Blue Sea 1830 M2 DC State of Charge Monitor

The Blue Sea Systems 1830 M2 DC state of charge monitor measures 8 to 70 volts and up to 5,000 amps, supplied with a 500 amp shunt.

This answers the question a voltmeter cannot: not what the battery reads now, but how much is actually left in it. State of charge is calculated from current flowing in and out over time. A voltage reading sags under load and recovers when things are switched off, which makes it a poor guide to remaining capacity.

Programmable shunt ratios mean a larger shunt can be fitted for a bigger system without changing the meter, up to 5,000 amps. The 500 amp shunt supplied covers most installations, and knowing the meter is not the limit matters when a bank is later expanded.

Alarms cover high current, high and low voltage and low battery, so a problem announces itself rather than being found on the next check. The OLED display auto-dims, the 92 dB alarm is adjustable, and an isolated MOSFET relay is included. Face 55 by 28 mm, running on 7 to 70V DC at 0.3 to 1.0 watt. Explore more marine electrical meters.

• Shows what is left, not what the voltage reads
• Voltage sags under load and recovers when idle
• 500A shunt supplied, programmable up to 5,000A
• Alarms on current, voltage and low battery