Liveaboard in the tropics: solar vs generator?

[Koeketiene]

What - if anything - do you have?
Happy with it? Would you choose the same again if you could start again?

Generator: what make/model? Output? How much petrol do you carry? Reliability? Noisy?

Solar: what make/model? How many W? Where do you mount them?

All feedback gratefully accepted.

 

[TQA]

Solar for me silent and eco friendly. When choosing anchor spots I am careful NOT to anchor behind or near the genny runners even if they are 1500 rpm water cooled wet exhaust diesels.

3 x 135 panels Arch mounted and tiltable feeding a MPPT controller 6 x golf cart batteries. Ice for my G&T is no problem. I maybe need to run the engine for charging 3 times a year.

 

[multihullsailor6]

Solar and wind generator for me.
- Solar: 6 panels with 460W in total, 4 semi-flexible ones on the cabin roof and two mounted on the side of the aft pullpit, foldable. Each feeding a MPPT controller, 550AH house batteries in total.
- Wind generator: Air X with SilentWind blades, charges also during the night if the wind blows. This generator is powerful in strong winds but I would go for a different make next time with an earlier start-up.

 

[yesod]

for the solar boys - be useful to know your latitude and typical daily output as well as the total installed wattage of panels... thanks

 

[geem]

320w of solar of which 160w is flat on deck with 160w adjustable. Duogen for towing and for windy anchorages. 4.8kva diesel genset for making RO water and hot water via immersion heater. 960amp hour of domestic batteries.

 

[Koeketiene]

960amp hour of domestic batteries.

960aH - that sounds like a lot. Was hoping to get by on half that.
What boat?

 

[demonboy]

Solar and portable Honda generator. Solar 6x40w panels. Before I broke one we could hit up to 15 amps during peak hours, say 11am to 2pm. From 9am we were pulling in around 7amps and by 4pm we were getting the same. We have ours mounted on the pushpit, not on a gantry (see pics on our blog), that swing up to 90 degrees when we need them. They drop down like dodgers when we're sailing. I've also fitted a 100amp alternator and a Sterling AB unit for faster charging under engine. I never bought a wind generator because I decided I prefer anchoring in sheltered places to windy anchorages, and many liveaboards I've spoken to will give preference to their solar panels over the wind generator (I'm sure some may disagree).

As photographer and writer Liz and I use a laptop each frequently. We have a separate ship's computer (netbook) too. We also like cold beer and wine and we have a water-maker that runs at 8amps. In short, we like our gadgets and comfort. When we switched to a 6v system (run in parallel to make 12v) we could abuse the power usage more since 6v batteries handle deeper discharges but that Honda generator is worth its weight in gold. It's not used frequently but allows us to really boost the batteries every five days or so when at anchor for two weeks at a time, and especially useful when we had engine charging issues in the Maldives. Great to have as back-up, minus the hassles associated with a fitted marine generator. Carrying petrol is not an issue if you have space for a 20lt can.

We were 200 miles or so north of the equator for a while.

I probably don't need to tell you this but the solar panels will never give your batteries a full charge if you frequently take them down to 80% charge or less like we do. They only trickle, so even with all these solar panels we still have to run the engine or generator in order to give the batteries a boost. Now that we have the Honda, we're pretty sorted and we don't need to run the engine at anchor, which you probably know is not ideal when it's not under load.

[edit] 4x 6v 220aH batteries, so 440aH for domestic

 

[tri39]

I have reached 150wts of solar into 450Ah of batteries now. And will add another 48wt Sunware panel next year.
Obviously it's easier on a multihull to find the deckspace for the expensive marine panels that can be walked on.
This enables me to anchor for up to five days b4 running the Yanmar. In practice of course we rarely anchor in one spot for this long.
Like Demonbuoy I'm not a fan of windmills, seeking a calm anchorage most nights (in the med). I realise it's different in the Windies.
I admired the Fuel cells at SBS but they're really expensive, and is Methanol widely available? However they might be preferable to a separate generator.

 

[geem]

960aH - that sounds like a lot. Was hoping to get by on half that.
What boat?

