Okay, I finally burned through my first set of Silver Oxide cells (Energizer 357). Got about a week of use out of them. Pretty good, really, for something that runs off of tiny button cell batteries.
For the record, LuckyDuck says the unit uses the "H" size battery, but what is included are L1154 cells, which are "J" size. These are also known as SR44/LR44, S76/EPX76/A76, 357/303 and several other variations of those letters and/or numbers. They are very common button cell batteries used in watches, cameras, clocks, kitchen timers and the like. Most available are the cheap Alkaline variants (A76/LR44/AG13) which work fine in watches and timers, but rather poorly in higher drain devices like cameras and lasers.
After trying the LuckyDuck Jasper Keychain green laser with Alkalines when I first received it I was ready to pack it up and send it back. I burned through 3 sets of Alkalines in a couple of hours of intermittant playing. Couldn't run the unit for more than 15 seconds without a significant drop in power, and had to wait a while for the batteries to recover before I could get any useful output again. Deffinitely not good with Alkalines (AG13/LR44/A76, etc.).
Decided to try some Silver Oxide cells before giving up on the unit, and I'm glad I did. MUCH better performance with the silver cells. Continuous on times of up to a minute without a noticeable drop in power (note: I didn't try anything much over a minute because green "pointer" style lasers are not designed for continuous running). Even after a week of use I could still get a minute of stable output.
There was some loss of brightness over the week of use. But it was still capable of producing a visible beam, and it didn't have to be totally dark to see it. This is not unexpected, as Silver Oxide cells do suffer from some voltage drop over their useful life (similar to Alkalines). Unlike Alkalines, though, they don't drop voltage under load so they are better suited to devices that draw moderate amounts of current.
On the 8th day, after some heavy playing, I finally started seeing the power drop off sharply (similar to what I experienced with FRESH alkaline batteries). I'm sorry I didn't keep track of the total run time I got out of it, but I am quite pleased with the useage I got from the silver cells. Battery life is still nothing to write home about, but it is more than enough to make this a useful tool.
If you use a green laser pointer heavily, and battery life and cost are a concern, then a "pen" style 2xAAA battery unit with rechargeable cells might be a better choice. But this pointer is around half the size of the pen style pointers, so it's a lot easier to carry around.
The down side to this is, or course, Silver Oxide cells are a lot more expensive than Alkaline button cells. Locally I found the Energizer 357 cells at Wal*Mart for $4.87 for a 3 pack. At Marukai I can get AG13 Alkalines for 99 cents for a 10 pack. That's a 49:1 price differential!
What's that you say? Buzz kill! Well then, have I got a URL for you!
SR44.COM!
As low as 49 cents a cell, and free shipping on orders of 25 or more. I ordered a 25 pack on the 25th and received it on the 1st. And that was to Hawaii!. At $16.49 and free shipping that works out to just a hair under 66 cents a cell. They are the exact same batteries I purchased at Wal*Mart, only bulk packed. The Wal*Mart batteries (with tax) were $5.07 for 3, or $1.69/cell. I'd say that was worth a few mouse clicks and a week wait.
Just a few more observations about this laser.
As I mentioned before, the chrome finish scratches off really easily. And I don't mean just scratches; I said scratches OFF, as in "oh look, there's brass underneath". If you care about appearance, then you should consider wrapping it in clear tape, or some clear heat shrink tubing. I'm going to try the latter, but I haven't gotten around to it yet (mine's already scratched to hell, so I'm in no rush). My only concern with the heat shrink is if the amount of heat needed to shrink the tubing will hurt the laser? Anyone know if heating up a greenie briefly will harm it?
The laser is supposed to be pulsed output, but it didn't look pulsed to me until my batteries got very weak. With fresh cells I tried sweeping it across a wall and didn't see any dashed lines. Maybe I wasn't sweeping it fast or far enough? Anyway... once the batteries got weak I did notice some dashed line effects when sweeping the beam.
The unit seems to have some kind of power regulation. When you press the button it turns on pretty bright, but it seems to fluctuate slightly for about a second, and then the beam brightens up notceably and stabilizes. It maintains this bright, stable output until you power it off (or the batteries poop out). Maybe something to do with the pulse circuit? I dunno... but it's something to be aware of if you want to use it in very short bursts since it will affect how bright it appears.
As for the parts unscrewing (per the LED Museum's review) I have not run into this problem. I have mostly been carrying it around hanging from my belt (clipped to a belt loop), or in my pocket. Maybe it's only a problem with a bunch of keys banging against it? Seems like a little drop of LocTite should solve that problem.
Well, this turned out to be a lot more than I had planned to type. Sorry for being so long winded... I hope someone finds this info useful.
Aloha, iG (Tim)