What the load output on certain Victron MPPT Charge Controllers is used for

Posted by Peter Kennedy on 4/4/2018 to Solar

A typical use for the load output is for a well pump. The well pump will run from the battery as long as the battery is charged. After the sun goes down and the battery starts to run down the load output will turn off and the well pump will stop.

Another use is the Street Light function. You can program that to turn a light on at sunset and turn it off at dawn, or you can tell it to just stay on for a certain number of hours. As long as there is enough power in the battery the system will operate automatically. If the battery starts to run down the program will reduce the hours that the light is running to stop the battery getting damaged.

Another use for the load output is to measure the amount of current being drawn by the device you have connected. If the system is online and connected to the VRM the load current is one of the values reported and can be graphed and documented.

This bus shelter system from Sun-In-One uses a Victron Smart MPPT 75/15 charge controller supplied by PKYS to provide lighting to the bus shelter for the full hours of darkness. The program is set to turn on at dusk and off at sunrise. The Battery Life algorithm is used to preserve the battery, so in the event of low solar yields the light will turn off early.

The load output feature is found on the following Victron MPPT Charge Controllers

MPPT Smart Solar 75/10

MPPT Smart Solar 75/15

MPPT Smart Solar 100/15

MPPT Smart Solar 100/20

MPPT Blue Solar 75/10

MPPT Blue Solar 75/15

MPPT Blue Solar 100/15

Here is how the programming for the bus shelter is set up:

And the load output is set to Battery Life which means its aim is to preserve the battery as much as possible, including getting it charged to full every so often to prevent sulfation.

When a system is hooked up to the VRM it is possible to see it in action. Here is the load output graph for the bus shelter for an entire week:

And here is the solar yield and state of charge of the battery for the same period:

And finally here is a video Victron made on the subject:

2 Comments

Ewky

Date 1/2/2021

I’ve used the load outputs for various uses on different projects... One example is using the solar irradiance on the panels as a ‘dusk to dawn’ sensor to switch on an external led light. Another example, was to charge the engine battery or bow thruster battery,only when the sun was shining and the house battery was in float(full)..(additional victron 12/12 9A dc/dc used)

Bob Greely

Date 6/20/2024

I want to configure my mppt 75/10 to do exactly what the video says it can be do. When my batteries are fully charged I want to switch to the load and when the batteries are not charged switch back to battery. I have tried to figure this out on my own, but do not think I have it configured right. Can someone direct me to a video or page that explains how to do this.

Peter Kennedy

What you are trying to do is not an exact option but the nearest would seem to be User defined algorithm 1, see below. Apart from the streetlight option here are the choices. This came from the Instruction Manual The available operation modes are:

BatteryLife (default setting) This algorithm is self-adapting and aims to maximise the battery's lifespan. For a detailed explanation of its functionality, please refer to the BatteryLife chapter for a description of its functionality.

Conventional algorithm 1 12V system: OFF when Vbatt < 11.1V, ON when Vbatt > 13.1V. 24V system: OFF when Vbatt < 22.2V, ON when Vbatt > 26.2V. 48V system: OFF when Vbatt < 44.4V, ON when Vbatt > 52.4V.

Conventional algorithm 2 12V system: OFF when Vbatt < 11.8V, ON when Vbatt > 14.0V. 24V system: OFF when Vbatt < 23.6V, ON when Vbatt > 28.0V. 48V system: OFF when Vbatt < 47.4V, ON when Vbatt > 56.0V.

Always off The load output is always OFF.

Always on The load output is always ON.

User defined algorithm 1 OFF when Vbatt < Vlow. ON when Vbatt > Vhigh.

User defined algorithm 2 OFF when Vbatt < Vlow or Vbatt > Vhigh. ON when Vbatt is between Vlow and Vhigh.

Automatic Energy Selector (AES) ON when Vbat > Vhigh. OFF when Vbat < Vhigh for the pre-selected AES time. OFF when Vbat < Vlow

What is the load output used for on certain Victron MPPT charge controllers

2 Comments

Ewky

Bob Greely

Peter Kennedy

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