On a recent 8 day hike around Kejimkujik in Nova Scotia (awesome trip and park BTW), the batteries died out. (I know that for some reason I took out the original Panasonic batteries and used a pair of SureFire batteries in it, and then put the Panasonics back in.) No problem. I pulled out my extra batteries, put in another pair of CR-123's (Evergreen), pressed the button, waited for the green LED to start flashing, put it in the water, I got a momentary flash of blue UV light, followed by a rapidly flashing red LED.

It wouldn't work.

So two days into a week+ long trip, I was forced to turn to Micropur tablets in my survival kit. Which ran out after 3 days. Then I had to boil water, which used up a limited supply of methyl hydrate. I had intended the alcohol to be used just for boiling water to rehydrate meals, not for purifying water. Eventually I was reduced to using fire to purify the water. Having to stop repeatedly to boil water is a pain in the ass. When it's the middle of summer and you're drinking 8 or more liters of water a day, having to wait for your boiling water to cool down is a pain in the ass. Pouring it from bottle to cup repeatedly helped cool it down. But it was all inconvenient to say the least.

When I got home I checked the batteries and they're fine. According to my battery tester they're at full power, and they have no problem sending forth a bright beam from either my Sure-Fire or Fenix lights.

I've been a bit hesitant about relying on a battery operated device for something as vital as water. I had it proved to me why. Water purifiers are really about the only thing that I, and others I've ever been out in the bush with, have had issues with. I strive to reduce the weight and bulk of what I'm carrying, but this is one area where the adage of two is one, one is none is spot on.

I got in touch with the company, and they told me that based on previous testing and experience, the lesser known brands of batteries are not very good performers. Many of the lesser known brands do not have the capacity to deliver more than 0.5A at the rated voltage. The high quality (well known) batteries can deliver 1.25A at the rated voltage which is why they are able to perform better. Basically, the more famous the brand, the better the quality. Energizer batteries are typically the best for the SteriPEN Adventurer followed by other well known brands such as Kodak, Sanyo, Duracell and Panasonic.

Maybe if I'd spent time over on CandlePowerForums reading up on obscure battery minutia, I'd have known, but anyway... I guess it just never even occurred to me. They worked fine in lights, why wouldn't they also work in anything else? You know what they say about assuming.

As it turns out, different batteries (especially CR123's) work very differently in different devices. Surefire batteries are made for tactical lights (low peak amps, maintain max volts for as long as possible, constant load and heat control), while Energizers are made for cameras (strong peak amp draw while charging the flash, then low load and minimal heat issues). Use a battery made for a different application and you will get bad results.

When it comes to, say AAs, I've put them in walkmans, flashlights, GPS', cameras, radios, etc., and they've always worked. Name brand, cheapo dollar store, rechargeable, whatever. They've always worked in anything.

Just never dawned on me that it wouldn't be the same with CR123s.

I get that cheap batteries that may not let something run as long. But for something to completely not function at all - totally unsat.

When I bought the unit from TADGear, I bought a box of Evergreen CR123's to accompany it, thinking I'd gotten a great deal. Certainly as compared to buying a single CR123 from a camera store, it was.

The discovery that they lack the oomph to power the Steripen though, leaves me unsure whether to be unimpressed with the batteries or the Steripen. To me this is a MAJOR flaw in the system.

Finding this out leaves me rather underwhelmed and regretting ever buying the Adventurer to be honest.

If I'd known this in advance I would have opted for one of the AA models. Easier to get, cheaper, and something tells me that I could throw any brand of AA in there and it would work fine. Although as it turns out, Steripen claims you should only use Lithium batteries as anything else won't push enough current through.

I guess I could go out and spend another $100 and buy another Steripen, one of the AA models. But if I'm going to spend another $100 on any water filtration system, I'll spend the money to make myself a gravity filter.

I'm not denying that I'm a dummy for not checking before hand to see that the Evergreen batteries would work. I made the assumption that they would work fine, and it caused me some grief.

The moral of the story: Either do not use bargain brand CR123's, don't purchase the Steripen Adventurer or any other model that is powered by CR123 batteries, or don't rely on a battery powered water purification method.

I'll get some better CR123 batteries and relegate the Evergreen ones to powering flashlights.

But I've already bought the components and I'm making myself a gravity filter. The Steripen is about to be relegated to a backup role.