Boat in build pics (2013 Fairline Squadron 78)

[MapisM]

You might remeber that OuterReef 70 featured on this forum last year whose owner I've met, and it's a beautiful boat, but the owner wanted ability to run airco for houses on batteries so he has massive inverters plus an unbelieveable amount of batteries in the keel.

Just for the records, actually that chap "only" wanted to be able to run the A/C fans for circulating air.
Running also the compressors was not even an option, even with all those batteries and inverter power.
He also wanted to be able to run the cooktop, at least partially, to boil some water now and then without necessarily turning the genset on.
For a full flagged meal preparation, he also needs the genset anyway.
That said, 'fiuaskme, I agree much more with your choices than with his.

 

[jfm]

Just for the records, actually that chap "only" wanted to be able to run the A/C fans for circulating air.
Running also the compressors was not even an option, even with all those batteries and inverter power.
He also wanted to be able to run the cooktop, at least partially, to boil some water now and then without necessarily turning the genset on.
For a full flagged meal preparation, he also needs the genset anyway.
That said, 'fiuaskme, I agree much more with your choices than with his.

Oh, I hadn't appreciated that MapisM. Thanks for clarification. Blimey, all those batteries and all that lead just to swoosh the air around but not chill it! Each the their own, and that is why custom boatbuilding is nice, but I wouldn't have chosen his set up. I think my 2x standard number of opening windows in master cabin for €500 was good value in comparison!

 

[Trundlebug]

T'other thing is, I have 500Ah@24 house batteries and then 250Ah@24 dedicated batteries for port engine and ditto for stbd. I thought on Match 1 of rewiring so that only one engine has dedicateds, and the other engine batteries join the house bank which would increase the house bank capacity 1.5X. I might do this on Match2 if I get around to it - I can't see why not, esp as the port/stb dedicated sets have a link relay

That's a fascinating insight into your thinking J, thanks for this.

Interesting to me because I went through exactly the same thought process when redesigning my batteries and charging system, ahem on a rather more modest scale I might add, although the principles are exactly the same.

The solution I ended up with was to have one engine start battery serving both engines, thereby releasing an additional battery for the house bank without adding extra weight or size. I note you haven't mentioned this as such, although you've considered having one engine started from the house bank.

My thinking was, I still have a dedicated engine start battery that won't get pulled down regardless of house bank state, and as long as I can get at least one engine started from the engine start battery then it can be recharged enough to keep having a go at starting the other engine. The only compromise I have is that I have to start one engine at a time, rather than both together. Well I did that anyway, so that's not a compromise at all to me at least. Given that a battery is well more than capable of starting an engine twice, it is therefore just as capable of starting two engines at least once.

I also still have a link to bridge across from the house bank if ever I needed to, so overall it seemed an easy decision.

(I should add, the charging configuration I designed such that either, or both engines charge both starter and house banks automatically).

Surprised you've not also considered this?

 

[Deleted User YDKXO]

I also specced an auto genset start by Capricorn-Controls.com so when the house batteries get down to the trigger level (21 volts or something) one of the gensets autostarts. Both batt chargers - 200amps - will be on so the genset will run 20 mins or something to fill up the batteries. So, in hot weahter I can expect a genset to run at 6am maybe, and in average weather it wont autostart and I would manually start a genset to make breakfast etc.

We do the same as you ie. run the genset+aircon until bedtime and then switch it off but I've often wondered whether there is any kind of thermostat controlled device which could auto start the genset+aircon if the temp in, say, the master cabin, exceeded a preset level?

T'other thing is, I have 500Ah@24 house batteries and then 250Ah@24 dedicated batteries for port engine and ditto for stbd. I thought on Match 1 of rewiring so that only one engine has dedicateds, and the other engine batteries join the house bank which would increase the house bank capacity 1.5X. I might do this on Match2 if I get around to it - I can't see why not, esp as the port/stb dedicated sets have a link relay

On smaller boats, it's normal to have only a set of engine batteries dedicated to only one engine and the other set dedicated to both domestic and engine starting duties. As you say, if you have a link switch and one or two gennies anyway, there doesn't seem much point in having a set of batteries dedicated to starting each engine although, of course, it is a belt 'n braces solution

 

[rafiki_]

On smaller boats, it's normal to have only a set of engine batteries dedicated to only one engine and the other set dedicated to both domestic and engine starting duties. As you say, if you have a link switch and one or two gennies anyway, there doesn't seem much point in having a set of batteries dedicated to starting each engine although, of course, it is a belt 'n braces solution

Rafiki has a variation on the theme. Domestic bank, 3x115 ah. Dedicated port batt, and 2 x batts for stb engine, anchor winch and b/thruster. So far so good

 

[MapisM]

the charging configuration I designed such that either, or both engines charge both starter and house banks automatically

I for one would be interested to hear more about the bit I emphasized.
Tx in advance!

