Thursday, October 27, 2011

Lights Revisited

My primary night riding light is an old NiteRider HID I bought about 12 years ago. The battery has long since died. A replacement NiMH battery costs almost as much as some new LED based light systems. Plus that battery weighed a ton.

Enter 2011.  LED technology has finally crossed the 100 lumens per Watt threshold. My HID was around 50 lumens per Watt and required heavy ballasting circuitry. Nobody uses NiMH batteries anymore either. They are lithium ion these days. NiMH batteries pack about 100 Watt-hours per kilogram density, while Li-ion pack more than twice that. So with the lights available today, I can get twice the lumens for twice the run time for less weight than my old system. That is a four-fold improvement just over 10 years.

I ordered a new XML-3 and updated 400L+ from DiNotte Lights this week. I was holding them my hands the day after I placed the order. Standard shipping, no charge. Benefit of buying local. Visually, the quality looks impressive. Reviews on the forums are quite positive on any DiNotte light. I spoke with Rob @ DiNotte when placing my order and he was happy to answer all my geeky technical questions.

The XML-3 and 400L+

I bought the XML-3 to go on the bar. It puts out 1200 lumens in high setting. My old HID did 500 lumens, and I thought that was way brighter than anybody needed. The new light weighs a fraction of my old light. The 400L+ will see dual use. Riding, it will go on my helmet. Rob threw in a headband mount so I could also use this light for XC skiing at night. I'd only need to run it on low in snow, so it would run several ski sessions on one charge. You don't want to look into these lights. You will see spots for a VERY long time afterwards.

I updated my metrics table from a prior post. A few other companies have updated their lights. Almost everybody uses Cree XPG or XML diodes. The XML's are newest with highest efficiencies. Performance metrics between lights vary widely. Many companies boast theoretical lumens, as in what some data sheet says is possible under some specific condition. Others will measure their lumens.

Lights to avoid are designs that push an extraordinary number of lumens per emitter. I believe anything over 500 lumens per XPG LED is asking for trouble, in terms of shortened diode life, overheating, and degraded efficiency.

You can see DiNotte compares favorably with the best. I highlighted in green the options I have to work with. I have one 2-cell and one 4-cell battery. You can see just by putting a bigger battery (2-cell to 4-cell on the 400L) on a light, you can improve the performance and cost metrics.

I would have liked the XML-1 instead of the 400L+. The problem is, the XML-1 wasn't designed for headband mount. It is tiny and very efficient. I could probably have cobbled something together, but Rob's headband for the 400L+ is one of the better headband light systems out there. I had to wear my bicycle helmet to use my HID light skiing. Goofy.

Exposure Lights boast some of the highest performance metrics in the industry. With batteries integrated right into light, they save on cable weight. Cost metrics are ok, but not best.

Generally, more LEDs used to generate the lumens raises the performance metric, but lowers cost metric. Lupine pushes this to the limit. They have the brightest, most efficient lights, but for almost $1000. The new DiNotte lights derive their high performance metric from the XML LEDs.

Could be a while before I get to use my lights. Need to let my leg get strong again. I'm walking pretty normally today on no pain meds, a vast improvement from yesterday.  My HR hasn't gone above 60bpm in three days. I was contemplating jumping on the trainer for a bit. But noooo. Apparently Dr Heaps recognized I would be Jones'n for fix before my first check-up next week. While I was in recovery Tuesday, he had a word with my wife. Cathy was instructed to block any attempt of mine to do something stupid. Bummer.


SteveS said...

I'd like to see someone do an analysis of how much light you actually need. I've been using a set of Ay-Up lights for 2 years and their 400 lumen lightset seems more than adequate for on and off road. Going much more beyond that and it seems like you're sacrificing weight or runtime for something you don't need.

Hill Junkie said...

How much you need is pretty subjective. I used to think 500 lumens from my HID was more than enough. I suspect I will run the XML-3 at the half power setting, which should still be brighter than my old HID, to get 5+hrs run time. The XML-3 weighs 355g, the HID 980g. More lumens, longer run time, and much less weight. I think of it more as having lots of margin. Going for a 2hr night ride with 2.5hr run time is risky, especially as battery ages or if it is cold out. Run at half power, there is still enough light. Generally, most light systems are sized to run about 2.5hrs. So if you want to go longer with enough light, get twice the lumens you need and run it half the power. The system runs more efficient at reduced power too, more lumens per Watt and more Watt-hours out of battery.

plum said...

Riding super technical stuff at night will make you a lumen junkie. I've hit my head way too much in the past, and this is easy insurance.

I run my 1200 on full; cold nights do get me to the 20% warning quicker than I expect, but I manage it thereafter and get out alive. I'll probably buy another 4-cell. The weight really doesn't bother me; at night I'm already carrying backup gear anyway.

rick is! said...

I love my dinotte 800l and 400l light set-up. I generally only use the 800 on full for fast downhills, otherwise I conserve battery life by using it at 50% and that is generally plenty of light.

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