Victron BlueSolar Duo LCD & USB PWM Solar Controller:

Victron BlueSolar Duo is a PWM two-battery controller for RVs, caravans, boats and cottages. Designed for 20 amps at 12 volts DC. Victron's range of PWM and MPPT charge controllers are both widely used to charge batteries with solar power. The PWM controller is in essence a switch that connects a solar array to the battery. The result is that the voltage of the array will be pulled down to near that of the battery.

A PWM controller is not a DC-DC transformer. The PWM controller is a switch which connects the solar panel to the battery. When the switch is closed, the panel and the battery will be at nearly the same voltage. Assuming a discharged battery the initial charge voltage will be around 13V, and assuming a voltage loss of 0.5 V over the cabling plus controller, the panel will be at V PWM = 13.5V.

The voltage will slowly increase with increasing state of charge of the battery. When the absorption voltage is reached the PWM controller will start to disconnect and reconnect the panel to prevent overcharge (hence the name: Pulse Width Modulated Controller).

More Product Features:

Liquid Crystal Display:

For status monitoring and set-up

External Temperature Sensor: 

Included

2 Separate Battery Outputs:

Charges two separate batteries. For example, the starter battery and the service battery of a boat or mobile home.

Protections:

Protected against reverse polarity connection of the solar panels and/or battery.

Programmable Battery Charge Algorithm:

Algorithms for AGM, GEL or Flooded lead-acid batteries and LiFePO4 batteries (with internal BMS).

Two 5 Volt USB Outputs:

A maximum current of the two outputs combined: 2A

Applications:

Marine

RV's

Caravans

Off-Grid Systems

Tiny Houses

Cabins

More about Victron:

Victron Energy has a strong, unrivalled reputation for technical innovation, reliability, and build quality. Their products are widely considered to be a professional choice for independent electric power. Efficiently combining two or more distinct power sources is what they do best. Their products include sinewave inverters, sinewave inverters/chargers, battery chargers, DC/DC converters, transfer switches, battery monitors and more.