My husband replaced the battery in our air-cooled Porsche 911 (964) with a lithium-ion battery, and he shared his impressions including the differences from before. Please take a look if you’re interested.

A Friend’s Story About Changing Their Porsche Battery

First, let me clarify that this is not a sponsored article. This is a personal review based on a purchase made out of pocket, with no requests or influence from manufacturers or stakeholders.

A little while ago, I met someone driving a 991.1 GT3 on the Royu Driveway. That owner told me they had switched their battery to a lithium-ion battery and said the driving feel changed dramatically after the swap.

When I asked for more details, they said they had replaced the original lead-acid battery with a MegaLife Battery, a lithium-ion battery. This reduced the battery weight from about 21kg to roughly 7kg—almost a third of the original weight—and right after leaving the shop, they noticed the steering felt lighter and the car’s response was completely different.

In recent Porsches, the battery is installed near the front windshield area, which is relatively high for a sports car but somewhat close to the car’s center of gravity.

Because of this, a battery weighing nearly 20kg has a significant impact on the car’s center of gravity. In fact, the 997 and 987 generations even offered an ultra-expensive factory lithium-ion battery as an option.

It’s easy to imagine that reducing the weight of a battery in this position by about two-thirds would have a positive effect on handling.

Additionally, this battery features an emergency start button that, in case of a dead battery, powers the engine from a built-in spare battery via a separate circuit.

Moreover, it supports charging and discharging speeds up to 10 times faster and has only about one-third the weight of conventional lead-acid batteries with a lifespan of 5 to 10 years.

On that day, I actually got to drive the GT3, and while the front-end response was excellent, the car felt very agile and comfortable overall, the suspension and wheels had also been upgraded, so I couldn’t personally judge the battery’s sole effect since I hadn’t driven it before the swap. That was a bit disappointing.

Still, this battery seemed very appealing, so I immediately ordered one to install on my Porsche 911 (air-cooled 964).

Replacing the Porsche 911 Battery with a Lithium-Ion Battery

According to the manufacturer’s compatibility chart, the 964 Porsche 911 fits a battery with the part number MV-072. It weighs only 7.6kg, less than half the 18-20kg weight of a typical 964 battery.

I found a local store that carries MegaLife Batteries—Super Autobacs at Sunshine Wharf Kobe—and placed an order right away. The price was 106,920 yen with a 2,200 yen installation fee. They contacted me a few days later to say it had arrived, so I went for the installation.

The swap was completed in about 30 minutes. I immediately tested it on my usual route and would like to share my review.

Engine Starts Dramatically Faster

After the swap, engine start-up became incredibly quick. The difference is dramatic. The starter motor spins with much more vigor and sounds completely different. The original battery was occasionally charged and showed no signs of deterioration, but the speed of starting is overwhelmingly better.

Also, the idling fluctuations almost disappeared, which was surprising. Lithium-ion batteries maintain low resistance and high output consistently, delivering stable power regardless of remaining charge.

I recorded a video, so if you own a 964, please compare it with your own car.

リチウムイオンバッテリー化した後のエンジン始動。
セルの回り方、始動までの時間が全然違う。964乗りの方なら違いが分かると思う。#メガライフバッテリー #MEGALiFeBattery#空冷ポルシェ#ポルシェ964 pic.twitter.com/sVAcuXRrMR

— Hiro@ポルシェがわが家にやってきた (@boxster_gts) April 20, 2021

Improved Ride Comfort and Handling

This improvement is noticeable right away. The 964’s battery is mounted well ahead of the front axle—specifically, just behind the left headlight, slightly below it, near the bumper. It’s quite low but positioned at the very front left of the car.

Because the weight in this spot is significantly reduced, the shop staff said, “You’ll definitely notice the effect.” And indeed, I felt it immediately after leaving the store.

The steering feels lighter—no, smoother. It’s like having Porsche’s optional “Power Steering Plus” installed. What surprised me most was how much the vibrations transmitted through the steering from the front were reduced.

Pitching motions are greatly suppressed, and the subtle vertical vibrations at the front are much less. Since the heavy component at the very front of the body, ahead of the front axle, is lighter, it naturally reduces the load on the front suspension. The car now glides over bumps more smoothly, improving stability and comfort at high speeds.

And the handling—it’s very satisfying, with the front end responding naturally and precisely. After switching to the lithium-ion battery, I realized something I hadn’t noticed before: there used to be a difference in how the car responded when steering left versus right.

Previously, steering right felt slightly sluggish. After the swap, there’s virtually no difference whether turning left or right. The car behaves almost identically in both directions. This left-right balance became clear only after changing the battery.

Thanks to this, winding roads are much easier to drive. The front end smoothly and effortlessly enters corners, allowing me to flow through S-curves gracefully.

I wondered if I was the only one who felt this way, so I asked TAKURO—who had driven this 964 before—to join the test drive. He was also thrilled, saying, “It’s completely different from before! It feels like a modern Porsche! There’s no heaviness at all!”

He even said, “This 964 is the true ‘Touring Package’!” That’s how comfortable and enjoyable it is to drive, making you want to take long touring trips.

By the way, I was initially worried that reducing front weight might reduce front-end grip and cause understeer, but after testing extensively, I found no such negative effects on my car.

More Powerful and Smoother Engine Performance

This is where the high discharge characteristics of the lithium-ion battery really shine. Just as the starter motor spins with more vigor, the spark plugs likely receive stronger power. Torque feels fuller and the engine runs smoother.

The smoothness and strength when starting off, and the strong acceleration when cruising in 4th gear on the highway and moving into the passing lane, are noticeably improved. Anyone can feel the difference clearly.

964 owners might notice that the engine feels smoother and more powerful when driving with the air conditioning off compared to on, and this effect is quite similar.

Smoother Tiptronic Response

This was completely unexpected, but after the swap, the difference was clear. Shifts are faster and smoother with less shock. The smoothness when accelerating from a stoplight feels like having fresh ATF installed.

No Need to Carry a Mobile Battery (Jump Starter) Anymore

As mentioned earlier, this battery has an emergency start button that powers the engine from a built-in spare battery via a separate circuit in case the main battery dies.

Initially, while the weight reduction was appealing, this feature was the main reason I decided to install it on my 964. Fortunately, I haven’t experienced a dead battery since the swap, but the peace of mind is completely different, and I no longer need to frequently turn off the battery kill switch. Thanks to this, the clock inside the car stays accurate, and the audio system’s time remains correct.

Now I don’t have to carry a jump starter on tours, which makes me feel much more relaxed.

Overall Impressions of the Lithium-Ion Battery

These are my impressions and the benefits of switching my car’s battery to a lithium-ion one. Honestly, I was surprised by how many positive effects it brought.

If it’s this good, I’d love to swap the battery on my 981 Boxster GTS too, but since I just replaced that battery at the recent inspection, I’m still undecided.