I thought it would be worth taking a look at some more recent versions of these. I've had some older ones on test for a while, and they do provide surprisingly useful light on demand in the event of power outages. For a while I had an issue with a failing appliance heater that would randomly trip the main RCD for the whole house (TT system) and these gave very reassuring light when the place was suddenly plunged into darkness. The lithium cell in the small unit has now been tested, and is a miserable 150mAh. The lithium cell from the device I showed does fit, but only barely, and with no room for an adhesive pad to stick it in. Other similar vapour devices may have slimmer lithium cells in them that are easier to fit in. As always, take extreme care when fitting lithium cells, due to their high energy release capabilities. If adding more cells in parallel, make sure their voltages are very close first to minimise current flow as they balance. The electrical tests at 4.2V (fully charged lithium cell) showed that the small unit uses between 7-70mA depending on the intensity setting, and will stay lit for twenty seconds after the last movement is detected. The standby quiescent current is a very good 22uA. I like this style of light a lot. They don't need recharged too often - especially when you boost the capacity a bit, and are perfect little lights for power outages or just late night prowling around the house. Keywords to find this type of light on eBay are:- USB rechargeable PIR light Typical cost should be around £$€5 for the small one. https://www.ebay.com/sch/i.html?_from=R40&_nkw=usb+rechargeable+pir+light&_sacat=0&_sop=15 Supporting the channel with a dollar or two on Patreon helps keep it independent of YouTube's quirks, avoids intrusive mid-video adverts, gives early access, bonus footage and regular quiet Patreon live streams. https://www.patreon.com/bigclive #ElectronicsCreators ... https://www.youtube.com/watch?v=r2mpU5Q7YeA

I'd never tried Fireball before. It's basically whisky with cinnamon syrup in it for a very sugary and aromatic taste. But will it carbonate? If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- https://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty. #ElectronicsCreators ... https://www.youtube.com/watch?v=6nWHpiTAVhY

I get the feeling that the primary survivors of an apocalypse will be technically inclined people who can scavenge technical stuff to provide basic comforts like food, light and heat. Heat is trickier, but light is surprisingly easy. This is a very relaxed project where you can scavenge things like solar panels and batteries from other products to cobble together a light that can harvest whatever solar energy is available for decorative or practical use. You can also buy the 5/6V solar panels from eBay very cheaply if you have nothing suitable laying about. This design will work perfectly with two solar panels from standard single NiMH cell garden lights wired in series, or a bigger 5V/6V solar panel. The NiMH cells can literally be anything you can find, as can the LEDs. The only thing to watch out for with the LEDs is duff ones that have developed a leakage resistance and will drain the batteries without providing light. Ideally the solar panel will be aimed at an area of the sky that the sun traverses across during the day for maximum efficiency. The amount of charge the solar cell can put into the batteries is dependent on location and cloud cover. Some days it may be a lot and some it may be low, but either way the LEDs will continue to glow at low level even after several very dark overcast days. This simple arrangement would be perfect for an ambient light in a remote log cabin. It could also be a source of visual comfort during power outages in areas subject to regular storm damage. If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- http://www.bigclive.com/coffee.htm This also keeps the channel independent of YouTube's algorithm quirks, allowing it to be a bit more dangerous and naughty. #ElectronicsCreators ... https://www.youtube.com/watch?v=tmHh7U5u_i0

With recent regulation changes to address the issue of RCDs/GFCIs being damaged when used in solar power systems that can feed power back to the supply network. The issue is that some (not all) RCDs/GFCIs have a short duty cycle coil designed to be pulsed at high current very briefly to trigger the breaker. They can rely on the breaker tripping to kill power to the coil. If the breaker doesn't trip or the power is being supplied from the wrong side, the trip coil and its drive circuitry will potentially be energised long enough to cause damage. ... https://www.youtube.com/watch?v=31YO-V-UBiY