In hindsight I'm thinking that there is possibly a risk that if the LEDs in the tap point for the charger circuit fail open circuit, then when the cell is charged and the charge chip tries to break the current flow then it will be potentially exposed to hundreds of volts and could fail, potentially letting the lithium cell continue charging until it too fails in a very overcharged state....
I have to admit that this is a very clever idea. It's a standard LED lamp with the addition of a lithium cell. In normal use it charges from the mains while lit, but in the event of power failure it will light up automatically, but only if the wall switch controlling that light is on. That basically means you can turn it on and off from the light switch even when there's a power cut. It does this by applying a small DC voltage to the lamps contacts and detecting if it is bridged. If the wall switch is off then no significant current will flow, but if it is on then current will flow through other appliances and circuits in the house and it will detect that and light.
This does mean that it can only really be used in a single lamp holder on its own, and the switch can only be a simple one with no active electronics.
My apologies for all the random noises. I filmed this at work and there were explosions and gunshots in the background. Some lights on part of the show also needed their positioning adjusted slightly, so there was some loud walkie talkie use too because I had the volume up quite high. (It's a very loud show.)
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