Inverter Install

[Guest]

3 hours ago, psychicsurveyor said:

Be wary of automatic switch overs, I had one already fitted when I got the boat,  it was meant to switch between shore power and the generator.  It worked well,  until it failed,  it then melted the supply cables.

I would only go for a manual switch that eliminates the possibility of both being powered together.

I have had the generator disconnected and an inverter installed. 

Totally agree manual switching is the way to go , not expensive or hard to wire , they just do the job with no drama or scary situations .

[tonplus]

I've got 2 separate sockets that are fed from an inverter the rest are from shore power.  No chance of a bang from out of phase voltage crossing.

Grendel's diagram for battery wiring is spot on.

Oh yes, it's not a good idea to pick battery terminals...unless you're an engineer, then it's encouraged.

[ExSurveyor]

49 minutes ago, tonplus said:

I've got 2 separate sockets that are fed from an inverter the rest are from shore power. 

Thats my set up, next to the telly and fridge.  The only downside is the inverter is not powerful enough to run the coffee machine. 

[tonplus]

1 minute ago, psychicsurveyor said:

Thats my set up, next to the telly and fridge.  The only downside is the inverter is not powerful enough to run the coffee machine. 

Coffee machine, now there's posh!

[Guest]

Er hang on does that mean that some sockets are powered by the inverter and some powered by shore power ? Surely that means swapping the appliance plug to the relivent powered socket and knowing which form of power is being applied  , that sounds like akot of hard work to be honest and the only other time iv known of it is broardland lapwing that half the sockets worked on the Inverter and half on shore power  , it doesn't sound very user friendly to me , a simple 2 or 3 ( gen set opinion ) position switch  isolates each circuit meaning only one can be used at any one time , its impossible to get say the water heater to work on the inverter as its only wired in to the shore power side but all the sockets within the boat work on both shore power ( when selected ) or inverter ( when selected) therefore removing the possibility of plugging an item in to a socket that's inverter powered while on shore power then having to remember which ones are actually live while using shore power , these are the switches I'm referring to the take all the guess work away and allow full use of all the sockets regardless of which source of power you wish to use .

[Guest]

When mains/shore power is not available,  the inverter should always provide 240v to the battery charger, that way the batteries will not go flat so fast.

[MBA Marine]

https://aquafax.co.uk/product/8-28132-blue-sea-panel-230vac-source-select-16a Here is the Blue Sea version I mentioned earlier, as said I usually opt for the rotary type above but I have done a couple of these. 

 

[Guest]

10 minutes ago, MBA Marine said:

https://aquafax.co.uk/product/8-28132-blue-sea-panel-230vac-source-select-16a Here is the Blue Sea version I mentioned earlier, as said I usually opt for the rotary type above but I have done a couple of these. 

 

I had these on my last boat, they are also circuit breakers.

[annv]

Hi Philosophical I think you meant to say that when the shore power dropped out the inverta automatically switches on to provide ac as a combo doe's, for say the tv,  hence my suggesting that not all power points should be on the same circuit.a bit difficult to power a battery charger from the same battery power that it is running it.it wouldn't be a good idea to run a immersion heater from the inverter without running the engine which would heat the water anyway. but you would use it on shore power with perhaps a electric blankets, fan heater  ect. John

[Guest]

18 minutes ago, annv said:

Hi Philosophical I think you meant to say that when the shore power dropped out the inverta automatically switches on to provide ac as a combo doe's, for say the tv,  hence my suggesting that not all power points should be on the same circuit.a bit difficult to power a battery charger from the same battery power that it is running it.it wouldn't be a good idea to run a immersion heater from the inverter without running the engine which would heat the water anyway. but you would use it on shore power with perhaps a electric blankets, fan heater  ect. John

a bit difficult to power a battery charger from the same battery power that it is running it

You mean I hadn't invented a way of generating perpetual electricity

[annv]

Hi Philosophical I just bet you wish you had, you would end up better of than midas a boat for every day of the week and world fame. John

