upgrade halogen to LED's

fuzzynavel

I have an old set of "Smart" halogen lights. It has two halogen bulbs, one is 2.5 watt and the other is 10 watt from memory.
There is a 6V, 4.5 mAh rechargeable lead acid battery too.
I would like to know if there is anyway to use the same setup but change the actual light emmitting bits from halogen to LED. I know it is a bit odd but LED's seem a lot brighter per watt than my halogens and should extend the battery life a lot. Currently on full power 10 watt + 2.5 watt at the same time I only get about 1 hour before the light gets noticeably dimmer. and 1.5 hours before it is unuseable.

aracer

Not with any simplicity - there's nothing that's a drop in replacement. Given it sounds like your battery is pretty tired too (and lead acid are a lot heavier than current options), then I'd suggest if you want to upgrade the best option is to ditch the Smart and start again - either a much discussed Fenix, one of the cheaper options from Dealextreme (or a Tesco torch for £10), or build something from scratch if you have the skills.

fuzzynavel

aracer wrote:

Not with any simplicity - there's nothing that's a drop in replacement. Given it sounds like your battery is pretty tired too (and lead acid are a lot heavier than current options), then I'd suggest if you want to upgrade the best option is to ditch the Smart and start again - either a much discussed Fenix, one of the cheaper options from Dealextreme (or a Tesco torch for £10), or build something from scratch if you have the skills.

I don't think the battery is tired....it was brand new a few weeks back..maybe it is just a bit crap. The halogens are reasonably bright but I think they used to be brighter...maybe the bulbs should be replaced.

alfablue

It is very easy to ruin the battery through overcharging, when I had Smarts I used a plug in timer to avoid this. As for the LED upgrade, even if you achieved it I am not sure the plastic housing would handle the heat from high powered LED's. Cut your losses, get a Fenix L2D CE Q5 or LD20 and enjoy 4.5 hours run time on high (2.5 on Turbo) on 2 AA batteries, and save 1.5kg weight on your bike.

aracer

fuzzynavel wrote:

I don't think the battery is tired....it was brand new a few weeks back..maybe it is just a bit crap.

Given your runtimes, it's nowhere near the quoted capacity, or a rubbish battery (if it's a generic replacement then that might explain things as normal sealed LA batteries aren't good at the high current you're drawing with your lights). Either way not worth keeping if you're upgrading other bits of the system.

fuzzynavel

aracer wrote:

fuzzynavel wrote:

I don't think the battery is tired....it was brand new a few weeks back..maybe it is just a bit crap.

Given your runtimes, it's nowhere near the quoted capacity, or a rubbish battery (if it's a generic replacement then that might explain things as normal sealed LA batteries aren't good at the high current you're drawing with your lights). Either way not worth keeping if you're upgrading other bits of the system.

I wonder if I could change the battery to a different type with a similar or higher output? Can I get a rechargeable Nimh pack with a similar output....should last a lot better.
I have a reasonable bikehut LED as my backup. It provides a decent amount of light but it is not very bright. It just creates a dull glow instead of lighting things up. I just use that one for flashing and annoying drivers.

fuzzynavel

I have had the bulbs out a few minutes ago and they are both 10W. so running at full power 20W on a 6 volt battery draws 20/6 = 3.33 amps. The battery I have is rated at 4.5Ah so should be fine....power just seems to drop off quickly

funkywindmill

I've converted several lights from bulb to LED ( not one like your,, but the principle's the same) There are two problems really, firstly, you have to dissipate the heat from the high power LEDs such as the Luxeon or the Cree, which means mounting with heat transfer paste on to a good heat sink. The other problem is the current limiting, most 3 - 5 Watt LEDs run from between about 3.1V to 4.5V depending on the type, Using a resistance as a current limiter is ok for smaller LEDs, but when drawing over an amp, you'll need a heafty resistor to do the job, and it's really inefficient.
Commercial units use electronic regulation, the regulator circuit boards are cheap enough, but you usually have to get about 10 at a time, (and from Hong Kong!)

I find the best high power LEDs are the Luxeon K2, I get them from Germany, they come the following day, and I think are post free from:

http://www.led1.de/shop/index.php?cName ... -c-111_206

These are very very bright, and will run at just about their limit direct from 3 NiMh cellswithout any regulation. You'll need to to use a reflector or collimator to make a beam.

I've just tried to insert an image of a converted maglite using a single K2, but can't suss out how to do so. Is there an easy way, I don't understand the options on the img button?

aracer

funkywindmill wrote:

I find the best high power LEDs are the Luxeon K2.

Where have you been for the last couple of years whilst every man and his dog has been making lights with and converting existing ones to use Cree XR-Es or SSC P4s? Those K2s are seriously superseded - less than half the light output for a given power input compared to either of those options.

fuzzynavel

Problem sorted now.

I took the bulbs out and gave them a clean....they had accumulated some yellow dust on them over the years that I have had them.....took a bit of scrubbing (and some solvents) to get it off but now the light is much more acceptable....I can do with only one light where previously I needed both lamps to be on....These bulbs are supposed to put out 200 Lumens and it actually looks like it now!....I got in excess of 4.5 hours last night which is much better. I can put the hotspot 20-30yards down the road and the light spill deals with anything closer.

alfablue

Hey good news!

andrew_s

These Everled bulbs are meant as replacements for the bulbs in the big 2/3/4/6 xD cell maglites. One may be useful in the 2.5W side of your light.

fuzzynavel

andrew_s wrote:

These Everled bulbs are meant as replacements for the bulbs in the big 2/3/4/6 xD cell maglites. One may be useful in the 2.5W side of your light.

Looks pretty good but the website doesn't fill me with confidence. Has anyone else used these?