| 85KG·CM STALL | 0.110S/60° NO-LOAD | 16.8V RATED |
| 92G WEIGHT | StainlessGEARTRAIN | 360°TRAVELCustomizable |
Overview
The BLS8185HV is the same 85 kg·cm servo as the BLS8185D with a high-voltage winding: identical 20 × 40 × 44 mm case, 92 g, same 25T-φ7.96 mm output, same 7075 horn. The difference is where the torque lives — 85 kg·cm arrives at 16.8 V here, not at 8.4 V.
That shift is the whole point of the HV build. On a 4S pack the servo holds its rated torque as the pack sags, where the low-voltage build would already be at its ceiling at 8.4 V. On 2S, the HV build is the weaker of the two: only 42 kg·cm at 8.4 V.
This page covers the PWM build: a standard 50–333 Hz pulse input, 1500 µs neutral and a 3–4 µs dead band. It is the version to pick when the servo hangs off a receiver or a flight controller and you want nothing between the two.
Performance at each supply voltage
| Supply | No-load speed | Peak stall torque | Idle current | Stall current |
|---|---|---|---|---|
| 8.4 V | 0.170 s/60° (353 °/s) | 42 kg·cm (4.12 N·m / 583 oz·in) | 320 mA | 4.0 A |
| 12.0 V | 0.140 s/60° (429 °/s) | 60 kg·cm (5.89 N·m / 833 oz·in) | 370 mA | 5.0 A |
| 16.8 V | 0.110 s/60° (545 °/s) | 85 kg·cm (8.34 N·m / 1180 oz·in) | 440 mA | 6.0 A |
Control specification
| Item | Specification |
|---|---|
| Command signal | PWM |
| Amplifier | Digital controller |
| Pulse width range | 800–2200 µs, customizable |
| Neutral position | 1500 µs |
| Dead band | 2 µs |
| Rotating direction | CCW (1000–2000 µs) |
| Travel | 360°, customizable |
Mechanical specification
| Item | Specification | Item | Specification |
|---|---|---|---|
| Dimensions | 20 × 40 × 44 mm | Case material | Aluminium, CNC |
| Weight | 92 g | Geartrain | Stainless steel |
| Bearings | 2 × ball bearing | Motor | Brushless |
| Output spline | 25T-φ7.96 mm | Horn | 7075 aluminium, CNC |
| Lead / connector | 300 mm, 3-wire | Mechanical limit | No limit |
| Operating temperature | −15 °C to 65 °C | Storage temperature | −20 °C to 70 °C |
| Ingress protection | Splash resistant (customizable) | Travel | 360°, customizable |
What’s in the box
- 1 × XQ-BLS8185HV servo
- 1 × 7075 aluminium horn
- 1 × mounting screw pack
How to size it
Torque is 42 kg·cm at 8.4 V, 60 at 12.0 V and 85 at 16.8 V, at 0.17, 0.14 and 0.11 s/60°. Below 8.4 V it is not rated. If your machine is 2S, the low-voltage BLS8185D gives you 85 kg·cm instead of 42 for the same money and the same footprint.
Stall current is 6.0 A at 16.8 V. On 4S, check the BEC and the wiring for the 4S voltage, not the 2S one — the current is the same but the pack voltage is doubled, so the same gauge dissipates four times the power in a fault.
FAQ
BLS8185HV or BLS8185D?
Pick by pack. 4S → HV, which reaches 85 kg·cm at 16.8 V. 2S → the low-voltage D, which reaches the same 85 kg·cm at 8.4 V. Running the HV on 2S leaves you with a 42 kg·cm servo.
Can I run it on 3S?
Yes — at 12.0 V it is 60 kg·cm at 0.14 s/60°. That is the middle of its range, not a compromise.
What pulse range does it accept?
The inspection sheet specifies a 500–2500 µs window (800–2200 µs on the 9130/9150) with 1500 µs neutral, both customizable at order. Feeding it outside that window is out of spec.
Can I drive it from a normal receiver?
Signal-wise yes, but check the supply. This servo wants 8.4–16.8 V, not a 6 V receiver pack, so the power rail has to be separate from the receiver’s.
Other interfaces
Downloads
- XQ-BLS8185HV inspection specification (PDF, 429 KB)
Torque, speed and current at each supply voltage, mechanical data, control specification, mounting dimensions. - 2D dimension drawing (image)
Mounting hole positions, case depth and overall height; the same drawing is inside the datasheet.
