Lagoon 420 hybrid + modern tech

[StuM]

Originally Posted by fabgo

Thank you Chris for your review. I wonder why hybrid electric systems are not more popular. It seems an ideal system for a sailboat.

Like you said, electric motors are much more reliable and require much less maintenance. The generator can operate very efficiently and also provides power for the rest of the boat.

Solar panels can provide enough power to run the motors for short periods such as docking.

The only downside I can see is that the techology is not as proven as diesel engines.

So why is it not more broadly in use? What am I missing.

- Fabian

Post #43!

[rabbi]

Originally Posted by fabgo

Thank you Chris for your review. I wonder why hybrid electric systems are not more popular. It seems an ideal system for a sailboat.

Like you said, electric motors are much more reliable and require much less maintenance. The generator can operate very efficiently and also provides power for the rest of the boat.

Solar panels can provide enough power to run the motors for short periods such as docking.

The only downside I can see is that the techology is not as proven as diesel engines.

So why is it not more broadly in use? What am I missing.

- Fabian

Even my small 36ft cat has two 14kW engines. It has some losses for the saildrive, so maybe each produces 10kW at the props.
To replace that i would need a 20+ kW generator to produce 2x 10kW at the props.

To give any electric cruising range the battery bank needs to be huge. And then there would be big wires, big throttle electronics, big charging electronics. If any of these things go wrong (and the marine climate is paricularly harsh for electronics and wires / connectors) the 100s of Amps can easily start fires.
And all these complicated gadgets can only be repaired by the manufacturer. Breakdown in Galapagos? Fly in the expert and DHL all parts required.

[svlamorocha]

Originally Posted by Stumble

So far it still isn't practical to run an AC from solar/batteries which draws a fraction of the power that propulsion does on a 40' Cat.

Not anymore. Earlier this year I enjoyed more than one air-conditioned siesta thanks to the 1.5 kW solar farm and lithium batteries in another CF member's boat.


Sent from my SM-G9287 using Cruisers Sailing Forum mobile app

[GALAWA]

Originally Posted by svlamorocha
... Earlier this year I enjoyed more than one air-conditioned siesta thanks to the 1.5 kW solar farm and lithium batteries in another CF member's boat.

What was the area of this 1.5KW solar farm ?

[44'cruisingcat]

Originally Posted by fabgo

Thank you Chris for your review. I wonder why hybrid electric systems are not more popular. It seems an ideal system for a sailboat.

Like you said, electric motors are much more reliable and require much less maintenance. The generator can operate very efficiently and also provides power for the rest of the boat.

Solar panels can provide enough power to run the motors for short periods such as docking.

The only downside I can see is that the techology is not as proven as diesel engines.

So why is it not more broadly in use? What am I missing.

- Fabian

The cost/benefit ratio.

Costs:

You need two electric motors of similar power to the diesels they replace. The speed controllers for these will be quite costly.

You need a very large battery bank. Preferably lithiums.

You need a genset which produces enough power to run both electric motors continuously.

This all costs much more than a pair of diesels.

While electric motors are very reliable, all the other equipment may not be.

All this added weight will reduce the sailing efficiency of the boat. Which may effectively neutralise the only real benefit.

Benefit:

It might be slightly more fuel efficient.

[gjorgensen]

Originally Posted by GALAWA

What was the area of this 1.5KW solar farm ?

Well, Sunpower x22 panels are 360 watts so 5 of them = 1800 watts. Each panel is 61.3 x 41.2 inches. 5 of them down the back of a decent size cat would be no problem, and would be 61.3 x 206 inches (1558 x 5230 mm) or 8.15 sq meter. Call it 8.5 sq meter with frames and air gaps. That would make a nice cockpit cover extender over the dinghy on, say, a Lagoon 450.

BTW, that gets you around 9-10 kw per day on average, which should emphasize the losing battle you'd have against general use electric motors on a sailboat. Used just for docking, sure it would work, but try motoring anywhere.

[fabgo]

Originally Posted by 44'cruisingcat

The cost/benefit ratio.

Costs:

You need two electric motors of similar power to the diesels they replace. The speed controllers for these will be quite costly.

You need a very large battery bank. Preferably lithiums.

You need a genset which produces enough power to run both electric motors continuously.

This all costs much more than a pair of diesels.

While electric motors are very reliable, all the other equipment may not be.

All this added weight will reduce the sailing efficiency of the boat. Which may effectively neutralise the only real benefit.

