LEDs with good brightness/low voltage ratio

I’m trying to source some LEDs for a current project - to be mounted on a power kite. LEDs will be controlled using Arduino. The LEDs will need to have a good ratio of luminous intensity to forward voltage to keep the weight of the power supply down. They should also have a wide viewing angle.

I’m new to LEDs so am not sure what is available - so far I’ve been looking at some LEDs at Maplins which are advertised as being 1900-3000mcd, with a forward voltage of 2.3-2.6V. Viewing angle is 15 degrees. Can I improve on this?

I’m also looking at options of mounting LEDs in clusters to improve brightness / angle (if mounted in a circular array). Another possibility is to use a small spherical diffuser - like a ping pong ball, but smaller. Again I don’t know what products are available.

I’d be grateful for any suggestions for products / suppliers (ideally in the UK). Any details/ingenious solutions would also be welcome!

good ratio of luminous intensity to forward voltage

No don’t consider the voltage it is the luminosity to current rating that is important.

In the UK Farnell is also a good supplier also try looking on eBay I got some good LEDs from China.

Surely one should look at power rather than current.

Since you mentioned a cluster of them, would that be to achieve brightness?

Luxeon LEDs are worth having a look at.
http://www.philipslumileds.com/products/luxeon/luxeonI

If you go with white over blue, you’ll lose some photons.
Whether you want to go with red, red-orange, blue or green will require you to weigh up the power draw vs luminous flux vs other constraints*

Red has a much lower forward voltage than green, but the eye is more sensitive to green (eye sensitivity is accounted for in lumen ratings).

As for things far away in the sky, I’m not sure if one color is better than another. Bit tricky, this apparent brightness thing.

To get the most out of your batteries(?), you might want to look at a DC to DC converter of some description to keep everything running when the battery voltage drops.

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