 

[grumpy_o_g]

We do the same as you ie. run the genset+aircon until bedtime and then switch it off but I've often wondered whether there is any kind of thermostat controlled device which could auto start the genset+aircon if the temp in, say, the master cabin, exceeded a preset level?

Don't some of the of gensets automatically fire up when the battery voltage drops below a certain level? If you just had the aircon on a thermostat that would sort of work as the aircon would soon drop the battery voltage for you...

 

[MapisM]

Don't some of the of gensets automatically fire up when the battery voltage drops below a certain level? If you just had the aircon on a thermostat that would sort of work as the aircon would soon drop the battery voltage for you...

Naah... That assumes to run the A/C from the batteries+inverter, to start with. Which would require huge battery banks, plus a helluva powerful inverters.
To do what Deleted User is asking, the thermostat should start the genset first, and then the A/C.
No rocket science, surely, but I've never seen or heard of any off the shelf thermostat with such functionality already built in.

 

[Trundlebug]

I for one would be interested to hear more about the bit I emphasized.
Tx in advance!

Quite simply, I installed a Sterling Alternator to Battery charger.
The alternator of both engines is connected to the input of the charger, which boosts and splits the charge between starter and house banks.
Priority charging is initially given to the starter battery, thereafter fast charging the house bank.
That way, whichever engine is running (or when both are running), the entire charging system works normally.

There was some discussion at the time about one alternator being the lead one and doing the majority of the work, but to all intents and purposes it doesn't matter a jot if one is working slightly harder than the other on some occasions and on others it is reversed - the benefits overall are substantial, and the downsides seemed only theoretical.

It's always seemed rather over the top to me to have a stand alone starter battery for each engine, when one shared between the two is more than adequate, especially when back-up and redundancy are built in (i.e. bridging facility)

 

[MapisM]

Quite simply, I installed a Sterling Alternator to Battery charger.
The alternator of both engines is connected to the input of the charger, which boosts and splits the charge between starter and house banks.

Interesting, but waddumean by "boost"?
I suppose it's the capacity of this component to add up the recharge power of both alternators, or is there anything else?
Btw, I googled a bit for it, and found this webpage of the thing:
http://www.sterling-power.com/products-altbatt.htm
But TBH, also from it I struggled to understand their claim about charging the batteries "over 5 times faster"...

 

[Trundlebug]

What they mean is, it boosts the voltage from (on a standard alternator) a max of 14.4v up to 14.8v to increase charging rate.

The idea of it is to have an "intelligent" i.e. multistage charging system in the same way that shorepower chargers work, but from the engines.
As normal alternator outputs aren't set up to do this, the unit is fitted between the alternator(s) and batteries and sorts the whole thing out.
Put very simply but I'm sure you can see what I mean.

The Sterling info is quite comprehensive and I read up extensively beforehand, although 4 years ago when I was looking it wasn't totally clear if I could connect the alternators from 2 engines to the input. I can now confirm it's fine.

 

[jfm]

To do what Deleted User is asking, the thermostat should start the genset first, and then the A/C.
No rocket science, surely, but I've never seen or heard of any off the shelf thermostat with such functionality already built in.

I agree that there doesn't seem to be one off the shelf but in case anyone ever wanted to do it, it is worth noting that the genset autostarter I have on M2 has separation of the "trigger" part and the "genset autostart" part. In my case the trigger is a low battery volts sensing circuit, but some people spec a time clock. I would think it is pretty easy to create a thermostat circuit to function as the trigger if you wanted. Or even a voice activated circuit where you shout "It's hot in here!"

 

[jfm]

What they mean is, it boosts the voltage from (on a standard alternator) a max of 14.4v up to 14.8v to increase charging rate.

The idea of it is to have an "intelligent" i.e. multistage charging system in the same way that shorepower chargers work, but from the engines.
As normal alternator outputs aren't set up to do this, the unit is fitted between the alternator(s) and batteries and sorts the whole thing out.

I had/have this on Match1+2. Both engines were specced without Caterpillar's normal 28.8v alternators, and instead Mastervolt alternators are fitted which have a multistage intelligent output like an intelligent shorepower unit. This allows for faster charging of flat batteries plus a better tickle charge mode than you get with ordinary automotive 28.8v alternators

 

[John100156]

........but I've often wondered whether there is any kind of thermostat controlled device which could auto start the genset+aircon if the temp in, say, the master cabin, exceeded a preset level?....

A simple thermostat with adjustable dead band should enable you to do this, you simply have it activate one two pole or if you like two single pole relays, one fitted to the Genset so it's contact starts that and one to start the AC system in a similar way.

However, the load on the AC system will likely be less at night, so it could end up switching in/out too frequently, so chose a make-on-rise thermostat that has an adjustable differential of say 4 degrees or so, some electronic thermostats have adjustable dead bands and should suffice.

