8/13/15 9:15 AM

I was under the mistaken impression that LED lights had consistent output until the battery died (for the load imposed.)

The other day (evening) I swapped out batteries because the taillight was dimming and "just wanted to make sure." It sure got brighter.

Today I decided my headlight was too dim and ran a simple test. Ask for test details if you want, but I used a camera for a light meter and tried to be consistent.

Old batteries: 1/30, f4, asa 2000
New batteries: 1/80, f4.8, asa 400

I don't know if that means the new batteries are 7x as bright, power of 7 as bright or whatever, but they look a helofalot brighter.

So how do we approach this?
It appears the batteries will last "forever," or at least many half-lives.

8/13/15 9:27 AM

not necessarily whether or not its an LED.

Last edited by walter on 8/13/15 10:58 AM; edited 3 times in total

8/13/15 9:29 AM

In other words, you get what you pay for?

8/13/15 9:36 AM

are you asking about batteries or lights?

8/13/15 9:50 AM

Yes.

;0)

But the lamps are the constant in this case. I knew my word choice wasn't supreme.

Also, the OEM battery is "heavy duty" and the new ones are drug store alkaline. I would've gotten NiMh but the drug store didn't have them in AAA.

Since my test is so quick I think I'll just run it occasionally and when the variables have fallen off maybe "1 f-stop" apiece I'll replace the batteries.

Unless this creative bunch here comes up with something better!

I like the circuitry direction, but I'm cheap.

8/13/15 9:59 AM

Your impression was indeed mistaken. In general, LEDs are very sensitive to voltage drop, and if the light doesn't have circuitry to maintain the voltage being delivered to the emitter, the lights will dim substantially when the batter still contains more than half its energy capacity. Better lights will maintain the voltage -- until the battery drops too low. So they won't dim, but will eventually just stop altogether.

As Walter's chart indicates, Nimh batteries have a flatter curve. They are also less resistant to damage from being recharged when only partly discharged (in contrast to Nicad). I use a lot of lights (including several cheap taillights without the fancy circuitry), and I just swap the rechargeable batteries on a regular schedule -- weekly for the commuter bikes. That way, I know I'm always getting full brightness.

It's worth investing in a smart charger and a few sets of the new-generation Nimh batteries, which resist the "self-discharge" the earlier ones are prone to (i.e., they don't run down just sitting on the shelf).

The worst choice is non-rechargeable alkalines; you'll either be running dim lights half the time, or throwing out lots of half-good batteries. Rechargeables are the only way to go, IMHO.

8/13/15 11:07 AM

sanyo "eneloop" were an early big name and honestly make the best batteries, but they are premium priced.

i've tried several niche brands and the QC just isnt up to snuff and the batteries suck.

better off spending your $$$ on real eneloops. although i did just start buying GS-Yuasa's low-discharge AAs this year -- they're pretty dang good and cost less than eneloops.

no matter which NiMH batteries you get, definitely get a multi-mode smart-charger.

8/13/15 11:18 AM

When the NiteRider Lumina hit the market at unheard-of pricepoints for the performance, I decided then and there that I was done with cheap lights.

Lumina 350 can be had for $59 online and provides years of full-bright lighting for safe riding at night.
I bought a Lumina 650 as well so have one in use and one sitting charged at all times. I can use both for night time mtb rides.

I kept my DiNotte 200 for the sake of it's performance using four rechargeable Nimh AA cells (which I always have around), but haven't really needed it for the last few years now.

I'm so glad that the light market is now mature enough that I don't feel the need to constantly be shopping for more-adequate lights.

The fifteen years that it took going from the really heavy, fragile, wire dangly, expensive and home-made systems to today's lightweight, self-contained inexpensive wonderlights feels like an eternity, but the future is now here and it is time to get yourself a decent, modern light!

8/13/15 9:32 PM

I bought some of Amazon's house-brand low-self-discharge batteries recently. They're a little cheaper than Eneloop (which now carry the Panasonic name, since Sanyo is basically gone). So far they seem good, with capacity as advertised. They haven't been through enough cycles yet for me to tell about long-term life.

8/14/15 4:21 AM

Legs turn, lights go on. Batteries are so 1990s....

8/14/15 4:22 PM

have there been any developments in affordable, ultra-bright tail lights? There are plenty of options for bright X-ML T6 front lights driven by a 18650 battery, but I have yet to see the equivalent in a tail light.

8/14/15 4:45 PM

NiteRider used to advertise it's "Cherry Bomb" tail light that was supposed to be very bright and daylight visible.

I do know there are some LET tail lights claimed to have 2 watt LEDs that should be very visible, perhaps annoyingly so. I've seen a couple that are painfully visible even in full daylight and from a remarkable distance.

8/14/15 5:32 PM

Do you need them? Obviously headlights need to throw a beam so you can see, whereas tail lights just need to be seen. I never have trouble seeing tail lights, and as Dave says, ultra bright ones may be annoying. That said, the generators I use drive both good quality head lights and tail lights.

Speaking of annoying, has anyone else noticed a trend for some riders to use blindingly bright, blinking head lights in broad daylight? I see this, need to look away they are so bright, and there is absolutely no reason to use them in good light. I have expressed my opinion of these, but I'm not sure it makes a dent. I think they must be new riders who figure the more light the better, in any circumstances.

8/14/15 7:18 PM

IIRC, the Dinotte was considered the brightest tail light a few years ago, and users pretty much swore by them.

An ultra-bright tail light is far less annoying and blinding than the equivalent front light. Furthermore, my main worries driving at dusk are being seen from behind. Especially left turns in traffic, overtaking cars with no/minimal bike lane.

I just don't understand why someone hasn't developed an affordable XM-L T6 tail light that you can pop in a 18650 battery and never have to worry about being seen from behind again.

8/14/15 7:19 PM

IIRC, the Dinotte was considered the brightest tail light a few years ago, and users pretty much swore by them.

An ultra-bright tail light is far less annoying and blinding than the equivalent front light. Furthermore, my main worries driving at dusk are being seen from behind. Especially left turns in traffic, overtaking cars with no/minimal bike lane.

I just don't understand why someone hasn't developed an affordable XM-L T6 tail light that you can pop in a 18650 battery and never have to worry about being seen from behind again. I mean, I just bought a small and lightweight XM-L T6 flashlight for less than $5.

8/15/15 7:33 AM

I am not sure how bright you are looking for but I have seen some bike lights that sure seemed plenty bright to me.

8/15/15 8:12 AM

fenix makes a skinny XML right-angle torch that would strap nicely onto a seatpost. just change out the white emitter for a red one, add some blinky modes, you have yourself a winner!