[TheQ]

9 hours ago, Ricardo said:

Er hang on does that mean that some sockets are powered by the inverter and some powered by shore power ? Surely that means swapping the appliance plug to the relivent powered socket and knowing which form of power is being applied  , that sounds like akot of hard work to be honest and the only other time iv known of it is broardland lapwing that half the sockets worked on the Inverter and half on shore power  , it doesn't sound very user friendly to me , a simple 2 or 3 ( gen set opinion ) position switch  isolates each circuit meaning only one can be used at any one time , its impossible to get say the water heater to work on the inverter as its only wired in to the shore power side but all the sockets within the boat work on both shore power ( when selected ) or inverter ( when selected) therefore removing the possibility of plugging an item in to a socket that's inverter powered while on shore power then having to remember which ones are actually live while using shore power , these are the switches I'm referring to the take all the guess work away and allow full use of all the sockets regardless of which source of power you wish to use .

I've a couple of those for my to be fitted installation.

One for Shore power, off, generator.

The other for: Input socket Port, Off, Input socket Starboard.

 

One thing I've not seen mentioned is galvanic isolation, I'll be building my own galvanic isolator, but for those not in Electronics, there are plenty of commercial units available..

[Guest]

15 minutes ago, annv said:

Hi Philosophical I just bet you wish you had, you would end up better of than midas a boat for every day of the week and world fame. John

Or indeed an electrical car named after me, but sadly unless I try harder it is not to be. 

[Guest]

6 minutes ago, TheQ said:

I've a couple of those for my to be fitted installation.

One for Shore power, off, generator.

The other for: Input socket Port, Off, Input socket Starboard.

 

One thing I've not seen mentioned is galvanic isolation, I'll be building my own galvanic isolator, but for those not in Electronics, there are plenty of commercial units available..

To be honest Q as I can't see the point in doing it any other way than s sector switch and would certainly prevent confusion as to which sockets work on which input , I'm a little concerned basically because its not been mentioned that these inverter sockets are feed directly off the inverter without going through a breaker as the shore power has to to satisfy BSS , maybe they do and its not been stated but they should do , some inverters kick out a lot of power , but even so they will zap you if you short them out just as shore power would and without breaker's its a case of relying on fuse's to break the circuit .

Galvanic isolators are an essential but of kit , impressed your building your own though , its kind of a  small unit that saves big bills .

[ExSurveyor]

16 minutes ago, Ricardo said:

would certainly prevent confusion as to which sockets work on which input ,

I have a sign that says inverter on the socket.  I also have a galvanic isolater fitted.

[Guest]

18 minutes ago, psychicsurveyor said:

I have a sign that says inverter on the socket.  I also have a galvanic isolater fitted.

Fine I'm just quoting standard practice that's all .

[TheQ]

The Boat, 240V Fuse / breaker / RCD Box is a separate Item. After the supply  choice switch mentioned above.

There will also be:

A breaker / Rcd at the input into my cable from the post. I don't trust something in the pillar that could be interfered with.....

On incomer side, is it connected round the right way LED indicators.

The galvanic Isolator will have LED indication that it hasn't blown..

 LED indications to show power is on from any source.

A breaker / switch for the Inverter Supply.

 

Notes,

40+ years in electronics helps,

A galvanic Isolator is in simple form a very easy to build circuit, the circuits are available on the net. Added refinements to improve safety and use, are a bit more interesting.

Commercially Galvanic isolators are about £70 upwards, I can build  one for about third of that, but that doesn't include my time..

 

[grendel]

I have always wondered, when using an inverter - where does the earth come from, externally there is only +12V and -12V going in, so is inverter AC earthed? and if so , where, does the inverter casing need to be earthed to the boat earth system?

[TheQ]

The Earth, on a house is directly or indirectly connected to the ... Earth. So the Earth on  a boat  should be connected to the nearest equivalent . The best way is a direct connection to a sacrificial anode on the boat, This would be connected the negative (on negative earthed boats) side of your DC electrics, which should be connected to the engine /  drive gear which also  connects your boat to the water. so some installations just connect to the earth bolt on the engine.

