XT30 vs XT60 vs XT90: Which Connector Does Your Battery Pack Need?
Pick the wrong XT connector and you will find out the expensive way: a housing that softens, spring clips that lose tension, and intermittent power loss halfway through a ride. The good news is that choosing correctly takes one calculation and about thirty seconds.
This guide covers what the numbers actually mean, why published current ratings disagree with each other, and which connector belongs on your build.
The naming convention (and where it breaks down)
The popular explanation is that the number is the current rating: XT30 handles 30 amps, XT60 handles 60, XT90 handles 90. That is roughly true, and it is what most guides will tell you.
It is also where a lot of melted connectors come from, because published ratings vary widely depending on who you ask and how they tested. Distributors tend to publish much more conservative continuous figures than hobby sources do:
| Connector | Commonly cited continuous | Conservative continuous | Typical wire |
|---|---|---|---|
| XT30 | 30 A | 15 A | 18–16 AWG |
| XT60 | 60 A | 30 A | 14–12 AWG |
| XT90 | 90 A | 40 A | 12–10 AWG |
Both columns are defensible. The difference comes down to wire gauge, airflow, ambient temperature, and how long the load actually runs. A connector fed by thick wire in open air will carry far more than the same connector buried in a sealed pack with thin leads, because much of the heat leaves through the wire.
The practical takeaway: treat the conservative column as your design target and the optimistic column as the absolute ceiling. If your continuous draw lands between them, size up.
How to choose in one calculation
Work from continuous current, not battery capacity and not peak current.
- Find your continuous draw: watts ÷ volts. A 750 W motor on a 48 V pack draws about 15.6 A.
- Add 30% margin: 15.6 × 1.3 ≈ 20 A.
- Pick the connector whose conservative rating exceeds that number.
For that 750 W example, an XT60 is the sensible pick. An XT30 would be running at or past its conservative limit with no headroom at all.
What about peak current?
Peak matters less than people assume. A hill start might pull 80 A for two seconds, but the connector spends nearly all its life at continuous current. Do not oversize on peak alone — but if your system holds near-peak load for extended periods, that is your continuous figure, and you should size for it.
A simple field test
Ride or run the system hard, then feel the connector. If it is too hot to hold comfortably, it is undersized. Temperature is the most honest rating chart you will ever get.
Quick picks by build
- Small DIY packs, Arduino, LED strips, 2S–4S: XT30
- Mid-size drones, RC vehicles, 2S2P and similar packs: XT30 or XT60
- Most e-bikes and e-scooters: XT60
- High-power e-bikes, large packs, controllers above 40 A continuous: XT90
Pigtail or bare connector?
Both do the same electrical job. The difference is labour.
Pre-wired pigtails arrive with silicone leads already soldered on. You strip, join to your pack, and you are done — no soldering into a small metal cup, no risk of deforming the housing with too much heat. Best if you are new to this or building in volume.
Bare connector pairs give you both halves with no wire, so you choose your own gauge and length. Cheaper per connection and the right choice when you need a specific wire spec.
Soldering tip that saves connectors
Mate the male and female halves together before you solder. Soldering a connector on its own lets the housing soften and the contacts shift out of alignment, and you will not notice until it does not seat properly. Mating them holds everything square while the plastic is warm.
XT30 connectors
XT60 connectors
XT90 connectors
What about DC barrel connectors?
XT connectors are for pack-to-load power. For charging and low-current accessory wiring — CCTV, LED strips, small chargers — a 5.5 × 2.1 mm barrel jack is the usual standard. Different job, much lower current, far easier to work with.
Common mistakes
- Sizing from battery capacity. A 20 Ah pack tells you nothing about current draw. Size from the load.
- Forcing thick wire into a small connector. If 12 AWG will not fit an XT30 cup, that is the connector telling you it is the wrong part.
- Soldering unmated. The housing deforms and the contacts shift.
- Mixing genders across a system. Convention is female on the battery side, so exposed pins are never live.
- Ignoring heat. A warm connector after normal use is an early warning, not a quirk.
Putting it into practice
If you are building a pack from scratch, both of our step-by-step guides use XT connectors and walk through the wiring:
- How to Build a 2S1P 7.4V 21700 Pack — uses an XT30
- How to Build a 2S2P 7.4V 21700 Pack — uses an XT60
Browse the full range in our connectors and contacts collection.
Current ratings vary by manufacturer, wire gauge, and operating conditions. Figures above are general guidance for selection, not a substitute for the specifications of the specific connector and wire you are using. Lithium battery packs can short, vent, or catch fire if wired incorrectly — work carefully and verify polarity before connecting any load.
