240v led bulb circuit

[guruji]

Anyone knows a 240v led bulb circuit or where can I obtain one?.Using about 5 led or more.

Thanks.

[richhagen]

I built a 120V light by rectifying the AC and running it through resistance and a bunch of LED's in series.  Based upon experience, I recommend against this.  The reason is that when LED's fail, they often fail to short.  If you are running a long string in series, that can result in over voltage applied to the remaining.  If I were building one now, I would look for the most efficient switching power supply to output a DC voltage such that you run no more than about 5 in series with resistance, and then parallel as many strings as needed to obtain the desired light output.  If one string fails, it is then not as big of a deal, and it is less expensive to repair.  LED's are still less efficient than many flourescents, so if you are trying to build an LED light to run off of 240V because you think it will be more efficient, you may want to research it a little more, and read the lighting fact sheet linked to from the front page of the Otherpower Site.  LED's can be best where smaller dispersed lighting is needed, such as Christmas/Holiday lights, or small directional lighting is needed such as under-cabinet lighting.

I don't know if any of this information helps you, but hopefully it will be of some use to someone.  Rich Hagen

[ghurd]

Guruji my friend, you are determined!

Rich is correct. Do not series very many LEDs in a single circuit.  It only works well on paper.

I would try to find a small efficient 220VAC to 16VAC transformer.

The 16VAC, rectified goes to 22.6VDC.  Supply that to a decent quality capacitor.

The output could supply power to 7 to 9 white LEDs in series, at less than 20ma with the proper resistor.

Then many circuits of LEDs and a resistor could be added in parallel.

If the total input is beyond about 5 or 7W, a CFL of decent quality will be more efficient.

Possibly an old laptop power supply could be used?  

They are often switching supplies (efficient) with inputs of 100 to 220VAC, 50/60Hz, with a fixed output voltage.

I have not tried it, but I do not see why it would not work well, on paper.

G-

[desertcoyote]

i tried the 24v automotive base led cluster lights from an led company from st louis. I was very disappointed. wasn't long before many of the elements went poof. don't know what it was, but i suspect the 29-30V high side on the battery under charge, or transient voltage spikes from switching on off. they had a warranty, sure, but i did not bother, just throw-ed them in the trash. I have had better luck with the compact fluorescent lamps, only problem, dont drop them or screw them in to hard while holding the lamps.  they will break off in your hand, bummer another $10 light bulb in the trash.

[guruji]

Ghurd what is the purpose exactly of a capacitor? and what type of capacitor should be added?.I had bought 240v bulbs and when I opened one there are 2 resistors; 4 diodes;1 capacitor and many leds.

I have comoponents of a energy saver bulb.Is there something good to modify to leds?

Thanks guys.

[ghurd]

A capacitor will help smooth out the pulses from the AC. Not sure what type of cap is best.

I expect 1 resistor limits AC power going into the circuit, then the 4 diodes are wired as a bridge rectifier changing the AC to DC, then the capacitor helps stabilize the voltage while the other resistor limits DC power to the LEDs.

Energy saver bulb meaning a 220V CFL?  I don't think the parts will be much help for LEDs.

To get any real hours of use from the cheap Chinese LED bulbs, it may be worth a try to replace the resistors with larger values, getting the amps down to 12ma per LED.

It won't be nearly as bright (because the cheap LEDs were probably very overdriven to be bright AND low cost), but its probably the only simple way to get one to last more than a few days.

A poor design and low quality parts are hard to fix.

[guruji]

Thanks ghurd for your help.

I have a nightlite with a sensor switch .Do you know at what voltage does this sensor switch works?Is this like a diode ?I would like to use this in my led bulb if it is possible .

[ghurd]

I can not say. There are many automatic nightlites, many sensors, many circuits, etc.

I am certain there IS a way.

My autonomous circuits all operate from DC, on battery power.

If the LEDs will be run from 240VAC, it should be simple to connect the LED circuit to an automatic nightlite that started with a 240V 5W incandescent light bulb.

Much like screwing the LED bulb circuit into the automatic nightlite.

Be aware, some day / night sensors take MORE power than leaving a LED bulb on all day and all night.

A circuit with only 5 white LEDs could use rechargeable batteries. Grid or RE charged.

What is the point of this?  To save grid power (money)?  To start RE?  To use some solar panels?  Just for fun?

[Bruce S]

desertcoyote;

   Kinda caught my eye on the St.Louis thing.

Got a company name ?

I'll go over and tell them about the problem. There's a company here Alt.energy or something like that ....

Expensive and not much more that a reseller from what I gather...

I have LEDs bulbs in my ole F100 and they are working just fine for the past few years. I usualy scrounge the parts out of ones people break and resolder new LEDs in and away I go.

Do let me know about the company here in St. Louis and I'll let them know about it..

Bruce S

[ghurd]

A well made LED bulb should handle the volts and surge while switching.

(eBay doesn't have them)

"Tom in NH" has a kit.

I also might have a kit later.

[guruji]

I have build a small vcr windmill and want to use it to recharge two small batteries for nightlite with leds to switch on/off with a sensor that I had on a one watt lamp.It's for fun mostly but take it as an experiment too.

About to rectify the 3vac I should do two diodes?.

Thanks for your interest ghurd and help.

[desertcoyote]

to whoever http://www.superbrightleds.com/led_prods.htm. I do not want to down them but these did not work for me, except one partially lit bulb that I have not disposed of yet hanging in the bath room.

For night lights the AC powered lime lights work good. these consume 3Watts and look like little tv screens. I was curious and took some apart and tryed to make them work with DC 10-200V to no avail. aparently they need ac. there is two ac "screens" with goo in between that make them work somehow.

[ghurd]

It will need 6 diodes, or 2 bridges.  See the second photo...

http://www.fieldlines.com/story/2003/9/11/84741/6758

Ed has a simple voltage doubler. It may help. I have not yet tried it, but plan to.

http://www.otherpower.com/images/scimages/15/3phase_doubler.JPG

My attempts at simple, lower than 7~8V, sensors have not gone well.  A 2.8V simple sensor may be difficult.

G-