Understanding Boat Electrics And Installing An Inverter

[Ray]

It would save a few bob that's for sure! 

I think I'll experiment a bit more with our gas cooker on our next few trips before deciding!

[Meantime]

10 minutes ago, Ray said:

It would save a few bob that's for sure! 

I think I'll experiment a bit more with our gas cooker on our next few trips before deciding!

Over complicating things also has hidden costs. Aside from the initial cost of the equipment, heavy discharging of batteries shortens their life, so there is a cost there, in addition heavy recharging comes at the cost of extra load on the engine, which in terms means more wear and tear on the engine, but also more diesel burnt. 

The governor of a diesel engine will regulate the flow of diesel to keep the revs constant. Therefore using more diesel when under a heavier load. It is noticeable when cruising if I put the 24V coffee maker on, you hear the engine note change, even though the revs remain the same. 

Likewise my friend has a cpap machine which is run of the 24V batteries. If we then make two or three cups of coffee before getting under way it is noticeable that the engine is under a heavier load for the first hour or so. This all means extra diesel burnt for the first hours cruising.

It is often overlooked how much extra diesel is burnt in recharging batteries, which all forms part of the 60/40 split of fuel duty.

As they say, nothing is for free in this world.

[Ray]

I find this sort of thing very interesting, I've wondered in the past why it is that using a car's aircon decreases mpg achieved... I think I have my answer 👍

[Meantime]

9 minutes ago, Ray said:

I find this sort of thing very interesting, I've wondered in the past why it is that using a car's aircon decreases mpg achieved... I think I have my answer 👍

Yes similar principle to when you reach a hill you have to press the accelerator harder to maintain the same speed. The noticeable one is when stationary and you turn the rear screen demister on you will probably hear the engine labour slightly. 

My current car has stop start technology like most new cars and when stationary in traffic when the engine stops the air con will slow down to try and conserve energy, until a point that it feels the cabin temperature is not being maintained and then the engine will restart and the air con goes into overdrive.

[DAVIDH]

What a fascinating thread. Speaking as someone who has absolutely no appreciation of what's involved, I now know why quotes for installation are so high. Great advice from all those contributing. 

[Ray]

3 minutes ago, DAVIDH said:

What a fascinating thread. Speaking as someone who has absolutely no appreciation of what's involved, I now know why quotes for installation are so high. Great advice from all those contributing. 

I agree, not only learned a lot but potentially saved a lot too.

Over the past year I've sorted out a recurring problem with the WC, identified the cause and rectified a lack of hot water and fixed a malfunctioning gas grill.. all thanks to the members of this forum!

Thank you all for your patience and generosity in sharing your knowledge and experience 👍

[Vaughan]

1 hour ago, Meantime said:

As they say, nothing is for free in this world.

Sod's Third Law of engineering!

A 90 amp alternator on full charge will take 5HP off the engine.

And as you only have a 40HP engine in the first place . . . .

[Vaughan]

10 minutes ago, Ray said:

Thank you all for your patience and generosity in sharing your knowledge and experience 👍

You are more than welcome!  I like to think that is what some of us are here for, on a forum such as this.  We can only give general advice, all the same.  Working on a boat is very much "hands on" and all boats, even of the same class, are different.  The only way to really be of help, would be to get on board the boat and have a look!

[annv]

Hi Ray As Grendel said Just follow the instructions that come with the inverta The 240 Ac earth connection goes to the galvanic iserlator the and shore power socket. The Dc earth/Neg is as Vaughan said separate.  the Inverta will automatically switch from mains supply from battery's to shore power plus battery charging unless you are talking about a cheaper standalone inverta. a 1000 Wk inverta will only run a 500Wk micro wave. The engine starter battery should be separate and only run engine electrics. solar is connected to battery side of iserlating switch through a fuze this will then keep batterys charged when boat is moored . see part of my installation below. John

[annv]

Oh and Ray i take it you know the difference between Pure Sine wave inverter's and the cheaper Quasi wave ones and there limitations. John

[Ray]

1 minute ago, annv said:

Oh and Ray i take it you know the difference between Pure Sine wave inverter's and the cheaper Quasi wave ones and there limitations. John

Yes! Thanks John, it's one of things that came up when I started reading the specs of different makes. Pure sine will be the way to go 👍

[MargeandParge]

Hi All

We have Kettle Micro Wave and all the bits but only when on shore power. Old Parge would struggle to justify the cost of a big invertor as leisure AGM won't take the drain.  We have a 12volt telly which is good.

