You can connect the camera to an external large capacity battery pack, this will give a much greater running time, there are battery banks for charging phones and laptops with very high capacities that are about £20-£45, these are two on Amazon as an example
27000mAh https://tinyurl.com/mwjre5jr
50000mAh https://tinyurl.com/5ehfrryr
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!