[Evan Monsma], the prolific experimenter with cameras, found himself with an issue: he had a small Sony action camera with good performance in every respect but battery life, which was as low as twenty minutes. This was too short for practical everyday use, so [Evan] built an external adapter to add a larger battery and a few other features.

In fairness to the camera’s designers, it wasn’t really meant for consumer use; it was meant as more of a stunt camera, where endurance is less of a concern than size and weight. [Evan] wanted to use it for more general situations, hence the new battery. He first attached a small CNC-machined aluminium half-cage, which provided mounting points for additional hardware, including a screw-mount for a neutral-density filter.

[Evan] next designed, 3D-printed, and attached a mount and battery clip for a larger Sony camera battery; the mount also held a voltage converter to step the battery’s 7.2 V down to the original battery’s 3.7 V. A USB power adapter slotted into the battery compartment and broke out the power leads to the converter. Unfortunately, short battery life isn’t the camera’s only issue; it also eventually overheats with continuous use, which kept [Evan] from running a real battery-life test. He is, however, confident that it will last long enough for practical use.

We’ve seen a similar action camera mod before, as well as a mod to allow the use of third-party batteries in a vendor-locked camera. For larger cameras, we’ve even seen a hot-swappable battery pack.

Thanks to [Luis Mercado] for the tip!