JJ mccr??

K

Kam

New Member
Hello.
I started to dislike few thing about my kiss classic after about 100 dives. Majority of the stuff is how it's built etc. I really like jj but I don't like eccrs:)
I was thinking about getting 2nd hand jj analog to get rid of solenoid. Has anyone converted jj to mccr? Will shearwater not lock out when solenoid is gone?
 
More than 20 years of experience with eCCRs and I don't share your dislike of them - ultimately both you as controller or the computer as the controller are dependent on the electronics of the cells and displays and I'd prefer a computer to do routine simple things which they are good at not a human (me) which we are not good at as we are easily distracted.

None the less, the system will work fine without the solenoid - you can just cap off the feed to the solenoid and not have to do anything else as you can add O2 through the manual add port.
 
Asking a dumb question; what's wrong with keeping the setpoint low and leaving the solenoid alone? You then run it manually but there's a kind of safety net should you be 'distracted'.

FWIW that's pretty much what I do with my Revo. Any time the solenoid injects is a massive kick in the backside to me for not paying attention.
 
Wibble said:
Asking a dumb question; what's wrong with keeping the setpoint low and leaving the solenoid alone? You then run it manually but there's a kind of safety net should you be 'distracted'.

FWIW that's pretty much what I do with my Revo. Any time the solenoid injects is a massive kick in the backside to me for not paying attention.
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Thats like sky diving using your back up as your main parachute :D I'd rather leave the solenoid and controller to do its job ... if you don't pay attention on a CCR you're dicing with death in either (any) case - I'd rather use my active capacity to notice there's a problem rather than using it to control PO2 and hoping the solenoid will save me if I get distracted. Each to their own though.
 
Wibble said:
Asking a dumb question; what's wrong with keeping the setpoint low and leaving the solenoid alone? You then run it manually but there's a kind of safety net should you be 'distracted'.
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Because, that's a hybrid. The KISS was an entirely different principle.

To the OP: the JJ is an ECCR; if you don't like ECCRs then it's not for you. I imagine that cannibalising one to create a manual CCR would be an expensive option.

FWIW that's pretty much what I do with my Revo. Any time the solenoid injects is a massive kick in the backside to me for not paying attention.
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You'd better hope that that solenoid carries-on working then.

FWIW, the JJ was originally planned to come as either a full ECCR or as a hybrid, but they ditched the latter idea. I know a few people that added their own hybrid stuff but to my mind it just added unnecessary complexity.

I'll never understand the mentality behind this 'parachute' thing. If you don't trust the solenoid as your primary means of maintaining set point, why the hell do you feel comfortable trusting it when you've screwed-up?
 
(For context; I'm a relative newcomer to CCR diving, reasonably experienced with trimix OC and decompression, predominantly solo diving)

As I understand it, most manual CCRs come with an oxygen orifice, the fabled leaky valve. I believe that's the case with the Kiss and it's also the case with the Revo - all versions. This orifice constantly injects a fixed rate of oxygen which is adjusted for the diver's quiescent O2 consumption level (consumption when relaxed and doing nothing - such as decompressing). If working hard, then the diver will manually inject O2.

As the orifice is continually injecting oxygen, it reduces the amount of oxygen that needs to be injected into the loop either manually or by electronic solenoid. Reducing the amount of solenoid injections will reduce wear and battery consumption. More importantly the orifice will slow down the change of PPO2 for a static depth when compared with full E-CCR.

The Revo is a 'hybrid' machine having both an orifice and a full solenoid injection controller as per any E-CCR.

I bought a Revo specifically because it comes from a manual background. I really want to be the person measuring my O2 consumption and manually injecting when needed. The setpoint is manually changed from 0.7 to 1.2 when I reach the bottom, and manually changed back to 0.7 when at the 6m stop. Again this is to make sure that I know what's going on. When I'm on the bottom phase I'll choose my own PPO2 to run the dive on, normally 1.3 or 1.4 (depending on depth, gas and duration).

I am very happy for the Revo to be looking after me in the background although any time it injects I like to think of it as a virtual slap in the face for me for not properly monitoring and managing my PPO2.


This E-CCR vs M-CCR/H-CCR debate is a bit like those awful automatic cars that are being forced upon us. Those ones that get it right most of the time, but are useless when you need control - steep descents or slippery surface. Oh, and those same automatic ones that waste fuel and increase emissions.

Continuing with that theme, it's absolutely fine for someone to rely on the system to handle all their O2 requirements; their decision. Personally I want to know and control what's going on at all times regarding the PPO2. When I've a few hundred more hours on my unit maybe I'll relax and change that attitude.
 
Wibs - suggest you read up on your automatic cars knowledge https://www.edmunds.com/fuel-economy/five-myths-about-stick-shifts.html.

Kinda like the myths about CCR diving "I want to be in control of my PO2 and the only way to do it is mCCR". I dived a full manual CCR (Mk15 and Mk15.5 with notorious electronics) in early 2000s for several hundred hours - now, particularly with more reliable electronics than the original inspo, ... why bother :)

To continue the driving analogy:

I might choose manual control of my PO2 at more challenging times - like ascent and deco stops, but in reality its only the unaware diver that struggles with these on auto mode.

But who wants to be drive a manual car in stop start traffic or not use cruise control (probably a better example) on 50 sections? I don't blame the car if I run up the ass up somebody because it was in cruise control hahahaha
 
Contemporary generation electronics are light-years ahead of their predecessors. Shearwater are brilliant compared with, say, a classic inspiration paddle.

New CCR divers (like me) could simply trust the electronics and let the unit get on with it.

