Is there a SteriPEN-like device that uses a UV LED?

[Lowell Mills]

After reading the extra-long post about some potential reliability issues with SteriPENs, just wondering if a portable device that uses an LED in the correct UV-C frequency might be in the works. My limited research indicates that such an LED would be expensive, however, it would seem to have advantages of durability, longevity, power efficiency, etc. Anyone know if someone is actively working on something like this? Thanks for any info in advance…

[Seth Brewer]

I know the Classics have lots of problems associated with sensor failure, but I used an Adventurer Opti on the whole A.T last year and loved it. Still use it and its going strong. Wouldn't trust any other model out there though from my experiences seeing about 8 of the Classic models die within 500 miles of use.

[Ken Thompson]

LED UV

Have heard a little of that around here. The technology is not quite there for backcountry use. Costs primarily.

It will come out 2 weeks after you buy something else.

[Colin Krusor]

Yes, I think the technology is not there yet. The wavelength would have to be in the 250-260nm range, which is shorter than most commercial UVB LEDs. Those that do emit at these wavelengths have very low power (less than one milliwatt), and cost several hundred dollars apiece. The power of these LEDs will have to increase a thousandfold, and the cost will have to drop a hundredfold, before an LED Steripen is possible.

[Roger Caffin]

This is something I have discussed with Steripen over the years. What is needed is a UV-C LED radiating at 254 nm. So far, we (the science community) can make LEDs in the UV-B range at about 350 nm (from memory). Progress to a shorter wavelength is slow as it is hard to make the required semiconductor material. 254 nm corresponds to a huge band-gap, and we don't actually have any obvious candidates.

Would a 254 nm LED be better than the Philips germicidal discharge tube used at present? (That also radiates at 254 nm.) It would be hugely better! I was going to say 'infinitely better', but I couldn't quite manage that. :-) The power consumption would drop massively.

We don't try to use UV-B photons for two reasons. The simple one is that the UV-B photons do not as much energy as is found in the UV-C photons, and you need a lot of energy to damage the DNA connections. The more complex reason, and the major one, is that we actually need photons at ~254 nm in order to break certain bonds in the DNA. If the photon has an energy significantly different from that, the bonds don't respond. It's a resonance thing.

It will happen, just not this year.

Cheers

[Drop Bear]

What happened with the mÜV micro-UV water purifier?

[Colin Krusor]

Roger, as a point of trivia, there are UVC leds, as I noted in my post above. Thorlabs and several other companies sell LEDs having emission peaks as low as 240nm.

Also, we use 254nm radiation for pathogen control because it happens to be a mercury vapor emission peak, not because that particular wavelength is ideal for germicidal applications. Pyrimidine dimerization (major germicidal mechanism) occurs more efficiently closer to 260nm, and 260nm LEDs are not hard to find.

They just cost too much and their power is too low.

[Kevin Babione]

The mUV is back and can be purchased directly from Meridian Designs for $49.

They've changed it – it no longer has the magnetic leads (which I, quite honestly, really liked). It now comes with a USB charging cable that retracts – you can see it on the website.

I've had one of their prototypes of the new mUV since last summer and really like it. I purchased a small solar battery that has a USB output and an internal lithium ion battery. I get 8-9 purification cycles per charge with my unit but I know they were working on improving that – which delayed the release of the mUV.

Now that it's available for purchase again I'll do a review and post it in the reviews section.

[Roger Caffin]

Hi Colin

The field of UV LEDs is advancing – slowly. Yes, one can buy the LED245W from Thorlabs, but it gives only 70 microwatts and costs $444, or the LED260W, 300 microwatts and $310. Somehow, I don't think either would provide enough power for realistic use in the field, and the cost would be … ultra. Thanks for the update.

I take the point that 260 nm is better than 245 nm, although there is actually a broad band between 240 and 280 which is usable if there is enough power.

> They just cost too much and their power is too low.
Exactly. Sadly.

Cheers

[Lowell Mills]

Much appreciation to all; great info here. Will be looking for an mUV review and how it compares to SteriPEN. Thanks again…

[Jim C]

Let’s revive this thread after a few years, shall we?

In October 2014, LG Innotek announced they had begun mass producing UV-C LED. If there are any products using this on the market now, they must be in more stationary applications (the article gives examples such as toothbrush sanitizers and air cleaning), and not yet in backpacking applications.

