Inverter wiring

[landrovereditor]

Looking through a lot of diagrams and threads on inverters, many just connect to the battery with no fuse or cut off switch.
The diagram below is the one I propose to follow for wiring my inverter and fuse block to my battery.
The cut off switch is my stumbling block, do I put it between the inverter and the fuse or before the bus bar which obviously will cut off everything.
The inverter has an on off switch, the battery terminal is a quick release. Do I need the cut off? If so where to place it?

 

[davep10000]

I would put the cut off switch AND the 250A fuse between the battery and the bus bar (Have just done similar with a 460Ah fogstar, and 2000W inverter).

I used a quality switch like this one, not the cheap £10 eBay ones!!

Pardon our interruption...

 

[landrovereditor]

I would put the cut off switch AND the 250A fuse between the battery and the bus bar (Have just done similar with a 460Ah fogstar, and 2000W inverter).

I used a quality switch like this one, not the cheap £10 eBay ones!!

Pardon our interruption...

thank you, I’ve not seen it done that way. I bought my parts from simply split charge.
Still made in China though.

 

[wildebus]

Looking through a lot of diagrams and threads on inverters, many just connect to the battery with no fuse or cut off switch.
The diagram below is the one I propose to follow for wiring my inverter and fuse block to my battery.
The cut off switch is my stumbling block, do I put it between the inverter and the fuse or before the bus bar which obviously will cut off everything.
The inverter has an on off switch, the battery terminal is a quick release. Do I need the cut off? If so where to place it?

There should always have a fuse protecting the cable from a supply to a load. So any diagram showing no fuse is not to be trusted.

You have already identified this requirement.
Now regarding a cut off (isolation) switch, what do you propose to use that for? Your inverter has an on/off switch and presumably that is how you turn off the inverter when you don't need it? So an isolation switch for the Inverter is redundant I would say.

Personally I would do the following:

1. Fit a fuse between the battery and the +ve Busbar to act as a 'catastrophic' fuse to isolate the supply in the event of an unplanned event/incident.
2. Fit a fuse between the busbar and the Inverter to protect that section of the cabling.
3. Fit an isolation switch between the fuse in 1. and the busbar as a way to easily and quickly isolate the supply for maintenance or if you suspect a problem and want to remove the supply from the system (say you smell something untoward or hear bubbling from the battery?). Turning a switch is a lot quicker than looking for a spanner to remove a fuse or use a battery quick-release.

Number 3 is optional; Number 1 & 2 are not.

I used a quality switch like this one, not the cheap £10 eBay ones!!

Pardon our interruption...

Durite is a budget brand no better than loads of other brands that import stuff Chinese factories and stick their labels on them. I don't distrust them, but I also don't trust them above plenty of other brands (or non-brands). I've bought lots of Isolation Switches and TBH I haven't had any problems with any of them.

 

[trevskoda]

Poor chap will be con fused.

 

[landrovereditor]

Poor chap will be con fused.

Brilliant thank you, so another Mega fuse is required close to the battery and before the + bus bar and the switch goes between the fuse and the + bus bar so it isolates everything.
Yes the switch I have is a Durite 300 Amp.

 

[merl]

Depending on cable gauge you're using I'm going to throw a spanner in the works and say if you've got lithium batteries a fuse is pointless. Ultimately a fuse is there to protect the wiring, a lithium battery isn't capable of delivering enough current to blow/melt/fuse the size of cable that you'd typically wire up an inverter with so what's the point of adding a fuse?

In the event of an over current situation the electronic cut off devices (FETs) in the battery BMS will operate in milliseconds and turn off way before a fuse has even though about getting warm let alone 'fusing'.

"What about if the BMS is faulty" I hear you ask? "Surely you'll get massive current flow so THEN you'll need a fuse"?
35mm (or even 16mm) cable has a greater cross sectional area than the tracks on the PCB of the BMS, in the highly unlikely event that a short circuit occurs AND the over current protection circuitry on a BMS fails then you'll still not protect the cable with a fuse because the main tracks on the PCB will fail before cable burns out. True a fuse MAY have saved the PCB tracks but IF the BMS is broken and knackered then it needs swapping out anyway.
Typically installers will still add a fuse based on tradition, habit, and 'just in case' thinking, just in case of WHAT Im not sure.