My Mag85 wa1185's keep blowing!

nifreaky

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Within a week I have gone through 2 WA1185's in my new Mag85.
awman.gif


The flashlight hasn't even been properly used yet. It has just been used for, at the most, a minute at a time on about 12 occasions.

I have built the Mag85 as follows...
Kiu's high temp socket,
fivemega's 9x14500 cell holder
9x AW's unprotected 14500
Tailcap spring resistance mod
Boro lens
MOP reflector

Cells are charged used Alin10123's Universal li-ion charger set to 12.6v. Pack was left a few hours to rest after charging and had a voltage of 12.54v after the last instaflash.

The flashlight was not abused/knocked/dropped in between testing after installing charged pack and first attempt a couple of hours later when it instaflashed. Photo below of blown bulb and good bulb.

Regarding the term "instaflashed"....does this mean when the switch is pressed the bulb goes
poof.gif
. In my case the button was pressed and I got nothing, not even a momentary flash.

I am now onto my last WA1185. I am reluctant to buy another set of bulbs but I really want to perservere because this light is just awesome when it works. The other night I was out on duty and shined the Mag85 from my car to a colleagues car about 20 feet away and it they had to cover their eyes to stop their retina's from burning. Later on the same colleague asks me if that was the big station issue halogen. I said no and pointed at my new P1D CE on my belt. She just looked at me in amazement! I just shrugged and walked away smuggly.
grinser2.gif


IMG_0800.jpg
 

yellow

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around here the Halogen Bikelight guys keep using their 12 V Bulbs with 14.4 V Li-Ions and non of them knows instaflashing.
To me it happened this often, that I built a "small" NTC into the wires.
There are 1 Ohm models, diameter ~12 mm/3 mm thick, that also can stand the current draw. Just cut one wire and solder it in between.

On start the cold resistor acs as a soft start, within 1 sec at maximum (at Your current) the value goes down to almost zero.
Its barely noticeable and saves from melting the cold hotwire, thus greatly expanding runtime.

Only advice I could give...
 

yellow

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2 WA1185's in my new Mag85.

9x AW's unprotected 14500
AHHHH!!!
do I read this right?
You are using a 3D to 9AA adapter with 14500 Li-Ions?

thats way too much Voltage for the bulb
Welch Allyn 1185 Bi-pin Bulb said:
Specifications:
9.6 Volt BI-PIN Miniature Halogen Bulb
3.15 Amps
30.24 Watts
50 hour lamp life
817 bulb lumen output
or is this holder a "3 in a row / 3 strings in parallel", not "9 in series"?
 

JimmyM

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Running on 3 series Li-Ions, you need a regulator, or a lousy installation to cut down voltage/current. The 1185 is a 9.6 volt bulb. It'll run on 9 rested NiMH cells @ 10.8 volts. On Lithiums, you need to limit voltage to 11.1 volts and reduce the inrush current spike.

On the good side, it sounds like you've got a nice low resistance setup.
 

Lips

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9x14500 (protected) lithium ion to use in stock 3D for WA1185 or WA1331 operation


The protected cells have more resistance and should not blow the WA1185. Safer too!
 

nifreaky

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Thanks for the fast reply yellow. That sounds like an ideal solution. I have no experience at all of NTC's. Are these easily available at component stores?

Any ideas where I could get one? Can you post a photo of one so I know exactly what I am looking for?
 

nifreaky

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yellow said:
AHHHH!!!
do I read this right?
You are using a 3D to 9AA adapter with 14500 Li-Ions?

thats way too much Voltage for the bulb

or is this holder a "3 in a row / 3 strings in parallel", not "9 in series"?
It is "3 in a row / 3 strings in parallel".

Shall I take out the tailcap resistance mod?
 

yellow

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its not a very sopisticated method, but works, so ...

alqv6k4hqx8mqxqic.jpg

PS: the jokers entered a pic of the 2.5 Ohms version for all the values they offer.
sizes in mm. 1 Ohms is rated for 9 Ampere, 2.5 Ohms for 6.5 A

placing/glueing it to the body will evade rattling and give a quicker cooling. Even then it needs a bit of time to get the resistance up to the starting value (but then the wire is already heated a bit and should survive on/offs)

edit:
I' d leave all the resistance mods inside. When heated up, the wire wont blow and any additional resistance dims the light (even when not noticeable, its just inside the head, right) ;)
 
Last edited:

DonShock

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......Shall I take out the tailcap resistance mod?
Although it will reduce your efficieny a little, it would add in a small bit of resistance that will probably keep your bulbs from blowing. Although I haven't used the 9x14500 battery pack, I have had Mag85's with 9xAA and 3xAW li-ion C cells and have lit off both lights with the cells fresh off the charger with no instaflashes. I use a Kiu switch but don't do the tail spring resistance fix.
 

yellow

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Hi norm,
member northernlights has a tread of such a setup in custom and modified.

I got them here at an electronics store, so on AU, Cutter might also have such.

Costs under € 1,-- here, if You cant find one, I might send it
(but i m sure its available at Your place)
 
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