Akbar Ramzan said:

Ok, yes that is ideal but what about the majority of existing batteries which require external overcurrent protection as per manufacturers instructions?

Are they "batteries" or "monoblocs" that are strung and paralleled together? Usually, I think, the latter.

Monoblocs can have high prospective short circuit currents without overcurrent protection. This provides risks of arcing and fire. Limiting any unprotected cables to be within the metal enclosure containing both the batteries and overcurrent protection reduces that risk.

Domestic properties are not really suited to the "battery room" or "battery container" that might be found in commercial and industrial battery installations, simply because the premises is under the control of ordinary persons and children (whereas in a workplace, risk assessments lead to measures being put in place to prevent access except when supervised by skilled or instructed persons).

Some monoblocs are currently installed by just putting them on the floor, so they are susceptible to damage (accidental or otherwise), or if they fall over can pull cables out etc. ... very poor practices. In addition, we need to make sure that ordinary persons and especially children can't get at the "click to connect, push button to remove" type connectors that can be removed (on load) without the use of a tool.

All, of course, preventable by a more sensible installation design.

Manufacturers of certain monoblocs provide suitable metal racking solutions, and the overcurrent protection could be installed in the racking solution. This is a strong recommendation I would make.

I do understand that the designer needs to think about temperature, but it doesn't make things impossible - other manufacturers provide complete solutions already in a metal enclosures with integral overcurrent protection.

PAS 63100 (see here: https://standardsdevelopment.bsigroup.com/projects/2022-00181#/section ) will hopefully be available very soon from BSI, and provide some clear requirements that I hope will address issues related to fire safety and domestic storage battery installations. Just to caution, that the final version of standards is rarely the same as the draft that was put out for public comment, as they are updated in response to comments received.

I think it would be classed as a battery. If we take this sunsynk one as an example, it has 16 lifepo4 cells in series totalling 52v nominal, an internal BMS and ports at the bottom for communication with the inverter and for paralleling with another battery. It requires an external fuse or MCB and it’s in a metal case that requires earthing.

If I’m not mistaken, monoblocs are usually those leisure style batteries or perhaps even the cells themselves?

I think it would be classed as a battery. If we take this sunsynk one as an example, it has 16 lifepo4 cells in series totalling 52v nominal, an internal BMS and ports at the bottom for communication with the inverter and for paralleling with another battery. It requires an external fuse or MCB and it’s in a metal case that requires earthing.

If I’m not mistaken, monoblocs are usually those leisure style batteries or perhaps even the cells themselves?

Though I see what you mean by the tool-free removability of the battery connectors. They can just be unlocked and pulled out

Whilst most leisure batteries are monoblocs, some popular EESS batteries are too, despite them having a metal casing.

Basically, if it's intended to series/parallel and it's got no internal overcurrent protection, it's probably a monobloc (unless of course we are talking about individual cells).