Victron Blue MPPT 100/30 Solar Controller SCC020030200

PWM and MPPT charge controllers are both widely used to charge batteries with solar power.

MPPT controllers, however, are more sophisticated as they will adjust its input voltage to harvest the maximum power from the solar array, and then transform this power to supply the varying voltage requirement of the battery plus load.

There are two main types of Victron MPPT Solar Controllers - the SMARTSolar MPPT range and the BLUE Solar MPPT range.

• The SmartSolar models have Bluetooth built-in. SmartSolar MPPTs also help maintain battery health and life.
• The BlueSolar models can be made Bluetooth accessible by connecting a VE.Direct Bluetooth Smart dongle which is purchased separately.

Generally, the BlueSolar range is cheaper if you do not need to add the smart dongle, but it usually works out to be more expensive if you add the smart dongle. 
Your choice, will probably depend on whether you want to connect the MPPT solar controller to your smart phone by Bluetooth or not. If you do not wish to connect to Bluetooth then buy the BlueSolar if you need Bluetooth to monitor the charging from a distance then get the SmartSolar version.