Quadrotor connectors galore
13 August 2020
[ UAV , hardware ]

A short guide to wire connectors for UAVs, for interfacing with power/pixracer/ESCs/motors, etc.

Terminology

the pitch refers to the distance from one pin to another.

A JST-SH 3-pin plug with 1.0mm pitch shown.
A JST-SH 3-pin plug with 1.0mm pitch shown.

The wire size (measured in American Wire Gauge AWG) determines the size of the wire that can be accommodated in the connector housing. The higher the number, the thinner the wire.

JST refers to Japan Solderless Terminal, which refers to a family of specific types of terminals. Wikipedia has a detailed list of them. One thing to note is that not all white terminals on a PCB are JST connectors, as we will see below…

Wire to board connectors

Name pitch Current (Amp) Voltage (V) Wire size (AWG) Pins Lock Uses Image
JST GH (info) 1.25 mm (0.049 in) 1 50 26 - 30 variable Yes Pixracer
JST SH (info) 1.00 mm (0.039 in) 1 50 28 - 32 variable No Flight Controllers, RC Receivers, Video Transmitters
Molex Picoblade (info) 1.25mm 1 125 26 - 32 variable No J121 auvidea TX2 connector board, amongst others
JST XH (info) 2.5mm 3 250 22 - 30 3-7 No Balance plugs for batteries
DF13 (info) 1.25mm 1 30 26 - 30 variable   Pixhawk connector

Wire to wire connectors

Name pitch Current (Amp) Voltage (V) Wire size (AWG) Pins Lock Uses Image
JST RCY (info) 2.5mm 3 250 28-22 2 Yes ESCs, LED Strips
Dupont black connectors 2.54mm (0.1 in)       variable    
XT30 2mm 15 500 18 2   Battery connector
XT60 2.5mm 30 500 12 2   Battery connector
XT90   40 500 10 2   Battery connector

JST XH

these are almost exclusively now used for the balance plugs on the batteries. The number of pins/wires is X+1 where X is the number of cells. So 2S batteries should have a balance plug with 3 pins, 3S will have 4 pins, etc.

A 4S LiPo battery with an XT60 male connector and a 5-pin JST XH balance plug.
A 4S LiPo battery with an XT60 male connector and a 5-pin JST XH balance plug.

Dupont connectors

The dupont connector are just a colloquial name for black pin header connectors. They are difficult to find, since “Dupont” isn’t the universal name for them.

XT series

the number following XT refers to the max current that can be put through these connectors


How to tell them apart?

  1. JST GH and Molex Picoblade are often confused as they have the same pitch. However, the GH has a clip that should lock into its housing on the board with a satisfying click, and the Molex Picoblade does not.

  2. Molex Picoblade and DF13 are often confused as well, since they have the same pitch and looks like they could fit in the same connector housing. However, the DF15 has a row of tiny slits at the bottom of the connectors, and should not fit into a Molex Picoblade housing easily, and vice versa.

  3. The JST SH should look like a smaller version of the Molex Picoblade, because of the pitch differences.

  4. JST XH has two clips that are arrow-like at the top of the male connector. Those clips should allow it to snap into the connector housing on the balance board of the battery charger.

  5. The XT30/60/90 connectors will have its type etched onto the connector, as shown in the photos.

Obvious size differences between xt30, xt60, xt90
Obvious size differences between xt30, xt60, xt90
  1. Sometimes, you just need to stare at all of them at once to figure out which one is yours. The following pictures are shamelessly scraped through the web: