the tractor to Charlie. So, I stopped between jump starting the small tractor to drive to Charlie's shop, lot of Snap-On tools hanging, nice smell of oil.
Small tractor, 12v. Charlie drills a hole thru the suspected post, and finds it hollow. He sees that it could have a repair, using a wood screw.
So, while applying the wood screw, possibly stainless, the battery makes a loud pop while he is directly over his work...
I'm about 12 years old, driving the tractor to our strawberry field that's about a half mile from the house, Charlie's shop between.
He says, "Fire it up". I drove a little bit south and to perform the work that my Dad owned that tractor for in our strawberry patch.
From what I learned, Charlie couldn't read, but he was smart. I watched him sitting in the pilot seat of a small plane, making marks on a piece of paper, to count to and count back, to see how much time or fuel he used in the plane he had flown. Amazing to me when I was young.
For the fact of knowing how Charlie amazed me, this helps me help folks that have the same capabilities.
My Dad used to take a coat hanger or insulated wire, to spark check, to see if the spark looked like the battery still had some life. Still Hot. Battery chargers that didn't stop before batteries blew up...
Some things have changed.......

 

I know I'm off topic. A nice memory road for me to describe. I know a story like this doesn't necessarily fit, and it's mine. What made me get here to us.

 

14.5 may be charging a little high, I like to see 13.8 to 14.1, mine charges at 14.1 all the time, more when the car sits for a few weeks in the cold. I recently had my internal GM regulator go bad. I noticed my lights getting brighter, first I noticed the dash and tach lights. Then I had someone in the car, had him watch the volt meter... it was spiking 16 to 18 volts when the lights brightened. I would see if the volt meter was doing something funky like that. I also use a battery tender in the winter months when I can't drive the car.

 

16 to 18 - Bad!

14.5 isn't necessarily out of line though, remember the charge voltage is a bit of a moving target. Depends on the battery state of charge - and also the outside temperature. In extreme cold a little over 15 volts is the corrected voltage needed because of the battery's increased internal resistance.

Should be measured while under load, with headlights on HI and heater blower running. Spool up the RPM to around 1500 or 2000 and measure at battery posts.

 

I run optima red top batteries. I don't have battery problems. Not saying you don't have a problem elsewhere, I usually start at the source. Lippy

 

Agreed on 14.5 volts. That is what my 10SI alternator put out. Then it started going to 15.1 intermittently. I replaced the internal regulator, but still had the problem. Replaced the internal diode trio and the problem was gone.
I would make sure that the sense wire from alternator is connected to some +12 volts near the battery.

 

i had an olds with a bad switch for the trunk light. it would run the battery down in 2 days.

 

the place where my boss sent me to work On Detroits I remember 14.6 is about as high as you want to go and will charge a battery nice and quick . and when I went for O/t cars the subject of battery life came up . and with all the gizmos the new cars have on them the alternators/batteries are taxed to the limits , and also the cars computers can stay active for up to a hour after the car is shut off .
I know my wifes o/t (car 10 Impala ) if you open the door it does something with the vents as you hear it cycle a motor in the dash .plus I have seen a draw from one of the computers for a 1/2 hour after the car was shut off . I look at my older stuff and start to like the simple stuff better ..

 

Like has been said, find the drain, and/or then hook up a battery tender, I've used one from HF for over two years, and alternate it between my '49 and the start battery in my dinghy....and both always start.

 

One thing I've found out.I had an old Century battery charger that finally died after about 40 years, replaced it with a "new computerized technology" Shumacher charger with lots of settings,battery type,size,etc , and will de-sulfate a battery.
My old one would bring back a battery from way down in volts,(I know , shouldn't let it get that "dead")
The new one won't even charge unless the battery has at least 11.5 volts to start....it looks like it on the indicator, but after a few days charging there is no extra charge in the battery.
I bought an old $3 garage sale special to bring it back to 11.5+ so I can put it on the fancy-shmancy new charger

 

The 12 volt system was implemented around 1956, when even a radio was somewhat of a rarity. LOTS more current demands today but basically, that same electrical system is still in use today and expected to handle it. There has been talk in recent decades of going to a 48 volt system in light of this but it hasn't happened yet.

Underhood temperatures are very high on OT vehicles too. The computer or ECU current draw is roughly equivalent to leaving a headlight on for a half hour or so after shutdown if my back of the envelope math is right. No wonder batteries don't last very well, they are always behind the 8 ball and chronically undercharged and then baked on "high". The battery really has one function - start the engine - but they keep adding more "ornaments" to the tree.

One thing I have wondered about, is why the manufacturers never included a battery charger with the car, integral to the electrical system or at least as an accessory pack. If it was built in, a rubber boot at the firewall, or a pigtail, a nice gauge etc. Could probably save on warranty service.

I'd think a clear plastic battery case would go a long way too.