2002 S60. Battery is getting old and won't hold a charge. Advance Auto's web site says H6 or H8.

I've noticed that there are extra holes for the battery hold down to screw into. So what is the biggest battery that I can physically fit into the car?

 

Do you mean physically biggest battery or the battery with the most CCAs? You didn't mention which engine but generally the I5s use a size 48/H6 and the V8s use the size 49/H8s. Take a look at what you have installed now - and measure end to end. The 48/H6 will be about 11 inches, the 49/H8 is closer to 14 (both are the same width). To note, the last two batteries I installed (VW and a Volvo) I used a size 48 from Napa Online (~730A / 84 month warranty) for about $140. Also since your battery is in the trunk, you need to make sure its properly vented etc. Napa Online usually has a discount code for online shoppers for batteries which you can use to purchase online, then go and pick up the battery at your local store.

 

I meant physically which usually amounts to more CCA. I wanted something larger with more reserve because it seems that the standard battery (H6) runs out of juice very quickly when I'm trying to things like play with the stereo and the engine off.

 

Later Volvos specify a H7 - Volvos says it's a 30772236 Volvo battery - The exact same battery is sold by interstate, Mt92-H7, or advance auto die hard gold t7 - they are all the SAME EXACT battery, has a made in Germany sticker on it - and is the ONLY battery that keeps the dreaded "low battery" message off the later model cars (2010?+) off when using the radio with the car off.

If you have a 2002 - I'm not sure this will apply.

 

I went with an H8 (group 49) from NAPA. I was surprised that NAPA was less than Advance Auto and has much longer warranty.

Put it in last night by flashlight.

Batteries reminded me of something that happened in college, over forty years ago. The county parks around here have no rules against "parking" in the evenings so they were popular sites. Only one rule, you had to leave your parking lights on. At midnight the cops would cruise around with flashing lights to let you know that it was time to leave.

One evening I was there with a date, parking lights on and the stereo playing. I thought "Maybe I should start the engine and charge the battery" Click, click, click. Damn. I was thinking that I'd have to call my brother but right then a car a few spots away started up and started to pull out. I leapt out the of the car, the interior lights came on exposing my date in her state of dishabille. I had cables so he jumped me and all should have been well. However, my date was rather pissed at me for exposing her like that. Lesson learned, start the engine frequently.