Bummed about UBH + E2C + P91 Configuration

[this_is_nascar]

My only intent for purchasing my 2-UBH was to run in the configuration above. Well, after recieving my P91 from Dan today, I thought I'd try it. Imagine my dissappointment to find out that in a short 8-minutes, my light shutdown due to the thermal cutoff of the SureFire 123-cells. I had certainly hoped I'd get 15 minutes of the 20 minutes from a constant on, before this thermal shutdown.

I'm still undecided as to whether I'm going to keep my 2-UBH's or not. If I decide to sell them, I will do so on the B/S/T Forum.

The UBH is great for the various other types of configurations which are possible, however it's just not handling the heat produced with the P91 setup. By the way, as soon as I achieved thermal shutdown, I reached for the light. Definately not a good choice. I've never felt a light get that hot and almost impossible to hold.

 

[brightnorm]

Nascar,

Sorry about your experience, it must be very disappointing.

Are your UBH's aluminum or brass? I think something similar happened to someone's brass UBH, which is a better conductor of heat.

Even though you bought the units for incandescent HOLA, I must say it's a marvelous vehicle for the KL1. At 3.9oz and only a 123's length longer than an E2e or ARC 2AA LS it will burn rock-steady for six hours and give you slightly less light for at least another half hour, before descending more rapidly.

As soon as I can find/make a proper holster it will be my EDC.

Good luck with yours.

Brightnorm

 

[Roy]

Well, I'm glad it wasn't something stupid that I did when I attempted a runtime plot(Reviews Forum)! I thought it might have been a function of my brass UBH, but I take it your's is al. I have had no problem with any other configuration of the UBH that I have tested.

 

[CiTY]

There's always the KL4, KL5 you could use it for, when ever they are shipped...

 

[doubleE]

If I bought a Surefire C3 with P91 would it suffer thermal shutdown after 15 min too?
Is this only a problem with the UBH or is it always an issue?

Thanks.
-doubleE

 

[eelnoraa]

Can someone tell me what is UBH?

 

[Klaus]

I think the C3/9P might behave similar when run left on its own - without cooling through the hand holding it - never saw any P91 runtime data with the light left unattended - I asked the very same question already on Roy´s runtime fiasco too.

The UBH might be worse due to less mass though.

Klaus

 

[monanza]

If the UBH was too hot to hold then it was not getting enough air cooling on the outside. This is not a UBH problem but rather a problem providing sufficient convective cooling on the outside of the body. Holding it should improve the runtime.

The UBH design could possibly be improved with slightly larger outer diameter, milled flats, deeper knurling, thinner anodize, and many other tricks that Doug has up his sleeve. One thing that may help is to wrap the batteries in metalic foil or shim (while avoiding an electrical short) thick enough to fit snugly in the pipe. This will eliminate the air gap around the batteries and help with the internal thermal resistance. It might even be enough to allow the batteries to run without shutdown (although I have not made any calculations to support this wild claim

).

Cheers.

 

[Charles Bradshaw]

UBH = Universal Battery Holder, made by Doug (CPF member). A custom item he came up with and got swamped with orders for. See the threads in Homemade and Modified Flashlights forum for more info.

 

[Klaus]

Originally posted by brightnorm:

As soon as I can find/make a proper holster it will be my EDC. Brightnorm

<font size="2" face="Verdana, Arial">@Brightnorm - I´m using one of the "old" Nite Ize "Spare Power" holsters - great fit for a UBHwKL1 as those were a bit too long for the the Mags they were originally designed for - and you can also carry a pair of backup L91 Lithiums - its a bit too tight for a spare set of 123´s though. If you want one and can´t get one those are on sale around here for real cheap so drop me a note (if your anonymous status isn´t such a nightmare anymore).

Klaus

 

[monanza]

Klaus, that truly is a nice setup. The surefire parts and the UBH fit hand in glove. Can't wait to get mine this week. The UBH's looked much greener in Doug's pictures. Yours looks very nice indeed. Congrats.

 

[Klaus]

Yup Monanza - but congrats to Doug - I´m just lucky

Klaus