03/05/2022

In this post, i would like to introduce the topic about how many watts can a 30 amp charge controller handle. Before we explore the topic, we first need to know the spcifications sheets

don’t normally indicate a maximum power rating in watts. After all, this can easily be figured out using volts and amps, right?

In fast, it is not that easy for us when dealing with the solar charge controllers that can have more than one input voltage and output voltage.

The output charging volts can be set or variable depending on the controller, which allows 12V, 24V, 48V or higher voltage battery banks to be charged.

First, we need to consider which type of solar charge controller is to be used, MPPT or PWM.

Solar charge controller power rating in watts is determined by output current and output charging voltage. A 30 amp charge controller with nominal 12 volt output can handle 360 watts. The same charge controller charging a battery with 24V nominal voltage can handle 720 watts.

PWM controllers operate in a basic way and are not very adaptable in terms of PV input.

If the battery charging profile calls for 30 amp charging current at 14 volts, then any extra power supplied by the solar panels will be simply wasted.

While there is some variation in PV input volts in the more expensive models, in general the input voltage level is much lower than MPPT.

Charge controller watts depends on the output charging voltage. For a 12 volt charging system, the power in watts would be:

60 amps x 12 volts = 720 watts

If charging a 24 volt battery bank at 60 amps, then the power calculation is:

60 amps x 24 volts = 1440 watts

MPPT controllers are often able to handle more power, as they operate in a completely different way.

In general, charging volts for higher amp charge controllers can be selected between 12 or 24 volts. In each case the power handled would be different.

If charging at 50 amps for a 12 volt battery bank:

50 amps x 12 volts = 600 watts

When recharging a 24 volt battery bank at 50 amps, it would be:

50 amps x 24 volts = 1200 watts

As the current rating of solar chargers get higher, the output charging voltage increases, particularly with MPPT technology.

A good quality MPPT charge controller may have output settings of 12, 24, 36 and 48 volts. In each case the power being handled would be different:

100 amps x 12 volts = 1200 watts

100 amps x 24 volts = 2400 watts

100 amps x 36 volts = 3600 watts

100 amps x 48 volts = 4800 watts

Lower current devices generally specify one PV voltage input of 12 volt nominal (22V Voc) and one output charge voltage of 12V.

20 amps x 12 volts = 240 watts

MPPT or PWM 40 amp charge controllers may or may not have variable input PV and battery charging output volts, but let’s assume 2 possible output voltages of 12 and 24 volts:

40 amps x 12 volts = 480 watts

40 amps x 24 volts = 960 watts