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.

 

[wildebus]

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?

It is a fair point , but I would still fit a fuse
Now for this specific one, I have made an assumption .... "the battery terminal is a quick release" ... You only have quick release on POST terminal. You get those on Lead Acid batteries but it is pretty unusual to fit post terminals on a Lithium Battery. Yes, companies like Fogstar provide post adapters, but I dont think many people use them (I certainly would not if I had any choice in the matter).

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.

 

[merl]

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?

I suppose the answer to be your question depends on what you're trying to achieve with the switch. If it's to isolate the inverter then put it in the inverter feed, having said that I'm not sure why isolating the inverter ONLY would be required TBF?
As has already been pointed out, a switch in the main battery feed makes more sense from a maintenance and emergency point of view but bear in mind that turning off this MAIN isolator would leave the solar controller unconnected to the battery, the jury is out as to exactly how damaging this is in practice BUT it's something that most if not all SCC makers recommend so also fit a switch on the panel side of the SCC anyway because it's generally handy anyway and don't forget to use it if you isolate the battery.

 

[landrovereditor]

I suppose the answer to be your question depends on what you're trying to achieve with the switch. If it's to isolate the inverter then put it in the inverter feed, having said that I'm not sure why isolating the inverter ONLY would be required TBF?
As has already been pointed out, a switch in the main battery feed makes more sense from a maintenance and emergency point of view but bear in mind that turning off this MAIN isolator would leave the solar controller unconnected to the battery, the jury is out as to exactly how damaging this is in practice BUT it's something that most if not all SCC makers recommend so also fit a switch on the panel side of the SCC anyway because it's generally handy anyway and don't forget to use it if you isolate the battery.

I don’t have solar, it really is a basic set up but I’m trying to keep it safe. Thank you all for your advice.
The company that fitted the battery took out the lead acid battery, changed the switch on the charger to AMG , there is no Lithium setting, and dropped in the new Lithium battery. Asked about the charger they said it was the correct rate to charge the battery whilst running the engine.
Do I need a B2B charger? No they said as it’s a 2016 Fiat Ducato, Fiat didn’t fit smart alternators until at least 2018.
It charges up to 100% when driving, so I have no reason to doubt them, they are a very reputable battery dealer, near Nottingham.

 

[trevskoda]

To save clambering around for hidden switches you could use a big 200ah relay with a of on switch at the dash, cost about 6 bucks on ebay.

 

[davep10000]

Sounds like you have all the advice you need, so good luck, and sometimes the simplest solutions are the most reliable.
Not sure which inverter you have gone for, but (you may already know) that they take a reasonable amount of current (typically 1.5 A) when on, with no load.
Many inverters have a remote on / off switch (my renogy does), which is a good idea. Otherwise, make sure the inverter front panel is easily accessible!!
There is nothing inherently wrong with a split charger, just they don't always fill the battery to 100%, but that may not be an issue on yours. Also the Ducato alternators are very high current output, so no problems there.

 

[merl]

I don’t have solar, it really is a basic set up but I’m trying to keep it safe. Thank you all for your advice.
The company that fitted the battery took out the lead acid battery, changed the switch on the charger to AMG , there is no Lithium setting, and dropped in the new Lithium battery. Asked about the charger they said it was the correct rate to charge the battery whilst running the engine.
Do I need a B2B charger? No they said as it’s a 2016 Fiat Ducato, Fiat didn’t fit smart alternators until at least 2018.
It charges up to 100% when driving, so I have no reason to doubt them, they are a very reputable battery dealer, near Nottingham.

If it was me I'd be using the Gel setting on the mains charger if it had one, AGM is arguably the worst setting for drop in lithium, flooded would be better if you've not got a gel setting.
A battery to battery charger would be better still because you'll get a consistent charge current rather than a current that tails off as the battery becomes charged but you've got the additional expense to consider.

 

[Fisherman]

Sounds like you have all the advice you need, so good luck, and sometimes the simplest solutions are the most reliable.
Not sure which inverter you have gone for, but (you may already know) that they take a reasonable amount of current (typically 1.5 A) when on, with no load.
Many inverters have a remote on / off switch (my renogy does), which is a good idea. Otherwise, make sure the inverter front panel is easily accessible!!
There is nothing inherently wrong with a split charger, just they don't always fill the battery to 100%, but that may not be an issue on yours. Also the Ducato alternators are very high current output, so no problems there.

That’s one of the many advantages of victrons inverters, on eco they use virtually nothing.
My Ve direct 1200 uses 3W on eco mode. Even on normal on mode it uses just 9.5w.
I have to use normal for really low usage, less than 50w.

 

[Nabsim]

I only fitted a fuse, was put off including a breaker after seeing a few vids where people had tried to throw switch in an emergency but high current stopped the switch operating. I do have an isolator between battery bank and positive bus bar but that was fitted for isolation purposes rather than use in emerbency

 

[wildebus]

I only fitted a fuse, was put off including a breaker after seeing a few vids where people had tried to throw switch in an emergency but high current stopped the switch operating. I do have an isolator between battery bank and positive bus bar but that was fitted for isolation purposes rather than use in emerbency

I think the majority of DC breakers for sale are total rubbish. They trip on a much lower current then they are meant to, or don't trip at all, or melt on at high temps (due to high current).
Sound like a good combo of a switch and resettable fuse but usually end up replaced.

 

[Lefty]

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?

Buy a 250amp trip fuse. Switch and fuse all in one.

 

[gasgas]

Renogy 3000W at £270 or Victron 12/3000 at £680? That's what I want to know . . . . . .

 

[andyjanet]

Renogy 3000 w for me! Never a days problem

 

[merl]

Renogy 3000W at £270 or Victron 12/3000 at £680? That's what I want to know . . . . . .

There's a real 5 year guarantee on Victron. Lots of reports of people struggling with making guarantee claims with Renogy even within the first year, this will sway it for many people.
You could buy 2 Renogy units for less than a Victron, this will sway it for the other people.
You pays your money and you makes your choice.