Still, it’s promising. I’m not sure if these numbers are meaningful (hopefully Roger can comment on this), but the article states this LED outputs light at a 275nm wavelength, with 10 mW power at 100 mA current.

[John Papini]

Is this still a long ways off? Roger, have you been in touch with Steripen at all?

I found these two articles about the state of the technology from 2018 and 2017:

https://www.prnewswire.com/news-releases/rayvio-drives-uv-c-led-innovation-with-new-xd-and-xr-series-300706373.html

https://www.prnewswire.com/news-releases/rayvio-drives-uv-c-led-innovation-with-new-xd-and-xr-series-300706373.html

If the bulbs will work now, Kickstarter maybe?

[James Marco]

I think the cost of the devices is still unreasonably high. I would guess (from the retail cost of the UV LED component only) that such a device would range from 150-300USD. When you can get a regular Steripen for <$60, this is a sort of big deal. However, they do not list the overall drain of the timer/senser apparatus needed, only the LED. Looking at it, I am sure I could cobble together a version for around $200, but the packaging (case, ancillary circuitry – water detector, timer, etc) would be rather crude…I think I’ll wait. I have a second Adventurer I will put into service this coming spring and I hate to waste it.

[Roger Caffin]

The march of technology continues. What was not possible two years ago verges on possible today. Yes, UV LEDs are coming. However, before you rush out and buy shares …

The wavelength of 280 nm is right on the edge of the useful range. That means you would need a lot more power (and have amore battery drain). It is a start, but that’s all. The smart money (imho) would wait just a little longer, until the technology reaches 270 nm or better still 260 nm. That’s not far away, and should be possible.

Hang in there: it’s coming. The UV chips are almost there. Oops: the 50 mW versions are over $200 each. That might be a little out of range at the moment. Give them another 6 – 12 months.

Now, Steripen. The founders sold out to (I think) the Swiss company Katadyn, traditionally makers of ceramic filters. This is not necessarily a bad thing, as K has lots of grunt, and they probably have recognised that filtration will give way to UV sterilisation. Hey – it is already doing so at a great rate. But that means I have lost my contact with the owner of Steripen.

Cheers

[J-L]

Roger, there is the LARQ water bottle that’s shipping now. It uses a UV LED cap, but it doesn’t seem intended for backcountry water purifying.

[Roger Caffin]

Some of the reviews (eg Forbes) are spectacular in their ignorance. For a start, they imply that the bottle will handle any of the impurities in city water – like maybe Flint’s lead? Sigh.

Yes, the bottle probably works, but at $99 it will be using one of the smaller low-power UV-LEDs. So leaving the UV running for an hour two will be necessary to get the results. That works … if you can recharge the battery. For my liking, a bit too close to the bleeding edge of marketing spin.

Edit: if you were touring Asia or Africa and had access to power for recharging, this unit might actually be useful. Even the big tourist resorts there have dodgy water.

Cheers
(Yeah, I am a professional cynic.)

[Rex Sanders]

Some comments on the Larq here:

https://backpackinglight.com/forums/topic/is-this-a-steripen-in-a-bottle-looks-cool-to-me/

Besides weighing too much for BPLers, (quoting myself):

Seems lower output than a Steripen – takes 60 seconds to clean 18 ounces of water in a stainless steel container that probably reflects photons well.

I share Roger’s skepticism. UV LEDs for lightweight water purification isn’t there, yet – even if the hype is.

— Rex

[David Thomas]

“if you were touring Asia or Africa”

Then just leave the water out all day in a PET bottle. Skip the PV panels to lithium battery to UV lamp/LED.  Promoted as the SODIS method, it was described in science journals a decade year ago.

https://www.sodis.ch/methode/index_EN

Doesn’t help you if you’re on the move, but for some of those cow ponds on the CDT, a station could be constructed of corrugated roofing, pitched a bit south, and labelled with days of the week.  Drain the oldest ones for your use, refill them, and place them in the appropriate spot.  Bungie cord loops at each valley in the roofing could secure them in the wind.

Every once in while, I’ve examined UV-oxidation for toxic organics in water.  It’s never pencilled out compared to activated carbon.  A few years ago, at a remote, off-the-grid site, I did consider filling a shallow pond each day, and running the groundwater pumps again when a set amount of solar exposure had elapsed.

