johnridley: (Calvin vs Bike)
[personal profile] johnridley
I got a tiny little $25 flashlight, and while my $250 HID system is brighter, it's not much of a difference, and the HID is like 30 times bigger and heavier.


First, for comparison, my 13W HID headlight - to be fair it's 3 years old and I don't think it's quite as bright as it once was.


Next, the new flashlight with a 14500 li-ion cell (3.7v 900 mAH) loaded:


Same flashlight with 2 AA NiMH cells:


With 1 AA NiMH cell:


For fun, here's a Nashbar "Brilliant 2" 5-LED headlight - this is the sort of thing you'd get if you went to a bike shop and bought a $25 or so "bright" headlight:

I have ridden with it in a pinch if my main light died, but it's not fun. It's not really quite as dim as that, it's the camera settings, but the comparison is valid, I used the same camera settings for all photos.

Here are all three on the bar:

That's the new flashlight on the far end. They backordered the proper headlight mount, so I improvised something. Yes, it's tiny; about 5mm bigger around and 50% longer than a single AA cell. It came with an extension tube so you can put in 2 AA cells, but it's brighter with the LiIon (you can't use two LiIons, you'd fry it).

2 AA cells are 2.4v x 2.5A = about 6 watt hours. 1 LiIon is 3.7v x .9A = 3.33 watt hours. So, less run time but brighter. But not a LOT brighter, and I have a whole lot of AA NiMHs, so I don't know which I'll use in the end. The LiIons and charger were only $15 combined so it was a cheap experiment, and if they last an hour each I'll just use them while they last and keep the extension tube and some AAs as backups.

Tomorrow I'm going to try this in real life. Assuming it works out, I'm going to get another of these flashlights and an extra mount. I don't ride at night without a backup light, and at $25 I don't think there's much need to use anything else as a backup. Also the HID has been getting squirrelly; it took me a couple of minutes to get it to strike this morning.

Frighteningly enough, there is another flashlight that's significantly more powerful than this. It uses a SSC P7 LED, and users say it's "about the same as a car headlight". It does require 18650 LiIon cells though, the same ones in laptop batteries, and about $5 each.

Date: 2008-10-08 01:24 am (UTC)
From: [identity profile] c0nsumer.livejournal.com
Tonight I rode with a friend who had a DX special P7 flashlight strapped to his helmet. It and my TriNewt were just about the same.

Date: 2008-10-08 01:31 am (UTC)
From: [identity profile] johnridley.livejournal.com
Thanks, that's useful. I may get a P7 for my primary and use this as a backup. The P7 comes in around $45, which is outstandingly cheap for this much light. The charger I bought will do 18650s so I just need some cells for it.

I don't think I'd use it on high much though; it gets hot and burns up batteries fast in that mode. But these lights all have multiple modes.

Date: 2008-10-20 01:27 am (UTC)
From: [identity profile] isherempress.livejournal.com
Have you considered anything like this? Side-visible bike frame lights: Down low glow... reviewed on Kevin Kelly's Cool Tools site.

Looks pretty awesome.

Date: 2008-10-20 11:40 am (UTC)
From: [identity profile] johnridley.livejournal.com
Yeah, there's a guy on bikeforums that's been posting pics of those for years.

Really more useful for city riders than for me. 999 out of 1000 cars that approach me are coming from front/back. I do have side visibility, some active lighting, mostly reflectors.

For me, that's just another damn battery to have to carry. The only people I've seen online that ride with them are either people building bikes for show, or people who are just noodling 3 or 4 miles around town.

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