PWM MPPT Charge Controller for PV Photovoltaic Water Heater Boiler

Model: ACTii AC7391

EAN: 6931240073919 SKU: 739155867

• PWM regulator for heating elements with MPPT maximum power point tracking algorithm from photovoltaic panels. The controller allows powering standard electric domestic hot water (DHW) boilers using solar panels.
• The controller is equipped with a temperature sensor, allowing heating to be stopped when the set temperature is exceeded. It is possible to change the set temperature.
• The controller displays: Voltage (V), Power (W) delivered to the heating element, and water temperature in the boiler.
• The controller can be switched on and off (plus and minus buttons).
• Flashing of the OUT LED indicates that current is being delivered to the heater.
• Relay output signaling when heating is interrupted. Can be used to connect external devices.
• The device is mounted on a TH35 DIN rail.
• The regulator has thermal protection and active cooling depending on the temperature of the actuator and power.
• For safety reasons, the high-voltage part is galvanically separated from the power supply part.
• Two operating modes: Automatic mode, Mode with the ability to set activation voltage thresholds.
• Made in the EU, CE certified.

Description

PWM regulator for heating elements with MPPT maximum power point tracking algorithm from photovoltaic panels.

The regulator allows powering standard electric DHW boiler heaters (operating at 230V or 110V AC) from PV solar panels.

A photovoltaic panel operates at maximum power only at optimal voltage. Connecting a heater directly to a photovoltaic panel causes it to be overloaded too much, resulting in a voltage drop. At reduced operating voltage, the panel produces even several times less current than at optimal voltage. Using a charge controller eliminates this problem. Even on cloudy days, it will be possible to heat water in the boiler.

A buffer module containing capacitors, a choke, and diodes is attached to the regulator, which allows for higher efficiency (up to 30%) and reduction of interference caused by PWM regulation.

The regulator is equipped with a temperature sensor, which allows stopping the boiler heating above the set temperature.

The device is equipped with an additional relay output (potential-free) allowing external devices to be notified that water heating has finished (set temperature reached) or that a device failure has occurred. This output allows for connecting additional equipment.

Specification

Parameters

Supply voltage: from 11V to 14.4V DC

Panel voltage: from 10V to 400V DC

PV panel current: up to 11A. The regulator has a function that allows safe operation with PV panels generating currents greater than 11A. If the PV panel generates a current greater than 11A, the controller will supply a maximum of 11A to the heater. In practice, it is extremely rare for a PV panel that generates 13A of current under ideal conditions to exceed 11A (ideal temperature, perfect sunlight, and a new PV panel are required).

Maximum heater power: 2kW

Maximum panel power: 2kW

Current drawn from the power supply without cooling: 0.08 A

Current drawn from the power supply with cooling: 0.23A

Temperature measurement accuracy 0.1°C

Operating modes

The regulator has the ability to change the mode to operate between min and max voltage.

First mode:

It is fully automatic and starts working immediately after connection. When the input voltage exceeds the minimum voltage threshold (MINUS button), the controller starts sending current to the heater using the MPPT maximum power point tracking algorithm.

If the voltage drops below the minimum value, the MPPT search is interrupted and current stops flowing to the heater. Setting the minimum value allows for free water heating and simultaneous battery charging.

Second mode:

Ability to set activation voltage thresholds (from which the PWM value starts to increase) and maximum voltage (from which the duty cycle is 100%), meaning all cell energy goes directly to the heater.

Additionally, using this method allows maintaining panels at the MPPT point (maximum power point).

Additional information

Regulator dimensions: 90x54x64mm

Buffer dimensions: 90x36x64mm

Temperature sensor cable length: about 100cm

What kind of heater should I use AC or DC and what power?

Since the only parameter describing the heater is resistance, you can use an AC or DC heater.

The heater must be matched to the photovoltaic panels.

If your photovoltaic panels nominally provide 140V DC 7.14A 1000W, the most suitable will be using a 140V DC heater with a power of 1000W,

but you can also use a 230V AC or 110V AC heater. You only need to match the heater power to the PV panels. (we provide an online calculator for calculating the correct heater).

According to the above, (since the only parameter of the heater is its resistance, as well as current intensity) it is possible to match a 230V heater to work with PV panels of different voltage, using Ohm's law. 140V / 7.14A = 19.61 Ohm. Our heater must have 19.61 Ohm. For a 230V heater P=U*U/R. P=230*230/19.61=2697W. For 140V 7.14A PV panels, we can therefore use a 230V AC heater with a power of about 2700W.

Other examples:

For 4x 400W PV panel with an operating voltage of 36V of a single PV panel, you can use a standard 220V AC heater with a power from 3 to 3.5kW

For 4x 450W PV panel with an operating voltage of 38V of a single PV panel, you can use a standard 220V AC heater with a power from 3.8 to 4.5kW

For 4x 500W PV panel with an operating voltage of 40V of a single PV panel, you can use a standard 220V AC heater with a power from 3.5 to 4kW

Heaters can have two independent coils. One coil can be used to heat water from PV panels and the other from the 230V network.

To connect the controller to the heater, it is safer to use a heater with a single coil.

Set contents

Controller

Charge buffer

Temperature sensor

Cable connectors (depending on the batch)

Packaging

Manual

Certificates and standards

CE, RoHS

Dimensions, Weight

Product dimensions: 90 x 54 x 64 mm (Depth x Width x Height)

Package dimensions: 100 x 120 x 60 mm (Depth x Width x Height)

Product weight: 330 g

Weight with packaging: 376 g

Zum Download

• User Manual
• CE Declaration
• SAFETY COMPLIANCE