Blue Sea 1838 M2 OLED AC Digital Multimeter

The Blue Sea Systems 1838 M2 AC Multimeter reads amps, volts and hertz on one OLED face, covering two voltages and two circuits from 50 to 250 volts.

Frequency matters more on a boat than ashore. Marina shore power is usually stable, but generator output drifts as load changes. Frequency wandering off 60 hertz is the first sign something is wrong with the set, well before voltage shows it. High and low alarms are available on frequency as well as current and voltage.

Programmable current transformer ratios let it match whatever CT is already installed rather than requiring a specific one. That makes it usable as a retrofit into an existing installation, which is where a fixed-ratio meter would mean replacing the transformer too.

The display auto-dims rather than running at fixed brightness, so it does not destroy night vision at the helm after dark. The 92 dB alarm is adjustable, an isolated MOSFET relay is built in, the face measures 55 by 28 mm, and it runs on 7 to 70V DC at 0.3 to 1.0 watt. Explore more marine electrical meters.

• Frequency drift is the first sign of a failing generator
• Alarms on frequency, current and voltage
• Programmable CT ratios suit an existing installation
• Auto-dimming display, adjustable 92 dB alarm