Need your expert advice!

[oldgrandpajack]

I am hoping to have DSpeck make me some AA battery holders for the new 5 watt Surefire KL series. From the posts I've read about the KL4, there is a substantial amount of heat to deal with. Plan on cooling fins. After reading the excellent posts by The Prophet, I think only Nickel Cadmiums will do. Want the longest runtime possible.

Tell me the highest capacity nickel cadmium AA batteries available and where to buy them. I also want good quality batteries for long life and less chance of leakage.

Thanks,
oldgrandpajack

 

[FalconFX]

Call me crazy, but Nickel Metal Hydrides would be the best choice for the longest runtime possible. Nicads are usually half the capacity of NiMHs, and NiMHs can deliver the same high power current as their counterparts.

And if you are worried with the discharge rate of NiMHs, you really shouldn't even be looking at rechargeable AAs in the first place...

 

[oldgrandpajack]

[ QUOTE ]
FalconFX said:
Call me crazy, but Nickel Metal Hydrides would be the best choice for the longest runtime possible. Nicads are usually half the capacity of NiMHs, and NiMHs can deliver the same high power current as their counterparts.

And if you are worried with the discharge rate of NiMHs, you really shouldn't even be looking at rechargeable AAs in the first place...

[/ QUOTE ]

Hi Crazy:
Thanks for your input. I know that NiMH would give me twice the runtime, but according to The Prophet they should be kept at about 20 degrees C. for long life. As with all flashaholics, I am afraid of the dark. When I light up that KL4 at the beginning of a walk, it's staying on till I get home. On another post, it was stated that the head of the L4 was 140 degrees F. after 15 minutes. The body was btween 110 and 120 degrees F.. I wish I knew how to link The Prophets post, about heat and NiMH batteries, here. It was very informative! My quick searches with Google have found 1,000 mah AA Nicad's. Are there higher capacity AA Nicad's available? Believe me, My first instinct was to use NiMH's. The Prophet's Post convinced me otherwise.
oldgrandpajack

 

[FalconFX]

I know Sanyo has some 1100mah (1100-1150mah) NiCads...

Their Cadnica series:
http://sanyo.wslogic.com/pdf/pdf/KR-1100AAU.pdf

Beyond that, most others are about 1Ah of runtime...

BTW, Sanyo's TwiCells (NiMH) were able to withstand 50-degrees Celsius discharge (122-degrees F), so I don't believe you'll need to worry about them crapping out on you if they get hot...

And also, check this out:

http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_NiMH_HHR200AAB.pdf

Panasonic has their NiMH battery rated to 65 degrees Celcius (150 degrees F) discharge, which should work fine in an L4...

 

[oldgrandpajack]

[ QUOTE ]
FalconFX said:
I know Sanyo has some 1100mah (1100-1150mah) NiCads...

Their Cadnica series:
http://sanyo.wslogic.com/pdf/pdf/KR-1100AAU.pdf

Beyond that, most others are about 1Ah of runtime...

BTW, Sanyo's TwiCells (NiMH) were able to withstand 50-degrees Celsius discharge (122-degrees F), so I don't believe you'll need to worry about them crapping out on you if they get hot...

And also, check this out:

http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_NiMH_HHR200AAB.pdf

Panasonic has their NiMH battery rated to 65 degrees Celcius (150 degrees F) discharge, which should work fine in an L4...

[/ QUOTE ]

Thank you FalconFX! That helps a lot. Have you used these much?
oldgrandpajack

 

[FalconFX]

Quite frankly, I don't think you need to worry about NiMHs crapping out on you inside the L4. 20 degrees C is recommended for optimal discharge, but that doesn't mean that the batteries can't handle anything higher. As a reference, the Nicads suffer the same drop in performance when their ambient temp rises...

Besides, if you're outside, moving air temperature itself is enough to dissipate some of the top end of the heat generated by the light. Your hands should also help to dissipate some heat. Plus, I seriously doubt the L4 is going to see anything like 120-140 degrees F, unless it's sitting inside a purse or otherwise isn't being moved around while it's constantly on...

And yes, I have a pair of the Cadnica series, although it's the 800mah series, not the 1Ah brand... It works quite fine, but ever since NiMHs rolled around, these cells have been relegated to the closet... I just don't use Nicads anymore...

 

[oldgrandpajack]

Well, it took a while for me to stop laughing. You haven't seen me walk. Takes me over an hour to go a mile. Not a lot of air movement there! Seriously, I'm tempted to try NiMH in spite of what The Prophet said. Could you tell me what the runtime should be with 4 2200mAh Powerex NiMH batteries, with a fresh charge? The L4 gets about 65-70 minutes from 2 new Surefire 123's.
oldgrandpajack

 

[FalconFX]

The NiMHs should give you a longer runtime than the 2X123s...

Hopefully, I'll get my L4 delivered to me today (it's scheduled for today)... I forgot what current the L4 was pulling from the top of my head, but I'm guessing if the 123s, with 1300mah capacity, gives you about 70 minutes of runtime before end of regulation, you should expect something in the neighborhood of 75% more runtime than that with 4 NiMHs (about 1.5 hours)... In that retrospect, I'd figure if it's draining about 1Amp of current, you should see a little more than 1.5 hours of runtime before it falls out of regulation...

 

[oldgrandpajack]

Wow! I was hoping for a longer runtime. I may have to wait for the KL5 and use 6 AA 2200mAh batteries.
oldgrandpajack

 

[FalconFX]

Remember, though, that this is REGULATED runtime, meaning possibly 1.5 hours of near-steady output before it starts dimming... It should provide hours of moon mode light afterwards...

I might have to try out the 4xAA route myself, just to confirm runtimes...

 

[Brock]

Actually I am currently test running the KL4 on 4 NiMH 1800mA AA's. So far so good. I have gotten about 55 min out of them. 5 works out a bit better and doesn't seem to overdrive the regulation, but 6 does get it above its regulation point.

I think 4 AA's would be the way to go with the KL4.