OPTIMA Batteries High Performance D35 YellowTop Dual Purpose Sealed AGM Car, Truck and SUV Battery, 620 CCA, Maintenance Free, Versitile Mounting

Confirmed fit in 2001 Porsche 911 (996) 3.4L Coupe. This battery is the best battery you will get for your Porsche. Typically I get about 7 years out of the yellow top and most of us don't daily our 911s so a deep cycle battery like this one won't let you down. Deep cycle batteries are tough and Optima gel cell batteries resist vibration, which is the primary killer of a battery. My 996 tends to sip down electricity just sitting. Repeated draining of the battery will kill a standard battery , even a red top Optima... which are trash (IMO) but the yellow won't suffer nearly as bad as a standard battery. Car cranks nice and strong every time even if she sits for a week or two.Pro Tip -Mounting : This battery is NOT a direct fit to the battery box. Optima doesn't make a direct fit replacement battery for a Porsche 996 at the time of this post. A custom spacer is needed to lock down the battery so it doesn't move. Some people use a high density plastic, like a thick cutting board to fashion one. I used a 12mm or 13mm combo wrench as a spacer. It was the perfect size, shape and had the rigidity to do the job. I was able to really crank it down and the wrench had enough tension to act like a strong spring on the hold down tabs of the battery. This might sound like a "backyard fix". It works, and works great. I have had the battery in the Porsche for a year and 6,000 mi now. It has withstanded a lot of spirited driving , jars and bumps and still it's solid.Battery terminals are in the correct orientation and the Factory Porsche Battery cables are plenty long enough to reach.

Upgraded to a yellow top after my car felt sluggish to start in the winter. The extra power behind this technology helps my car start in below freezing temperatures just like warm or hot days. It came with adapters to help get the right fit. It's a car battery so just like any others it definitely has weight to it. As mentioned before my car starts quickly with no issues. Installation was easy.

1-23-2011b, Yellow Top D35.Hi there,Summary:The price was good, it arrived without any shipping damage, so far the battery works fine. D35 Battery, $167, $194 after shipping. It took Amazon more than 2 days, UPS 3 days, for a 5 day total to ship to me. This (Amazon time) should be shorter...Background:I'm a HAM Radio operator, and my radios dont like Voltages less than 11.7V (They claim). I have a FT-857d, and and after talking on the radio for about 2-3 minutes, my cars battery battery was running at 12V, and in less than 5 minutes it was at or below 11.7V. This was on my 2-3/4 year old Autolite Platinum (RC=100) battery. It started my car fine, but its Voltage sagged under a 20 Amp load. And I was tired of the effects of battery acid leaking. So I decided to change to a AGM type battery, because it was more designed for how I was using the cars battery. And, it dose not leak or out gas acid...So far the Yellow top battery is holding up much better, than my 2 year old (flooded cell) battery was.One reason I choose this battery is it claimed its charged open circuit Voltage was (fully charged) 13.1V instead of the more common 12.65V. However, I'm seeing more like 12.9V, and 12.65V once its lightly loaded (used)...Bottom line:The price was right, took longer than I expected to ship to me, seems too work good so far...PS. It arrive at 12.6V that about 80-90% charged...PPS. It would be nice if they made a D34R (R = reversed positive/negative connections) its like a BCI-35) Yellow or Blue top battery...B

This product does not hold charge after less than 18 months. Won't even keep enough juice to unlock the doors from the remote (overnight charge = nothing).Terrible product and terrible service on the warranty by both Amazon and Optima. Still don't have a battery or money back. Buy 3 cheap $100 batteries, they will outlast this one.Shame on Amazon for not honoring the warranty and using stall tactics to avoid and defer refunds.Despite the warranty information file that amazon publishes on their own site, they are trying several tactics, like requesting denial of service emails from Optima being forwarded to Amazon customer service, likely hoping consumers will just walk away. Clearly Amazon has refunded others based on the reviews, so they are aware of Optima's policy, so this is purely a stall tactic. All this despite the clearly stated policy that is published on Amazon and Optima websites below:OPTIMA Batteries, Inc. expects its distributors/dealers to warranty to the original user batteries used within the United States for models D27F, D34/78, D75/25, D34, D35, D51, D51R; the following Guarantee Warranty : PERSONAL CONSUMER USE 36-MONTH GUARANTEE OPTIMA Batteries, Inc. guarantees to the original personal/commercial user that the above OPTIMA deep cycle batteries will be free from defects in material or workmanship for three years after purchase date. User must promptly report any alleged defects to authorized distributors/dealers, provide the original sale receipt to establish proof of purchase and warranty date, and permit examination by their service personnel. If the authorized distributor/dealer finds the battery to be defective as a result of material or workmanship, they will provide a replacement F.O.B. their location . All replacement batteries will be warranted for the balance of the original warranty period.