JST-XH
What people call it
XH, "JST 2.5," balance connector, balance lead, "JST 2.54" (wrongly), printer connector.
What it actually is
The genuine JST XH series: 2.5 mm-pitch wire-to-board family — board header plus wire housing with XH-specific crimp contacts — rated in the 3 A class per the official JST datasheet.1 Marketplace "XH" may be genuine JST, a decent clone, or a loose lookalike; the figures here describe genuine parts.
Where it shows up
3D printers (endstops, thermistors, fans, steppers on many budget boards), LiPo balance leads, and low-cost wire-to-board harnesses across budget electronics.
The XH you probably know: balance ports on a LiPo charger. Photo: Laurenz Wagner, CC BY 3.0, via Wikimedia Commons.
How to identify it
2.5 mm pitch (measure across the row — this is the classic 2.5-vs-2.54 trap), friction-lock shroud on the header (no positive latch arm like GH), white nylon housing. Distinguish from PH (2.0 mm, smaller), VH (3.96 mm, much larger power family), EH (also 2.5 mm but a different, slimmer family — check the drawing), and generic "JST 2.54" kit parts (a contradiction — see the kit decoder).
ID marks: 2.5 mm pitch, boxy open-top shroud, friction fit — no latch arm.
What to buy
Housing + XH contacts (separate line items) + the board header, or pre-crimped XH leads from a reputable supplier. Genuine JST from an authorized distributor costs pennies more than mystery parts — see Buying the Right Mating Parts. Contacts are XH-specific: not PH, not EH, not kit-drawer "Dupont."
Common traps
- Balance-lead assumptions. The balance-connector convention makes XH common on packs — it does not make every XH harness appropriate for every battery use. Balance leads carry small balancing currents; main pack current belongs on a real power connector.
- Polarity/pinout is per the board, not the connector. Printer boards and battery pigtails differ vendor-to-vendor — verify against the silkscreen/documentation before powering.
- 2.5 ≠ 2.54. An XH housing forced onto a 0.1 in header binds and mis-seats; it will "work" until it doesn't.
- It is not sealed or rugged. Indoor, protected, low-vibration use — no wire seals, no positive latch.
Source status
Pitch, family type, and the 3 A-class headline rating are sourced to the official JST XH datasheet;1 genuine-part figures don't transfer to clones, and application current still depends on contact, wire gauge, and temperature — verify the exact datasheet. See Hobby Source Notes.
When to move to the engineering track
Vibration, field exposure, real battery current, or someone else building the harness — see When Hobby Connectors Are Not Enough and, for sealed field wiring one step up, rugged on a budget.