Blue Sea 1839 M2 OLED Tank Level Monitor

The Blue Sea Systems 1839 M2 OLED Tank Monitor tracks up to four tanks from one face at 1 percent resolution, with auto calibration for unusual shapes.

Auto calibration is the feature worth paying for. Production boats rarely have rectangular tanks, since they are molded to fit the hull. A sender reading half travel on a shaped tank does not mean half volume. The M2 learns the actual shape so the display corresponds to usable gallons rather than a percentage of stick travel.

It works with common sending units, so existing senders usually stay in place rather than needing replacement alongside the meter. Four tanks on one face covers fuel, water, holding and a second fuel or water tank without a row of separate gauges.

An isolated 500mA MOSFET external circuit relay can switch an external circuit based on any value the meter reads. That allows a transfer pump or a warning lamp to be triggered by tank level directly. The alarm is 80 dB, the display auto-dims, and it runs on 7 to 70V DC at 0.3 to 1.0 watt. Explore more marine electrical meters.

• Auto calibration learns a molded tank's real shape
• Half stick travel is not half volume
• Works with common existing senders
• Relay can trigger a transfer pump on level