| 48KG·CM STALL | 0.106S/60° NO-LOAD | 8.4V RATED |
| 73G WEIGHT | StainlessGEARTRAIN | 360°TRAVELCustomizable |
Overview
The S8045D is the drop-in replacement in this series: 48 kg·cm at 8.4 V in exactly the same 20 × 40 × 38.4 mm case as the S8035D, at the same 73 g and the same 25T spline. If a bay is already cut and a 40 kg-class servo has started to feel marginal, nothing has to be re-drilled.
PWM input, 800–2200 µs, 1 µs dead band — the same signal any receiver or controller already provides. What you give up is transit: 0.106 s/60° against 0.088 on the S8035D, because the extra 20% torque comes from a taller gear ratio rather than a bigger motor.
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 | PWM (50–333 Hz) |
| Amplifier | Digital controller |
| Pulse width range | 800–2200 µs |
| Neutral position | 1500 µs |
| 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-S8045D 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: a 7 kg surface with its centre of pressure 35 mm from the spline centre needs 7 × 9.81 × 0.035 × 1.5 ≈ 3.61 N·m. The S8045D delivers 4.71 N·m at 8.4 V, about 31% headroom. If that looks generous, shorten the horn before stepping down a model: 35 mm to 30 mm removes roughly 0.5 N·m of requirement and costs nothing but a slightly higher linkage force.
FAQ
Will it drop into a bay cut for the S8035D?
Yes. Identical case, identical mounting holes, identical 25T spline and lead length. Only the gear ratio — and therefore the speed — differs.
The photo says 48KG but the datasheet header says 45kg-cm — which is right?
48 kg·cm at 8.4 V is the measured peak stall in the inspection table, and the product photo carries the same number. The header string predates the top-rail measurement.
Why are there three torque figures?
They are one servo at three rails: 37 kg·cm at 6.0 V, 43 at 7.4 V, 48 at 8.4 V. Size against the rail your BEC actually holds under load, not the nominal pack voltage.
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. Do not exceed it.
Does it rotate continuously?
Travel is 360° when commanded over 1000–2000 µs, as a factory customization. Standard units work across the 800–2200 µs window.
Is there a serial version?
Yes — the XQ-S8045TTL is the same servo with a TTL serial command layer. Same 48 kg·cm, same case, different wiring.
How much is 48 kg·cm in oz·in?
About 667 oz·in, or 4.71 N·m.
Downloads
- XQ-S8045D inspection specification (PDF, 766 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.
