| Parameter | Value |
|---|---|
| Model | RS309-MD-EV (125A / 150A / 175A / 200A) |
| Brand | SINOFUSE (Sinofuse Electric, China) |
| Type | Round-tube bolt-connected EV fuse, fast-acting |
| Rated Voltage | DC 500V |
| Rated Current | 125A / 150A / 175A / 200A (series covers 50A–630A) |
| Breaking Capacity | DC 20kA (time constant 2±0.5 ms) |
| Usage Category | EV — road-vehicle application |
| Fusing Characteristics | Wide breaking range, low I²t |
| Reference I²t (125A D-type) | Pre-arcing 1,800 A²s / Melting 7,600 A²s |
| Power Dissipation (125A D-type) | 27W at rated current (6.1W at 0.5×In) |
| Weight (125A D-type) | Approx. 81g (81±5g) |
| Mounting | Bolt connection, M8 — recommended torque 12±1 N·m |
| Body Material | Ceramic tube, copper terminals |
| Standards | IEC 60269 / ISO 8820 / GB/T 31465; RoHS compliant |
| Applications | EV high-voltage systems, EV chargers, ESS, solar / DC circuits |
Note: I²t, power dissipation and weight are quoted for the RS309-MD-EVD125A reference type; other current ratings vary. All test data in the SINOFUSE datasheet is measured under DC conditions per GB/T 31465.
SINOFUSE RS309-MD-EV is a round-tube bolt-connected fast-acting fuse designed for road-vehicle DC power applications. It is rated DC 500V with a DC 20kA breaking capacity (time constant 2±0.5ms) and offers a wide breaking range with low I²t characteristics, giving fast, clean interruption that protects power semiconductors and downstream components. This SKU covers the 125A, 150A, 175A and 200A current ratings for electric-vehicle high-voltage systems, EV charging equipment, energy-storage DC circuits and solar applications.
Typical protected positions include the battery system, drive power system, power conversion system and on-board charging equipment of new-energy vehicles, plus backup protection for relays, isolator switches, circuit breakers and ultracapacitor banks.
RS309-MD-EV belongs to the SINOFUSE vehicle & energy-storage fuse family. The catalog reference charts below show the surrounding series: EV315 (10A–50A auxiliary-circuit fuses for BMS/PTC/DC-DC), RS309 (50A–900A bolt-connected main fuses for PDU / motor controller / OBC), SFM pyrofuse (fast <2ms disconnection for collision safety), EV8MKM (500A–1000A main drive fuses), plus the wind-solar-storage RS306 / RSZ307 / FGB series.
Designed for road-vehicle duty and environmental conditions, with performance and reliability referenced to IEC 60269, ISO 8820 and GB/T 31465 — the fuse standards applied by global EV makers.
Wide breaking range up to DC 20kA at 500V with low pre-arcing and melting I²t clears faults fast — protecting IGBT/SiC modules, contactors and busbars from prolonged short-circuit energy.
Round-tube construction with M8 bolt terminals (torque 12±1 N·m) gives a low-resistance, mechanically rugged joint that survives high-strength vibration and shock in vehicles and cabinets.
125A, 150A, 175A and 200A options under one model family simplify BOM and qualification — standardize on RS309-MD-EV and select the rating per circuit.
Sized for EV battery packs, PDU, motor controllers and OBCs, and equally at home protecting EV chargers, ESS DC buses and solar circuits — plus backup protection for relays, disconnectors and ultracapacitors.
Supplied from SINOFUSE (Sinofuse Electric) original production with official datasheet PDF, RoHS compliance and factory test data available — sourced through authorized distribution.
The SINOFUSE RS309-MD-EV series is qualified to international vehicle-fuse and low-voltage fuse standards:
IEC 60269 — Low-voltage fuses (performance reference).
ISO 8820 — Road vehicles — Fuse-links (performance & environmental reliability).
GB/T 31465 — China road-vehicle fuse-link test standard (all DC test data per this standard).
RoHS — Restriction of hazardous substances compliant.
Factory test reports and the official SINOFUSE datasheet are available on request.
Overcurrent protection for traction battery packs, PDU, motor controllers, DC-DC converters and OBC of new-energy vehicles.
DC output and power-module fuse protection in fast chargers and charging piles.
DC-side and battery-rack circuit protection in ESS, with backup protection for relays, disconnectors, breakers and ultracapacitors.
Fast-acting DC protection for solar arrays and general 500V-class DC bus circuits — confirm rating selection for your fault conditions.
Per the official SINOFUSE datasheet, RS309-MD-EV is rated DC 500V with usage category EV. Some marketplace listings also mark it AC/DC 500V; if your application is primarily AC-side (e.g. PV inverters at AC 690V), ask us about the SINOFUSE RS306 / RSZ307 series or confirm selection with our engineers.
Select by the continuous current of your protected circuit (fuse rating ≥ circuit continuous current, with margin for load profile and ambient conditions). Send us your working voltage, continuous current and expected fault current and we will recommend the right rating using the official time-current curves.
It means the fuse can safely interrupt an expected short-circuit current up to 20kA at DC 500V (time constant 2±0.5ms) without bursting the tube or sustaining an arc. Combined with low I²t, it clears faults quickly and limits let-through energy to protected devices.
The M8 bolt connection (recommended torque 12±1 N·m) gives a low and stable contact resistance and stays mechanically secure under the vibration and shock profile of road vehicles and power cabinets, unlike clip or wire connections.
Yes. We stock SINOFUSE RS309-MD-EV in 125A–200A and can provide samples, the official datasheet PDF, RoHS declarations and factory test reports, with OEM and volume pricing on request.
