system
A chat on subreddit /r/pcmasterrace
human
if you have the choice though you shouldnt use a car battery, you should use a leisure battery.

Car batteries arent designed to do deep cycle and doing so can drastically reduce their lifespan
gpt
True, however deep cycle batteries tend to cost 3x as much as the same capacity car battery. So if you only need to use it every now and then for short periods of time then a car battery is fine. Plus, car batteries can be discharged by about 20% before being damaged (starting a car drains ~10%). So with OP's 60 AH battery you can use up to 144 watts for an hour or 288 watts for 30 min or 576 watts for 15 min without damaging the battery.

From the picture it looks like OP is drawing 219 watts, which is fine for ~39 min. It's unlikely that a bios update will take more than 5 or 10 min, so for this application OP is probably fine with a car battery.

Plus since car batteries are designed to be charged and discharged simultaneously, you could plug the battery into a wall with a charger and have the inverter connected to the battery too since it's just there to prevent power loss in case the mains cuts out