[Eric Blumensaadt]

I gotta agree with Seth Brewer, My Steri-Pen Adventurer pit has held up for years of backpacking and still works fine. I got it with the optional solar charging box for rechargeable batteries. That also works but I never take it backpacking, only one set of extra lithium batteries. (And those batteries also are for my SPOT beacon and Garmin GPS. Whichever fails first gets them.)

My backup for the Steri-Pen is Katadyn chlorine dioxide tablets. Great for hydration bladders & hoses.

[James Marco]

Yeah, I agree with Eric/Seth about the Adventurer. Like Eric, I also bought one with the rechargeable batteries & solar box, but never used them. A spare set of lithium batteries is lighter by far and gives far better service. Anyway, it performed really well until it was lost on a trip where I ripped my pack and didn’t notice it for about ten miles. I got an opti and it worked reliably till last year when it started flashing the code for a used up bulb. ‘Corse this after about 7-8 years of 50-60nights per year out with about 6-8 uses per day. I picked up a second one, but still used the old one for another 3 weeks. Pretty good service out of it considering I just drop it in my pocket.

Anyway, I have found that a bivy and tarp are heavier or the same as a somewhat larger tarp and a piece of netting. The thin plastic ground cloths (polycro and the like) are smaller and only weigh about 1oz. A longer tarp usually adds about a yard of material (1.5oz or so) and the netting only weighs something less than an ounce. Anyway, you can drop or add as needed for the weather expected. Worst case it ends up the same, but the larger tarp means you can cook under it, or, set it up in a myriad of configurations depending on terrain. Much better than dealing with a tent footprint. In early spring/fall, you can usually drop the bug net.

[Jerry Adams]

Theoretically, LED UV should weigh less and should use less power so the batteries (for a given trip) should weigh less

I asked a UV LED manufacturer a couple years ago and they said the UV LED cost about the same as the current cost of an entire Steripen.  Cost needs to come down a bit more.

I bet Steripen will come out with an LED UV model some day probably soon.  It will sell many units because it’s a new, technological thing.

[J.A. M]

Keeping this dream alive.  Actually it’s not a dream.  I’m pretty sure UV LED is the future of water purification for backcountry and developing world travel.  In fact, the implications for potable water for locals in the developing world are profound.

I found this list of UV-C LEDs currently for sale.  Based on a post above, the best spectral frequency seems to be 260nm.  But what power output is needed?  Currently, there is a 1mW at 265nm with a list price of $270.  There is another one with half the power for $235.

These are still too expensive, but I would be surprised if Katadyn isn’t already prototyping and testing to be ready with a product when the price hits a target.

The interesting thing to me is, I can see a sales success for a $200, smaller, more power efficient, tougher, more reliable device.  But I can also imagine prices continuing to fall to where headlamp manufacturers build UV purification onto the headlamp and kill the market for Katadyn.  It’s going to be interesting to watch.

http://www.qphotonics.com/UVTOP-LEDs/

[Roger Caffin]

@JAM
Yep, one day it will be UV LEDs, around 260 nm, for Steripens.

First, the very idea of a UV LED was ‘not realistic’. Then-current semiconductor diodess simply could not do it.
Then new semiconductor diodes became available at longer wavelengths and microwatt power, but up near $1k each.
Then they crept down to under 260 nm, by using more exotic semiconductors. Power was still microwatts, price was still high.
More recently the power has crept up to a ‘usable’ level, but they are still very $$$.
Now we are in the price ramp-down phase. A bit chicken and egg right now: ‘they’ have only limited sales due to the high price, so funding for R&D is limited, but …

Why do you think that there a number of companies busting their guts to get 260 nm UV LEDS at reasonable prices to the market? Because there is a HUGE market out there waiting for them. Really HUGE.

Right now some Councils are treating their water (after filtering out the big bits as it were) with banks of UV tubes from the likes of Philips, but the installations are expensive. That’s where the Steripens come from.

But once the price comes down far enough (and the life is long enough), the market could be the water supply for just about every town and city in the world. Can you imagine the prize?

Cheers

[Lowell Mills]

The Larq water bottle claims to get great results with a 280nm UV-C LED for purification and, at $95, it seems like the technology is getting closer…

[J-L]

The Larq bottle has always looked interesting, but it seems it’s only been tested for E. coli. Not sure how that compares to other water treatments. I also wonder if you could just use the cap, but the bottle could be part of its effectiveness. Getting closer though.

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