The above is of course why you need a Galvanic isolator, as you form a loop between your boat and the boat moored along side through water and the shore power electrics. Without isolation one of you will very rapidly start having his prop etc eaten away..

[grendel]

yes, but if you are using a stand alone inverter, and battery,  what is the AC earth connected to ( I have managed to stump most of the electrical designers where I work with this one too in the past)

[TheQ]

Earth... the river.. you should have somewhere to drain the current away , any metal such as the engine is earthed anyway. If your inverter goes live to case you need the earth to cause everything to trip out.

 

[Guest]

1 hour ago, TheQ said:

The Boat, 240V Fuse / breaker / RCD Box is a separate Item. After the supply  choice switch mentioned above.

There will also be:

A breaker / Rcd at the input into my cable from the post. I don't trust something in the pillar that could be interfered with.....

On incomer side, is it connected round the right way LED indicators.

The galvanic Isolator will have LED indication that it hasn't blown..

 LED indications to show power is on from any source.

A breaker / switch for the Inverter Supply.

 

Notes,

40+ years in electronics helps,

A galvanic Isolator is in simple form a very easy to build circuit, the circuits are available on the net. Added refinements to improve safety and use, are a bit more interesting.

Commercially Galvanic isolators are about £70 upwards, I can build  one for about third of that, but that doesn't include my time..

 

All that's bang on right as I see it , n heck I should have got used to knowing now its certainly not my first rodeo when it comes to fitting out .

[annv]

As in most cases the system you have be fitted by yourself or inherited is cost.There is not a perfect system for every body.In my case i have shore power that goes to a panel that tells me if polarity is correct it then goes to a r c d then to three m c b one for immersion heater one for Sterling Combo the other one to circuits in kitchen for toaster, kettle,,plus spare sockets. The inverta/combo then then goes to 12v mcbs for cooker, hob ,tv, dvd,pumps, lights, central heating ect. My fridge runs on ac shore power it then switches automatically to 12v when shore power disconnects.I have two alternators 180 and 65 connected to a Sterling alternator/charger that looks after both banks with max charging accomplished as i sail along. I have a 12v dc generator of 140 amps to charge batteries if moored for any length of time, i chose dc as it more efficient than a ac generator of 6 kwh then use a 12v charger of perhaps only 60 amps. I have a 120 w solar panel to maintain batteries when moored permanently so i don't have to rely on shore power and its free. I find this works for me without much input from me and is to all intention does it all automatically accomplished. Not everybody would go to these lengths or cost but big boys have big toys and i enjoyed building it.John

[WherryNice]

1 hour ago, grendel said:

yes, but if you are using a stand alone inverter, and battery,  what is the AC earth connected to ( I have managed to stump most of the electrical designers where I work with this one too in the past)

I had been wondering that same thing, perhaps it doesnt actually go to earth as such but goes back to the unit where some kind of electronic trip would cut the supply if necessary? Just an idea?

Also isnt the point of bonding the dc neg and the ac earth to prevent current being discharged into the water? I could very well be wrong about most of this, I have been researching this kind of stuff but a lot of the info out there seems to conflict.

[LondonRascal]

It’s not worth it on a little boat like Teixie is but an Isolation Transformer is the way if you have space. Also the galvanic corrosion tend to happens far more aggressively in salt water.

On Independence, almost all her Anodes have been eaten away - no doubt from being moored in a salt water marina for so long with masses of other boats all around connected to shore power supplies not to mention her own - without any form of galvanic isolator onboard. Clever stuff but just more items to attend to now she is in fresh water as will change the type of metal to Aluminium (don’t fancy Magnesium) from Zinc.

Trixie needs a good going over so far as the mains power side of things goes, it looks tidy and safe enough but I have no idea if was a DIY job or professional and when dealing with mains voltage I’d rather be safer than sorry.