NiMH rechargeable batteries has been available for quite a while and are something very common in our life with a lot of low power gadgets such as remote controls for example relying on them. Recharging NiMH batteries is interesting because they do have an interesting feature, namely that they start to get hot when they are fully charged. The reason for that is actually quite simple, when the NiMH battery cannot store more charge it starts dissipating the extra power as heat. So when you touch a battery that is inside a charger and it feels hot it is most likely charged or will soon be charged, so no wonder that some chargers for NiMH batteries actually use the temperature of the batteries to decide if they are charged already or at least have temperature sensors as a safety measure. If you are charging the batteries with a low rate they will manage to dissipate the extra heat, but if you try to push them with lets say 1 Amp or 2 Amps of power and if the charger does not stop the charge if batteries start getting hot, then you might be facing problems that may even include a fire. On the thermal image above you can see two smart NiMH battery chargers that are charging AA size rechargeable batteries, the two hot sports on the sides of each charger are apparently the power elements that are responsible in providing power to the batteries while they are being recharged. The batteries on the left are about half charged and these in the charger on the right are almost fully charged and their surface temperature is slightly higher


Taking a thermal image of a standard computer keyboard may not be very interesting thing as these are normally very low power devices that use the computer’s USB port for the needed power and communication with the PC. If we take a look at a high-end gaming keyboard like the Logitech G19 keyboard designed for gamers however things might get a bit more interesting in terms of temperature of the devices. So we took a thermal image of a G19 keyboard after an hour of it being powered on, enough to have some parts of the keyboard get hotter than the rest of it. As expected the LCD display on the keyboard does get hotter and you can also see a spot on the top right side of the Logitech also getting hotter – this is where the keyboard controller apparently is located, so it is normal that this area also gets hotter over time. One thing that is interesting with keyboards and thermal imaging is if you can guess a password that was entered on the keyboard by the eat signature left on the keys by pressing them with hotter fingers. This thing however is something that we are going to explore later on, so stay tuned for more details about that.


When we are talking about computers and cooling the two things that need serious cooling solutions are the CPU (central processor) and the VGA (video card) as they are the two components that are most powerful in terms of performance as well as use the most power. But they are not the only things that get hot inside your computer and if you decide to overclock the system you may end up having trouble due to other overheating components even if the processor and the video card are properly cooled. On this thermal image you can see an open frame computer with Nvidia GeForce GTX 980 video card and Intel Core i7 CPU on a Z97 chipset motherboard. The system is running idle and as you can see the temperature of the video card and the processor is higher in general when compared to other components on the motherboard, but there are actually some spots on the motherboard that are hotter than them. Such places are for example the chipset and some additional chips that are responsible for various functions on the motherboard and this is in idle mode, when the system gets loaded with a game or a benchmark things can change. The CPU and VGA will get hotter for sure, but also the mosfets that power the CPU, the memory etc. and if you overclock the system some components may start overheating, so it is not only the processor and the video card that may need attention and proper cooling in your computer.