I wanted to make a small table lantern (7x9cm) that can be used at home on the table, on the balcony, in urban camping and similar situations. The general idea was to use some host or a cheap lantern and modify it. But most of them come with multiple leds, horrid color, dreadful batteries, etc. So I had an idea to build it from scratch using 3D printing.
This is the rough sketch, and the idea is basically that. The appearance might change. In the lower portion there will be a holder for 3x18650 in parallel. It should work with 1,2 or 3 batteries. The driver will be flashlight type with 0.5A, 1A, 3,5A roughly, and will be using one high powered led. The lid has two holes, one of them is for the switch which is flashlight type, and the square one on top is for the heatsink 50x50mm. The “windows” will be holes, or if the light is too harsh I will put some frosted sheet to make them diffuse the light. The led will be mounted upside down shining downward and not causing glare. Above the battery holder there will be matte reflective aluminium surface to bounce back the light. The batteries will be open to the air from the bottom. The heatsink will have a temperature sensor to shut off above ~65 degrees C to protect the plastic, and the hands.
More problematic stuff. I want to put a charger for the batteries with micro usb plug. It will charge them slow, and that is okay. Like this one here But can I leave it connected all the time, without it draining the batteries? Parasitic draw?
And the other thing is the led. I want to use as low as possible light temperature led. Like this one and the XPL is the lowest that I could find at 3000-3125K. But it has a rather low CRI of 80+ and IOS does not offer high CRI versions of warm white leds. I haven’t had much luck on these emitters on Fasttec/Kaidom/Aliexpre/Banggo/ ebay . Cree says there are XML2 and XPL leds that offer high CRI at very low kelvins but it seems they are rather hard to find.