Victron SmartSolar MPPT 100/20 Solar Charge Controller

The Victron SmartSolar MPPT 100/20 accepts up to 100V of PV input and delivers up to 20A of charging, with Bluetooth.

Reading the model number is the quickest way to size these: 100 is the maximum PV input voltage, 20 is the maximum charging output in amps. Both figures matter independently. The PV voltage limits how many panels can go in series, while the amperage limits how much of their output reaches the battery.

Twenty amps at 12V is roughly 260 watts of array, so panels beyond that will be wasted on this controller. Working backward from the panels rather than picking a controller first is what avoids buying either too little or too much.

BatteryLife logic progressively raises the load-disconnect threshold when daily solar production is insufficient. That forces the battery to reach a near-full charge periodically instead of sitting chronically undercharged, which is what quietly kills a bank on an undersized solar system. Explore more solar charge controllers.

• 100V PV input, 20A charging output
• Both figures limit the system independently
• 20A at 12V is around 260 watts of array
• BatteryLife stops a bank sitting chronically undercharged