18650 Charger Carousel

18650 Battery Carousel Charger using Magnets and a Pogo Pin

Holds/Stores up to eight 18650 standard batteries...
Type 1: Can be powered by an external 18650 battery charger...
Type 2: Uses a low cost internal TP4056 charger module...
Simply rotate the selector (rotor) to select the battery to charger (charges one at a time)...
Positive Magnetic contact... it clicks ;)
Very easy to use, very convenient...

Note, most 18650 cells I use are charged at recommended 1 Amp, my high capacity cells are charge at 2 Amps.
To ensure longer life and greater charge cycles, charge at the lower current (1 or 2 Amp) even if battery can handle more...
The GF55 Pogo Pin I use is rated at 8 Amps, I use it at 2 Amps for my high capacity batteries...
The H009 and GB30 Pogo Pins can handle up to 3 Amps...

We use eight 6x3mm neodymium magnets and a piece of hookup wire (~1mm Ø) to make ground connection...
A Pogo Pin and a piece of metal strip for the positive terminal with an optional 6x3 magnet for better contact...

To ensure proper contact without a spring mechanism can be difficult (intermittent at best), so we use strong magnets overcome the lack of compression (tested many times, works well)...

One of my batteries is a little shorter (2mm) that all the others, here I had to add a weight to the top of the rotor to ensure contact, all standard 1650's charge without issues. I designed a second rotor to allow for small variations in size (up to 3mm), no weight required, if you have any contact problems, try the new rotor (V9RotorNew.3mf), only takes a few minutes to print...

Printing:
Print time (3 parts) is about 2.5 hour...
No support needed...

Parts (AliExpress)

Metal Strip 50mm x 8mm x 0.1mm €2.50 (5Meters)
Pogo Pin (H009 or GB30, 3 Amp), about €1.50 each...
Pogo Pin (GF55, 8 Amp), charge is normally limited to 2 Amps for 18650 cells, €2.10 each...
TP4056 (€1 for 10)...
Magnets (N52 6x3) €4.45 (for 30), or €2.19 (for 10)...
Length of solid wire (22SWG, about 20cm) ...

Construction MagBase
Lay the solid wire along the grove (under the magnet holes), leaving enough for contact to the charger or TP4056 negative terminal...
Press the eight magnets into their holes pressing on the wire to form the common ground circuit...
Fit the TP4056 for 1 Amp charge, or wire directly to external charger for up to 3 Amps, if that's your preferred option...

If you choose the TP4056 version you could add a piece of double sided tape to ensure it does not move, then attach the USB cable before fitting.
Complete the assembling by fitting the shaft section (rotate it so that the battery cutouts are aligned with the magnets, then press fit (add a drop of glue if required).
Version 10 includes holes for M3 brass Inserts in the Shaft, and four holes in the Base to accommodate 4 x M3 screws...

Construction MagMain
Cut a length of wire to join the Pogo Pin to the TP4056 positive terminal, or long enough to reach an external charger..
Solder the wire to the pogo pin base and TP4056 positive terminal, or long enough to reach the external charger...
If using external charger, you might solder the two wires to an appropriate connector...
Note, on my test build, I simply striped the wire (about 10mm) and pressed the Pogo Pin into the hole trapping the wires.
The fit is very tight, should be sufficient for low currents as some high quality connectors reply on less compression... if in doubt, solder...

Construction MagRotor
Cut a short piece of metal strip (50mm) and insert into the slit on the rotor (see image), check the hole(s), you should see the strip.
The metal strip connects the Pogo Pin to the battery positive, a 6x3mm magnet is used to ensure connection between metal strip and battery positive terminal...

Insert one 6x3mm magnet at the pogo pin end (see image)...

Caution, before testing the charger, insert a good battery and meter the B+ and B- on the TP4056, is it polarized correctly?

If using USB to power the charger (TP4056) check polarity...

TP4056
The TP4056 is normally set to charge at 1 Amp max, Red Led when charging, Blue Led when complete...
If no lights, check connections and press the top of the rotor down to ensure good contact...

External Charge
As some 18650 batteries are high current type and can charge at two or more amps, you can power the device directly with an external (current limited) LiPo charger, just ensure the positive and negative wires are long enough to reach the external charger or solder on an appropriate connector...

Notes on Charging

Charge and store lithium ion cells in a safe place, never leave unattended while charging...*
Most quality chargers will include some type of thermal monitoring for the battery being charged...*

A note on Pogo Pins
As Pogo Pins are very small, they can be difficult to handle (for us old people), I tend to use the larger GF55 type, but the 3 Amp version is also an option. It should be noted, different Pogo Pins require different prints, as the hole diameter and length of the shaft change. Both prints included...

Notes on Files
V9_Base_External_Charger.3mf : Use this base with external battery charger...
V9_Base_TP4056.3mf : Use this base with internal TP4056 charger board...
V9RotorNew.3mf : Optional Rotor Design...
V10DirectShaftM3Inserts.3mf : Part (shaft) used with GF55 (large Pogo Pin), with holes for M3 brass inserts...
V10DirectBase.3mf : Slight reroute of 0.1mm wire channel, larger M3 holes for screws to connect to the shaft M3 brass inserts part...

V9_Shaft_GF55_Pogo.3mf : Main body (shaft), for both Inter and External charger, and GF55 Pogo Pin (up to 8 Amps)...
V9_Shaft_H009.3mf : Main Body (shaft) for use with H009 or GB30 Pogo Pin (3 Amps)...

Notes on Images
First image shows the completed Carousel (early version), the TP4056 has since been moved to the center, the USB cutout is now circular. The TP4056 can be powered by USB or you can solder wires directly to the pads and route them out through the cutout adding a connector if required. The second image shows both types (exploded view), latest versions...

Part numbers / Info
GF55-12850-4061 8.0A (Pogo Pin from AliExpress)...
GB30-13030-1528 3A (Pogo Pin from AliExpress)...
Nickel Plated Strip 8mm x 0.1 (suitable for lithium 18650 battery)...

Disclaimer:
Always read the instructions from the supplier of the charging equipment used...
Don't leave charging batteries unattended and always charge in a safe environment...
Keep small printed parts out of reach of children...
This design is provided "AS IS" and without any warranty of any kind.