My battery on my 2006 Audi S4 (B7) was on it’s way out, so I decided to do some research and try to find a good aftermarket battery to replace the OEM one in my car. My primary goal was to find something affordable and something that is lighter than stock – after much research, I settled on the Optima 34R Red Top as my battery of choice, both due to its affordable price (approx $160 shipped on Amazon) and the fact that it’s 20 lbs lighter than the OEM battery, weighing in at 37.9 pounds versus the OEM battery at approximately 59 lbs. After finding numerous reviews of others running the Optima Red Top without problems, as well as knowing of Optima’s good reputation within the industry, I went ahead with this battery and am quite pleased. This battery will also work on all 2002-2008 Audi A4, S4 or RS4s, known as the B6/B7 platform by Audi enthusiasts.
Check out this battery on Amazon here – ignore the warning that it doesn’t fit your 2006-2008 Audi, it definitely does. Best of it, it ships for free 2-day shipping with Amazon Prime:
Review:
My car starts up quicker with a noticeable improvement in cold-cranking power, and although you can’t feel a weight savings of 20 lbs on the “butt dyno” I know that every little bit of weight I can save off this otherwise heavy car is going to help. Between my battery (20 lbs), my carbon fiber hood (50 lbs), lightweight wheels (10-15 lbs) and a big brake kit (10-15 lbs), I figure I’ve saved about 100lbs or more off the front end of the car…It’s also really nice to have a fresh battery, as my car was starting to have annoying problems such as losing the time & date off the dash each time I would leave the battery on without the car running, such as when I was working on the car or detailing/cleaning it with the radio on.
Red Top vs Yellow Top:
If you’re in to high-end electronics, I would recommend the Optima Yellow Top 34 rather than the Red Top, as the Yellow Top is more suited for the deep cycle power you’ll need to power amplifiers and electronics – the Red Top is best suited for cold cranking power as a starting battery. You’ll also want a size 34, but unfortunately Optima doesn’t make this battery with reverse terminals, so you’ll need to install it flipped around to have the positive terminal connect with the positive wire and vice versa. This battery is a little more expensive, but not bad – you can also find it on Amazon.
Installation:
Installation was fairly simple – I had a nearby shop called Parts Score install it for me while I was having my oil changed and it only took about 10-15 minutes. You could also follow this guide if you try to do it yourself. Afterwords you may need to reprogram your key fob (simply turn between off and accessory on 7 times, you don’t need to start the car just to the first “on” position), and also reprogram your memory seats and radio settings, but that’s it. The Optima Red Top fits just fine in the OEM compartment and no modifications to the mounting brackets are needed – it’s pretty much plug and play! With the battery cover back on, you can’t even tell there is an aftermarket battery installed, as shown above…
Other Options:
I have seen more advanced weight saving batteries and even heard of folks relocating the battery to the rear, but I avoided these for a few reasons. The super lightweight batteries like Braile, although they weigh only like 20 lbs, are much more expensive, ranging from $300-1,500 per battery, and at some point the weight savings just isn’t worth the price. A rear battery relocation also seemed like more work than it was worth, especially when you factor in the weight of adding 0 gauge wiring the length of the car – I also want to keep an OEM look and functionality to everything, so that option didn’t seem worth it to me. The Optima Red Top seemed like a good compromise of OEM performance and quality at a lighter weight and simliar if not cheaper price – a win-win in my book.
Questions or Comments?
Anyone else running an Optima Red Top on their B6 or B7 Audi A4, S4 or RS4? I’d love to hear your thoughts…
Thanks for this! Used it today to replace my B7 S4 batt with a red top 34 R. Your info made it simple to buy and the link provided made the swap a snap.
You rule dude!
+2 karma
Right on, glad to help!
Did you ever consider relocated it to the spare tire well? JHM has a kit but it would require removing the spare. Could help even more weight savings and better weight distribution
I thought about it, but it’s a lot of work and also the cables to relocate it add a few pounds of weight so it just seemed like a lot of hassle. It’s a good kit though and I’m a big JHM fan, just kind of thought that particular mod was not worth the effort and cost for me.
Thanks Nick for the nice article!.
i would need your advise on this battery, is it good enough for a daily drive R8 V8 engine?
Hi JamesN – I’ve been daily driving with it in my B8 S4 for about 2 years now, so I don’t see why not…the R8 V8 and S4 V8 are slightly different but doubtful to have any noticeable difference on battery drain.
Thanks Nick! When I went to Amazon, it said that this battery does not fit my 06 S4. Just double checking with you to confirm you installed it in the same year/model. Thank you for your help!
Yep, exact same one I have – it just differs slightly in size and specs from the OEM battery, so Amazon flags as not a direct fit…you can safely disregard 🙂
Thanks for the reply. Happy driving!
Hi Nick, FYI the guide link above is dead.
Thanks for reporting that – EuroAddiction closed. I updated the link to a comparable guide, check this one out: http://audirevolution.net/forum/index.php?topic=215.0
Hi NICK.,Am interested in buying either 2003 Audi A6 3.0 CVT or Audi S4-B6 and most importantly A4-B6. Pls i’ll be glade if you could help me make an option based on your experience
I would avoid the CVT A6 because that transmission is awful, and go B7 A4 or B6 S4, depending on whether you want fuel economy or power. Check out this post for more advice on A4 vs S4: https://www.nickscarblog.com/cars/audi-a4-vs-s4-which-should-i-buy
A superior battery choice is the Odyssey 1350 AGM which can be ordered directly through Battery Systems or the Odyssey website. Just replaced the original factory battery today into an 08 S4 Avant mt6.
I had used Optima for several years in two other vehicles but they just don’t hold up as well. I’ve had an Odyssey in my Land Rover since 2007 and it’s still testing near 100% of original levels.
All AGM are not created equal!
An alternative is the Sears Platinum AGM which is made by Odyssey.
Nick, got it and installed but it still slides around. Are you sure it’s suppose to be like that?!
Just did a little research. It fits but it goes back and forth. Now have to go to the store and get some self tapping screws to drill in the plastic so it does move left and right. You should include this in your article. Ughhhh
Hi Dan – I reused the stock mounting bracket, I didn’t have to modify anything – are you on a B6 per chance? It’s worked for me, although I found the OEM retainer to be such a pain in the ass that next time I’ll probably do something like you’re doing rather than try to deal with it myself.
Hi Nick, I’m looking to replace my stock battery in my B7 S4. My mechanic told me that I should just go with a stock battery since the batteries need to be coded to the car or else some systems will suffer overloading and shut down…you mentioned in another comment that you’ve been running it for two years so I’m not sure if that’s entirely true. Looking to get your opinion on this. Thanks!
Yeah, closer to three years now…no issues. Hundreds of others run this battery too between Audizine and my blog and I haven’t heard of any issues like that. This option is cheaper, lighter, and IMO better 🙂
Received the Red Top from Amazon yesterday right on schedule. Install was a breeze, this is the third battery for my 2005.5 S4 so I knew the drill. Had one minor hiccup. When I first put it in, the clamp didn’t have enough bite on the base to keep the battery from sliding back and forth. In the box there’s an adapter for DIN applications. It snaps easily onto the base of the Red Top and gives the clamp something to hang onto. Problem solved.
Great Post! My S4, back and wallet thank you!
B7 RS4 has the battery in the trunk, the engine bay just has remote terminals.