NiMH or LiIon for daily D10 use?


Jun 16, 2005
Home of chocolate and chalets
I am using my D10 daily about 30 min as my secondary bicycle light. I am wondering which rechargable battery would make more sense for this purpose. NiMH seem to have 100-200 recharge cycles, whereas LiIon have several 1000 cycles. From this perspective I should go with LiIon.

On the other hand, with a LiIon in the D10 the light runs on direct drive (see Chevrofreaks runtime graph In my case my light would run on direct drive most of the time. This just might shorten the LED lifespan. An argument not to use LiIon.

What do you think? Should I stay with NiMH or switch over to LiIon?


Nov 9, 2005
Um.... depends what your goals are:

NIMH: You can get good AA NIMH cells for about $2 each. Which is much cheaper than the cost of a single quality protected 14500 li-ion cell. Eneloops will probably last longer than 100-200 cycles as they are very robust cells. You can probably pick up a 4 pack and cycle them for years in this application.

Li-Ion: Considering the direct drive behavior of the light with a li-ion cell, the drain rate for what the cell is designed for is on the higher end of the scale, you will not get 1000 cycles out of a lithium cobalt chemistry cell that is used in this manner. I would venture to guess that you won't get any more cycles out of a 14500 li-ion in this application than you would out of an eneloop.

With that in mind, pick the 14500 if you want more output and don't care that the cost of operation may be slightly higher or similar. (either way you are using rechargeable cells and the cost of operation is going to be very low if you are using the flashlight daily). Pick the eneloop if you want a more conservative drive level that might be easier on the flashlight ("might" being the key word here, when you consider that on the NIMH cell, the boost circuit is working a lot harder).

If you already own a good NIMH charger, I see no reason to switch. If you have both charger types, then you can experiment and see what you like and you're only out the cost of a couple cells and shipping. If you are seeking more output, your best bet is to upgrade to a more powerful setup and not try to obtain that higher output by switching to a li-ion cell as the difference probably isn't going to be enough to have an MAJOR impact in actual use.



Newly Enlightened
Dec 28, 2005
Good question! I just purchased a D10 for the same application--secondary bicycle light. Though I'm currently using only NiMH, I will be getting a couple 14500s for it, mostly because it's a hobby and I want new stuff. But I'm justifying it by telling myself I'll get somewhat better performance from the 14500. My one way commute is about an hour, so dimming down the Li-ion cell a few steps should ensure me adequate runtime with no loss in output relative to NiMH. Note that I won't typically have it on the whole ride--just a few areas where I appreciate the extra lumens. However, if my main light goes out, it will become my primary handlebar light.

Given your shorter ride, I might stick with NiMH.



Feb 16, 2008
Oklahoma, USA
I love my Eneloops. They feed my D10 for nightly walks. The light would always last the full 45 minute walk on full brightness, and when I got back I could pop a new cell in for the next night.

I actually like that on NiMH it doesn't run direct drive like it does for the first few minutes of runtime on 14500. And, you can get a pack of 4 Eneloops for about $10. That translates to more runtime per dollar spent which makes Eneloops the winner for powering my D10.