| 48KG·CM STALL | 0.106S/60° NO-LOAD | 8.4V RATED |
| 73G WEIGHT | StainlessGEARTRAIN | 360°TRAVELCustomizable |
Overview
The S8045TTL is the 48 kg·cm member of this series with a TTL serial command layer: same 20 × 40 × 38.4 mm case and 73 g as the S8045D, same stainless geartrain and 25T spline, addressed over a bus instead of driven by a pulse train.
It is the sensible middle of a bus-driven assembly. 48 kg·cm is enough that you are not sizing the linkage around the servo, the case is still the shallow 38.4 mm one, and because the bus is multi-drop a mixed set of S8035TTL / S8045TTL / S8050TTL runs on one harness.
Performance at each supply voltage
| Supply | No-load speed | Peak stall torque | Idle current | Stall current |
|---|---|---|---|---|
| 6.0 V | 0.144 s/60° (417 °/s) | 37 kg·cm (3.63 N·m / 514 oz·in) | 320 mA | 3.7 A |
| 7.4 V | 0.122 s/60° (492 °/s) | 43 kg·cm (4.22 N·m / 597 oz·in) | 370 mA | 4.5 A |
| 8.4 V | 0.106 s/60° (566 °/s) | 48 kg·cm (4.71 N·m / 667 oz·in) | 440 mA | 5.2 A |
Control specification
| Item | Specification |
|---|---|
| Command signal | TTL serial (addressed over a bus) |
| Amplifier | Digital controller |
| Dead band | 1 µs |
| Rotating direction | CCW (1000–2000 µs) |
| Travel | 360°, customizable |
Mechanical specification
| Item | Specification | Item | Specification |
|---|---|---|---|
| Dimensions | 20 × 40 × 38.4 mm | Case material | CNC aluminium |
| Weight | 73 g | Geartrain | Stainless steel |
| Bearings | 2 × ball bearing | Motor | Coreless |
| Output spline | 25T / 5.94 mm | Horn in box | POM plastic |
| Lead | 300 mm | Travel limit | 360°, customizable |
| Operating temperature | −15 °C to 65 °C | Storage temperature | −20 °C to 70 °C |
| Ingress protection | Splash resistant (customizable) |
What’s in the box
- 1 × XQ-S8045TTL servo
- 1 × POM horn set
- 1 × mounting screw pack
Optional: metal horn, sold separately.
How to size it
Torque budget = load at the horn × horn length from spline centre × 1.5 safety factor.
Worked example: an 8 kg surface with its centre of pressure 32 mm from the spline centre needs 8 × 9.81 × 0.032 × 1.5 ≈ 3.77 N·m. The S8045TTL delivers 4.71 N·m at 8.4 V, about 25% headroom. Note that on a shared bus the stall current of each node adds up — check the supply, not just the servo.
FAQ
What command set does it use?
TTL serial with a factory-fixed frame format. Request the command set before writing firmware, and do not assume Modbus — sharing a physical layer is not sharing a protocol.
How many can I put on one bus?
The bus is multi-drop and the servos are individually addressable, so the limit is your controller’s drive strength rather than the servo count. Mixing models on the same bus is supported.
Can I drive it from a normal receiver?
No — a pulse train is not a serial frame. Take the XQ-S8045D instead if your controller is PWM-only; same torque, same case, pulse input.
Can I run it directly from a 2S LiPo?
Yes. 8.4 V at full charge is the top rail in the sheet and the rail the 48 kg·cm figure is measured at.
Does it rotate continuously?
Travel is 360° when commanded over 1000–2000 µs, as a factory customization. On the serial build the same range is commanded over the bus.
Does it fit where an S8035TTL fits?
Yes. Same case, same mounting holes, same spline. Only the gear ratio and the speed differ.
How much is 48 kg·cm in oz·in?
About 667 oz·in, or 4.71 N·m.
Downloads
- XQ-S8045TTL inspection specification (PDF, 771 KB)
Torque, speed and current at 6.0 / 7.4 / 8.4 V, mechanical data, control specification, mounting dimensions. - 2D dimension drawing (image)
Quick view of mounting hole positions and case depth; the same drawing is inside the datasheet.
