JJ CCR Questions

[Dubio]

Get a sensor cover - I have a 3D printed one and already took sh!t for running through 8,5k€ of unit and cheaping out on the original cover but it works just fine.

I always carry the full o-ring set with me as well as the DSV o-ring kit. Set of flapper valves, spare Safts, spare 9V, spare scrimfilters. When I travel without access to spares I take at least one spare sensor with me. On top standard bits and pieces like a first stage service kit, silicone grease, standard o-rings and M8 bolts and nuts.

Exchanged the original harness with a standard DIR webbing because I just couldn’t stand all the dingling on the front with the original one. I’ll probably swap the original backplate with a longer one in the future, gonna try the Heser one.

I have a piece of 1x2“ wood with me. Why? I use it to mount the tanks exact same height by putting it under the valves before fastening the tank straps. At Techwise Malta they called it the „JJ special tool“

When you start travelling you might wanna look into a Pelicase or something for the unit. I personally don’t have one yet as I just use a regular airline accepted hard case trolley that fits the unit. If you buy one consider AIR variants (that’s what Peli calls them) to save on container weight as with a regular Pelicase the 32kg limit is not far.

I have sewn myself loop covers from 500 Cordura. Then I had lots of Cordura left and just sew myself a little carrying bag that fits the head and has compartments to stuff controller and HUD in. Keeps the controls from being dragged around when moving the head around and not paying attention for a second.

 

[bubblemonkey2]

Except the head isn't drawing a constant power. It's not that sophisticated. It's drawing a consistent amperage to do the same thing with both batteries. The unit can operate on the lower voltage, and the Energizer operates vastly longer with a much more predictable discharge curve than the 3.7V 14500 rechargeable

Yeah I don't know the precise design details of the Shearwaters or CCR electronics to discuss exactly how much current they need, or what and where the current and voltage conversions are at different points in the internals. But I trust they have a better handle on it than either of us do, and they include 3.7V rechargeables in the supported battery types--including for vibration. I think the round battery in the JJ is for the Shearwater HUD? A low amperage component.

Separate discussion for 9V rechargeables to run the rest of the head/solenoid. No experience with those, but possibly worth testing observantly. Manual PPO2 is one of the JJ skills that is thoroughly practiced on a good course

As for discharge, what about this discharge profile for a 3.7V 14500 battery?

Shearwater perdix2 14500(flat-top) work?

Given that it would have no vibration support or fuel gauge support, even if it "works", I would use something else....

scubaboard.com

It looks like a nice predictable linear discharge profile to me?

Preliminary experience with the XTAR 3.7V 14500 rechargeable seems consistent. The battery life indicator on the Shearwater shows the battery as being "not full" sooner, long before it is fully discharged. It will continue to work thru the dive, plus you have fair warning that it's time to charge or swap before the next dive.

I have heard that the 1.5V and the SAFTs are the ones that don't show an accurate drawdown, as in they the curve is more flat for a longer time (maintain relatively higher voltage), but then a downward hockey stick near the end of their charge? Hence people recounting they have had batteries die during the dive, despite the voltage seeming "still good" in the predive.

A nice thing about a rechargeable is that you're less likely to keep diving a partially used up disposable battery. You can just charge or swap without "wasting" an old battery, or playing that "good for one more dive" game.

Not that I see anything wrong with using the standard 1.5V lithiums. They are wonderful batteries, easily obtained, rated for a huge number of hours, and still Shearwater's first recommendation.