I have had a cell start to die during a dive, the unit told me which one and how it was failing, I elected to bail out and continue the dive OC (25m NDL wreck dive with an AL80 bailout and OC buddies). That cell was right at the end of it's rated life anyway so not a unit issue. I have had some pre-start tests fail, usually due to user error, I have never lost a dive due to it.
The only test it does are those you would do on any unit pre-dive, if it fails those should you be diving anyway? It makes normalisation of deviance a much harder concern, which would maybe have saved the lives of a few people we know.
There has always been a repack scrubber available, everyone I know dives with those for their own diving. Molecular have announced they are ceasing production, Poseidon is bringing out their own repack very shortly. The solenoids and gas manifolds are inside the head, those do require sending to the factory unfortunately. Customer service has not always been what it could be from Poseidon, sadly, especially in the US though I believe that is much better now.
Not a dig at you, Gareth, but that is what happens on a LOT of CCR discussions. People make their own assumptions based on their perceptions and then fight to the death on those.
The upgrade path is purely to get the appropriate training, then get the appropriate battery. A full path is as follows:
Buy CCR in rec config. 40m NDL battery (green) is sent to your instructor, if you aren't certified.
Do Tec40 equivalent, get yellow battery (40m, deco enabled)
Do normoxic (either 48m or 60m trimix battery depending on agency and add MAV and inverted tanks)
Hypoxic (Deep battery (black))
It does suck that you end up with batteries you don't really use, but there is a 2nd hand market for them as spares and for people upgrading.
It's not that simple. Every time the unit adds O2, that blows across the face of the primary sensor. The unit knows depth and temp and the gas, so it knows what it SHOULD read, and compares that to the actual reading. It also compares that to the reading of the 2nd cell which gets a dil squirt every time you add, and that then gives you an O2-high calibration and an O2 low calibration, continually compared to each other and to the theoretical comparison.
In practice, it means that all the maths we are doing on a "normal" unit (mV readings at 6m O2 flush, linearity check, dil flush etc) are being done continuously by the unit. It is one less thing for ME to get wrong...
In Rec mode, yes as that is the philosophy of Mod1. As you enable more features the machine holds your hand less and does more to enable you to safely stay on the loop.
For US versions, yes, as the valves on the tanks are all DIN. CE versions have the M26 O2 first stage so not possible.
That is reflective of the type of diver you are, for those looking at recreational CCR diving, which is the point of the unit, all units that they see out in the wild will be the same. It is why mods are not encouraged. If you gave me a random Poseidon unit to dive right now, if it passed the pre-dive checks and a 5 minute visual inspection, I am confident that I can go and do a NDL, warm water dive with it. Deep, long deco etc? I would take my own, minus the tanks and auxiliary gear that I can get that side.
As above, its NOT every 10m. Its after very phase. So, the phases are : NDL 40m, deco 40m, 50m trimix and 60m trimix (that is agency dependent. You do NOT have to get both.) and then 100m+ full trimix. Those batteries are 250 USD so IF you got all of them, and did not sell your used ones, you would be 1000 USD in (you would get one with your unit). The CCR industry has always looked for ways to limit liability due to the huge impact of only one or two fatalities. They used to have PIN on the handsets, only sending a unit to an instructor who would then unlock it after training etc.
I do not believe that it is in the interest of the CCR manufacturers OR us as divers, to have someone be able to do a 100m+ dive on a unit they have just received in the mail and are not trained on. Others may have different opinions, and there are other units for them.
Poseidon CCR diving is a philosophy change from other units. That philosophy is not for everyone, sure.
In aviation, there was HUGE debate around autopilot when it first came out. Horror stories of how the machine would take all choice away and try kill pilots left and right. Same with fly-by-wire.
Now, all commercial flights are conducted with autopilot from 200' and above. The philosophy now is, let the machine do what it does well (maths, calculations, split second monitoring etc) and let the human do what it does well, which is monitor the machine and make choices of when the machine is not behaving and take over. That has resulted in an unprecedented level of safety since the human is almost ALWAYS the weak point.
In CCR diving, the Poseidon is a Dive-by-wire system. I know what causes failures, I know what failures look like and I know which I can recover from and how. For the rest of it, I am a fallible human. The machine does a WAY better job of monitoring the "boring" stuff than me, so I let it do that and I watch it.
