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I'm responding to your message in the spirit of open communication and free dialog. Flames to /dev/null, please. >Scott - while I have no doubt you had a bad experience with the Nemesis >Nitrox, I must point out that that sort of occurance has been extremely >rare. There are several thousand people (myself included) who each put >hundreds of rather taxing dives on a Nemesis without seeing a battery >problem. I AM aware that Cochran got a bad batch of batteries from >Duracell and, as a result, changed vendors. But as far as I'm concerned, >that's one of the better arguments for user-replaceable batteries. The >Nemesis displays the EXACT battery voltage on each predive scroll. >There's no reason to get in a situation where it's out of battery power. This is my point. And, the one other diver that I know who bought one feels even more strongly about it than I do. I recall a mix dive we shared last year on the USS Monitor. I had my cochran attached to record the dive profile. He said "look at that piece of junk attached to Scot's manifold" - that sort of covers it. His also behaved in an unpredicatable fashion, and he also sent his back. So, well, that's two out of two. Granted, two data points hardly make a line, but hey, I'm not planning to start gathering statistical data with my backside on the line. >Also, it is important to point out that the Nemesis II has implemented >some extremely agressive power management functions that were not in the >original Nemesis Nitrox. So batteries will last much longer than in the >original unit. And they can be replaced, on the fly, between dives >without loss of ndc or log data. That's wonderful. Unfortunately, I have been provided no information to this effect. >As for the Air-X battery life being far more linear and predictible: >Hogwash. The Air-X uses lithium batteries. These are NOTORIOUS for being >unpredictible. One cannot tell from the output voltage on a lithium what >the remaining energy is. The output voltage cutoff curve is extremely >steep and sudden. This is why military equipment using this type of >battery uses elapsed run time rather than battery voltage to approximate >remaining life - and why this kind of equipment generally uses a large >time-based fudge factor for battery replacement. This is my experience, dealing with the UWATEC products. And, dealing with the Nemesis Nitrox. That is to say, regardless of theory, I've had much more predictable results with the Alladin Pro, and, so far, with the Air X. Regardless of batteries in the Nemesis, it's performance was erratic and unpredictable. >Alkaline batteries, on the other hand, have a reasonably linear voltage >decay curve which is proportional to remaining energy. So measured output >voltage under load is very indicative of remaining life. If you'd like >more information I can point you to an article on batteries I wrote for In >Depth last year. I'm aware of the theory. Empirical evidence would seem to indicate more to this picture than battery burn-curves. >And as for battery replacement cost on the Nemesis being "pricey" - you >can buy 12 AA Energizers for less than seven dollars. That's less than >$2.50 per battery change, compared to the $100 or so it has been estimated >that an Air-X battery change will cost. I fail to follow your logic on >this point. I recall being instructed to buy specialized batteries, available generally in photo shops, for the tank unit. These were not cheap. Seems to me, the instruction was somewhere in the manual. >>>The wrist unit is in a cheesy rubber holder thing that did not instill >confidence.<< > >I agree with you on his point. I was less than thrilled with the boot on >the original Nemesis. It turns out to have held up very well over a few >hundred dives but this was my least favorite part of the Nemesis design >and I said so in a review I wrote. > >One of the best things about Cochran, however, is that they LISTEN to >their customers. Their first move was to build a tougher boot for the >original unit. This was provided for free to all customers who asked. >They then designed a far more durable strap than the original velcro >design... also provided for free. They apparently have not listened to us. And neither of us is your average sport diver, either. >They started from scratch on the new products. The Nemesis II (and >Commander) have a GREAT integrated strap design. Far better, in my >opinion, than the elastic strap arrangement on the Air-X. I think the >Air-X ergonomics are very well thought out, by the way. Right up to the >strap which looks like a completely different designer took over. > >I'm sorry your experience was unfavorable with the Nemesis Nitrox. As I >say it earned the respect of a great many very serious technical divers >including Ed Betts, Billy Deans and scores of others. It has continued to >work reliably under the polar ice in McMurdo when all other computers >failed. And the Nemesis II has been much improved over the original >Nemesis design. I'd encourage you to take a look at the changes. Well, after buying the Nemesis on faith and being so unhappy, I'm not inclined to put good money after bad. Besides, I gave my computer to the dive shop where I bought it. The other guy did too. The dive shop guys sent it back to Cochran, with a note explaining our problems and complaints. and there has been no word since. So, well, sorry, but my personal experience with that equipment does not support much of any of the stuff you say here. ---------------------------------------------------------------------------- Scot Anderson <scot@bt*.co*> http://www.btg.com/~scot/ BTG Corporation http://www.btg.com/ Voice: 703.761.6536 Fax: 703.761.6555
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