Hi All,
I tried to install simple and cost effective LED lighting, aim being to drive the lights of my home directly from a battery which is charged by solar panels and to avoid an inverter.
Here are some pictures of the units I built using the 3W white LEDs.
These available here in Mumbai, India are mostly unbranded and are from chinese sources, approximately priced at 50 INR (less than a USD) per piece. Noone specifies lumens delivered/ permisible current etc. These LEDs need a heat sink and are expected to be more stable than those w/o a heat sink (I have tried some of such non-heat-sink units in my post at
http://www.fieldlines.com/index.php/topic,145701.msg992212.html#msg992212 )
I am sure these units as built and seen in below images are very much crude looking and do not have much asthetic get-up, but I am happy with the light they give and I want to test their stability and deterioration in the output over a few days/months.
Each unit has 6 such LEDs, with a LM317 connected in a voltage regulator mode to give 9.7 VDC for a string of 3 LEDs in series. Each LED is said to support an input voltage of 3.2 to 3.4 VDC.
The backing and holding strips made of aluminium C sections are seen to provide good heat sinking. I have seen the aluminium surface temparature to rise to 65 DegC max approximately in standstill room air. Well this is measured only by finger-touch-sensing :-)
A pair of 2 Such units in one room is failry equivalent to a 40 Watt fluroscent tubelight (the 4ft length standard lamp) in terms of light output.
With thanks and regards,
Prasad