Quick battery disconnect inside and close by

Brodie Allen · Guru

Quick battery disconnect inside and close by

Whenarewethere · Guru

It would be a very good safety feature. Also from an inverter issue, let alone batteries themselves.

I carry a pair of parrot cutters, but usually not in a readily accessible location. I might rethink location.

Mamil · Senior Member

The regs do have a requirement for automatic disconnection of supply in the case of a fault:-

Clause 5.4.7.1 Protection Device: Batteries and associated wiring shall be protected against overload and short circuit by means of fuses or circuit breakers in each unearthed pole. Protection devices shall be accessible, protected against accidental damage, and installed in one of the following locations- a) within 200mm of the battery terminals, or b) directly outside the battery compartment, or c) 1m from the battery terminals, provided each conductor is contained within a protective covering such as sheathing, conduit, or cable trunking for its entire length from battery terminals to the circuit protection device

Meanwhile a switch is usually for isolation, ie to disconnect the batteries for storage or servicing, not to protect in event of a fault.

It is of course good practice to have both.

Note also that it says that protection device should be in "each unearthed pole" so that means in an isolated system (as in most caravans), there should be a fuse/circuit breaker in both positive and negative battery cables.

TimTim · Guru

The Li ion batteries in scooters, phones etc. are a different chemistry to the LiFePO4 that we use. There has never been a fire with LiFePO4 but they can swell up and vent nasty substances when over charged or over discharged but to get to that stage you will have needed a failure in your BMS and/or a failure in your charger, whether it be a dc to dc charger or a solar controller.

https://www.youtube.com/watch?v=yiOljillLRY

This second video has no relevance and a word of warning Please do not try this.

https://www.youtube.com/watch?v=07BS6QY3wI8

LiFePO4 is very safe smile .

Aus-Kiwi · Guru

By old bus / motorhome had a 50mm piece of lead as a fuse off the main supply . 50mm long X20mm I guess 4mm thick . Fuso. Older vehicles had a disable wire we wouldnt really know it was a protection wire, fuse .

Brodie Allen · Guru

An over-temperature warning device might also be helpful in detecting
rising temperatures in the batts in time to avert a tragedy.

Mamil · Senior Member

Brodie Allen wrote:
An over-temperature warning device might also be helpful in detecting
rising temperatures in the batts in time to avert a tragedy.

If you're talking about Lithium, then the regulations require not just a warning device, but also automatic disconnection of the battery...

Clause 5.4.12.3 Lithium Ion Batteries, Battery Safety System: Each lithium ion battery pack shall be protected with a battery management safety system either integrated into a battery pack or as a separate component. The battery management safety system shall continuously monitor the voltage, current and temperature of the battery and protect against the following by automatic disconnection - a) over and under voltage, and b) over and under temperature, and c) over current

These functions are usually performed by the Lithium battery's BMS. Lead acid batteries have no such requirements.

Of course, having it in the regulations is one thing, people following the regulations is quite another. It doesn't help that the electrical regulations tend to lag the technology available by a good few years, and new rules are not applied retrospectively.

-- Edited by Mamil on Wednesday 15th of February 2023 08:03:20 PM