DC watt meter
Inline DC watt meter · 4.8–60 V · 0–100 A (130 A peak) · 0.25 mΩ shunt on the negative side · shows V, A, W, Ah, Wh, peak A, min V, peak W · powered from the source side
Try it on the benchThe lab drops it on an empty bench and opens its datasheet card.
Typical part: Inline DC watt meter (RC-hobby style, 60 V 100 A, 16×2 LCD)
Pins
- SOURCE +
- SOURCE −
- LOAD +
- LOAD −
Ratings and limits
| Voltage | 4.8–60 V (it runs from the source side, so below 4.8 V the screen is off) |
|---|---|
| Current | 0–100 A continuous, 130 A peak; 0.01 A resolution |
| Shunt | 0.25 mΩ on the negative side (SOURCE − to LOAD −); the positive line goes straight through |
| Own supply | about 18 mA from SOURCE + to SOURCE −, not counted in the reading |
| Readings | A, V, W, Ah, Wh; peak A, minimum V, peak W, run time. Totals reset at power-up or with the RST button |
| Direction | reads current flowing from source to load only; reverse current reads 0.00 A |
How to use it
Put it between a supply or battery and the load: SOURCE side to the supply, LOAD side to the device. Click the screen to change page, click RST to zero Ah and Wh.
Lessons and builds that use it
- Phone charging: volts, amps and watts
- 200 Ah power station from four 3.2 V prismatic LiFePO4 cells: 4S BMS, 2 × 12 V, 3 × USB, mains charger (build)
- 200 Ah power station on a 12.8 V LiFePO4 battery: 2 × 12 V, 3 × USB, mains charger (build)
More in instruments
- Oscilloscope
- Logic analyzer (8 channels)
- Schematic sheet
- Function generator
- Electronic load
- Clamp meter
- LCR meter
Sources: Typical 130 A RC watt meter specifications (4.8–60 V, 0.01 A / 0.01 V resolution, 16×2 character LCD)