I have a stand alone invertor to install just to run an electric blanket when it is a bit chilly around the edges. Looking at 150 watts for a timed hour. It is pure sign wave so could be useful for anything we don't have a charger for only one socket attached to the the invertor. I will use stronger leads than the ones it came with although they are the same as light jump leads and run it from our domestic 3 X 115 amp hr AGM battery bank through a separate isolator .

How many times would you have used your microwave when there was no sure power ? We have a gas top toaster if I need me BEANS  which our Marge purchased from ebay and it works very well. (especially when she uses it)

Your electrics that are installed look like a very professional expensive job to me and if they were mine I would leave well alone if all works well .

Kindest Regards and enjoy your ping dish when plugged in .

Marge and Parge

[Ray]

7 minutes ago, MargeandParge said:

Hi All

We have Kettle Micro Wave and all the bits but only when on shore power. Old Parge would struggle to justify the cost of a big invertor as leisure AGM won't take the drain.  We have a 12volt telly which is good.

I have a stand alone invertor to install just to run an electric blanket when it is a bit chilly around the edges. Looking at 150 watts for a timed hour. It is pure sign wave so could be useful for anything we don't have a charger for only one socket attached to the the invertor. I will use stronger leads than the ones it came with although they are the same as light jump leads and run it from our domestic 3 X 115 amp hr AGM battery bank through a separate isolator .

How many times would you have used your microwave when there was no sure power ? We have a gas top toaster if I need me BEANS  which our Marge purchased from ebay and it works very well. (especially when she uses it)

Your electrics that are installed look like a very professional expensive job me and if they were mine I would leave well alone if all works well .

Kindest Regards and enjoy your ping dish when plugged in .

Marge and Parge

Sounds like you have a good setup all sorted out. I think we all tend to find what works best for us over time 👍

[annv]

Hi Ray i have just had a chance to enlarge your photos! with out being critical i suggest that if you fit a combined inverter charger you can then get rid of many of your items this would make things neater and take less room,  your battery's arnt wired for best results (see diagram) your agm battery's are to near the engine and will get too hot (agm's are not as forgiving as lead acid). What does your fridge power converter do? normally it would be wired to fuse board with 50amp cable straight to fridge. i suspect that various items have been added over the years and fitted where there was space.would it be possible to move fuses etc into a cupboard out of engine room? if not fitting a extractor fan to engine room to reduce temperature would be very beneficial. If you would like speak to me on this,  message me with your no and i will call you. John

[Ray]

Many thanks for taking so much trouble John. I can see the sense in what you say, a fresh clean installation would be an ideal way of upgrading and simplifying. 

I fear though that not only is this way out of my experience level to do personally but also possibly out of my "wallet level" to have done! 🙂

[annv]

Hi Understand There are some items that could be made redundant and along with a bit of wiring and new ends would be a lot safer and little cost. ANY BODY CAN DO ANYTHING IF THEY PUT THERE MIND TO IT it just might take a little longer plus give you enormous satisfaction and enjoyment.just follow the instructions and connect the ends John

[annv]

Hi If nothing else you really should remove the heat from those agm battery's. John

[Ray]

That is something I will get onto, thanks John 👍

[Karizma]

Excellent thread - always good to read and then compare with ones own installation.

Agree with all the key points made on here and my experience is that we use our's mostly when connected to shore power (mostly for convenience with domestic appliances, knowing we'll definitely have hot water in a morning! and fully charged batteries), or whilst cruising to make a cuppa with the canopy down (as it blows out the gas hob ).

Thanks again to all those for sharing their knowledge and experiences