Blue Sea Systems DC Digital Ammeter -500 to 500A

The Blue Sea Systems DC Digital Ammeter gives a precise, real-time reading of current flowing into or out of a battery bank, displaying anywhere from -500A to +500A with a bright, splashproof digital display. It ships complete with the 500A shunt needed to take the measurement.

Key features

• Displays -500A to +500A in two ranges, 0.1A resolution below 100A
• Includes a 500A shunt (PN 8255)
• 3 levels of display brightness, manual sleep mode for power conservation
• Splashproof front, surface mounts in a 2in round hole
• Applicable for 12, 24, 32, 36, and 42V DC systems

This meter installs on the negative side of the circuit only — the shunt goes between the battery's negative terminal and the boat's negative bus, with all loads and charge sources landing on the far side. For positive-side installation, such as monitoring an alternator directly, a separate Shunt Shifter (PN 8242) is required to correct the polarity.

This is a common addition for anyone who wants to actually see how much current a windlass, inverter, or thruster draws in real time, rather than relying on a fuse rating as a rough guide. Pair it with the matching DC Digital Voltmeter (PN 8235) for a complete picture of both current and battery voltage side by side.

Because it operates in two ranges with finer 0.1A resolution below 100A, it's precise enough to spot a small parasitic draw that would otherwise slowly drain a battery over days or weeks at anchor or in storage over the off-season.