So for instance, say you normally leave your normal daytime setting on your AC set to switch-on the compressor at 23C and it cools down to switch it off at say 21.5C. When you retire, you can switch off the AC and enable your night thermostat circuit.

The internal temp rises to say 25C which activates your night t'stat starting the gennie and AC, the AC control senses the temp is much higher than its setpoint (23C) so it switches on and cools the space down to 21.5C and then switches the compressor off, but because the night t'stat has not reached its lower switch-off differential (25-4=21C) the gennie is kept running. If the temp inside falls below 21C then both Gennie and AC is held off. It will not start again unless the space rises to 25C again. Just playing with setpoints but you get my drift.

 

[Deleted User YDKXO]

A simple thermostat with adjustable dead band should enable you to do this, you simply have it activate one two pole or if you like two single pole relays, one fitted to the Genset so it's contact starts that and one to start the AC system in a similar way.

However, the load on the AC system will likely be less at night, so it could end up switching in/out too frequently, so chose a make-on-rise thermostat that has an adjustable differential of say 4 degrees or so, some electronic thermostats have adjustable dead bands and should suffice.

So for instance, say you normally leave your normal daytime setting on your AC set to switch-on the compressor at 23C and it cools down to switch it off at say 21.5C. When you retire, you can switch off the AC and enable your night thermostat circuit.

The internal temp rises to say 25C which activates your night t'stat starting the gennie and AC, the AC control senses the temp is much higher than its setpoint (23C) so it switches on and cools the space down to 21.5C and then switches the compressor off, but because the night t'stat has not reached its lower switch-off differential (25-4=21C) the gennie is kept running. If the temp inside falls below 21C then both Gennie and AC is held off. It will not start again unless the space rises to 25C again. Just playing with setpoints but you get my drift.

Thanks, John, thats interesting. This is another item for the specification of my dream boat

 

[Hurricane]

The internal temp rises to say 25C which activates your night t'stat starting the gennie and AC, the AC control senses the temp is much higher than its setpoint (23C) so it switches on and cools the space down to 21.5C and then switches the compressor off, but because the night t'stat has not reached its lower switch-off differential (25-4=21C) the gennie is kept running. If the temp inside falls below 21C then both Gennie and AC is held off. It will not start again unless the space rises to 25C again. Just playing with setpoints but you get my drift.

Thanks, John, thats interesting. This is another item for the specification of my dream boat

Just careful use of hysteresis - here's a link to a DIY circuit for a "home brew" thermostat with adjustable hysteresis
http://www.zen22142.zen.co.uk/Circuits/Switching/therm_sw.htm

I would be more worried about how the generator was starting up and shutting down.
I would hate the thought of starting a generator up into equipment already "switched" online.
The whole thing would need to have careful switch control and timers etc.
However, if the boat has an inverter with some kind of auto start for a generator, this might be the way forward.

For me, though, I don't want generators running overnight anyway.
Last year I bought some DC fans which I've fitted over the beds.
Hardly any electrical consumption so don't affect the batteries at all.

 

[Portofino]

At anchor we have been there after "turning in " wake up - too hot even with widows open - breeze not quite enough .
Our A/ C control is by the bed in the cabins so we can turn it on without getting out.this is great for a marina when hooked up to shore power,but at anchor its me who has to get up go into the saloon and turn on the Geny.( closing the windows)
So as a back up to the " auto everything" idea ,how's about having a separate remote normal switch pannal in/ on a bed side cabinets both so wife can control too.
Just in case tech has moment ?
Maybee linked to touch screen thingy

 

[rafiki_]

Actually, I think this where Fuel Cells are really going to useful in a boat, silent (or near silent) power generation. Too early for M2, but I think there is a seed for JFM for M3.

 

[jfm]

At anchor we have been there after "turning in " wake up - too hot even with widows open - breeze not quite enough .
Our A/ C control is by the bed in the cabins so we can turn it on without getting out.this is great for a marina when hooked up to shore power,but at anchor its me who has to get up go into the saloon and turn on the Geny.( closing the windows)
So as a back up to the " auto everything" idea ,how's about having a separate remote normal switch pannal in/ on a bed side cabinets both so wife can control too.
Just in case tech has moment ?
Maybee linked to touch screen thingy

With Onan at least, it is dead easy to wire an additional start-stop switch. They will sell you a kit or you can diy it

 

[jfm]

Actually, I think this where Fuel Cells are really going to useful in a boat, silent (or near silent) power generation. Too early for M2, but I think there is a seed for JFM for M3.

Yup - if we could get even 15bhp from a non reciprocating engine that would be fantastic for overnighting.
Hmmm. I wonder how small a (diesel burning) gas turbine+gearbox+alternator you can buy...