Lithiums ok in PT Attitude?

I've got 2 PT Attitudes that I don't use much anymore. I was thinking of putting them in my bug-out bags. I'd like to use lithium AAA's in them for the shelf life. Will lithiums hurt the Attitude?

Thanks.

Hmm, I don't think it's a great idea, the Attitude is already slightly overdriven. Lithiums would increase the current by 50% or so. You could pop open the heads, replace the leds with Nichia CS leds and increase the limiting resistance, to compensate for the lithiums' higher voltage. You'd then get somewhat less output with alkalines, but it would be hard to notice.

from what I recall, the LED's are driven pretty hard on alkalines, and lithiums aren't such a great idea.

You might want to try three lithium AAAs and a dummy cell.

I think it was milkyspit that used to use three lithium AAs and a dummy cell in a SL 4AA 7LED because four lithium AAs had to much voltage for the LEDs. He seemed to be pleased with it.

Can some one pls explain to me how with an 150 hour runtime (unreg of course
and about 50hrs to 50% I'm told) how those 3 leds are "overdriven"?

Thanks

MB

The "150 hour" runtime means that only a faint glow is left through most of that time. The leds are overdriven during the first few hours.

How could 3 sepearate LEDS be over driven by
6V when this light puts out just barely less than
my 1 LED Photon 2 which is also driven by 6V?
That's six VOLTS all to one led!

If the Attitude is "overdriven" it's the most anemic
"overdriven" output I know of.


MB

Overdriving is determined by the actual current that passes through the LED, not the nominal battery voltage under no load. As far as the current load and light output of the Attitude goes, I don't know a lot of the specifics. I used to own an Attitude, but I sold because I didn't like the strongly blue tint. The light output seemed OK to me given that it was small and had only 3 LEDs. That was 2 years ago, though.

The attitudes have resistor(s) in them to limit current using standard batteries but on AAA lithiums they push the LEDs at about 50ma/each which is pretty hard. IMO if you want to use lithiums put them in something else for awhile to drain them down to about 1.5v each or 6v/set instead of about 6.8v or so. Nichias can take 50ma but it does reduce the life over time.

The three leds in the attitude are in parallel, all going through a single limiting resistor. Unless the led Vf's are carefully matched, the current won't be quite equal between the three leds. So if 150 ma is going into the head, rather than 50 ma each it might be 70+50+30. Experiment has shown that Nichias survive 50 ma for long periods though. So if lithiums are putting just 150 ma through the head, that's less than I expected, and it might be safe, to at least one and probably two of the three leds, and maybe all three. The Attitude does have some nice built-in redundancy in the three parallel leds.

I think I'd just use alkalines unless you're concerned about freezing weather. You should check your BOB's once a year or so anyway, and keep the batteries fresh.

mykall said:

How could 3 sepearate LEDS be over driven by
6V when this light puts out just barely less than
my 1 LED Photon 2 which is also driven by 6V?
That's six VOLTS all to one led!

If the Attitude is "overdriven" it's the most anemic
"overdriven" output I know of.


MB

Click to expand...

Wow, I wonder if there isn't something wrong with your Attitude.
Maybe you need an Attitude adjustment! ;o)

Typically, a stock attitude puts out ~50 lux, and a stock Photon light about 30 lux.

Maybe you got an excellent bin Photon!!!
FYI a single new Nichia CS will put out more light than the Attitude.

Bob

pedalinbob said:

Wow, I wonder if there isn't something wrong with your Attitude.

Bob

Click to expand...

Well Bob there IS something wrong with my attitude since it
is probably putting out only about .001 lumen right now ...
mashed contacts..."dead Attitude syndrome" or whatever
they call it.

Anyway, I knew there had to be some sort of resistor limiting
current since how ever you slice it, there isn't much output
for a light that packs 4 1.5V batts. By comparison, I'd say
my RR 2xAAA puts out a smidgeon less than twice the output.

MB

If you were up to it you could try replacing the resistors in the attitude with ones that would allow a more comfortable margin of use and/or use the new nichias also.
It would be a $5 upgrade but would make a great forever emergency light (at least 15 years in standby mode).