Practical Application (Beijing Region)

We know that Beijing belongs to Class II region based on the sunlight conditions, with a sunshine duration of 8.2 to 8.7 hours. In this example, the median value of 8.4 hours is taken.

The power consumption of solar repeaters (wireless 10W, frequency shifted 10W, and 6-frequency selected 10W) is around 85W, and 24V power supply is uniformly used. Currently, the battery used is 200AH/12V/piece, and the battery panel is 55W (peak)/17V (peak)/piece. The current consumed by the repeater every day is (24V power supply):

(85w/24v=) 3.54 × 24 hours=85 (AH)

Assuming that the designed battery capacity can meet the continuous operation of the repeater for 5 days, the minimum battery capacity is:

eighty-five × 5=425 (AH)

Although the nominal capacity of a battery is its rated discharge capacity, we only design it based on 75% discharge capacity to have a certain margin. Therefore, the total designed battery capacity is:

425/0.75=566 (AH) takes an integer of 600AH,

We need three 24V batteries, while we actually use 12V batteries, so we need six 12V batteries.

Assuming the worst scenario of 5 days is 2 days on a sunny day, 2 days on a cloudy day, and 1 day on a rainy day (without charging) to calculate the battery panel configuration:

The charging current of one battery board is

On a sunny day: 3A × 4 hours+(3A+0.7A) ÷ 2 × 4.4 hours=20.14 (AH/day)

twenty point one four × 2 days=40.28 (AH)

On cloudy days: 0.7A × 8.4 hours=5.88 (AH/day)

five point eight eight × 2=11.76 (AH)

Total: 40.28+11.76=52.04 (AH) Take the integer as 52AH