Case study: Provide lighting of 10 lux at a height of 5 meters

10 Lux is what is recommended for typical sidewalks and footpaths. A typical light pole is around 5 meters tall. A good LED produces 120lm per watt with a beam angle of 120°

What solar light system would we need to provide light at 10 lux at 5 meters?

The answer is 785.4 lumens or 6.5W of power.

Lets put the above information in our solar light calculator with our all in one 80W system.

Our all in one 80w system has an 80w solar panel and a 256WH battery capacity. We notice that it can handle this configuration quite comfortably.


8.5W is the maximum watts that we can use

Most Lithium batteries are rated 80% – 90% of the rated capacity. To be safe we should allow 20% charge left over at dawn to compensate for this.

As a result, using our solar light calculator we can use 8.5W which leaves the Minimum Battery % at Dawn at 23%. 

Use only what you require

We have the option to use 8.5W which would give us 13 lux at 5 meters. However, 13 lux vs 10 lux is really not very perceivable to the human eye. They both will seem as bright as each other.

The human eye will see 40 lux is twice as bright as 10 lux, but at the cost of 4 times as much power.

But keeping the system at 10 lux instead of 13 lux will make a big difference with the longevity of battery life as we will use less energy.