Direct replacement for Watt's Up and Doc Wattson DC digital inline meter.
Functions: Watt Meter and Power Analyzer
The Watt Meter measures eight parameters that are essential to electric power safety and performance.
Use it to: prevent peak currents from damaging a battery. Motor control, motors, wiring and connectors.
Set cutoff voltages, check battery capacity & health. Balance battery cells, Confirm proper battery
Inline DC Meter
You can think of the Watt Meter as a set of jumper cables. Connect it in the same way and you can
measure what the jumper cables are connected to. Like jumper cables, the Watt Meter is essentially a
direct connection between the same colored SOURCE and LOAD wires. For example, both the SOURCE and
LOAD leads are electrically "hot" when a battery is connected to either side. Current flows from
SOURCE to LOAD. Make sure connections are secure to prevent component damage.
Each time power is applied across the Watt Meter (or by auxiliary power connector) a startup screen
with logo is briefly displayed and peaks, minimums, Ah & Wh are reset to zero. Then the display
changes to the measurements screen.
The measurement screen continuously displays Amps, Volts and Watts. All other measured values are
presented sequentially, every second, in the Data-Queue position of the display. Data values
are identified by their units (Ah, Wh, Ap, Vm, Wp). All measurement screen values are updated every
The Measurement Screen layout: Amps, Volts, Watts & "Data Queue". The "Data Queue" shows Ah, Wh, Ap,
Vm, Wp in sequence.
Current: Amps & Peak Amps (A, Ap)
Only current from SOURCE to LOAD is measured. Amps values displayed are the average current over the
last screen update interval. Peak Amps value (Ap) displayed is the maximum current drawn from the
LOAD side, since the meter's startup. Peaks lasting only a fraction of a second, can be captured.
Supplying auxiliary power with a voltage greater than the meter is measuring removes the meter's
operation current from measurements. To reduce meter heating, measure currents over 65 Amps for
reduced time and consider using connectors which can handle large current.
Voltage: Volts & Minimum Volts (V, Vm)
The displayed Volts value is the average voltage over the last screen update interval. The displayed
Minimum Volts value (Vm) is the minimum voltage (or "sag") measured on the SOURCE side, since the
meter's startup. The Volts value is measured on the SOURCE side.
Energy: Watt-hours (Wh)
The displayed value is the total energy delivered in Watt-hours since the meter's startup. It is
measured on the LOAD side. For accurate results, be careful not to interrupt the SOURCE connection
to the Watt Meter during an energy measurement.
Charge: Amp-hours (Ah)
The displayed value is the total energy charge in Amp-hours (x1000 = mAh) delivered since the meter's
startup. It is measured on the LOAD side. For accurate results, be careful not to interrupt the
SOURCE connection to the Watt Meter during a charge measurement.
Power: Watts & Peak Watts (W, Wp)
The displayed value is the average power delivered in watts (=Volts * Amps) over the last screen
update interval. The displayed Peak Watts value (Wp) is the maximum power drawn on the LOAD side
since the meter's startup. Watts values are measured on the LOAD side.
- Operates from 4.8 ~60 V (0V with optional auxiliary power cable)
0.1 ~ 130 A, resolution 0.01 A
0 ~ 60 V, resolution 0.01 V
0 ~ 6554 W, resolution 0.1W
0 ~ 65 Ah, resolution 0.001 Ah
0 ~ 6554 Wh, resolution 0.1 Wh
- 16x2 blue backlit LCD display
- Size: 3.3 x 1.7 x 1.0" (85 x 42 x 24mm)
- Weight: 0.18 lbs. (82 g)
Wiring, Connections & Applying Power
WARNING: Loose connections can cause component damage! Only switch power between meter & LOAD.
The Red SOURCE wire goes to positive (+) battery or other device terminals and black to Negative
(-). User is responsible for attaching connectors rated to handle the voltage and current expected
in users' application. Qualified individuals should make sure any high current connections.
Verify there are no exposed wires or connectors that may short circuit before connecting a battery
or power source to the Watt Meter. Only use female connectors on batteries. By connecting an
auxiliary battery of 4.8 ~ 60 V to the auxiliary power cable 3-pin connector, the Watt Meter can
measure down to 0 V.
CAUTION: Shorting a rechargeable battery or Watt Meter connected to a rechargeable battery can
supply huge currents, causing fire, explosions, personal injury, and damage to equipment. Ensure
that all wiring and connections are rated to handle the input or output current, and are properly
assembled for each application.
Input Voltage & Current Handling Limitations
The Watt Meter is designed to be safe in systems using less than 60 V and carrying currents up to
130 A. CAUTION: Exceeding these limits will damage the Watt Meter and may cause personal injury.