This discussion is mainly about equipment operating in hazardous locations. Basically, a shout out to engineers that are/were involved in similar projects.
The standrad is known as ATEX (EU), Hazloc (NA).
Various protection techniques are available based on the area classification and what level of potential hazard is available in the environment.
One of the challenges I am facing is to design an ultra low power device to operate in "Zone 1". The approach is to use a flameproof enclosure instead of designing an intrinsically safe circuit, mainly to avoid energy losses in all fuses, diodes and other protection components necessary. The surprise I came across in the standard "IEC 60079-0 & 60079-1" is that battery cells are not allowed to be connected in parallel, mainly to prevent batteries charging each other in fault conditions.
The application needs to run on batteries for as long as possible and a solar cell is meant to recharge the batteries. I was wondering if a workaround like the figure below can be considered by the certification body:
Any thoughts appreciated.