Inverter Install

[LondonRascal]

Onboard Trixie there has been installed (when and by whom I know not) a shore power system which incorporates the standard three pin connector, a domestic consumer unit which then powers the mains battery charger and two double sockets in the cabin space.  There is however surprisingly no Inverter.

As an interim measure I have been using a small 150w unit plugged into one of the many 12v accessory sockets that the boat has pre-wired since build. I plan to upgrade this to a 300w fan assisted model. This can be 'hard wired' into the battery bank which could then be mounted out of the way. I'd need a transfer switch to go between 'shore' and 'inverter' and it would be a pain in the short term with an Inverter that had no remote panel to have to get to where it was situated to turn it on and off when not in use.

Anyway, the question is you've got your domestic batteries - say three of them wired in series but you wanted your Inverter to draw off all three batteries so the load is spread over your domestic capacity. Would I be right in assuming you would wire the Inverter to effectively the last battery in the series run positive and negative terminal (option 1 photo) or would you have one positive lead on the first battery in the series and the negative on the last battery in the series (option 2 photo)  to cause all three batteries to power the inverter?

Once set up I could then upgrade the Inverter in due course, but would be nice to have something other than using an accessory socket and a single plug Inverter.

 

 

[Londonlad1985]

Harking back to a GCSE lesson won't wiring them in series increase the overall output by more than you'd want? (I'm not very good with electrickery)

[TheQ]

Picture one is for an inverter supplied with 12 Volts

Picture two  is for an inverter supplied with 36 Volts.

You can get a higher voltage supplied inverter, and that would give more overall power available..

volts X Amps = watts

 you must have an inverter rated for the correct input power, I will have a 48volt input Inverter on my boat when I get round to it.

 if you connect a 12v inverter over 36volts, if you are lucky you'll blow a fuse, unlucky and you'll find electronics is powered by smoke...

[grendel]

This would be how I wired into 3x 12 V batteries (12v output)

3 batteries in Parallel, the inverter wired to + at one end and - at the other, this should even out any consumption between the 3 batteries, you can wire into one end, but then the resistance of the wiring between batteries comes into play at the high loads used by inverters and you can get one (nearest ) battery taking the brunt of the load - then you have unbalanced batteries when it comes to recharging.

[grendel]

NB red goes to all the + terminals, black to all the - terminals

[annv]

Hi Robin All battery banks should only be wired as your option two, if you wire as in option one you only use the first battery which will have a shorter life. if four or more batteries are used as one bank there is another way of connecting them it is as option two but doubled, i have a diagram filled some where, by having the pos and neg leads on different batteries make them work as one there for more capacity and longer life your inverta should have a seperate on/off switch otherwise it will use a small amount of current to power it self,don't use any electrical equipment that has diode lights on it they will burnout you can only use analog on quasi inverters you need a pure sine wave inverter for diode equipmentor or any equipment that has a thyristor control ie more up market microwaves and dvd players. Oh and a microwave uses twice the power that its rated for .John

[grendel]

Also note that good wiring practice would have the charger/ alternator wired similar to the inverter (though maybe to the other two terminals) for similar reasons that the charger also can input a high current.

[Guest]

42 minutes ago, grendel said:

This would be how I wired into 3x 12 V batteries (12v output)

3 batteries in Parallel, the inverter wired to + at one end and - at the other, this should even out any consumption between the 3 batteries, you can wire into one end, but then the resistance of the wiring between batteries comes into play at the high loads used by inverters and you can get one (nearest ) battery taking the brunt of the load - then you have unbalanced batteries when it comes to recharging.

Now what's the punch a Judy catch phrase , ah yes " that's the way to do it "  .

I woulI defiantly recommend a cross over switch between shore power and inverter its by far the easiest solution and the safest way , as for remotely controlled its easy enough to extended the cable from the switch so you can then place the unit out of sight , iv actually done this twice now and basically for convenience , now I can turn on / off the inverter on the dash rather than go in the cabin to switch it on at the remote which is next to the bed to save me getting up to do it last thing at night ( lazy ) , that said I wouldn't do it on an item in warranty .

Other than that Peter's drawing is entirely correct 

[vanessan]

Welcome to the forum annv (John). Now I believe you post elsewhere on a forum and, from what I have seen, you will be able to add a lot of knowledge and information to the already vast array of subjects here. 

[Vaughan]

In my experience, an inverter is fitted to give you a 220V supply from your batteries.

This has nothing to do with a shore supply at 220V, which is there to charge the batteries, which are supplying the inverter. This supply may also have its own 220V plug points, which are not connected to the inverter. Otherwise you would need switchgear to ensure that you are not trying to use both at once.

So you either charge the batteries with the engine alternator, or from a 220V shore-powered charger. This is why, on the average hire boat, you have to run the engine when you want to use the microwave oven.

 

[annv]

Thank you Vanessan, yes.  John

[Guest]

16 minutes ago, Vaughan said:

In my experience, an inverter is fitted to give you a 220V supply from your batteries.

This has nothing to do with a shore supply at 220V, which is there to charge the batteries, which are supplying the inverter. This supply may also have its own 220V plug points, which are not connected to the inverter. Otherwise you would need switchgear to ensure that you are not trying to use both at once.

So you either charge the batteries with the engine alternator, or from a 220V shore-powered charger. This is why, on the average hire boat, you have to run the engine when you want to use the microwave oven.

 

It does if both are switched on using the same consumer unit hence the cross over switch , that way it makes things completely foolproof , its impossible to have both shore power and inverter trying to supply mains voltage at the same time which is possible without a cross over switch on less the shore power only feeds the battery charger and no sockets those being taken care off by the inverter , which means inverter on even when hooked up to shore power which kinda  defeats  the point really .