Trintella 44. there is room for more in the battery compartment but that should be enough! Domestic bank weighs 1/4 ton

 

[rogerthebodger]

30 degrees south so not quite tropics

8 80 watt for 1260ah total domestic batteries in 2 banks which we combine when liveaboard

regulators for domestic are 2 on/off for 2 80 watt and 2 PWM to the rest

we do have an air x but only use it when it had been very overcast for a week or so.

Engine battery kept topped up when away by 40watt with maplin regulator. This can be switched to the domestic bank if needed.

main usage is fridge LED lights and TV/radios and CD's. Fridge is the most

When we are away we separate the battery banks and have one 80 watt for each bank to keep them topped up.

Mains power if needed is by inverter / honda suitcase generator of internal diesel 4.2KVA generator.

 

[noelex]

I probably don't need to tell you this but the solar panels will never give your batteries a full charge if you frequently take them down to 80% charge or less like we do. They only trickle, so even with all these solar panels we still have to run the engine or generator in order to give the batteries a boost.

If you have enough solar (relative to your use) and a good regulator there is no reason why you should not get your batteries up to 100%, or very near.

The batteries don't know where the electrons come from.

 

[TQA]

Latitude 10 N to 15 N

If going solar it is REALLY worthwhile making sure you can tilt them to follow the sun and make sure there is as little shading as possible. Mine are up on a rear arch.

I get up to 24 amps at midday and on a sunny day if I am diligent about following the sun I get around 180 amp hours.

Numpties bolt them down and fit wind generators above them, even a single thin shadow will halve the output of a panel.

 

[KellysEye]

We inherited a wind generator and a 3,000 rpm generator. As a Ketch with a wind vane, there was nowhere to put solar panels hence the previous owner's decision. The generator committed suicide at 550 hours, 3000's are lifed for 400 to 600 hours and may last 1,000 with lot of expensive repairs. We replaced it with a Westerbeke 1,500 rpm generator and this type are lifed for 8,000 hours the same as a normal engine.

I asked a number of generator repair shops which generator they had to least repair, the yellow jersey went to Northern lights and a close second was Westerbeke. A generator allows you to run a 240 volt fridge and watermaker both of which are more reliable and last longer than boat kit which is designed for weekend/holiday sailors (as is the 3,000rpm generator). We used to run our two hours a day but always after people got up before the 18.00 drinks started.

 

[jdc]

Urban myth?

...3000's are lifed for 400 to 600 hours and may last 1,000 with lot of expensive repairs...

I wonder where you obtained this information? I looked at Kubota's spec for the OC60 for instance, and also at MasterVolt's service manual for the engine of a generator which runs at 3000rpm. Kubota have a service schedule including items 'every 1500 hours', Mastervolt have the same items requiring checking every 2000 hours, which implies that the engines are expected to last >2000 hours. To interpret it otherwise would imply that they are being deliberately misleading.

I tried to find some independent literature on mechanisms for disproportionate increase in wear due to faster running, and find none. I suggest that an engine run at 3000 rpm should last at worst half the number of hours of an engine run at 1500 rpm, and it's very much a worst case as the limiting factor is rarely simple wear-out of bearings and piston rings or cylinder bore. The limiting factor for the lifetime of a marine engine is usually expected to be corrosion of the exhaust or other ancillary systems. The service life is thus likely to be rather weakly dependent on engine rpm. I do accept that there is a correlation between 3000rpm gen sets and small engines, and small engines are likely to be single cylinder with attendant increases in vibration and forces on bearings, so perhaps this is a factor.

In any event I would expect an engine to last at least 1 billion revolutions before major maintenance. At 3000 rpm this is about 5500 hours.
We are also encouraged to run diesels hard or all sorts of curses (mostly mythical I think) - will befall us. 3000 rpm out of a max of 3600 is the same proportion as 2250 rpm out of a max of 2700. Many run their Volvos or Kubotas or Yanmars at 2250rpm and don't feel they they are accelerating the wear unduly.

