Security Lighting at Aoral, Cambodia

The journey to Aoral is 4 hours drive on a vehicle, a mini bus, from Kg Speu. The road was rough and muddy. Its like having a full massage for 4 hours. The driver was skillful, able to turn the mini bus into a 4 wheel drive vehicle. At times, we have to come out and push the vehicle because it got stuck in the mud.

Finally we reached Aoral. A brick building, just completed, is use as a medical outpost for humanitarian work where visiting doctors can provide basic medical health care services to the poor in this region.

There is no grid electricity and clean water in this region. Everyone uses their own generator for electricity. This medical outpost will only turn on the generator at night for 3 hours, 6.30pm to 9.30pm, when volunteer medical teams are there.


The project centred around the installation of a Perimeter Security Lighting system – comprising 25 super bright LED (Light Emitting Diodes) lamps, a control box, a switch box, lead acid batteries (purchased) and a diesel generator – at a medical outpost in Aoral, a district in Kampong Speu. This lighting system will provide security lights around the medical outpost throughout the night after the generator is shut down at 9.30pm.

The system consist of a control box, lamps, battery and a switch box.

The control box includes a charge controller with a switching mode power supply, harmonic filters, main fuse and switches.


The lamps are install around the perimeter of the building and driveway.



Two sealed lead acid batteries operating at 24Vdc, each having a capacity of 120AH. From the graph below, the 3 hours of rapid charging by the switching mode power supply at 28.8Vdc and 18 Amperes followed by 9 hours of discharge from the batteries to the 25 lamps is sufficient to sustain for the whole night operations.

The temperature in the control box never reaches 40 degrees Celcius during the battery charging process but the humidity in the box can reach above 80% humidity during the day time.

The switch box controls 4 lighting zones in the area. Mission House Inside, Mission House Outside, Area behind and side, Driveway & Guard House.



At night, the lamps are turned on. The compound is well lit as seen below.

Batam Medical Mission 2007

On 18 August 2007, I joined my church group on a 2 day Medical Mission to Batam Island, Indonesia. The medical team provided free services and medicines to the villagers.

The lady is having her wound treated by a nurse.

A doctor is examining a child, doing a health check.

Finally, a sumptuous dinner at a restaurant. The trip was meaningful. I can see good works done by the medical team.

Solar 3 - LED Lamp Installation & Maintenance

On April 2007, we went to Hope Village again. This time to install more LED Lamps at the orphanage.

The LEDs Lamps are new design with its electronics capable of working at 24Vdc directly and uses 2 Luxeon Star LEDs operating at about 5 watts. We install altogether 5 lamps to new areas where are there are no lightings previously.

We have to replace one faulty lamp which is damaged when rainwater enters the lamp housing and corroded the electronics.

Mission Lightings for Pahang

We were blessed for being able to visit churches in Pahang jungle through a Christian friend. Through his local contact, we went in to provide lighting for the churches in the jungle using LED Lamps powered by Lead Acid Batteries.

On our way to the base camp, Tual, the road was rough and muddy. The locals would hitch a ride from us to return to their village.

When we reach the base camp, it was like a sanctuary, very peaceful, with basic amenities available, like fresh water from the hills, electricity, food (must say, the food was very good) and proper shelter.

Next morning, we went to a church at Regang, we gave a sermon, had fellowship meals with them.

In the afternoon, we return to Tual. We had another church service at Tual. We gave a sermon. Offered our prayers and had fellowship meals with the elders.

In the late afternoon, we set off to Senderut. They have a church located at Senderut. It is 510 meters above sea level. It had just rained, the road was muddy and slippery. Fortunately, the vehicle did not get stuck in the mud. We finally arrived after sunset. The church was dark, we quickly install 6 LED lamps in the church and powered them by a 12Vdc lead acid battery. We conducted the church service at night with the lights on, we had fellowship dinner with them and stayed a night in the church. The temperature in the morning was 17 degrees Celsius.

Immediately, the next morning, we set off to Kaki Bukit Long. Finally we reach there, park our vehicle outside the church and walk up hill to Tigol and Saweh. It was 468 metre above sea level.

We passed by Tigol church. It was 543 metres above sea level. There was no church service that day but the service was at Saweh.

We continued walking up hill and went to a church in Saweh, they had their morning church service, we gave a sermon and had breakfast fellowship with them. This place is 570 meters above sea level.









Finally, we return to the church at Kaki Bukit Long. We attended the service and had some sing along session. We installed 6 LED Lamps at the church, powered by a 12Vdc Lead Acid Battery.

Solar Two - Solar Food Dryer & Vacuum Sealing

We attempted to build a solar food dryer, using the sun energy to hygienically dry fruits in Cambodia. We have search through the internet and came across a design which we can try out.

We bought wood and cut the to shapes and assemble them together. Finally, we painted it and allow it to dry before using it.

Sun energy is collected through the transparent plastic and heats up a wire mesh inside. Air intake from the front sucked in and heated up by the wire mesh, the hot dry air rises because of convection in the dryer and flow into the drying chamber behind. The fruits prepared for drying are placed on trays to be dried in the chamber. On a hot day, the temperature in the chamber reaches about 50 degress Celcuis and humidity falls to below 30%. Drying takes about 3 days.

The temperature and humidity of the drying chamber was measured from night time till the next evening. It was noted that the humidity at night reaches above 80% while its temperature drop to below 30 degress Celcius. During the day, the temperature in the chamber increases to above 50 degrees Celcuis and the humidity falls close to 30%. Drying of the fruits takes place only during the day time.

The result was partially successful. Somehow we could not get complete drying of the fruits. Probably due to condensation of moisture at night.

Hence for the next improvement to the design, we must introduce continuous drying process through the night which we will require some heating process.

In conjunction with the solar dryer, we design a vacuum sealing machine to store the dried fruits in a vacuum sealed plastic bag. The machine does not use electricity but working on the priciple of a reverse bicycle pump for sucking the air out of the plastic bag and using fire from a candle stick to seal the plastic bag.