Yet Another DIY Maglite USB Rechargeable 18650 Cells for 3xD Replacement.

Looking for quick print ? Here is my Printable post

After looking online for a solution to upgrade my MagLite, i found this post https://www.instructables.com/Maglite-USB-Rechargeable-18650-and-LED-Upgrade/ from JGJMatt . Unfortunately his solution was made for 2cells battery pack, too thight for my 18650 cells and, i didn't wanted to modify the Maglite it self. So i clearly inspired my version from his work to make what i wanted.

My design requirements:

1. No modification on the original MagLite
2. Removable battery pack
3. Using positive and negative plugs that where already in the torch light
4. Easy maintenance (removable 18650 cells, easy access board)

First of all, a little disclaimer :

You will play with 18650 lithium cells, those little bad boyZ have enough chemical energy to burn you, your house, your pet, and even your grandma all at once if you don't pay attention to what you are doing.

I'm not an engineer, but i've seen enough electronic material in my life to be aware of what i'm doing. I assume that you are intelligent enough to notice if you are doing something stupid or not. If you are sure that you have the skills to do so,

... think about it again...

... i've said, thing about it again...

... well if you are sure.

Wires :

The length i advice are mostly to prepare everything before you go, and give you enough cable length to tear everything down if you need so. I stripped all wires by 30mm to secure them on the knurled nuts, and cut the excess.

i used 1.5mm thickness wires, but 1,75mm is the maximum.

2x 300mm black (strip 30mm) negative cells plugs

1x 200mm yellow (strip 30mm) positive cells plug

1x 300mm orange (strip 30mm) positive main pack plug

1x 15mm black (strip 30mm) negative main pack plug

(if you have white wire it may work also, i don't know, i haven't tried my self.)

(if you are color blind... well... use the brown ones...)

(all joke a side, i used color for the understand-ability of the montage and soldering)

Knurled Nuts // (I made it possible only with screws if you don't have any nuts laying around. I prefer deeze nuts for the conductivity and durability.) :

2x M3x5x5 negative cells plugs

1x M4x5x6 positive cells plugs

2x M4x5x8 positive/negative main pack plugs

Screw :

1x M4x 5-8mm(length)

Washer:

1x 12mm copper washer (maximum 14mm) negative main pack plug (or any conductive washer)

Board :

the basic HW-107 TC4056 board

3D Printed parts :

I printed everything in PETG, ABS other filament that has enough durability.

Springs are printed in 0.2 quality, 15% infill, printed on the side

Main body 0.2 quality, 15% infill, printed face down(cells part down), only support the tiny plugs on each side. Brim by security but maybe useless.

Positive cell plug (borne+) 0.2quality, 40% infill (i tried and fail with 15% infill)

If you don't have nuts you may use screws only for springs. For the positive plugs, be creative... i didnt test other posibility.

Negative cells plugs:

2x 250mm black (strip 30mm) negative cells plugs

2x M3x5x5 negative cells plugs

Now that you are really decided to make this battery pack, we will begin with the negative springs of the 18650 cells.

A convenient little hole on the side let you slide the cable in the spring, make it loop as on the picture first in the nut, then on the side of the nut.

Use your soldering iron about 200°C to insert... the insert. let 1mm out of the spring or you won't have any contact.

Do it twice.

Positive cells plug:

1x 200mm yellow (strip 30mm) positive cells plug

1x M4x5x6 positive cells plugs

Same work as negative plugs. Pay attention that you need to push out something like 0.5mm each side to make the contact.

Clean the excess of plastic on the plug.

Positive MainPack:

1x 300mm orange (strip 30mm) positive main pack plug

2x M4x5x8 positive/negative main pack plugs

Same work, you'll find a little hole going through on the back of the pack right to the hole for the positive plug. It let you insert the wire as well as in other steps and secure it.

Negative MainPack:

1x 15mm black (strip 30mm) negative main pack plug

2x M4x5x8 positive/negative main pack plugs

1x M4x 5-8mm(length)

1x 12mm copper washer (maximum 14mm) negative main pack plug (or any conductive washer)

Same work. again.

Screw the washer.

I clearly forgot to make a hole for the wire to go to the plug... but well... i'll say that in definitive, that it's a feature and not a mistake... hum... joke aside, when i wire the negative plug, there was no easy way to solder it on the board if i had made a through hole, so... not a mistake xD

"Le fil rouge sur le bouton rouge, le fil noir sur le bouton noir"

"QUI EST LE C** QUI A FAIT SAUTER LE PONT?!"

I ASSUME AGAIN THAT YOU ARE SOMEBODY INTELLIGENT, AND YOU DID NOT FORGET TO CHARGE YOUR CELLS FULLY BEFORE MAKING THE BATTERYPACK HUN?!

(for the two not listening at the back of the class, if your cells are not charge equally, when you will plug the charger, it may cause fire. I refresh your memory : burn house, grandma etc etc...)

I think i don't have to describe everything.

Before solder everything, check the continuity of your wire with a multi meter and one of the 18650 cell in place.

Before solder again, check if your battery enter in place with the positive plug. First insert the negative of the cells with positive outside and positive plug in between try to push the cells and positive plug in the pack. If it doesn't fit, you may push the negative plugs a bit by giving them a iron solder slap and give you more clearance.

The positive plug has a "foot" that will slide in the pack on opposite side of the black wire!

Check again if you have 3.7v at each side of the pack with the wire.

You can use capton to lock the spring cable in place. Bring all you wire at the bottom.

Orange on OUT+

Yellow on B+

Two Black from cells on B-

Black from mainpack to OUT-

Cut the excess of solder and wire on the bottom of the board.

When done pull all your wire inside the pack, pulling in the board face outside.

You can remove "easily" the cells, by pushing the foot of the positive plug if needed.

When screwing the bottom cap of the MagLite, the spring should touch the washer and bend a little bit making sure that you will always have contact.

I hope it will be useful for somebody, and at least i hope i've made you laugh a bit.

As usual, all files are provided, STL, M3F and also pre-configured pruslicer files with the right orientation etc etc...