There are many components that go into making up your solar system and after your SunPower flexible solar panels the second biggest part is your MPPT charge controller(s). One of the MPPT controllers that we recommend, and that many customers have been very happy with, is the Victron Energy SmartSolar range of controllers. We can help you size the correct charge controller for your system, based on the wattage & number of solar panels and your battery bank voltage. Email us if you need help with this.
Victron Energy SmartSolar MPPT charge controller
In the photos above we see four angles of the same Victron 100|15 controller. In the model name the first number (100) represents the maximum PV open circuit voltage, so check your solar panel spec sheet for the open circuit voltage (Voc) and multiply by the number of panels and be below 100V. The second number in the model name (15) represents the maximum charge current, so 15Amps is the max output from this controller.
The charge controller is connected after the solar panels and before the battery bank, closer to the battery bank the better. It's job is to regulate the flow of power from the panels to the battery bank and it is constantly 'talking' to the solar panels to see what power they have available and 'talking' to the battery bank to see what they need. It will go through three stages of charging; bulk, absorption & float. The important thing is that the controller won't allow the solar panels to overcharge your batteries.
MPPT stands for Maximum Power Point Tracking, the alternative (and some may say older technology) is a PWM controller, which stands for Pulse Width Modulation. Most MPPT charge controllers are called 'buck' controllers and they will take a higher voltage panel eg 18V and reduce (buck) it down to charge a lower voltage battery bank eg 13.5V (for a 12V nominal battery bank) The controller will then take the extra volts and convert it into more amps (whereas a PWM won't) and as such can produce up to 30% more power than a PWM controller.
Note: there are 'boost' charge controllers available should you need to take a lower voltage panel eg 18V and increase (boost) it up to charge a higher voltage battery bank eg 27.5V (for a 24V nominal battery bank)
As you can see from the photos above of the Victron 100|15 controller there are 6 small holes to connect wires to. You would simply strip the PV extension wire coming from the panels, put the bare wire into the hole and tighten up the flathead screw on top of the controller. From left to right these are labelled:
BATT - this is your positive and negative wire going to the battery bank
PV - this is your positive and negative wire coming from the solar panels
LOAD - this is your positive and negative wire going to any 12V load.
For the majority of installs you will only use PV in and BATT out, the LOAD is rarely used. LOAD does allow you to directly wire a 12V (or 24V depending on your battery bank) load from the charge controller. A good example is your anchor light, which via the app can then be set to turn 'on' at sunset and 'off' at sunrise.
The SmartSolar range has built-in Bluetooth capabilities, just download the free VictronConnect app to your smartphone or tablet and start monitoring your system in great detail. The range of the Bluetooth is typically 20-30ft. Should you have the BlueSolar range then a Bluetooth dongle can be purchased and hard wired in to then work with the app.
Some tips when first setting up the app and pairing your MPPT controller with your phone/tablet is that you will likely have to do a few restarts of your device as there will be some updates it has to go through. You will also very likely be asked for a password - this will be six zeros, 000000. You can then change the password to another number if preferred.
The status tab on the app will show you exactly what is happening in real time with your PV system. In the example below right you can see from the solar we have:
425W - the amount of watts being generated from the panel
36.00V - the voltage from the panel to the controller
11.8A - the current (amps) from the panel to the controller
Next we see what the function of the MPPT controller does in taking a higher voltage from the panel (36V) and drop it down to charge the batteries at a lower voltage (28.30V) and then taking this voltage difference of 7.7V and turning it into more amps. So the MPPT charge controller is giving:
28.30V - the voltage from the controller to the battery bank (24V nominal battery bank)
15.0A - the current (amps) from the controller to the battery bank
So the MPPT controller is giving us 3.2A 'extra' or an increase of 21.1% more power than we are getting from the solar panel - bonus!
The history tab on the app will show your power production each day for up to the previous 30 days. The bar for each day can then be clicked on to show you in more detail your solar power production.
Each bar is made up of three sections:
Bottom (white) - time spent in bulk charging
Middle (light grey) - time spent in absorption charging
Top (light blue) - time spent in float charging
Just below the bar there is more info on each day's production:
Yield - 1.23kWh, your total solar production for the day (1.23kWh = 1,230Wh)
P Max - 446W, your peak (highest) solar production during the day
V Max - 44.56V, your peak (highest) solar voltage during the day
V Max - 29.7V, your maximum battery voltage during the day
V Min - 24.91V, your minimum battery voltage during the day
Consumption - 65Wh, how much power you used during the day
*Warning: we have had many customers say the app is very addictive!