Someone fitted a Pixel 5a battery into a Pixel 4a for 17% extra battery life

What do you do when your phone’s battery starts showing its age? You definitely don’t replace it with a higher-capacity battery from that phone’s successor. At least not without a good amount of knowledge, testing, skill, and, shall we say, an appetite for some risk. Why are we talking about this? Because a Redditor claims they managed to replace their Pixel 4a‘s 3,885mAh battery with the Pixel 5a‘s 4,680mAh battery.

The Redditor says they have many years of experience in PCB design and repair. They figured the batteries of the Pixel 4a and 5a looked identical and procured the latter on this hunch. The Pixel 5a’s battery turned out to be 4.5mm taller, 0.4mm thicker, and 1.4mm less wide than the cell in the Pixel 4a. Clearly, it wasn’t going to be a perfect fit, but it was a close enough match to pack inside the older Pixel 4a with some adjustments.

So the modder moved the Pixel 4a’s battery management system, a tiny board that connects to the battery, to the left side. It helped that the ribbon connector of both phones is identical. After connecting everything and closing the phone, a slight bulge remained at the back, which the modder claims is “visually imperceptible.” The result is a 17% increase in battery life.

What about battery expansion, the threat of the battery exploding, and software compatibility? Well, the Redditor seems confident they’ve taken care of all this.

“I’ve eliminated all points of potential failure in the event of expansion, namely the NFC sticker in the back, which shaves off just under a millimeter and is a potential conductor, the left side of the battery where the BMS now sits has a comfortable amount of insulation and space for expansion as well,” the Redditor wrote in the thread.

The Pixel 4a user also said they will monitor how battery percentages are displayed over time and whether the readings are accurate.

While it seems like a cool hack, we wouldn’t recommend you try this at home. The modder appears to know what he’s doing, but there could still be some risk involved in the long run. Let’s hope we get some updates from the person to see if the DIY battery replacement worked out as intended.