LED Tiki Torch by darthmuffin

Last crawled date: 3 years, 3 months ago

General:
PETG required, at least for the upper, as I saw the charge controller chip get to at least 170F during testing. Tolerance on printed parts accounts for a 0.40 nozzle. I printed with 0.30 layers bottom, 0.20 layers top, 4 perimiters and 15% infill using a 0.40 nozzle on a Prusa Mk3. Lower is Atomic Glow PETG (discontinued) and upper is Atomic CF PETG. I used supports for upper and lower, but especially the lower you might not need it if your briding is tuned well.
The flat portion on the lower section is for a name tag, or if you're fancy edit in an embossed name. For my use I see them left out in group camping areas, etc. and I wanted to make sure they come home.
Environmental Notes:
This is not water resistant without the cap. The stock globe has a vent on the top and there are vents in the model to aid the convection cooling. Is it really needed, especially with the converter gone? Dunno so the optional rain cap comes with the caveat of possibly shortening diode lifespan through overheating. Cap has a reinforced center in case you want to screw in an eyelet to tether it.
Parts:
LED flame light: https://www.amazon.com/gp/product/B07Q1CJJN1 (the version with the black base)
Charge controller board: https://www.amazon.com/gp/product/B07PKND8KG
A 16mm push on/off switch. I used a blue version of this because it's what I had on hand. https://www.amazon.com/Aexit-Switches-Self-Locking-Indicator-Pushbutton/dp/B07L6B4K6H I didn't hook up the indicator light in the switch.
Four 18650 batteries, matched as far as capacity, age, and state of charge. Power use is 220-250ma depending on mode. 4 x 3400mAh batteries would give 56hrs runtime. The cheapest 1000mAh cells you can find would still give 16hrs.
Two 3mm LEDs, different colors (red/blue are the stock colors)
Three 3mm x 12-15ish mm machine screws and washers
Three 3mm hex nuts
Wire. I used 24ga silicone sheath.
4 scraps of any type of 1.75mm filament, 12-13mm long
3/4" SCH-40 PVC pipe for the support shaft (tip, if budget allows look for "furniture grade" for better looking, stronger, UV resistant, and colors).
A stake or length of rebar to pound in the ground and slide the PVC over.
CA glue
optional: RTV silicone sealant and hot glue
Disassembly of stock flame light:
Use a spudger or similar to pry the white globe off. It's held on by a spot of glue on opposite sides.
Grab the edison bulb base with a big pair of pliers and pull/twist it off, you'll probably bend the base making this irreversible.
Cut the wires between the converter board and the edison base.
Feed the converter board up the tube and cut the wires at it which go to the LED circuit board. You won't need the converter.
Cut off the black base to give yourself a little more mounting room (see pictures). A dremel with cutoff wheel worked well.
Batteries:
Wire the four in parallel. Joining two pairs with hot glue then joining the pairs before soldering worked for me. Kaptan tape is optional but a good idea. A small wire connecting the cells is fine, they will see a max of 1A charge and 250ma discharge (collectively). Check youtube for tutorials on soldering to batteries--a light sanding, solder flux, pre-tinning both parts and being quick are the key.
Assembly:
Place the battery pack in the lower section, wires should come out the center or the side opposite the flat.
If the pack is a little loose use a few wraps of electrical tape until it's a snug fit, or seal with silicone.
Don't block the drain hole at the bottom of the battery bay with silicone, just in case water does get in.
Use the bits of filament in the holes as pegs to align bottom and top piece for gluing with CA glue.
After pieces are joined, set the charge controller board into place.
Solder battery leads onto board.
If you're replacing LEDs:
Break off the stock LEDs, I just used pliers.
Install new LEDs into the holes and bend the leads so they're coming down onto the terminals.
Cut the new LED legs to length and pre-tin with solder.
Install heat shrink or electrical tape onto the + leg to prevent the possibility of shorting.
Solder.
Repeat for second LED.
Install a short (2 inch) wire onto the board + for the switch, and a long (8 inch) onto - for the bulb.
Tack down the board with hot glue or silicone on a top edge, or CA underneath.
Install the switch.
Solder the other end of the short lead to the switch. To the other side of the switch solder an 8 inch wire.
Install the 3 hex nuts. Tacking down with a bit of glue or slightly melting the entrance closed will make life easier.
I recommend a small dremel burr bit to make the holes in the black LED base. A drill is too big and cumbersome and the LED board is very delicate. One nick and you lose a column (ask me how I know). You can use the injection molding marks on the inside of the black part and line up as best you can from the outside for two of the holes, third one split the difference between two marks.
Feed the two wires up the tube and solder them to the two existing bulb leads and cover with heat shrink or electrical tape. The circuit board seemed too delicate for me to try to solder directly, but maybe you're more confident in your soldering skills.
Insert the 3 3mm machine screws with washers into the top of the black base and gently snug down into the nuts, a bead of silicone is optional.
Snap the translucent dome back on, optionally apply a drop of silicone or hot glue to the inside edges first if you're worried about it coming off.
Test and enjoy!
The first time you charge it do so in a safe place in case something is wired wrong, or batteries or charger are bad. Outside on concrete or in a metal basin is good.
Improvements:
I'm not planning another version of this but if you feel like remixing it, the following suggestions come to mind as nice improvements:
Not happy with the filament pegs for alignment, some more substantial grooves or clips would be nice.
Some bevels below the nut holders and on the ledge above the button would probably make it printable without supports.
Moving the nut holders to 120 degrees apart would probably be smarter, and aligning them with the injection molding dimples inside the flame base would make easy drill guides.
Lots of room for improvement on the switch, the one I used is chonk (but free for me).
Find room for a small expoxy-on heat sink on the charge board. It's supposedly designed to tolerate the heat but that chip gets uncomfortably hot for me.
"gutters" below the battery from the corners to the drain hole. Or get really fancy and work up a gutter right below the LED cylinder to channel water outside, then no hat needed.
Perhaps light pipes (clear filament?) for the existing charge LEDs rather than extending them (which is a pain). I couldn't find any large fiber optic or small acrylic rods locally.
A "male" peg to go inside the PVC rather than outside might look cleaner and take less filament to print, but may be weaker.