Found qty 5 of 303030 battery on ebay for $10. Going to put a connector on the camera/battery and just stick the battery to the outside. When it goes bad, I can just stick a new one to it.
I’m also finding an alternate battery number of 303030. Might find cheaper replacements with that number.
The battery also retains the date and time, which I believe will cause the camera to overwrite the newest (now seemingly oldest due to incorrect date) video. My theory is that you are in an accident, camera is recording, you shut the car off to check damage, you restart car to move. Now you just overwrote the video of the accident. the circuit board attached to the battery is likely the protection circuit to keep the battery from over charging/discharging. As long as the replacement battery has the board, is a pouch style and somewhere near the same capacity, it should work electrically. I considered replacing my battery with 3 externally mounted D cell batteries connected in series with a silicon diode so the camera can’t try to recharge them. The stock battery is claimed to be 210mAH, a D cell is 10,000mAH. 1.5V x 3 = 4.5V. 4.5V - 0.7V + 3.8V. 3.8V should be within the voltage range to work fine. My guess is the batteries would last 6 months and be readily available and easy to change.