Battery Failing?

[Touring5]

The battery in my Outback has some small evidence of dried acid on the top of the case. Otherwise, it's acting normally. In fact, last week one of the dome lights stayed on for close to 20 hours with no ill effect. It has a date sticker from 2012, so it's got some age on it.

The main reason I'm suspicious is because I had a battery one begin boiling and chucking acid but assumed it was from a shorted cell.

Any thoughts?

 

[wrcsixeight]

A dome light on for 20 hours might not have been enough to drain the battery so low it could not start the engine, but it has had the effect of lowering the state of charge of the battery.

It takes no less than 3.5 hours, when held in the mid 14v range, to charge a healthy battery from 80% to 100%. Older/unhealthy and lower voltage will increase that time, possibly significantly.

Your battery wants to be at 100% state of charge. Put it on a charger, as your dome light dragged it below 80%, and even if you have driven 3.5+ hours since your charging system is not optimized for quick battery charging

Mix a little baking soda in some water, put it on the 'dried acid' mark. Does it fizz?

Either way an 8 year old battery owes you nothing. YOu have some time to shop. Use it wisely, its not going to make it another winter, in my opinion.

 

[Oro_O]

I did a pre-purchase inspection on a 2017 Crosstrek (4cyl engine) - which it failed for battery issues.

I don't know what year your Outback is, but look hard around the engine compartment for other signs of acid venting. This one, for example, has the faces of all pulleys rusting, as well as hose clamps, and bad corrosion starting at where the radiator bolted into the front cross-member. Bad signs of grounding or other issue which is how many experts say the dreaded headgasket failures start. This was a 2017, lived all the time in mild PNW weather, and it was being re-sold off-lease by the local Dealership - and it was bad.

 

[BlueOvalFitter]

My 2 year battery is going on it's 4th year. Knock on wood.

 

[Donald]

The battery for the OP is 8 years old. Probably time to replace since it's almost winter at least in the northern states.

I would also get the charging system tested.

You can get the battery tested but at 8 years I would replace unless it tested really well.

 

[alarmguy]

The battery in my Outback has some small evidence of dried acid on the top of the case. Otherwise, it's acting normally. In fact, last week one of the dome lights stayed on for close to 20 hours with no ill effect. It has a date sticker from 2012, so it's got some age on it.

The main reason I'm suspicious is because I had a battery one begin boiling and chucking acid but assumed it was from a shorted cell.

Any thoughts?

I Replace every 4 years so you got you use out of it as far as I am concerned.