Nor does fast idling, ie running engines fast but with little load, cause any problems - despite many saying it does. I found no authoritative or quantitative papers supporting the hypothesis (that running under no load leads to problems), whereas a US Army study looked at many different makes of engine over a considerable period and found no correlation of (un)reliability with extended periods of running at fast idle.

 

[geem]

My perkins derived 4.8kva genset broke the hour meter at 1000 hrs and it still runs sweet. God knows how many hours its done now. Runs at 3000 rpm as well.

 

[rustybarge]

Nor does fast idling, ie running engines fast but with little load, cause any problems - despite many saying it does. I found no authoritative or quantitative papers supporting the hypothesis (that running under no load leads to problems), whereas a US Army study looked at many different makes of engine over a considerable period and found no correlation of (un)reliability with extended periods of running at fast idle.

We had two tractors on the farm, a little runabout MF135 and a Ford 6600 for ploughing and heavy duty work.
The small tractor suffered from glazed cylinders, chronic blow back into the crank case, and a rebuild at 2500 hrs. The ford ran sweet as a nut. We used max rated continuous speed if 2100 revs under full load ( max2200) for thousands of hours pulling a four furrow plough. Sold at 6000 hrs in perfect running order. The only cure for glazed cylinders is to take out the pistons and re- hone the bores, the rings can then grip the cylinder walls. In my experience running the engine a full chat won't cure the problem.

Diesels are high compression heat engines, they hate slow revs/ no load conditions.

 

[Ariadne]

6 x 95W panels, a 1Kva Honda generator + a DuoGen; 760A/h of domestic batteries and a dedicated starting battery. SO long as we have sun we can have power to run everything including the fridge and the 240v inverter.

What would I do differently? I'd invest in an efficient main engine that has a genset built into it and do away with the DuoGen, Honda and possibly the alternator as well.

I'd also seriously think about just having a generator an A/C drive system for motoring and supply of power to batteries so I could use a decent inverter for 240v/110v domestic appliances instead of expensive boaty/caravan kit. In other word do away with an engine, gearbox, alternator and have all electric motors like proper ships have.

 

[rustybarge]

6 x 95W panels, a 1Kva Honda generator + a DuoGen; 760A/h of domestic batteries and a dedicated starting battery. SO long as we have sun we can have power to run everything including the fridge and the 240v inverter.

What would I do differently? I'd invest in an efficient main engine that has a genset built into it and do away with the DuoGen, Honda and possibly the alternator as well.

I'd also seriously think about just having a generator an A/C drive system for motoring and supply of power to batteries so I could use a decent inverter for 240v/110v domestic appliances instead of expensive boaty/caravan kit. In other word do away with an engine, gearbox, alternator and have all electric motors like proper ships have.

Don't get a shock, it's 400 volts dc, you'll stick to the cables and fry............

 

[Ariadne]

Don't get a shock, it's 400 volts dc, you'll stick to the cables and fry............

I'd be building/converting a boat to go down that route, but it sounds more attractive than big diesels, big gear boxes, separate generators and all that ****.

In the meantime I'm still saving for a Steyr motor with an integrated flywheel generator which produces 5KVA, one engine does all - I like that!

http://www.steyr-motors.com/marine-diesel-engines/2-4-and-6-cylinder/integrated-flywheel-generator/

 

[ccscott49]

4 x 80w solars on wander leads and MPPT, on wheelhouse roof. 550 ah @ 24 volt, domestics, separate 220 ah @ 24 volt engine start bank + anchor winch, plus three other 12 volts for gennys etc. Two gennys, 1 x 3.8kw, 1 x 6.5kw. Two chargers 100 amp, 75 amp @ 24v. one 25amp. 55amp alternator on port engine, (engine start) 140amp alternator on Stb engine (domestics).
2 x inverters, 1600w @ 3500w both pure sine wave.
Solars keep us running during the day, by positioning them and trying to keep them out of shade.
Most of the time motoring or motor sailing between places keeps batteries up, if at anchor for some time, need genny. If I want to make water, wash clothes, make ice etc. Then run big genny whilst at sea, best to minimise upset to others.