Another LED power question? Answered
I bought some LED modules with the intention of using them to replace florescent tubes in some fixtures. But I am now getting a bit confused about the power requirements because the numbers don't seem to add up.
These are like the ones I bought.
In the details description it says that each led is .25 watts and with 5 LED's per unit that makes the power requirements for each one at 1.25 watts. There are 20 units in a strip or module so that would mean that each module would require 25 watts. If the LED's are ,25 watts then that makes sense since there are 100 LED's per module.
Now the thing is when I put power to them they are requiring a lots less. With only a little AC adapter with an out put of 12 v and 2 amps or 24 watts I am able to power SIX of the modules. The power adapter does get warm after a few minutes but if I drop a module and go with 5 it is just fine. So if I go according to what they are actually using the power draw appears to be no more than 5 watts per module. Did they miscalculate? Or am I wrong in my simple math? I tried several different adapters and get the same results. A simple wall wart of 900MA can power 3 but overheats at 4. How is it that they are figuring these at 25 watts when real life usage is saying its more like 5 watts? Its the 5 watt figure that would be more reasonable to me anyway.
I am guessing that it will take 8 modules to replace one dual tube 80 watt florescent. If they are 25 watts each I am loosing on the power consumption because that would be 200 watts as opposed to 80. At 5 watts I am doing a lot better coming in at about 40 so that gives me an almost 50% power savings.
If I am correct in my estimates then a simple 30 or 40 watt power inverter like this would work perfectly.
Any ideas as to why there is such a discrepancy in these numbers?