Shockwave LED w/ NiMH C cells?

[sidwise]

Does anyone have experience using this light with NiMH C cells? The scant "brochure" that comes with the light recommends using it with alkaline batteries. It also says you can use it with other types, but to expect reduced output.

Anyone have first hand experience with this? How dramatic was the decrease?

BTW, I tried a borrowed Shockwave LED last Saturday night (with alkaline batteries) in a turbid quarry. Compared it with other lights I own. Certainly not as bright as my Light Cannon, but enough light that I wasn't disappointed. Seemed better than my UK C8 (with NiMH batteries). Any other real, underwater comparisons folks can comment on?

 

[herman]

Hi Sid,
Interesting question. I did a little digging and found some interesting stuff. Seems the light out of the shockwave output drops really fast for the first hour or so then does a gradule drop for the next several hours with alkalines.This follows the discharge curve of alkalines. Per Duracel, the MaH of their C's is around 1800 @ 1.5V. NiMH's have around 5000MaH @ 1.2V. The loss of 2.4V is surely going to drop the output but when you look at the voltage graphs of the NiHM and the alkaline batteries an interesting trend appears. The voltage (and light output) of the alkaline batteries does a quick drop and then slows but continues to drop fairly constantly. The NiMH voltage on the other hand drops fairly quickly from full capacity to around 20% discharge then hold steady until around 80% discharge. Considering that the capacity of the NiMHs is better than double that of alkalines, the time to 20% discharge is going to be fairly long. My guess is that while the light output for the first few minutes will be brighter with the alkalines but after the first few minutes and over the next several hours the NiMHs will outperform the alkalines. I have an LED 4-AAA light that I use NiHMs in. I will get a set of alkalines and see if I can tell any difference.

http://www.flashlightreviews.com/reviews/pt_sw_led.htm

 

[sidwise]

Thanks, Herman.

I'll take a look at the link. I may also try some unscientific testing this weekend, and see how things look.

- Sid

 

[GoBlue!]

Thanks, Herman.

I'll take a look at the link. I may also try some unscientific testing this weekend, and see how things look.

- Sid

Hey Sid, any followup on using NiMHs?

Jim

 

[Charlie99]

Per Duracel, the MaH of their C's is around 1800 @ 1.5V. NiMH's have around 5000MaH @ 1.2V. ........ Considering that the capacity of the NiMHs is better than double that of alkalines.......

Everything I've seen shows that alkalines have higher capacity. The 1.8AHr for an alkaline C cell you quote is either a bogus number, or is only for an unusually high cutoff voltage. The more typical spec for an alkaline C cell is 7.5Ahr.

 

[herman]

You may find this interesting reading on the subject.
http://www.greenbatteries.com/greenbatteries-store/nibafa.html