Acrel ADW300 (charge)
The Acrel ADW300 is a three-phase DIN-rail energy meter designed to sub-meter individual loads on low-voltage networks, including EV charging points. This template targets the charge metering role and reads the ADW300 over Modbus RTU via RS485. It collects per-phase voltages (A, B, C), per-phase currents (A, B, C), per-phase active power (A, B, C), total active power, and cumulative active energy. Connecting the ADW300 to the ModbusCloud Gateway gives installers a live view of charging consumption per circuit, enabling accurate cost allocation and load management across multi-point EV charging installations.
- Protocol
- Modbus RTU
- Connection
- RS485
- Registers
- 11, read only
- Brand
- Acrel
- Last updated
Registers (11)
11 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read | |||
| energy | Wh | Read | |||
| currents_a | A | Read | |||
| currents_b | A | Read | |||
| currents_c | A | Read | |||
| voltages_a | V | Read | |||
| voltages_b | V | Read | |||
| voltages_c | V | Read | |||
| powers_a | W | Read | |||
| powers_b | W | Read | |||
| powers_c | W | Read |
Loading registers…
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Use cases
- Monitor total active power on an EV charging circuit to verify the wallbox draws within panel capacity.
- Track cumulative active energy per charging point to allocate electricity costs to individual tenants or fleet vehicles.
- Compare per-phase currents to detect phase imbalance on a three-phase charging installation before it trips protection.
- Alert on unexpected power readings at address 36 to spot a stuck contactor or meter wiring fault quickly.
- Report monthly energy totals from the cumulative energy register to feed into building energy management reports.
Installation
Enable Modbus RTU on the ADW300 by pressing the meter's keypad to enter settings, then configure the slave address, baud rate, data bits, stop bits, and parity to match your RS485 master settings.
Wire the ADW300 RS485 terminals (A+ and B-) to the ModbusCloud Gateway RS485 port using a twisted-pair cable; keep the run under 1000 m and terminate with a 120-ohm resistor at each end of the bus.
In the ModbusCloud portal, add your Gateway, create a new device, import the Acrel ADW300 (charge) template, and assign the correct Modbus unit ID matching the slave address set on the meter.
Verify the connection by checking the live value on register 36 (total active power): apply a known load on the metered circuit and confirm the portal reading matches the expected consumption.
Things to watch for
No values appear in the portal after importing the template. What is wrong?
Confirm that the slave address, baud rate, and communication parameters (data bits, stop bits, parity) set on the ADW300 keypad exactly match the settings configured in the ModbusCloud portal. A mismatch in any one parameter will cause all reads to fail silently. The evcc reference configuration for this meter uses 1200 baud, which is unusually low: verify the meter is not set to a different rate.
Power and current values look far too low compared to a clamp meter. Why?
The ADW300 uses external current transformers. When the CT ratio is not set to 1, the raw Modbus values are secondary values and must be multiplied by the CT transformation ratio configured on the meter. Confirm the CT ratio in the meter settings matches the CTs installed on site; a mismatch produces systematically under-read power and current figures.
Phase A current reads correctly but phases B and C show zero. What should I check?
Verify that the three-phase voltage and current wiring is connected in a one-to-one correspondence for phases A, B, and C on both the meter terminals and the CTs. A wrong-phase or missing CT connection on one phase returns zero for that phase's current register while leaving the others unaffected.
RS485 communication fails intermittently under load. What could cause this?
Check that external CTs are positioned more than 30 cm away from the ADW300 transformer inputs to avoid magnetic interference. Also inspect RS485 cable termination: missing or wrong-value termination resistors at bus ends cause reflections that corrupt frames at higher baud rates. Try reducing the baud rate if the cable run is long.
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