Safiery SHSA4804JMount 48V BMG for J180 mount – 12V 1500W auxiliary power48V BMG on Yanmar J180 mount with integrated Scotty AI 1500W

Overview

SHSA4804JMount is the 48V bidirectional motor generator on a Yanmar J180 mount with an integrated Scotty AI V3 1500W. It provides up to 10kW for the 48V house bank of a sailing yacht or motorboat, and Scotty supplies up to 1,500W to the 12V system for the starter battery and 12V loads. The over-running clutch pulley is standard and the system appears as an alternator on Victron GX devices.

• 10kW peak, 5kW continuous at 105°C
• Hybrid excitation for useful output at engine idle
• Dual three-phase hairpin stator, 30° shifted
• Fully digital CAN control by Scotty AI V3
• Pad, Sprinter, J180 and Volvo Penta mounts
• Shown as alternator on Victron GX (v3.63 or later)

How it works

The BMG (bidirectional motor generator) pairs a claw-pole permanent-magnet machine with an integrated inverter instead of a diode rectifier. Hybrid excitation adds controlled field windings on the stator to the permanent magnets, so the machine produces useful power at low speed, and two three-phase windings shifted by 30° give a 12-pulse output with less ripple and the ability to keep running on one winding.

The BMG cannot run without Scotty AI V3, which acts as master controller. Scotty reads BMG speed, motor and inverter temperature and the battery state over CAN, works out how much power the engine can give at the current speed and sends voltage and current setpoints. It stops the BMG on battery alarms or charge limits and starts derating at about 120°C inverter temperature.

Key figures

According to the operating manual the BMG works at 40–57.9V, peaks at 10kW above 5,000rpm for 20 seconds and delivers 5kW continuously above 6,000rpm at 105°C, with ±0.5V voltage accuracy and 150ms response. It measures 150mm in diameter and 155mm in length without shaft and pulley, weighs 7.3kg without the over-running pulley, is air cooled and rated IP25 for the motor and IP6K9K for the inverter.

Installation and compatibility

Mounts cover pad-type installations on commercial engines, the Mercedes-Benz Sprinter second-alternator position, the J180 standard of Yanmar marine diesels and Volvo Penta D2 to D11 engines; an over-running clutch pulley is standard on the Sprinter, J180 and Volvo versions. Belt tension must keep the hub load on the pulley below 2,000N.

The 48V terminals are two M8 studs tightened to 15–19Nm and there is no reverse-polarity protection. A MEGA fuse near the battery is recommended, for example 200A with 35mm² or 300A with 50mm² cable on a 5m run. KL15 and KL30 accept 12V only, and the battery isolator should include an interlock so the BMG cannot run with the battery disconnected.

Monitoring and settings

Commissioning takes place on the Scotty AI tuning page: maximum charge voltage and current, float voltage, absorption time and the BMG speed and current points between which power ramps up. On a Victron Cerbo GX or Ekrano GX with firmware 3.63 or later the BMG shows as an alternator; with Victron lithium batteries the manual advises setting the bank as a non-CAN battery.

Questions and answers