Power Hungry. Advice please kind folks :)

[charles_reed]

I can only speak from my own experience but we 'solved' this problem a couple of years ago and we are very power hungry. I think you need more solar panels and they need an MPPT controller. We are on a Catamaran so have the space but use two 250w domestic panels with an MPPT controller. The panels are 50v nominal in series and will charge from first light pretty much till dusk producing up to 80v. The controller sorts this out and give us a sensible charge. I can see up to 30a at the height of the day and we can get about 200AH a day out of them (although in fact the batteries are usually fully charged by lunchtime so we dont need it). The wind generator gets nowhere near that.

Costs where about £200 each for the panels and £300 for the controller plus some steel work. We do have the space though.

We have a generator as well but seldom use it apart from when we do the washing, its not been working this year anyway and we have not really missed it.

I agree with this comment.

I've just added solar panels until I can lie at anchor indefinitely (during the months June-September) without having battery volts go below 12.2.
My daily budget is 58ah/day and I have 328 watts nominal of PV panel feeding @ a nominal 24v through a BZ Products MPPT1500 controller into 220 AH of 12v domestic batteries.
I did have an Ampair wind generator, when it went NU, it was not worth replacing as the capital cost was x3/AH for the equivalent daily input of PV panels.
Unless adjustable to maximise insolation, even @ 40N you can expect no more than 40% of PV panels claimed output.

 

[charles_reed]

Not at all. The unit is a Lewmar mamba drive which is rated for yachts up to 50ft ( i think). We have never had the boat out in a blow. It was installed from new at the fit out of the boat by Northshore and looked "out of the box" when we removed it to send back to lewmar.

I have asked Lewmar to be honest about whether their units are fit for purpose, and await with baited breath. I have been advised that there is a history of these units failing. Apparently the clutches are the weak point.

Sounds like you have a duff unit.

My Raymarine 4000ST has done <25K nm in 21 years, regularly serviced and has never failed. Mind it's x2 sizes larger than the boat needs. The techie advised me to ignore the marketing hyperbole.

 

[charles_reed]

I don't think so. It was installed by Northshore/ Southerly and their electrical engineers. Apparently they do this all the time, so I dont think it is a problem with the physical installation .

The motor is possibly overspecced for a 40ft boat, so i dont think it is too small.

Aside from that it is a totally sealed unit with 2 power wires and 2 clutch wires.

I have asked lewmar for a reason why the unit failed , so that I am not left worrying about the reliability of it.

Optimists are always disappointed - that's why I'm a pessimist ( especially about marketing claims) and am sometimes pleasantly surprised.

 

[charles_reed]

I'm very pleased to hear it. Others have not been so lucky.

If you set off across an ocean with only an electric autopilot, then you MUST have plans for if it fails. If you have no wind vane, then you will have to steer by hand. As long as you understand that, and accept it, and can cope with it, you will be fine.

Sage advice, I always carry a spare actuator, if one goes NU (crew sitting heavily on it x 2, brushes burnt) it's an easy changeover task.

 

[pmyatt]

We are currently in the last stages of fitting out for our long term cruising lifestyle and hope ( sincerely) that we leave the UK next spring. Our plan is to spend one or two seasons cruising the med, then head across the atlantic for tropical cruising.
Hopefully this will turn into a circumnavigation.

My question asks about how long term cruisers receive their power while underway and also at anchor.

We took six weeks to cruise western france this summer and shake the boat down.

at present we have an electronic autopilot, 2 x 100 w solar panels zipped onto the bimini and an air breeze wind generator.

The yacht is a 40ft modern beast ( Southerly 38) and we do like our fridge/home comforts on board, so dont really want to compromise on those things.

The problem is that our ( new ) autopilot motor packed up mid biscay with clutch failure and I am questioning the efficiency of the solar panels after 6 months of use.

So what to do now? And on this I would love advice.

1 .we have discounted self steer until we are ready to cross the atlantic. this will give us a chance to see how the new clutch works. Is this the right thing to do or should we simply bite the bullet? We need a unit we can remove and also offset from centre as the design of the boat does not lend itself to centre mounting.

2. We could install a genset. But it would seem as if we are looking at about £10,000 all in with fitting and bits. However this would provide all our power.

3. We dont have the room to fit a 2nd alternator so thats out.

4. We are looking at watt and sea hydrogenerators but by now the stern is going to look crowded.

What do you use? and what would you suggest in our case?

many thanks.

The first question you have to answer yourself is what type of cruiser/liveaboard you intend to be. Are you going to be:
1. Anally retentive power saver.
2. Boy Scout.
3. Economic cruiser.
4. Comfortable camper.
5. Environmentally self sufficient.
6. Bijou Seaside Villa.
Or a combination of all of the above.

