MPPT Solar Charge Controllers

It constantly adjusts the voltage coming off your panels to squeeze out the most power possible. Whatever your array produces at any given moment, the controller finds the sweet spot for getting it into your batteries.

Your panels put out more voltage than your batteries need, and a PWM controller just throws that excess away. An MPPT solar charge controller converts it into extra charging current instead. You can also run higher-voltage arrays with MPPT, which means longer wire runs between your panels and the controller without losing power to voltage drop.

MPPT for most systems. PWM only makes sense when your panel and battery voltage are closely matched - like one 12V panel charging a 12V battery. Once your array voltage runs higher than your battery voltage (it almost always does), PWM bleeds the difference as heat. MPPT turns it into a charging current. An MPPT solar charge controller pays for itself in recovered energy if your system runs over 200W.

Look at your solar array’s voltage and current, battery type, and system size. The controller’s max PV input voltage must be equipped to handle your array's open-circuit voltage. You also need to confirm the output current rating covers your charging needs. Battery compatibility matters too, especially if you're running lithium. Not sure what fits? Call us. We help people size these every single day.

Give it good airflow. Heat kills these units over time, so don’t mount them in a sealed box. Check wiring connections once or twice a year for corrosion, especially if the enclosure lives outside. Stay on top of firmware updates if your model supports them. For example, Victron's SmartSolar controllers update through the VictronConnect app.

Absolutely. A lot of the Victron Energy and SRNE controllers we stock are built specifically for lithium iron phosphate batteries. They have programmable charging profiles for safe integration.

A Victron BlueSolar 75/10 can only handle a couple hundred watts. The OutBack FLEXmax Extreme and Xantrex MPPT80 600 handle full commercial arrays. We can do the math for you, but you’ll simply multiply the controller's rated output amperage by your battery voltage to figure out the max wattage it can process. 

Yes, as long as each one charges the battery bank independently. Each controller manages its own array and its own charging profile. Some off-grid systems run a smaller PWM controller on a secondary circuit with an MPPT handling the main array. Just don't wire the controllers to each other. Each one needs its own panel connections and its own battery leads.

A 20-amp controller gives you the headroom you need on a 12V battery. Even a 10-amp unit handles a 24V bank. Pay attention to max PV input voltage, too. Your panel's open-circuit voltage needs to stay under the controller's limit. Most 200W panels sit around 20-24V VOC, (every unit in this collection handles that).

At least a 35-amp controller on a 12V battery. A 24V bank cuts that in half, so a 20-amp unit is plenty. Check that the controller's VOC rating clears your 400-watt solar panel's open-circuit voltage. Most sit between 37-50V. Planning to add panels down the road? Go bigger on the controller now. Cheaper than swapping it out later.