Atmospheric CO2

Diving video lamp Accumulator reconditioning

Diving lights are of capital importance for cave divers, depending their life on their lights, with several backups. Zero risk implies buying a lot of very expensive stuff.

Video lights for diving use request the same safety conditions to avoid any risk for the user. But what if your equipment manufacturer has retired? Batteries and accumulators don't live forever. The cells are getting tired after several hundreds of charging and discharging cycles and your nice expensive video light is still too good for the dump.

This project was carried out to replace a tired 22.4V diving video lamp accumulator, keeping the lamp and the charger. Rather than to replace several cells in the existing battery, the whole design was adapted to actual Lithium manganese nickel technology, combining safety and low resistance of manganese with the high energy of nickel. With recent development of INR (LiNiMnCoO2) cells, 6 series of 3.7V LiPo's should replace 7x 3.2V Lithium-iron cells, delivering 33% more power and permitting high current drain, at an even lower cost. Single tape insulation of the system was upgraded to a combination of shrinkwrap, hot glue and custom 3D printed components holding the individual cells together.

(Come back regularly. Updates coming soon !)


To achieve great things, two things are needed: a plan, and not quite enough time.
(Leonard Bernstein)

Project status : prototype working

3D printed components Tryouts in biodegradable PLA Components to be wired Hilumin bridges of nickelplated steel to be welded onto the cells. Next- investment would be a spot welder!

3.95mm JST connectors for lamp output and fuse (I would have taken an other type for the fuse connector but we want to stay compatible...)

Barrel jack at the charging side. It gets sealed into the battery holder with liquid glue

the PCB: a 10 Amps charge/discharge MOS protection board protecting the LiPo's

Il faut que ça brille... oh I'll get one fine spot welder soon!

Acrobacy in 3D by 3D printed components... sublime soldering action!

Two out of 3 sausages wired. Time for some tie-wrapping

Output connector. Smells like the end...

...Not quite, yet. Some more soldering. I'm really dreaming of a spot welder!

Assembled and aligned, the pack fits perfectly into the housing of the dead pack

Fuse and charging port

Lamp connection for test run

That's all folks!

Conclusion: don't try this at home, kids !!

More Lab.vKîng projects...

Cave climate monitoring station in Aven de la Forestière

Prototype 9.0.4 of Co2vKing, our smallest CO2-meter, waiting for its 3D-printed jacket before its departure underground...

Co2vKing-Alti, prototype for detecting layered CO2-beds in vertical caves.


Where possible, instruments, lab equipment, battery chargers and lights are running on green energy. Prototypes are built from biodegradable 3D print filament and materials respecting our planet. We're also trying to avoid needless courier services between their country of production, suppliers w'd like to buy from here in France, and their warehouses... far away!

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