I have a large (40AH) Lipo battery which I keep in a fire-safe, but the fire-safe is no use to me if all it does is delay any conflagration by silently containing the fire until the fire-safe itself is compromised, which with a large Lipo it undoubtedly will be. What I need - and what I can't find - is a temperature alarm that sounds when the outside of the fire safe starts to warm up, i.e. while it is still containing the fire within. I see a need for a product with two temperature sensors, which alarms when one of them is a preset number of degrees warmer than the other. (The control sensor being placed somewhere similar to the fire-safe location that would be expected to be at the same ambient temperature as the fire safe.) The difference need not be very much - maybe 3 or 4 degrees would be enough to avoid false positives. The temperature sensors would be on relatively long wires (eg 6 to 10 feet), so that the device was not located immediately next to the fire-safe in a way such that the device itself would also be compromised in the early stages of a fire.-- gtoal, Feb 28 2024 I found something slightly similar after posting: https://www.amazon....ouse/dp/B083Q7YRBM/I may have found something close - this controls a power outlet rather than sounding an alarm on a temperature difference. I guess you could plug in an alarm bell to the power outlet. [gtoal, Feb 28 2024] The link shows a "Dual Probe Reptile Thermostat". I'd think getting a single probe in would be difficult enough.-- doctorremulac3, Feb 28 2024 [ Just curious - What's the battery for? And why do you store it in a safe? ] It was for an eBike that I no longer have. And I keep it in a fire-safe because a big Lipo fire would be no joke. Especially needed because you're supposed to store Lipos with some charge on them - running them down to 0 is very bad for the battery. So the fire safe not only suppresses the initial breakout of a fire, it also keeps the battery pack from getting punctured by cat claws which would be the most likely cause of a fire in the first place!-- gtoal, Feb 28 2024 random, halfbakery