Expert Advice Needed!!!

[oldgrandpajack]

Just took the shrink wrap off my Surefire T4. The T4 is the 3" Turbo Head with the N4 Lamp Assembly. The N4 is very rare and difficult to find. I have one, unopened, spare N4 Lamp Assembly. The N4 is the turbo equivalent of the R60 Lamp Assembly. Both the N4 and R60 are designed to be used with the Surefire B65 rechargeable battery. The B65 is a battery stick consisting of 4 NiCD batteries. Runtime is about 15 minutes with the N4 and R60 bulbs.

I want to improve the runtime by using 4 AA rechargeable batteries. Feel very comfortable using 4 AA NiCD batteries with the N4. Would 4 AA NiMH batteries have the same output under load with the N4? I don't have any electrical background. I don't want to shorten the life of these rare lamp assemblies.

Desperately need professional advice on this matter. I don't want to know that the NiMH batteries will work and give me longer runtimes than NiCD batteries. Know that already. I want to know if NiMH batteries will shorten the life expectancy of the N4 Lamp Assembly because they will be running at higher voltage and or current under load? /ubbthreads/images/graemlins/icon15.gif
Thanks,
oldgrandpajack

 

[JSWrightOC]

NiCd and NiMH cells have practically identical voltage output characteristics. However, NiCd cells typically have a lower internal resistance, which means that under a heavy current load the NiCd cells would be providing more voltage at the terminals than an equivalent-sized NiMH cell. If possible, I would measure the current drawn on the original NiCd pack (or if the lamp has a voltage and wattage or current rating, go by that) and first make sure that it does not exceed the discharge rate of the NiMH cells you plan to use. So, at least to my understanding, the lamp is at no risk of being subjected to overvoltage by using NiMH cells.