How Many Solar panels to Charge a 220Ah Battery?

If you’re building an off-grid solar system for your shed or cabin to keep your battery bank topped up then it’s important that you have the right capacity of solar panels from the get-go.

In the case of a 220Ah battery bank, how much solar should you install?

Read on to find out this, including how many solar panels and how long it’ll take to charge the battery.

Note: The information provided assumes that the battery bank is discharged to the maximum recommended levels of 50% AGM and 80% for LiFeP04 batteries.

If the power consumption of the connected appliances is much lower, you can get by with fewer watts of solar.

How Much Solar to Fully Charge 220Ah Battery?

Note: This depends largely on the number of sunshine hours a location receives and the voltage of the battery bank

Using 12V AGM Battery Bank

To keep the batteries topped up, aim for at least 500-600 watts of solar panels.

This assumes your location receives at least 4 hours of sunshine per day and therefore at least between 2,000-2,400 watt-hours of energy (500-600 watts of solar x 4 hours) should be available from the solar panels to fully charge the estimated 1,320 watt-hours of AGM battery capacity even when the sky is overcast or cloudy.

How Many Solar Panels (AGM Battery)?

To generate at least 2,400 watts from solar panels, you can use any of the listed arrangements.

Note that this list is not exhaustive and there are other combinations you can use besides the ones listed below.

  • 6 pieces of 100-watt solar panels (2 parallel strings of 3 solar panels connected in series), or
  • 3 pieces of 195-200 watt solar panels ( 1 parallel string of 3 solar panels connected in series).

How to Calculate the AGM Battery Capacity (watt-hours)

Battery capacity (220Ah) x Battery voltage (12V) x Recommended Depth of Discharge (50%) = 1,320 watt-hours.

12V LiFeP04 Battery Bank

Aim for at least 800 watts of solar panels. With at least 4 hours of sunshine per day, the 800-watt solar panels should be able to generate at least 3,200 watt-hours of energy (800 watts of x 4 hours of sunshine).

This should be more than enough to fully charge the 2,112 watt-hours of LiFeP04 battery capacity even when the sky is overcast or cloudy.

How to Calculate the LiFeP04 Battery Capacity (watt-hours)

Battery capacity (220Ah) x Battery voltage (12V) x Recommended Depth of Discharge (80%) = 2,112 watt-hours.

How Many Solar Panels ( LiFeP04 Battery)?

Here are some solar panel combinations that you can use. Note that this list is not exhaustive.

  • 8 pieces of 100-watt solar panels (2 parallel strings of 4 solar panels connected in series), or
  • 4 pieces of 195-200 watt solar panels ( 2 parallel strings of 2 solar panels connected in series).

How Much Space (sq. ft) for the Solar panels?

Assuming each 200-watt panel takes up about 12-14 sq. ft, for 800 watts of panels, you’ll need at least 60 sq. ft of available space to mount them.

How Long to Charge the Battery Bank?

The battery bank should be able to fully charge in about 6-8 hours give or take depending on the amount of sunshine available provided it is not discharged beyond the recommended levels (50% for AGM and 80% for LiFeP04 batteries).

Related Topics

1. What Size of Charge Controller?

Consider a 60 amp MPPT charger or larger if you have plans to increase the number of solar panels later.

2. What Size Inverter for 220Ah Battery?

Your choice of inverter capacity (watts) should be determined by the combined power consumption of the connected appliances (watts) and the battery bank voltage.

Consider using an inverter with a power rating in the range of 1,000-3,000 watts.

A lower power inverter would work too but would limit the number and power consumption of appliances you can run simultaneously.

Make sure to use a 12V model in the case of a 12V battery bank and a 24V model for a 24V battery bank.

Closing Thoughts

This mainly depends on the number of sunshine hours a location receives and the voltage of the battery bank

For a 220Ah AGM battery bank, consider 600 watts of solar. With a LiFePO4, invest at least 800 watts of solar to fully charge the batteries each day.

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