We have lived aboard in the Eastern Med, sometimes for 12 months of the year, for about 8 years now. Forever Freedom is US built, so has a very big fridge, and is 22 years old. We have been through all of the stages - from 2 batteries and a 1-2-both-off battery switch and paper charts, to our present system using a 4 kw inboard generator, solar panels, high output alternator with smart controller, 120 amp charger and 2 kw inverter; we are now definitely at Stage 6, with electric windlass, radar, chart plotter, SSB radio, computers, big auto-pilot, water maker, washing machine, induction hob, microwave/combi oven (no gas on board), electric immersion heater and, finally, air conditioning. We had a HydroVane, but sold it to someone returning to the Shetlands, because we were hardly using it in the Med compared with passage making in the Atlantic. The game-changer was the generator; once we decided to put that in, the rest followed as the money became available and, what-is-more, we now live on board with all the comforts of home, but able to potter around doing about 850 NM per year. We use anchorages and harbours, but have not used a marina now for the past 15 months. Hope this helps.

 

[Oscarpop]

The first question you have to answer yourself is what type of cruiser/liveaboard you intend to be. Are you going to be:
1. Anally retentive power saver.
2. Boy Scout.
3. Economic cruiser.
4. Comfortable camper.
5. Environmentally self sufficient.
6. Bijou Seaside Villa.
Or a combination of all of the above.

We have lived aboard in the Eastern Med, sometimes for 12 months of the year, for about 8 years now. Forever Freedom is US built, so has a very big fridge, and is 22 years old. We have been through all of the stages - from 2 batteries and a 1-2-both-off battery switch and paper charts, to our present system using a 4 kw inboard generator, solar panels, high output alternator with smart controller, 120 amp charger and 2 kw inverter; we are now definitely at Stage 6, with electric windlass, radar, chart plotter, SSB radio, computers, big auto-pilot, water maker, washing machine, induction hob, microwave/combi oven (no gas on board), electric immersion heater and, finally, air conditioning. We had a HydroVane, but sold it to someone returning to the Shetlands, because we were hardly using it in the Med compared with passage making in the Atlantic. The game-changer was the generator; once we decided to put that in, the rest followed as the money became available and, what-is-more, we now live on board with all the comforts of home, but able to potter around doing about 850 NM per year. We use anchorages and harbours, but have not used a marina now for the past 15 months. Hope this helps.

Thanks you for the detailed and comprehensive answer. We are definitely going to be 5 & 6.
Ideally we would have settled for 5 alone. However the reliability factor will mean that it may not always be possible to allow for a totally green approach.

 

[noelex]

With a big solar array (and possibly wind) it is possible to have all the comforts, (with the exception of air conditioning). It does need more care selecting components, but the added reliability lack of heat noise and maintenance are powerful attractions

The days of non generator equipped boats roughing it are fortunately over.

Undeck autopilots have become very reliable, most of the horror tales are from wheel mounted autopilots, or poor instalation. The advice to have a backup plan is always sensible with any boat system especially when long distance cruising.

 

[pmyatt]

Thanks you for the detailed and comprehensive answer. We are definitely going to be 5 & 6.
Ideally we would have settled for 5 alone. However the reliability factor will mean that it may not always be possible to allow for a totally green approach.

I forgot to add that, with only a 24 hp engine, our size of alternator is limited to 70 amp; both by the power a really big alternator would need but also the fact that things like water pump bearings will not accept the big increase in side-loads. Another thing to consider is that batteries like to be kept cool; for every 10℃ above 20℃, the battery life is reduced by 50%; batteries in the engine compartment are a definite killer.

 

[RAI]

... batteries in the engine compartment are a definite killer.

Provide lots of forced ventilation when the engine is running.
The alternator doesn't like being cooked either. Unlike the engine, it is air cooled.

 

[pmyatt]

Provide lots of forced ventilation when the engine is running.
The alternator doesn't like being cooked either. Unlike the engine, it is air cooled.

Not a problem for us as there are no batteries in the engine compartment anyway. The problem is not so much getting fresh air into the engine compartment but, in a small yacht, getting the hot air out without it heating the boat. Anyway, no matter what fan system is used I don't think you would be able to get the engine compartment temperature down below 40℃ so, not much point in trying. Also, if you try extracting air from the engine compartment without increasing the ingress, you may run the risk of starving the engine intake. WRT the alternator, we use Balmar because they have dual cooling fans and are designed to run "Hot".

 

[Cheoy Lee 41]

I have not seen any mention of a "power consumption audit" to ascertain exactly what uses what. If preaching to the already converted I apologise but its an essential part of the research. I respect the desire for the comforts of home but are you sure you actually want to be a live aboard with all that it entails. Home comforts cost more than just money. Would strongly recommend as already mentioned night time reading of Nigel Calders Bible.

