SF N62 Extended Run Heat Question. [Moved to Mods Forum by Al]

[K-T]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lemlux:
(...)Brock's site says that the SF 500 L N62 LA draws 7.65 V at 3.7 A.
(...)<HR></BLOCKQUOTE>

I have a different question concerning these values. I guess if the voltage under balast is more than 7.65V the bulb will break. Now if I try to build this rechargeable pack How do I know how the voltage will drop when the bulb is connected? Should I build the pack close to the 12V and expect it to drop or close to the "voltage under balast" (in this example 7,65V)? I hope you guys get what I mean.

This is something I am wondering/thinking about for some time.

lemlux: When SF sold the lexan 3" turboheads did the MN61 already exist? I am not sure but the highest/longest use for these lexan lenses might have been the N62.
I suggest you get a KT-series Pyrex Turbohead.

Klaus.

 

[ToddM]

If you really wanted to get crazy, you could wire those packs into a 14.4v configuration and run a 12 volt 50 watt MR16 bulb. You'd end up with ~7.5amp/hrs battery. Course further down the insaity line I think they make MR16 12 volt bulbs all they way to 150 watts. Though the most options are found from 20-50 watts.

You'd drop down to oh 80 minutes of runtime but with the overvolting you'd probably have near 70 watts of light. At least twice the N62 beam.

That is a 20% overvolting, however the bulb life on most those MR16's is 3000 - 4000 hours so even if you cut in a hundreth of that with the overvolting it's still longer than a N62's life stock.

You'd also not have to worry about a lens and have choices on your beam since they come with a glass lens and are usually available in flood, narrow flood, spot and narrow spot. Price is about $8-16 depending on brand/quality.

Course if it won't fit in your housing it won't work either.

I've used several 35 watt narrow spot mr16's in bike lights I've built and they throw a very smooth beam. I've since gone to mr11's for bike lights since they are smaller.

I'm still working on a way to get a 15 watt 6 volt mr11 narrow spot bulb into a maglight with 6 D 5000mah nicad's. It would be big, heavy and ugly, but it would run a equivalent of oh 20 watts in a tight spot beam for ~2 hours and be rechargeable. Either way it would see more use than my 6D maglite is now

Todd

 

[lemlux]

Size 15:

I just bought a pile of parts (excuse me, a construction kit) from member Surefire M6 that should arrive later this week.

- 3" turbo head (not the 2.5"!)
- 9P body + tailcap
- A19 Adaptor
- P90 LA
- Old style round bezel (to use with 9P)
- N2 LA for 3cell use
- MN60 225lm for 4 cell use
- N62 500lm for 4 cell use
- 4 new DL123s

It occurred to me that when I didn't feel like running the 3 cell N2 or the 4 cell MN60 in the Turbo head, it might be fun to use the N62 constantly with a larger power supply. I'm new enough to Surefire that I only presumed that the 3" lens was lexan.

I had visions of potting an A19 adapter with a dummy cell making bulb contact into the DB 8AA head or the Daycor project head. The dummy cell would be wired to the flashlight switch circuit. Then, whenever I felt like using the otherwise extremely limited use N62 I could simply screw the Turbo head on and go.

I'm not inclined to either:

a.) place any SF turbo head in a high battery capacity mod unless it delivers 350 L or more, or

b.) invest in another Turbo head to get a Pyrex lens at present. Am I correct that no 3" Pyrex lens retrofit is available?


Klaus:

When this 3" head was built the MN61 probably wasn't in production. I don't know if the MN61 was designed or if its run time was engineered to be non destructive for a full battery constant run in the 12PM. Ken Good simply asserted on the SF discussion board that the MN60 and MN61 would be runable in the 12PM turbohead.

Klaus:

I doubt whether any SF 123 LA normally sees nominal voltage for more than a few milliseconds during turn-on because of the significant lithium voltage drops under load. I would also hypothesize that NiMH cells which are nominally lower voltage might provide a "softer start" at turn-on that could enhance bulb longevity.

 

[lemlux]

Todd M:

I have considered, and may go ahead with a 14.4 V battery configuration. Perhaps with a compact round 55W aftermarket Pia halogen running light.

I've also considered and may go ahead using Welch Allyn's 552 L 7.2 v 2.77 A T-2 1/4 bulb. I have found that a Carley 1" deep 1 3/8" diameter aluminum reflector fits perfectly into a 2" long copper 1 1/4" union. It sits flush with the top because there is a detente in the middle so that pipes soldered into the union each meet in the middle. This 2" long copper union, in turn, has almost hte same OD as the ID of the threading in the middle of a Mag Light D head. If the top of the union touches the lens, the bottom of the union is recessesed about 1/16 inch from the opening. The union can be potted ito the Mag head and the reflector / lamp assembly can be easily removed from potted Mag head / copper union assembly.

I just haven't figured out where I would drill holes in the mag head to mount it to the light. I suppose I might simply pot a copper 1 1/4" pipe stub into the DB 8AA or project base and locktite the pipe stub into the bottom 1" of the union in the Mag head.

 

[Size15's]

I really should move this to the Homemades & Mods Forum...

The 3" diameter SureFire TurboHeads are Lexan. They are not retrofittable with Pyrex.

You could Mod a Pyrex Lens since the Lexan lens is snap-fitted and can be removed. How you'd go about fitting a Pyrex Lens into a SureFire TurboHead designed for Lexan is another matter.

Have you throught of regulating the supply to the bulb using electronics?

Al

 

[lemlux]

I'm toying with temporarily plugging a 3" SF Turbohead into a project light (30-year old Daycor 800 housing) stuffed with 6@ packs of 2.45 Ah 7.2 V NiMH A packs. That's almost 15 Ah in a combined battery pack that measures a little more than 2" by 2 2/3" by 6".

Brock's site says that the SF 500 L N62 LA draws 7.65 V at 3.7 A.

Txwest and others are down on the N62 lamp because it can run in a 4 cell SF for only about 3 minutes before causing 123 battery thermal shutdown, and because it quickly lowers delivered battery voltage to a point where it (a) isn't much brighter than a 200 L lamp and (b) blackens the bulb because it no longer gets enough power to properly execute the Halogen cleansing cycle.

My project light concept theoretically would deliver enough current within 10% of the starting 4 cell voltage to run for almost four hours compared to 3-minutes max in the SF. (As a rule of thumb, running 10% above or below the design voltage of a lamp will increase or decrease light output by about 30% but stay inside the working halogen cycle limits.)

(Alternatively, I could mate the T-Head to a DB8AA with 7 2450 mAh A cells and a dummy. and meet or exceed 500 L for almost all of a 35 minute run time. With 8 cells I could meet or exceed the 8.35 V that the 350 L MN 61 normally sucks at 2.3 A, but I'm afraid that I'd overdrive the lamp too much.)

My question:

Will the lens on the 3" Turbo take the heat from the 28W n62? It's longest SF intended runs are 20 minutes with a 350 L lamp or 60 minutes with a 225 L Lamp.

 

[Size15's]

Will it take the heat?

I doubt it - not for more then 5-10 minutes at a time.
Depends if you're out in the cold rain & wind.
You intend to use this as a constant-on light?
Why not run the N62 through a Pyrex Lens TurboHead?

Good Luck!

Al