12v inverter and Victron battery charger ?

[Ardenfour]

I have a Victron hard-wired battery charger fitted - if I connect a shore lead it automatically starts charging the batteries. I want to fit a 12v to 240v inverter. If I wire this to the existing 240v sockets this will also put 240 to the output of the battery charger. Does this sound ok? Or how is this setup usually wired? Thanks.

 

[Daverw]

Not the best way for efficiency using inverter to power mains charger, can you change charger feed to direct from shore power? also some inverters allow power through when on shore power, our victron multiplus does.

 

[Ardenfour]

I'm not planning to use the inverter to charge the batteries- if I had shore power I wouldn't need the inverter. But, I'd be wiring the inverter output to the 240v circuit of the boat so the 13A sockets are powered. To which is also connected the victron charger. My query is should I disconnect the victron when the inverter is connected?

 

[Daverw]

Bit confused, are you going to use the inverter to supply all 240v sockets via your12v house bank? and not use shore supply when you can?

 

[KompetentKrew]

I want to fit a 12v to 240v inverter. ,,, this will also put 240 to the output of the battery charger.

Do you mean to the input of the battery charger?

You presumably have 240v shore power going to the sockets and to the charger - if you connect the inverter to the existing sockets then it'll also output to the charger, causing the charger to run off the inverter like an ouroboros, flattening the battery as fast as it can.

The simple ways to do this are either:

1. have the shore power connecting only to the battery charger and all the sockets connected to the inverter's output - loads on the sockets discharge the battery, but that's ok because (whist on shore power) the charger is charging at the same time. But then you can never exceed the output of the inverter, and running a heavy load (e.g. fan heater) off the inverter for a sustained period can flatten the batteries as maybe the charger can't keep up (depends on the specification of each, obviously).
2. just split the 240 sockets - have the existing ones supplied by shore power and add one for the inverter's output.

The sophisticated way to do this is with a transfer switch. Victon's combo inverter-chargers have a built-in transfer switch - the shore power goes to its input and it charges the batteries and supplies the mains sockets; shore power is used if available, or inverter if not (or inverter assist if shore power is limited). I have a Multiplus 1600 and it's quite good, but it's not cheap. Looks like Victron also sell separate transfer switches for £200 - £300.

 

[Ardenfour]

Do you mean to the input of the battery charger?

Sorry, yes, meant the input.

You presumably have 240v shore power going to the sockets and to the charger - if you connect the inverter to the existing sockets then it'll also output to the charger, causing the charger to run off the inverter like an ouroboros, flattening the battery as fast as it can.































































































































The simple ways to do this are either:































































have the shore power connecting only to the battery charger and all the sockets connected to the inverter's output - loads on the sockets discharge the battery, but that's ok because (whist on shore power) the charger is charging at the same time. But then you can never exceed the output of the inverter, and running a heavy load (e.g. fan heater) off the inverter for a sustained period can flatten the batteries as maybe the charger can't keep up (depends on the specification of each, obviously).































just split the 240 sockets - have the existing ones supplied by shore power and add one for the inverter's output.































The sophisticated way to do this is with a transfer switch. Victon's combo inverter-chargers have a built-in transfer switch - the shore power goes to its input and it charges the batteries and supplies the mains sockets; shore power is used if available, or inverter if not (or inverter assist if shore power is limited). I have a Multiplus 1600 and it's quite good, but it's not cheap. Looks li







Do you mean to the input of the battery charger?















You presumably have 240v shore power going to the sockets and to the charger - if you connect the inverter to the existing sockets then it'll also output to the charger, causing the charger to run off the inverter like an ouroboros, flattening the battery as fast as it can.















The simple ways to do this are either:







have the shore power connecting only to the battery charger and all the sockets connected to the inverter's output - loads on the sockets discharge the battery, but that's ok because (whist on shore power) the charger is charging at the same time. But then you can never exceed the output of the inverter, and running a heavy load (e.g. fan heater) off the inverter for a sustained period can flatten the batteries as maybe the charger can't keep up (depends on the specification of each, obviously).



just split the 240 sockets - have the existing ones supplied by shore power and add one for the inverter's output.



The sophisticated way to do this is with a transfer switch. Victon's combo inverter-chargers have a built-in transfer switch - the shore power goes to its input and it charges the batteries and supplies the mains sockets; shore power is used if available, or inverter if not (or inverter assist if shore power is limited). I have a Multiplus 160



Do you mean to the input of the battery charger?







You presumably have 240v shore power going to the sockets and to the charger - if you connect the inverter to the existing sockets then it'll also output to the charger, causing the charger to run off the inverter like an ouroboros, flattening the battery as fast as it can.







