The other day, my husband wrote a review article about installing a MegaLife Battery (lithium-ion battery) in a 964 and its effects. This time, he installed a MegaLife Battery in a 981 Boxster GTS and wrote a review about it as well. Please take a look if you’re interested.

The Lightness of the MegaLife Battery

The battery installed this time is also the MV-072 model. The Boxster’s battery location is the same as in the 991 and others, just in front of the windshield. Although it’s positioned inside the front axle, it’s placed quite high, so it likely has a notable effect on the center of gravity height.

As before, the battery replacement was done at Super Autobacs Sunshine KOBE store. While talking with the staff, it seems that about five Porsche owners who had already read the previous blog post came to have their batteries replaced (laughs).

Before the swap, I held the battery in my hand to feel its weight, and the MegaLife Battery really is light. It weighs just over 7 kg, light enough to lift with one hand. On the other hand, the lead-acid battery weighs about 20 kg, which hurts your hand if you try to lift it with one hand. You need to use both hands and put in some effort, and depending on your posture, it can strain your lower back.

Considering that such a heavy component placed so high becomes this light, it’s no wonder the driving performance is affected. Moreover, the cost is about 110,000 yen, and you get a weight reduction of over ten kilograms.

The 991 GT3 RS Weissach Package costs about 3.2 million yen and achieves 18 kg of weight reduction with a carbon hood and titanium roll cage. Compared to that, this is an extremely cost-effective way to reduce weight.

Impressions in Town?

After replacing the battery, as soon as we started driving, just like with the 964, the steering feel was different right from leaving the shop. Describing the steering as simply “lighter” doesn’t quite capture it; it’s better described as the steering friction disappearing. In any case, the steering feels smoother to turn.

The front-end grip feels less like it’s being pressed down by weight, giving a Porsche-like feel with PCCB brakes. You can clearly feel the suspension working well even over small bumps in town. Regarding ride comfort, there’s no harsh bouncing; in fact, it even feels like the suspension moves more supplely.

My wife also drove it around town afterward, and she said, “I can tell it’s more nimble! Plus, the acceleration feels stronger.” This might be due to the lithium-ion battery’s consistent high discharge rate, which could be influencing engine power to some extent.

When I consciously paid attention, I also felt

How Did It Change on Winding Roads?

We moved to the Royu Driveway to check the handling on winding roads. When taking normal curves, the steering feels smooth, making it easier to sense the road surface and the tire’s direction and feedback.

Moreover, on slightly uneven surfaces, the stability seemed much improved compared to before. This is probably due to better front suspension compliance. The reduced influence of vertical movement makes cornering feel more stable.

On smooth roads, uphill corners don’t feel much different, but on flat or downhill corners, the difference is significant. This is likely influenced by the Boxster’s mid-engine layout.

Understeer on downhill corners is reduced, allowing the car to turn more neutrally. While it’s not quite as easy to drive downhill as a 911, I think this improved downhill stability is the biggest difference after the battery swap.

Impressions on the Highway?

I also drove a bit on the highway, but since steering inputs are minimal there, I didn’t notice any major difference in handling feel.

On the other hand, in terms of ride quality or rather ride feel, there was a change. Specifically, the front feels lighter than before, yet somehow the sense of security and stability feels stronger. It’s hard to put this feeling into words, but in any case, it’s definitely a positive effect.

By the way, this was not noticeable at all with the 964, and there was no such change, but in the Boxster, when cruising on the highway with the soft top closed, a faint high-frequency noise resembling alternator noise can be heard in sync with engine RPM. This is at a volume that some people (depending on age) might not hear at all, and it’s completely inaudible with the top down.

The voltage and current fluctuations might be affecting the audio system or speakers slightly. I want to investigate a bit more to find exactly where the sound is coming from.

[Update 2021/6/7]
Regarding the alternator-like noise, the following was discovered afterward:

• It’s not coming from the speakers but seems to be heard from somewhere behind the dashboard. Later, when the amplifier fuse was pulled and the car was driven, the noise disappeared completely, confirming it was coming from the speakers.
• The noise is not heard during normal driving in Normal mode.
• However, when switching to Sport or Sport Plus for sporty driving, engine control changes and the idle RPM rises. Battery voltage quickly rises from around 13.2V to about 14.5V. The noise occurs in sync with engine RPM during this voltage increase (lasting a few minutes).
• When voltage stabilizes around 14.5V, the noise stops and is no longer heard. In Normal mode, voltage stays around 13.2V and no noise is heard.

So, it seems the noise occurs during active charging of the battery. This lasts only a few minutes and is unlikely to bother most drivers, especially if focused on driving, listening to music, or with the top down. However, sensitive individuals should be aware.

[Update 2022/2/6] The noise issue has been completely resolved.

• The cause was identified as the factory amplifier (or wiring from the Clarion navigation system to the amplifier).
• By bypassing the amplifier and connecting the speakers directly from the navigation system, the noise disappeared completely.

Overall Evaluation of the MegaLife Battery

As with the 964, I believe this battery has a significant positive effect. Of course, everyone’s perception varies, but since even my wife noticed the difference, I think many people would feel it too.

While the battery is quite expensive, considering its lifespan and the benefits of weight reduction, it’s a highly cost-effective tuning option. If you’re thinking about replacing your battery, it might be worth considering this one.