Good Battery Keeps Dying

[strokeZ]

The battery is about a year old and about 10k miles. I had it tested at a few different places and it has always come back okay. The alternator was charging good per dealer and the battery shop. I know there are issues with the battery testers so I have had it checked at three places. All came back as OK. The things starts just fine if I let it sit for a day or two, but seems like if it sits past four days or so it dies.

UPDATE: Just checked the battery with a multi meter - with the car running it reads between 14.38 and 14.45V. With the car off it reads ~12.6V. Also with the car off I am showing a draw of 0.15 mA - not sure if that is spec or not?? I wonder if I cracked my battery during the last "baja run" over the trails at Big Bend - I suppose that is possible as well. Hmmmmm

[Sal-XK]

That's more then possible and like I said earlier very hard to diagnose. I swore my mustang bat was good and it ended up being an internal thing what threw me off too was the battery was only about 1 year old.

[Matt]

You mean 15mA, right? That sounds about normal.

If a module or something was draining the batter after a few days I'd expect to see a 500 or more mA draw.

[Sal-XK]

One thing comes to mind not sure if it makes a difference or not. Traditional batteries leak there fluid when tilted past a certain degree like while were off roading. I know mine has done it on the trails. That's why I like the optima batteries there suppose to be sealed. Not sure if that could cause this or what just a thought.

[strokeZ]

@Matt - yeah 15 mA @Sal - well I am going to bring it to where I purchased it to have them put the battery under a 45 min load. That should be the tell tale (I hope). Curious - what Optima did you get? I asked for one but was told there was none made for our vehicles. After checking it I am almost certain its a bad battery - for whatever reason.

[lekmedm]

Curious - what Optima did you get? I asked for one but was told there was none made for our vehicles.

I think you could put a D35 size battery in there. The poles are out on the edges, so reaching for them should be easier. I have a D34/78 and had to bend the connectors to make them reach.

I think the OEM battery is a Mercedes battery. It's really mostly a question of size, and since the Mercedes battery is so large, it's not a big deal to put in an Optima that's generally smaller.

[strokeZ]

Thanks all for the comments - I know its usually a simple thing, but for some reason this did not make sense. I will check the fluid level today and if low refil with demin water. If not low I am taking it back for (hopefully) a replacement.