The simple ways to do this are either:



have the shore power connecting only to the battery charger and all the sockets connected to the inverter's output - loads on the sockets discharge the battery, but that's ok because (whist on shore power) the charger is charging at the same time. But then you can never exceed the output of the inverter, and running a heavy load (e.g. fan heater) off the inverter for a sustained period can flatten the batteries as maybe the charger can't keep up (depends on the specification of each, obviously).

just split the 240 sockets - have the existing ones supplied by shore power and add one for the inverter's output.

The sophisticated way to do this is with a transfer switch. Victon's combo inverter-chargers have a built-in transfer switch - the shore power goes to its input and it charges the batteries and supplies the mains sockets; shore power is used if available, or inverter if not (or inverter assist if shore power is limited). I have a Multiplus 1600 and it's quite good, but it's not cheap. Looks like Victron also sell separate transfer switches for £200 - £300.







0 and it's quite good, but it's not cheap. Looks like Victron also sell separate transfer switches for £200 -

 

[Alan S]

Why not just switch the charger off when using the inverter?

 

[Alex_Blackwood]

I'm not planning to use the inverter to charge the batteries- if I had shore power I wouldn't need the inverter. But, I'd be wiring the inverter output to the 240v circuit of the boat so the 13A sockets are powered. To which is also connected the victron charger. My query is should I disconnect the victron when the inverter is connected?

Simple answer. Yes. otherwise you have a vicious circle with the batteries supplying the inverter and at the same time trying to charge themselves. You also need a change over switch to ensure that you cannot have shore supply and inverter suppling your sockets at the same time! Overall I think what you suggest is inherently dangerous. The suggestion of the combo inverter / charger makes more sense.

 

[Alan S]

Looking again at your first post, you say "If I wire this to the existing 240v sockets..." dont hard wire it to the sockets. It must be arranged so that it is impossible to connect shore power 230V and inverter 230V simultaniously. Easiest way is to use a flying 16A socket on the inverter output and just plug it in to your shore power inlet.
And switch off your charger.

Edit Alex beat me to it. Equally valid but I think my option is easier/cheaper.

 

[Graham376]

I have a Victron hard-wired battery charger fitted - if I connect a shore lead it automatically starts charging the batteries. I want to fit a 12v to 240v inverter. If I wire this to the existing 240v sockets this will also put 240 to the output of the battery charger. Does this sound ok? Or how is this setup usually wired? Thanks.

No it won't work, you need a switch in the feed to the battery charger to isolate it. To avoid the chance of both being switched on together, my shore power socket and inverter are wired to a double pole two way switch before the RCD so I can choose either but not both.

 

[PaulRainbow]

As said, you absolutely must have a changeover switch to make sure you can only select shore power or the inverter

You need the mains charger to only work from shore power. This is easy to automate. Take a second supply from the shore power input to the isolator switch, from here, connect a RCBO and connect the mains charger to this. You should also consider other high current loads, such as a calorifier, which you would normally not be use with an inverter. If you have such loads it's a good idea to fit a split system, where you have two consumer units, one that works with shore power and inverter and the other only works with the inverter.

There are also Earthing considerations to be made.

Do not take inverter installations lightly, the 240v output will kill you the same as the stuff you use at home.

 

[Graham376]

Another reason for the changeover switch is to prevent the shore socket with exposed male pins under the cover from being live when the inverter is on.

 

[jackho]

I have a Victron hard-wired battery charger fitted - if I connect a shore lead it automatically starts charging the batteries. I want to fit a 12v to 240v inverter. If I wire this to the existing 240v sockets this will also put 240 to the output of the battery charger. Does this sound ok? Or how is this setup usually wired? Thanks.

Will try and answer your question by explaining what I am doing similar to you. Given the price of Camping Gaz I intend to install a 12v DC to 240V Inverter to power my boat appliances (when not connected to shore power}. I have on board mains shore powered Quick battery charger to maintain battery bank when shore power is available.
My simple solution is to connect inverter to 12v battery bank and keep 240v separated from shore power. Most inverters have one or more 13a 240v outlets so given the close proximity to battery bank I will take a 13a extension lead from socket and install another 13a socket independent from mains (suitably colour coded etc) at galley.
(Have avoided the technicalities around specification and installation.)

