Battery Condition?

[VinceF]

Wonder what you guys think. I have an 07' 4cyl Subaru with the original batter in it, and noticed it cranked slow when cold last winter. Don't use the car that often, maybe once a week, and only have 15K mi on it. Have 5W30 QSUD oil in it. Thought the battery was probably the min size or getting old being 5 yrs old, but batts have less power in the cold, and then sitting so long might be the reason. When the battery goes I was going to get a bigger one. Back in the day I had a 4cyl Mercury Capri, and a friend with a Caddy convertible had to junk the car so I bought his batt, and it was the biggest Sears Die Hard. I had an alternator go, and had to get one from out of state, so ran the car without one for a few mo. I used to check the capacity with a hydrometer, and could crank the car when the float was at the bottom.

Wondering how long a battery will last with limited use? Does that matter? Wonder if it could last much longer than the rating? Wonder about the timing belt also. Supposed to be good for 9yrs/105K mi I believe, but don't want it to break. Subaru changed to a timing chain which I would have preferred, OR a Non interference engine so the valves Couldn't hit the pistons if the belt broke. One car with an interference engine had a Tripple Chain.

 

[901Memphis]

Get a battery tender If you have a garage.

Also this isn't much a pcmo thread.

 

[Kuato]

On an '07, the battery was likely manufactured in '06 so you are going on 8 years. Personally, I'd change it, or at least get it load checked.

Agree 100% with 901 to get a battery minder to keep it up in the winter.

 

[VinceF]

I park on the street so can't use a tender/minder. Just remembered the batt went dead a few mo ago. Thought it was just because it sat for a few weeks, but maybe not. Gona have to check it. Wonder if a hydrometer will tell me anything?

Was was in Walmart last week buying oil, and across the isle were the batts. I bought one there 2 yrs ago and a lot cheaper.

 

[901Memphis]

8 years is a healthy life for a battery. Have it replaced if possible.

 

[eljefino]

Sounds like the subies parasitic loads are something of a problem.

VW acknowledged this and sticks a solar charger in them at the factory so they'll start during and after the slow shuttle to the final customer.

Though your OE battery is probably near its end of life.

 

[JethroBodine]

Originally Posted By: VinceF
Wonder what you guys think. I have an 07' 4cyl Subaru with the original batter in it, and noticed it cranked slow when cold last winter.


That means it is time to get a new one. A battery tender will extend the life of a new one.

 

[Corvette Owner]

From batterytender.com

"Use a voltmeter to measure the voltage between the positive (+, red) and negative (-, black) posts (lugs, or terminals). For this method to work at all, the battery should sit idle for at least a couple of hours. When the battery is not being charged and not delivering charge to a load, this is the rule of thumb. For a 12 volt, lead-acid battery, the voltage measured between these two points should be between 11 and 13 volts. The closer the voltage is to 13 volts, the closer the battery is to being fully charged. The closer the voltage is to 11 volts...

So a 12-volt battery will measure at about 12.9 volts when it’s fully charged and about 11.4 volts when it is fully discharged."

 

[Maximus1966]

Originally Posted By: Corvette Owner
....about 11.4 volts when it is fully discharged."


It may not function in a 12 volt system, but I would think a "fully" discharged battery would measure 0 volts by definition. No?

 

[meep]

no, 0 would mean more like dead as a post.... completely gone--- the acid has turned to water and all the sulfur is stuck to the plates....

Lead Acid batteries at 0 load will sit at 12.6V charged full and about 11.9 dead. Those numbers vary with temperature. Any load on the battery at all will also alter those numbers.

Voltages above 12.6 suggest a "surface charge" which is a miniscule, momentary "overcharge" of sorts. happens daily. you have to let that wear off first, to get a true V reading.

Also, vehicles after shutting down may run the ECU and do internal tests for a while. Chryslers I believe exercise the ECU for about 20-30 minutes. I've read it's common with other brands too.

Voltage readings alone are a very crude way to determine state of charge.

 

[SwampSurvivor]

Originally Posted By: meep
no, 0 would mean more like dead as a post.... completely gone--- the acid has turned to water and all the sulfur is stuck to the plates....

Lead Acid batteries at 0 load will sit at 12.6V charged full and about 11.9 dead. Those numbers vary with temperature. Any load on the battery at all will also alter those numbers.

Voltages above 12.6 suggest a "surface charge" which is a miniscule, momentary "overcharge" of sorts. happens daily. you have to let that wear off first, to get a true V reading.

Also, vehicles after shutting down may run the ECU and do internal tests for a while. Chryslers I believe exercise the ECU for about 20-30 minutes. I've read it's common with other brands too.

Voltage readings alone are a very crude way to determine state of charge.


I've noticed on Chrysler products you can hear the electronic throttle bodies moving around for quite a while after the vehicle is shut off

 

[Durango]

VinceF,

I'd just have the battery re-charged. I'll bet when it was installed it was never charged to it's fullest anyway. Find out it's current condition and if it appears to be OK then get it re-charged and see if you get the same condition.

Durango

 

[dparm]

The voltage may still read as in-spec, but the CCA will fall off as the battery gets older.

If you remove it and take it to an auto parts store, they have testers that can check the cranking power. When mine finally went on my old S4, it was only generating 220CCA! (stock was 850+)

 

[Donald]

Load test the battery with a carbon pile tester that puts a load of 1/2 CCA.

 

[Thermo1223]

Subaru's use tiny Panasonic batteries compared to other cars of similar size. The battery in the 09 is ready to be replaced, only putting out close to 400cca on the test at the garage.

The battery in my previous one last 6 years or so before not needing replacement but doing so wasn't a bad idea as it was a little weak.

Those 5F mornings had it groaning when turned over.

Only buy a new battery if you intend on driving it enough or you'll just be wasted money when you kill the new one after the warranty.

Also based on time the timing belt is good until at least 2015 so budget for it at that time appropriately. At least have it inspected to make sure it is not wearing prematurely.

 

[VinceF]

Yea, I guess the batt is getting old.

 

[Rolla07]

Originally Posted By: 901Memphis
8 years is a healthy life for a battery. Have it replaced if possible.


Have it tested and see how it looks. If you replace it, do yourself a favor.. try to drive it a bit more..

 

[SubLGT]

Originally Posted By: VinceF
................Don't use the car that often, maybe once a week, and only have 15K mi on it.........


By this time, it is likely that the battery is heavily sulfated. Time for a new one.

When you do drive the car, how long (in minutes) are your trips?