Will all LED's take rechargeable NiCad's

lightfreak

Newly Enlightened
Joined
Aug 9, 2006
Messages
7
I'm sorry if this has already been posted. I have tried contacting Premierlight and they don't seem to be answering my emails. Thanks
 

vortechs

Enlightened
Joined
Feb 11, 2006
Messages
859
Location
Tucson, AZ
It depends on a lot of things. If you post the specific type of flashlight you want to use NiCad's in you'll get a better answer. Rechargeable NiMH cells are much more popular here than NiCads.

The lower voltage of a NiCad cells (1.2V) and NiMH cells (1.2V) compared to an Alkaline cell (1.5V) can make a direct drive light rather dim.
 

Planterz

Flashlight Enthusiast
Joined
Dec 14, 2005
Messages
1,162
Location
Tucson, AZ
I think it depends more on the flashlight's circuitry than the cells.

Some lights will be dimmer with a NiMH than with an alkaline because they have lower voltage (1.2 vs 1.5). Lithiums will be brighter still.

Some will have identical (or close enough to it) output with either alkalines or NiMHs. These have regulation circuits that boost the lower voltage.

In either case the NiMH will still give better overall performance. An alkaline simply can't pump the juice like a NiMH can, nor does it sustain its voltage as well.

Thus, even in a flashlight where the initial brightness is higher with an alkaline, after a bit of time, the alkaline will be dimmer while the NiMH is still going strong. For example, with the full 3 volts your stock Minimag bulb will burn brighter on fresh alkalines, but this doesn't last. With NiMHs it might not burn as brightly at first, but it'll still be going strong when you're at the point with your alkalines where you're looking for another set of batteries.

With flashlights with boost circuits, using NiMHs will not only give you the same output, runtime will be greatly increased. Take a look at the runtimes for the SL Propoly Lux or Fenix L2P.
 

Planterz

Flashlight Enthusiast
Joined
Dec 14, 2005
Messages
1,162
Location
Tucson, AZ
Er, I just noticed we're talking about NiCads, not NiMHs. :ohgeez:

NiCads have fairly good discharge curves when compared to NiMHs, definitely better than alkalines. However the capacity is much less than NiMHs. I really can't say how NiCad capacity in high-drain devices like flashlights compares with alkalines. I'd expect that you'd get great performance until the big "dump", while with an alkaline you get a more gradual, consistant drop in performance. But I have no idea where the standard 50% output curves would be compared to each other.

All things considered, I guess this still begs the question "why bother?" Many companies that make rechargable flashlights still make them using NiCads (Surefire, Streamlight, Mag) rather than NiMHs (or even li-ions) because they're more durable (abusable), but most of us more knowledgable types prefer NiMHs (or li-ions) over NiCads. Just don't over-discharge them.
 
Top