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Catalogue · 2 products

PWM Solar Charge Controllers

PWM charge controllers, 20 A and 30 A, for small 12 V and 24 V solar setups: a panel or two on a shed, boat, gate opener or trickle-charging a parked vehicle.

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A PWM controller connects the panel to the battery directly and pulses the connection to regulate charge, so it is simple, cheap and reliable, but it cannot use any panel voltage above the battery voltage. That is fine when the panel is a 12 V nominal type and the array is under a couple of hundred watts. Above that, or with higher-voltage panels, an MPPT controller pays for itself in extra harvest.

Choose the controller by panel current: panel watts divided by battery voltage, with 25 percent headroom.

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PWM Solar Charge Controllers
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MPPT or PWM: choose a charge controller

ControllerBest forConfirm before ordering
MPPTLarger arrays, panels wired in series, and residential-style panels on a 12V/24V/48V batteryMaximum PV input voltage (Voc) in cold weather, and output current at your battery voltage
PWMSmall systems where the panel voltage is matched to the battery (for example, a 12V panel on a 12V battery)Panel nominal voltage matches battery voltage; array current is below the controller rating

Rough current sizing: array watts ÷ battery voltage = charge amps (for example, 800W ÷ 12V ≈ 67A, so an 80A MPPT controller). Panel open-circuit voltage rises in cold weather, so keep the series string's cold-weather Voc below the controller's maximum PV input.

Not included unless listed

  • Solar panels, batteries and mounting
  • PV and battery cables, fuses and breakers
  • Temperature sensor or remote display, unless listed
Can I use residential (60/72/108-cell) panels with a PWM controller?

Not efficiently. Their voltage is much higher than a 12V battery. Use an MPPT controller.

Does the controller work with lithium batteries?

Check that it has a LiFePO4 or user-defined charging profile, and set it to the voltages in the battery datasheet.

MPPT controllers · PWM controllers · Solar panels · LiFePO4 batteries

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