How To Program Solar Charge Controller

How to program solar charge controller? A charge controller is a device that regulates the voltage and/or current going to the battery so that it does not overcharge. It manages the voltage and current supplied by solar panels to the battery. Because most “12 volts” solar panels generate roughly 16 to 20 volts, if there is no regulation, the batteries will be destroyed from excessive charging. To be fully charged, most batteries require around 14 to 14.5 volts.

Do You Always Need A Charge Controller?

Yes, but it depends on the battery and how often you are going to use it. Small maintenance or trickle charge panels, such as 1 to 5-watt panels, do not always require a charge controller. If the panel produces roughly 2 watts for each 50 battery amp-hours, there is no need for a charge controller.

A typical flooded golf car battery has a capacity of 210 amp-hours. To maintain a pair of them (12 volts) just for storage or maintenance, you will need a panel with a wattage of about 4.2. The 5-watt panels are very close and do not require any control circuitry. If you are keeping AGM deep cycle batteries like the Concorde Sun Xtender, you can use a 2 to the 2-watt panel instead.

Charge Controller System Design

There are a few things to think about while choosing a charge controller system:

Price and Performance – MPPT charge controllers will generally be more expensive, but they will also provide greater power. Using an MPPT controller is comparable to having extra panels in your array. If you don’t have a lot of roof space, which is often the case with an RV, MPPT charge controllers will help you get the most out of what you have.

Battery Bank/Array Voltage – To charge a battery bank, the solar array voltage must be greater than the battery bank voltage by a small amount. The difference in potential (pressure) between the panels and batteries causes electrons to flow from the panels to the batteries. Without this gap, the batteries would not receive a charge. A solar array typically produces voltages of around 18 V while a battery bank ranges from 11.0 V to 14.6 V.

Voltage Limits – On a 12V battery system, PWM-type charge controllers are commonly used. Most 12V battery systems employ PWM-type charge controllers with an open circuit array voltage over the limit of 24V. Other MPPT designs may have a higher voltage limitation of 150V or more. Check to see if your charge controller can handle the Voc (Open circuit Voltage) for each panel; if not, you risk frying it. The VOC is usually shown on the label on the back of the solar panel.

Current Limits – The output current of a charge controller is measured in amps (from the controller to the battery). You can figure out the maximum output current by adding together the operating current for each panel, or Impp (Maximum PowerPoint), as long as your panels are connected in parallel. The Imp is generally marked on the panel label.

Multiple Charge Controllers – If the charging current of your chosen solar array is greater than the charge controller’s maximum current rating, you may use multiple controller charges. These parallel-connected charge controllers would be connected across the battery bank. In a single system, the Blue Sky IPN-ProRemote can monitor up to eight charge controllers.

How To Program A Victron SmartSolar Charge Controller

The Victron SmartSolar charge controllers may be tailored most simply with the VictronConnect app on a smartphone. After you’ve downloaded and installed the app, make sure your phone’s Bluetooth is switched on and select “Battery Settings” from the menu.

Choose which charge controller you want to program by clicking on it.
Select the cog icon in the upper-right corner of the screen.
Select ‘Battery’ from the drop-down menu.
Fill in the values as needed for the battery bank with which you are programming the charge controller.

What Is Equalization?

Equalization is a function of DC balance. It is an effect of DC balance, but it tries to equalize the charge in all cells in the battery or battery bank. Essentially, it is a period of overcharging, which is typically between 15 and 15.5 volts. If you have some cells in the string that are lower than others, they will be brought to full capacity.

It also has an important function in flooded batteries, stirring up the liquid and causing gas bubbles. This does not usually work much for you in an RV or boat unless you have been stationary for months because typical movement will achieve the same result. Furthermore, in systems with small solar panels or enormous battery systems, you may not be able to produce enough current. Batteries in many off-grid appliances can also be balanced using a generator + charger.

What Is PWM?

There are various PWM charge controls on the market. PWM is a type of pulse width modulation. PWM is frequently employed to charge batteries in float mode. Instead of relying on a steady output from the controller, it sends out a series of short charging pulses – an instantaneous “on-off” switch.

The battery controller checks the state of the battery on a regular basis to determine how quickly to fire pulses, as well as how long (wide) the pulses will be. It might “tickle” every few seconds and send a brief pulse to the battery when it is fully charged and there is no load. The periods would be extremely long and nearly continuous in an exhausted battery, or the controller may switch to “full-on” mode. Between pulses, the controller monitors the battery’s state of charge and adjusts itself accordingly.

What Is The “Sense” Terminal On My Controller?

A pair of “sense” terminals may be found on some charge controllers. Because the current from sense connections is quite small, no voltage drop occurs. It examines the battery voltage and compares it to what the controller is producing. If there is a voltage difference between the charge controller and the battery, it will raise the controller output by a tiny amount to make up for it.

While this list is not comprehensive, it should get you started. These connections are only utilized when there is a significant wire run from the controller to the battery. They do not carry any current and might be as little as #20 AWG. We like using #16 because it can not easily be trimmed or squished by accident. They connect to the SENSE terminals on the controller and also to the same terminals as the two charging wires at the battery end.