 # How long to charge a 12V 100Ah battery w/ 200W panel and 10A PWM controller?

To determine the charging time for a 12V 100Ah battery using a 200W solar panel and a 10A PWM charge controller, we first need to calculate the effective charging current and then use it to estimate the charging time.

## Solar Panel and Charge Controller Efficiency:

The solar panel has a capacity of 200W, meaning it can theoretically generate 200 watts of power under optimal sunlight conditions.

However, it's important to note that solar panels typically operate at 60%-80% of their maximum capacity due to factors such as the angle of the panel, the intensity of sunlight, and the efficiency of the charge controller.

A 10A Pulse Width Modulation (PWM) charge controller is used in this scenario. PWM charge controllers are less expensive but also less efficient than Maximum Power Point Tracking (MPPT) charge controllers.

PWM controllers generally have an efficiency of around 70%-80%. In our calculations, we assumed an average efficiency of 75%.

## Effective Power Output:

Taking into account the efficiency of the PWM charge controller, we can calculate the effective power output of the solar panel.

Effective power output = Solar panel capacity x Charge controller efficiency
Effective power output = 200W x 0.75 = 150W

## Charging Current:

To determine the charging current, we need to divide the effective power output by the battery voltage.

Charging current = Effective power output / Battery voltage
Charging current = 150W / 12V = 12.5A

However, since the charge controller has a 10A capacity the actual charging current provided to the battery will be limited to 10A, as the charge controller cannot exceed its maximum rated current.

## Charging Time:

To estimate the charging time for the 12V 100Ah battery, we divide the battery's capacity by the charging current.

It's important to note that this calculation assumes a fully discharged battery and optimal charging conditions.

Charging time = Battery capacity / Charging current
Charging time = 100Ah / 10A = 10 hours

However, the estimated charging time of 10 hours for a 12V 100Ah battery using a 200W solar panel and a 10A PWM charge controller should be taken as a rough guide.

Actual charging time may vary depending on a range of factors, such as weather conditions, solar panel orientation and tilt angle, the battery’s starting state of charge, and the presence of any shading or obstructions that may affect the panel’s output.