However... I am working hard to develop my experience as quickly as possible; I don't have many years of diving ahead of me and it could end suddenly at any time. Therefore I want as much understanding of my equipment and my physiology, particularly my oxygen consumption rates. By having that as "muscle memory", i.e. subconscious understanding and reactions, I feel I will be able to progress more safely to the dives I want to do and have to do in the next couple of years.

Thus I'm exceedingly happy with manually running the unit which forces me to monitor and predict ahead how things are going. The controller system is acting as a safety belt; when it injects it means I've failed to monitor and manage correctly.


Automatic gearboxes -- aside from the expensive direct shift ones with their flappy paddles -- cause higher fuel consumption, especially the CVT variety. These gearboxes cannot predict that, for example, you're going to overtake and need to be in a lower gear now. OK, experience with older automatics was awful; foot down and wait for the system to work out what's happening. Also using the engine as a brake is standard with a manual transmission, but is more difficult on an auto unless you manually select gears.

Or put another way; the diver/driver has the brain. The systems only have a limited set of logic; anything outside of that and, oh, it's back to the driver/diver who's not done this for a while.

It's more of a philosophical thing :-)
 
Wibble said:
Automatic gearboxes -- aside from the expensive direct shift ones with their flappy paddles -- cause higher fuel consumption, especially the CVT variety. These gearboxes cannot predict that, for example, you're going to overtake and need to be in a lower gear now. OK, experience with older automatics was awful; foot down and wait for the system to work out what's happening. Also using the engine as a brake is standard with a manual transmission, but is more difficult on an auto unless you manually select gears.
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What the hell are you on about?

The last auto gearbox such as you describe that I drove was on a late 70s Ford Capri. The modern (for quite some time now) gearboxes such as the Volkswagen DSG or the amazing Porsche PDK can do things that very few human beings can come close to achieving. If I want to get out of dodge quick in my RSQ3, I could downshift with the flappy paddles (never use them) or just pull the stick back to 'S' (assuming it wasn't there already!) and I'm away before you've even got your foot off the clutch.

Porsche have just announced a manual 911 Carrera S for purists (or contrarians like you) but they don't expect to sell many.
 
I understand wanting to drive manual transmissions. One of many reasons we have idiots on the road that don't know how to drive.. we are dumbing down everyone,so all you need to do is step on a pedal and steer.
I am a much better driver , more aware, paying attention when I drive a standard than an automatic... I do like kiss system. It dosen't let you fall asleep.
Ever steer with you knees,clutch, shift,and eat lunch while driving and stay on the road? Why do real dirtbikes not go automatic ? I say good driver can out perform an automatic most of the time. Travis pastrana.... automatic are nice for something's if you have tons of hp in mudbogging. But I would much rather learn from my mistakes and be a better driver. Diver.
 
Kam said:
Hello.
I started to dislike few thing about my kiss classic after about 100 dives. Majority of the stuff is how it's built etc. I really like jj but I don't like eccrs:)
I was thinking about getting 2nd hand jj analog to get rid of solenoid. Has anyone converted jj to mccr? Will shearwater not lock out when solenoid is gone?
Click to expand...
Cap off the JJ solenoid, add an O2 inlet to one of the T-pieces for the O2 feed, fix the IP and put an orifice on the o2 hose.

After all that you'll have an mCCR with a 5lb axial scrubber plus backmounted counterlungs. Basically a Kiss classic minus the backplate counterlung case.
 
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rjack said:
Cap off the JJ solenoid, add an O2 inlet to one of the T-pieces for the O2 feed, fix the IP and put an orifice on the o2 hose.

After all that you'll have an mCCR with a 5lb axial scrubber plus backmounted counterlungs. Basically a Kiss classic minus the backplate counterlung case.
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Sounds like a plan
 
Kam said:
Sounds like a plan
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Seems like a huge waste of money and effort to me. Just use the classic like the mCCR it was designed to be or the JJ as an eCCR like it was designed to be.

You never did say what was actually wrong with the Kiss.
 
rjack said:
You never did say what was actually wrong with the Kiss.
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I don't like:
-counterlung case
-Water ingress recovery capability
- I'd rather have removable head with cells rather than permanently attached to the rig
Jj seems to have more up-to-date design.
Perhaps I'll just convert it into hybrid with a needle valve
 
Wibble said:
Seems the most logical option and gives the benefit of less solenoid firing.
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What benefit?

I still don't understand this obsession with sparing the solenoid. The batteries in my JJ last about a year - 2 * Ultralife 9V lithium = £11.

I can't imagine anyone wearing the solenoid out. They are more likely to fail from rust through water ingress, so hearing it fire regularly offers a lot more comfort than trusting that it will if I forget to watch my PPO2.
 
For me, and it's only an opinion, I'm very happy with running the unit manually and having the electronics back me up.

I'm still in early days with the rebreather (60h) and am very focussed on understanding and being aware of everything that's happening around me and my rebreather. The best way, or rather the only way, I can do this is to manually choose a setpoint, say 1.3, with the controller set to 1.2 and stick to that. Whenever I move in the water column, I need to ensure that my PPO2 is within bounds. When I ascend or exert myself, should the controller inject, I take that as being a slap on the wrist from the controller telling me that I've let the side down. Monitoring the PPO2 at deco is something I'm very interested in too as I want to know how the off-gassing's going.

I fully appreciate many people being happy to run fully electronic. I'm most definitely happier with my brain knowing what's going on and not relying on the electronics. Maybe after a couple of hundred more hours on the unit I may relax that; or maybe it will be fully "unconscious competence" where I'm almost unaware of injecting. Much like using a manual gearbox to change gear: I know I've done it, but I didn't think about it.

BTW the solenoid battery on a Revo is a small PP3 9v battery. These do need replacing and monitoring its voltage (and the two Shearwaters) is very much part of the build process.
 
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