Glossary

MPPT

Also MPP tracker

What is MPPT?

Maximum Power Point Tracking: a solar controller that continuously seeks the operating point at which the panel delivers the highest power, and converts the excess voltage into charging current.

What matters about MPPT in practice?

The gain over a simple controller is typically in the double-digit percentage range and is greatest when the panel voltage is well above the battery voltage or when it is cool.

With partial shading, the tracker works against a panel with several power maxima. Several small controllers instead of one large one are often the better solution there.

When is an MPPT controller worthwhile?

Whenever the panel voltage is well above the battery voltage: with panels of 60 cells or more, with several panels in series and in cool weather, when the panel voltage rises. With a small 12 V panel on a 12 V battery the advantage is smaller.

What to watch when choosing one

  • The open-circuit voltage of the panels, including in cold weather, must stay below the controller’s maximum input voltage.
  • The output current is roughly panel power ÷ battery voltage: 400 W at 12 V is about 30 A.
  • The controller needs an adjustable LiFePO4 profile if a lithium battery is charged.

How much yield is realistic?

That depends on location, season and shading. The solar calculator gives an estimate from panel power and sun hours.

Related terms

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Still unclear?

We are happy to explain it for your specific case.

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