RV & Marine Battery Monitor

DOC Wattson model R102 digital panel meter

An RV or marine battery monitor should at least tell you the Amp hours drawn from your battery and the Amps being drawn. Our "Doc Wattson" battery monitor does that and much more.

Doc Wattson DC Ammeter
Ah, KWh, Amps, peak & min values are shown
sequentially in display's lower left corner

* Review the Doc Wattson user's manual *

Measures seven DC values:

  • Amp-Hours: (0 - 6554)
  • Kilo Watt-hours: (0 - 650)
  • Amps: (0-100 peak)
  • Watts: (0 - 6554)
  • Peak Amps & minimum Voltage ("sags")
  • Voltage: (0 - 60)

Works with 12, 24, 36 or 48 volt batteries up to 60 V. Lead acid, SLA, Gel Cell, and other battery types are all compatible.

The Amp hour (Ah) and Kilo Watt hour (KWh) measurements are much more accurate "fuel gages" than voltage measurements which depend on many other factors. Kilo Watt Hours are better than Amp hours because the effects of voltage change are included in calculating the actual energy delivered to the load. Ah and KWh are much more accurate than the voltage based RV or marine "Battery Indicator" measurements.

Peak Amps and minimum volts measurements show you even short duration load events and help you troubleshoot hard to find electrical problems. Statistics are reset when power is removed.

Doc Wattson helps you evaluate the effect of component changes and of system tuning on performance.

Easy To Use

See example connection diagrams. Doc Wattson is supplied without connectors so you can connect it however you like.

Try applying our AX7-C connector protectant to your installation's electrical connections to maximize performance and prevent corrosion and failure.

Feature Summary

  • Low cost
  • Easy to use
  • Made in USA to ISO 9001 (like Hewlett Packard uses) quality standards
  • Self powered (~ 0.007 Amps) or use an auxiliary battery
  • Built-in 0.001 Ohm current shunt
  • High contrast LCD display
  • 14 gage, stranded, high flex, high temperature silicone rubber insulated wires. Supplied without connectors
  • Small size and lightweight - 2.8" L x 1.7" W x 0.83" D, 2.3 oz.
  • Full manual with electrical tutorial
  • One Year Warranty


See more detailed Doc Wattson specifications and features.

Power Options

Doc Wattson draws very little current (~ 0.007 Amps) from your main battery. Or you can choose to power it (using our auxiliary power connector cable) with an auxiliary battery or power source. Auxiliary power has a wide voltage range.


R102-BK Price

Supplied without connectors.

Doc Wattson model: R102  


Try our meter simulator and see how the similar "Watt's Up" meter works.

Note that the Simulator doesn't have the range of the R102 meter.

RV Battery Monitor