 

[PaulRainbow]

Will try and answer your question by explaining what I am doing similar to you. Given the price of Camping Gaz I intend to install a 12v DC to 240V Inverter to power my boat appliances (when not connected to shore power}. I have on board mains shore powered Quick battery charger to maintain battery bank when shore power is available.
My simple solution is to connect inverter to 12v battery bank and keep 240v separated from shore power. Most inverters have one or more 13a 240v outlets so given the close proximity to battery bank I will take a 13a extension lead from socket and install another 13a socket independent from mains (suitably colour coded etc) at galley.
(Have avoided the technicalities around specification and installation.)

How about fusing, RCD/RCBO etc,, Earthing ?

 

[William_H]

OP would be far better and safer to have separate power outlets for the AC from inverter. ie do not connect to 240v ring main in boat.
As said it would be a disaster if by chance you had inverter and 240 v mains connected in parallel.
To explain AC changes from positive to negative 50 times per second. It goes to a peak voltage of around 320 volts. Now when you paralell another AC source the changing form positive to negative will almost certainly not be in syncronisation with mains. Worst case scenario one is trying to deliver 320v positive one is trying to deliver 320v negative. A short circuit of 640 volts at some amps. Like connecting 2x 12v batteries in paralell but one around the wrong way. Your inverter will take up smoking and mains CBs will hopefully operate.
Don't risk it. If you keep outlets for inverter separate you also have a chance to control just what is plugged in ie what load you will put on battery.
Yes if you do as you propose the charge will try to keep batteries up from AC supplied by inverter. Resulting in gross inefficiencies and flat battery. ol'will

 

[PaulRainbow]

OP would be far better and safer to have separate power outlets for the AC from inverter. ie do not connect to 240v ring main in boat.
As said it would be a disaster if by chance you had inverter and 240 v mains connected in parallel.
To explain AC changes from positive to negative 50 times per second. It goes to a peak voltage of around 320 volts. Now when you paralell another AC source the changing form positive to negative will almost certainly not be in syncronisation with mains. Worst case scenario one is trying to deliver 320v positive one is trying to deliver 320v negative. A short circuit of 640 volts at some amps. Like connecting 2x 12v batteries in paralell but one around the wrong way. Your inverter will take up smoking and mains CBs will hopefully operate.
Don't risk it. If you keep outlets for inverter separate you also have a chance to control just what is plugged in ie what load you will put on battery.
Yes if you do as you propose the charge will try to keep batteries up from AC supplied by inverter. Resulting in gross inefficiencies and flat battery. ol'will

None of this can happen iif post #11 is followed.

Why double up on wiring and sockets, rather than just fit a simple changeover switch ? Millions of boats have such setups, some including generators too, all without issue.

 

[Robih]

None of this can happen if post #11 is followed.

Why double up on wiring and sockets, rather than just fit a simple changeover switch ? Millions of boats have such setups, some including generators too, all without issue.

I’ve a changeover switch to source supply from either shore or genny then onward to Victron Multi. Thereafter the Multi deals with providing 240v whether from battery or pass through the 240v supply. It is so simple and the Power Assist functionality is so good I can’t imagine having inverter functionality any other way. Fit a Quattro and don’t even need to select source, but I couldn’t justify that cost!

 

[GHA]

Will try and answer your question by explaining what I am doing similar to you. Given the price of Camping Gaz I intend to install a 12v DC to 240V Inverter to power my boat appliances (when not connected to shore power}. I have on board mains shore powered Quick battery charger to maintain battery bank when shore power is available.
My simple solution is to connect inverter to 12v battery bank and keep 240v separated from shore power. Most inverters have one or more 13a 240v outlets so given the close proximity to battery bank I will take a 13a extension lead from socket and install another 13a socket independent from mains (suitably colour coded etc) at galley.
(Have avoided the technicalities around specification and installation.)

I have shore power terminating in a socket with an RCD next to the inverter, all mains sockets on the boat end up at a plug which can go into the inverter or just unplug & go into the shore power socket/RCD if shore power is available. Mains charger has a separate switch so it can stay plugged in but not run when inverter is used. Handy to force back into bulk as well.
Too lazy & cheap to source & install a mains voltage crossover switch & enclosure, shore power is such a very rare occurrence anyway

 

[PaulRainbow]

I have shore power terminating in a socket with an RCD next to the inverter, all mains sockets on the boat end up at a plug which can go into the inverter or just unplug & go into the shore power socket/RCD if shore power is available. Mains charger has a separate switch so it can stay plugged in but not run when inverter is used. Handy to force back into bulk as well.
Too lazy & cheap to source & install a mains voltage crossover switch & enclosure, shore power is such a very rare occurrence anyway

No circuit breakers ? No RCD at the inverter ?

 

[GHA]

No circuit breakers ? No RCD at the inverter ?

yes. Both.