To me have both via the same consumer unit and a cross over switch to eliminate any confusion between the 2 sources of mains voltage .

[LondonRascal]

Thanks all.

 I have to admit when it comes to several batteries and wiring I get in a right pickle and had I continued would have no doubt gone and wired up as 24v or 36v.

The reason this all came about was a super cheap Maplin Inverter I bought yesterday that is small and low powered but has proper terminal connectors so you can hard wire it to the battery bank. I thought this will be better than nothing and once the wiring is in place for it, so long as I use the right gauge (in the case of this Inverter it would be way overkill) the basic skeleton of wiring then is sorted for a future 1.5Kw Inverter I have my eye on. There is a handy cupboard which houses the domestic consumer unit and where the mains battery charger is wired to, and this is about 2 feet away from the batteries - but I can probably get the Inverter a little closer and in a less enclosed area which will also help it keep cooler.

However the next update will have to move all the sockets (goodness knows why they were put on the floor) and being plastic surface mount style it will not take much to knock one and you will crack the plastic. I know where they need to be put but that will take a back seat as I need to get 10 more double sockets put in on Independence to convert her to proper sockets from the plastic rubbish that are on there at the moment complete with their fake plastic brass shiny surrounds.

[grendel]

4 minutes ago, LondonRascal said:

I need to get 10 more double sockets put in on Independence to convert her to proper sockets from the plastic rubbish that are on there at the moment complete with their fake plastic brass shiny surrounds.

I would get a weatherproof one to replace the one that was drenched and caused the generator to cut out (or move that socket)

[LondonRascal]

2 hours ago, Londonlad1985 said:

Harking back to a GCSE lesson won't wiring them in series increase the overall output by more than you'd want? (I'm not very good with electrickery)

I forgot a bunch from school including how you actually wire in parallel and series - looks so simply in diagrams then with a bunch of wires in the real world you are left thinking..urm. Still I tend to get there in the end and so far without any bangs, sparks or deaths. It is always good to check twice, and in this case with peeps here before I go and destroy some perfectly good equipment lol.

[grendel]

that is why you bought a multimeter - once you have wired up - check the voltage - if its 12V you have probably done it right - if its 36V you have done it wrong

[StillCruising]

Our 2Kw inverter is connected as in Grendel’s diagram,  it is hard wired to the batteries but through an isolator switch and a fuse.  The 240v output is not hard wired to the boat, if I need to use it I have a lead that I can plug into on of the inverter 13 amp front sockets and plug into my shore power socket.  Using this method there is no risk of any conflict between the inverter 240 volts and shore power. Also having a separate isolator guards against somebody switching the inverter on accidently and drawing the quiescent current. 

[Guest]

1 hour ago, StillCruising said:

Our 2Kw inverter is connected as in Grendel’s diagram,  it is hard wired to the batteries but through an isolator switch and a fuse.  The 240v output is not hard wired to the boat, if I need to use it I have a lead that I can plug into on of the inverter 13 amp front sockets and plug into my shore power socket.  Using this method there is no risk of any conflict between the inverter 240 volts and shore power. Also having a separate isolator guards against somebody switching the inverter on accidently and drawing the quiescent current. 

Yep that works but still I'd rather flick a switch , call me lazy but I just convenience , my boat is my home n the easier its to live with the better .

That said your absolutely right the last thing is conflicting sources of mains supply getting involved with each other iv seen as he aftermath of a gen set and inverter fighting each other n it cost a packet , not to me I hasten to add , thing is it was an inverter charger so both units disappear for repair  , major inconvenience n also why I disagree with combos , one goes pop n you lose both .

[ExSurveyor]

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. 

[StillCruising]

Hi Ricardo

The inverter is mounted under one of the steps in the cockpit next to the battery locker so that I could keep the wires as short as possible but there is a good chance that people can kick the on/off switch inadvertently and turn it on without realising it. The 12v cables go straight onto the batteries not through the normal boat Isolator as it was too far away and not heavy duty enough to take the maximum potential current draw. At the time I had a spare 700amp isolator  hanging around (like you do) so I fitted that making the inverter totally isolated from the rest of the boat when not in use.

[annv]

It is good practice to have the shore power ac sockets on a seperate circuit to the inverter circuit then if the shore power drops out,card runs out, you then wont run the battery's flat by the inverta wich will switch over automatically without you being  aware of shore power dropping out,  sod's law will make this happen at night. and of cause then the two can't interact and implode accidently . John

[LondonRascal]

1 hour 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.

Oh, but I had my eye on a $10 one of Alibaba lol.

[MBA Marine]

Two sources of AC going to the same point of distribution, one inverter and one shore, turn both on and inverter goes ****! technical term there, I have had to replace someone's whoopsy having done just that!

AC source selector switch required, now say that after being on the sauce.

I do tend to stick to the Rotary style but be wary of the very cheap direct from china ones as I have tried them to find they were close but not quite right, the 'real' ones have a built in link that links a couple of terminals together, the cheapo ones did not have this and i had to add my own link wires to make the switch function as it should, next problem was life expectancy, I replaced one of my cheapo switches a year later, the replacement was not the budget variety.

Blue-sea used to make a nice panel for two AC sources, comprising of a pair of breakers and a sliding tab, the tab covers one switch and allows you to switch the other on, then to swap sources you turn off slide tab to switch on the other.

As for batteries , well covered by others above, wired in parallel (unless you wanted 36v) then draw and charge using the Pos & Neg at opposite ends of the bank.

If in doubt as a friendly engineer to lend a hand.

just posted and noticed I got censored ****!  can we not say P O OF 

[grendel]

1 hour ago, MBA Marine said:

just posted and noticed I got censored ****!  can we not say P O OF

Well I guess not, I havent looked at the list of censored words yet.

[Guest]

2 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 .