Solar planning tools

MPPT / PWM charge controller

Check cold string voltage and estimate input and battery-side current requirements.

Your inputs

Editable example values

Your estimate

Live calculation

Cold string Voc

107.32 V

Candidate max: 150 V

PV Isc design requirement

35 A

Output current estimate

62.5 A

2200 W array · MPPT

Planning estimates, not equipment approval. Review the assumptions below before choosing a system.

No location or tariff is detected automatically. All results use the values you enter.

What is this tool used for?

Use this calculator to screen selected electrical requirements for an MPPT or PWM charge controller connecting a solar array to a battery bank.

How to use this calculator

Choose controller type, array arrangement and panel specifications. Add the cold-temperature assumption, voltage coefficient, battery operating and charging voltages, current margin and candidate controller's absolute PV voltage limit.

Understanding your results

Review cold string voltage, PV short-circuit current and the battery-side current estimate together. These describe different limits. PWM and MPPT behave differently, and passing this screen does not replace checking the full controller datasheet and battery charging limits.

How this is calculated

Cold Voc = module Voc × series count × [1 + (Voc coefficient / 100) × (minimum temperature − 25°C)]. Design PV short-circuit current = Isc × parallel count × margin factor. MPPT output estimate = rated array watts ÷ minimum battery voltage × margin factor. PWM current estimate = parallel Isc × margin factor.

Understand the modelling approach →

Before you use the result

This checks selected limits, not full compatibility. Verify manufacturer maximum PV short-circuit current, input operating current, MPPT range, hot-weather string Vmp, startup overhead, allowed PV wattage and charge-current limits. PWM requires a battery-matched array; excess panel voltage does not convert to extra current. Margin is a planning assumption, not a code certification.

Can I choose a controller using output amps alone?

No. Its PV voltage, PV current, operating window, array power and battery charging specifications must also match.

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