Double-Barrel max modification - help & opinions ?

Just recently became one of the 4AAA DB´s into my fingers and thought about maybe moding it with some LED - but thinking through it I thought why not use the CPF-proposed voltage-mod (reversing one barrel) to drive the voltage to 6v and have some real tiny really powerful cheappo E1/E2 wannabe competitor (OK - SF lovers don´t throw any rocks now). The bulb used is somewhat bigger than the usuall mag-like T1´s and are named TX15-2 according to the energizer website - so for the mod I would need a TX15-2 bulb with 5-6V - I thought that the DB 8AA might fit (runs on 4AA) but

T2-2 Bi-Pin 4/AAA 2.8 0.550 20
T2-3 Bi-Pin 6/AA 4.2 0.700 54
T2-4 Bi-Pin 8/AA 5.5 0.700 81
TX15-2 Bi-Pin 4 / AA 2.8 0.55 20

the energizer site lists the 8AA to be T2-4 ?

I haven´t one of the (I think older) 6AA/8AA to check against and would be happy if someone could comment on this - would the bulb of the 8AA (820) which seems to be a T2-x would fit in either the 4AA (420) or 4AAA (410) which both use the TX15-2 ?

If this works (if such a bulb does exist) I could imagine a very nice beam out of a not too big flashlight with acceptable runtime. Using the 0,7A rating would give probably 2H on the AAA and 4H on the 4AA on 81lm ..

Ideas & comments wellcome

Klaus

Klaus, got your email.

I don't have (have not seen) a newer style DB like the 4AAA.

The bulb in my 6AA is rather large, 7 mm diameter. The pins on it are thick, .75 mm. The pins are 4 mm apart (center to center).

Any other info you want?

Update

The 8AA bulb fits after **SLIGHT** modifications - had to enlarge the hole in the reflector a bit as the original bulb is 4,5mm and the 8AA´s is 7MM. The straight 4XAA/AAA instead of the serial/parallel setup is more or less easy - reverse two batts and slightly modify the end-caps to re-do the reverse protection - the switch assembly mod is just a tiny tape&bend-job.

And got the 8AA bulb from Energizer - now thats a nice complete warranty -

Result: nice & REALLY bright - worth the effort - recommended

Cons: Used it only with 700ma/1600mA NiMh´s - might be taking too much from Alkalines to get the same quality/power beam.

Klaus

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Klaus:
Using the 0,7A rating would give probably 2H on the AAA and 4H on the 4AA on 81lm ..
<HR></BLOCKQUOTE>

That's really good, you got any pics? What kind of run time does the DB's normally have anyway?

YC

UPDATE II

as I measured just around 4.2 to 4.4 V under load using the 8AA bulb using 4AA/4AAA Sanyo NiMh rechargeables I switched the 700ma 8AA bulb rated at 5.5V against the 700ma 6AA bulb rated at 4.2V - even brighter anbd whiter beam now - recommended ! Especially the small 4AAA DB I like a lot now after this tiny but effective modification.

Klaus

Klaus

YC,

no pics so far - the DB looks as usually and taking pics of the beams I didn´t got into so far - but will look into it and try.

No idea on the runtime of the "normal" DB - there had been other threads on the forum on the DBs earlier - you might check them out - I was modifying the DBs the minute I got them (almost) as I wasn´t impressed with the brightness "out of the box" - now I am - in my setup the runtime I calculated with the NiMh´s is approx 1 hour for the 4AAA and slightly above 2 hours for the 4AA based on the cell capacity and load - the 4AAA might be a bit less as the load is reaching 1C which might decrease the overall capacity a bit - but its my smallest/brightest light so far and I´m quite happy with it - I didn´t did any runtime tests so far with the DB´s as my 50 bucks project light kept me busy.

Klaus

OOOHH!!! A DB 4AAA actually utilizing 5-6V?? COOL! I have a double barrel 4AAA that i have been wanting to tamper with. I already have it wired for 6V operation but have not seen any bulbs that will accept that kind of voltage. I never thought of using an 8AA bulb. hmmm - a couple of questions:

1) how did you get a bulb from energizer?
2) how did u get it to fit? Dremel the
socket out?
3) what would happen if u used a battery
greater than 700MAH? like the new 800s.
Or alkalines?

COOOL modification!

P.S. Do u have any other lights u can compare it to? Like a SF E1 or E2?

Ledagent,

to answer your questions which mostly were talked about already earlier in this thread

1 - at least here in europe - I had to call Energizer for the bulbs as I was unable to buy them anywere else

2 - just enlarge the hole in the reflector from approx 4.5mm to 7mm - as I have no Dremel I just used a knife - the bulb socket itself is OK no need to modify it.

3 - with NiMh´s of 800ma instead of 700ma I would just expect a slightly longer runtime (didn´t saw any 800´s yet) - not really a lower voltage drop / higher voltage - with alkalines I guess you would get a higher initial voltage (so possibly better to use the 8AA bulb) but it would drop rather quickly as we know Alkalines to very fast drop the voltage under heavy load - I think with Alkalines the runtime/cost wouldn´t be as cool - Energizer actually must have had a reason to use the seriel/parallel setup - think about that the 700ma bulbs I´m using in the 4AA / 4AAA were intended for the parallel usage with double AA´s - now in the 4AAA we are running on single AAA´s - using the NiMh´s I believe is the right solution for that load and having the 6AA bulb also available solved the voltage drop problem almost perfectly.

Oh BTW - Energizer rates the L91 Alkaline AA at 0.4 hours to 0.9V under 1000ma load and 2.7 hours to 0.9V at 400ma - so maybe at 700ma load it would be around 1 to 1,5 hours - and this is for AA - with the AAA at less than half the capacity I believe it woudn´t make too much sense - but if you have four spare AAA to kill for a try ?

Sorry - no SF so far available - I compared it against a Mag 3D modified with a 60 lumen halogen bulb and it is pretty much on the same level - but with a nicer beam possibly due to the better reflector. Energizer rates the 6AA at 54 lumens and I´m slightly overdriving it so lumen-wise should be around 60 as well - Pelu mentioned Willie Hunt to have measured the Energizer specs to be a bit marketingdriven but so far for the 6AA I think they seem OK to me - the 8AA bulb is possibly too high speced at 81 lumens anyway as even Energizer themselves rates the flashlight using the bulb just at 60 lumens.

Klaus