 

[charles_reed]

I can only speak from my own experience but we 'solved' this problem a couple of years ago and we are very power hungry. I think you need more solar panels and they need an MPPT controller. We are on a Catamaran so have the space but use two 250w domestic panels with an MPPT controller. The panels are 50v nominal in series and will charge from first light pretty much till dusk producing up to 80v. The controller sorts this out and give us a sensible charge. I can see up to 30a at the height of the day and we can get about 200AH a day out of them (although in fact the batteries are usually fully charged by lunchtime so we dont need it). The wind generator gets nowhere near that.

Costs where about £200 each for the panels and £300 for the controller plus some steel work. We do have the space though.


We have a generator as well but seldom use it apart from when we do the washing, its not been working this year anyway and we have not really missed it.

I'd agree with this - my break-even occured when I got to 330 w of panel with the MPPT controller - even then it was only adequate during the summer months.

 

[Neil_Y]

We had aquair 100 towed gen and that produced more than enough power to run everything, this was using an ST6000 electric autohelm. Seeing as you have to have someone at the wheel all the time anyhow, unless you are single handed you can steer when on watch. I've done one Atlantic E to W where we steered probably 90% of the time. My boat was also easy to set up balanced where she would steer herself. Part of using an electric autohelm is to set the boat up so that it does very little work. And yes you can set it to sail to wind angle.

The Aquair was good for the Caribbean as there was always plenty of breeze so it was used as a wind gen when we were at anchor, in the Med I would think solar panels would be better.

 

[quimby]

im sure I read that a few of this years ARC entries had to divert/turn back with autopilot failures.

I can't remember the source though

Wimps! we did the Arc without auto pilot, 4 hours on in pairs so each steered for a 2 hour stretch 24/7 6 crew. Had a great time.

Then there was an incident with a yacht having to randezvous with another to take on supplies as their Freezer had failed!

 

[fuss]

We are currently in the last stages of fitting out for our long term cruising lifestyle and hope ( sincerely) that we leave the UK next spring. Our plan is to spend one or two seasons cruising the med, then head across the atlantic for tropical cruising.
Hopefully this will turn into a circumnavigation.

My question asks about how long term cruisers receive their power while underway and also at anchor.

We took six weeks to cruise western france this summer and shake the boat down.

at present we have an electronic autopilot, 2 x 100 w solar panels zipped onto the bimini and an air breeze wind generator.

The yacht is a 40ft modern beast ( Southerly 38) and we do like our fridge/home comforts on board, so dont really want to compromise on those things.

I work on the basis that the power taken out needs to be put back without dedicating/compromising your day too much trying to achieve this. You run your engine sometimes, the sun is shining sometimes... maximise these times.

Maybe do a power audit and see how much power you use every day for a month then divide by 30 to get an average for each day.
In this month, you should do some passages and also some anchoring for at least 4 days.
You said you like your comforts....Lets say the daily average is 250amps at 12v because you run computers, watch movies, dry hair, have a microwave, run instruments and auto pilot and the fridge is not too efficient and uses 90a a day.

Lets also say that whenever the engine is on that your fridge , watermaker and inverter also get some use, making the battery draw 25amps in total.

Lets also say that at any normal part of the day you see no less than 6a draining from the batteries and sometimes 9a

So now optimise everything that produces electricity to make the most it can in the time it runs.

Engine - lets assume it runs for 20 mins in the morning out of an anchorage and 20 mins in the evening into an anchorage. Thats 40 minutes, so lets make the alternator industrial and capable of running hot and producing at least 160amps (200amps would be better) with a smart controller and charge in bulk at the maximum the battery manufacturer recommends. lets say 14.8 volts.

So, when underway the alternator is capable of 160a minus say 10% for losses = 144, minus 25amps as mentioned above which then leaves 119amps to go into the batteries.
If the batteries are at 50%, then they might get an 80a contribution each day the engine is run for 40 minutes.

Now the solar should be sized as big as possible with mimimum to no shadowing. Lets say 300w (450w better) and an mppt controller, which I guess during the summer in the med will give you about 150a

We should not forget that wet cells need to be brought to full charge at least once every 2 weeks (AGMs maybe more often) and equalised maybe once a month after being brought up to a full charge. If you want 5+ years battery life.

so now lets also assume your batteries are 600a at 12v

so now in summer you get 150amps a day solar contribution, 80a a day diesel to electricity contribution so you are down by only 20a... sounds good

and in winter...
you get 70a a day solar, 100amps a day diesel to electricity contribution, because you run the engine for 1 hour a day, so you are down by 80a a day (eberspacher heater?? could throw calulations out a bit)

After making these mods, you would have a good base installation from which to make further decisions after a year...
How often did I need to make up amps by sitting there running the engine?
Is the airbreeze contributing much?
do I need more heating in winter?
can I make the fridge more efficient in summer?
would a 2kw honda generator be a worthwhile?
Is there room behind the gearbox for a propshaft alternator? (needs about 27cm diameter pulley)

Thats how I'd do it