Benefit:

It might be slightly more fuel efficient.

I looked into this actually and found costs to be comparable to diesels. Initial costs were slightly higher, but it does include a battery bank and a generator you may otherwise have to acquire separately. Also, when I did the research I found that the total weight was less than the weight of two diesel engines.

I have also spoken to some owners of hybrid electric systems, and they all claimed the solution was very reliable.

The main drawback I can see actually is the resell value, as a lot people are skeptical, and prefer diesel engines.

And I agree reliability is a risk, as the systems are not as proven.

- Fabian

[Stumble]

Fabgo,

You won't be using the same size generator for propulsion and for house loads. You will need two generators. A 60-80kw (assuming a 40' cat) for propulsion and then a 8ish kW for house loads. You could probably get away with twin 40kw DC generators for propulsion and a 8kw AC generator for house loads or some mix and match adding up to 60-80 kW.

The reality is that it just doesn't work. If you want enough grunt to motor into a storm when dragging anchor, or motor long distances, you pretty much need diesel propulsion. Either you use a mechanical transmission, or you use an electrical transmission, but either way you need a big diesel moving the boat.

[gjorgensen]

Originally Posted by Stumble

Fabgo,

You won't be using the same size generator for propulsion and for house loads. You will need two generators. A 60-80kw (assuming a 40' cat) for propulsion and then a 8ish kW for house loads. You could probably get away with twin 40kw DC generators for propulsion and a 8kw AC generator for house loads or some mix and match adding up to 60-80 kW.

The reality is that it just doesn't work. If you want enough grunt to motor into a storm when dragging anchor, or motor long distances, you pretty much need diesel propulsion. Either you use a mechanical transmission, or you use an electrical transmission, but either way you need a big diesel moving the boat.

Yup. Also remember you need independent house and propulsion battery banks typically. Even the two 8kw (10 HP at the shaft) motors the Lagoon 420 had would draw close to 700 amps EACH at 12 V. So instead you have a high voltage battery pack (e.g. 96 V) to feed the motors. You could use a DC-DC converter for house loads but given the range of the battery packs is only on the order of 20-40 miles as is, you wouldn't want to eat into that for house consumption. And the independent banks means 2 independent charging systems....

[cwjohm]

This discussion always comes down to the use of the boat. If you want to putt putt out from the marina in flat water and then sail around and then come back again then there is no problems with electrics.

If you want to passage with your boat then I would not venture out without enough capacity to operate both motors strongly into big seas and a large headwind for 4 hours minimum and I would want to operate at least one motor for 48 hours constant. The power delivery requirements are way beyond what any practical electrical or hybrid system can deliver.

So you will always get people who will state they are quite happy with an electrical/hybrid system but then ask them when they last did a passage of 500nm+ in tough conditions and nobody would dream of attempting such a feat with an electrical boat (notwithstanding the one off that have been specially built for the purpose).

[valhalla360]

Originally Posted by ranchero76

Here we go again
Let's repeat - hybrid+solar will not replace or eliminate engines.
But:
1.About 70% of engine wear accrues at start-up (no, it's not joke). So every time you start engine for short run, you basically kill it. Electric motor will eliminate short engine runs, drastically prolonging their life.
2. Even kids know that any engine most sufficient on high RPM, high power. That's when they should be used. For anything else - there are electric motors, which have close to 100% efficiency on any RPM and load.
3. Sail boats created for sailing. Motoring is intermittent every now and then. So in many cases there should be enough time in between for battery re-charging.
4. Good power setup (say 20-30 kWh battery bank and at least 2-3kW solar panels) is something that any modern big boat should have regardless of having electric propulsion. There are lots of power hungry toys, they all need power. While these batteries and panels still not cheap, they becoming more affordable. So most parts for hybrid is ALREADY THERE, just install electric motors end enjoy

1. The vast majority of marine engines die from abuse and lack of maintenance. Wearing out is just not an issue.
2. When you account for conversion losses, diesel-electric isn't gaining you anything.
3. For purists. For normal people, they want the ability to motor when they choose.
4. We have nothing close to that. 130w solar and a single deep cycle battery, no shore charging... never been an issue. Not to mention, by the time you buy the system you propose, you could just buy a generator and fuel for the next 10yrs.

To the original question: Run the math for a 50mile run at 7kts. It becomes obvious very quickly why it failed.

[valhalla360]

Originally Posted by SDChristian

Another way of stating this is, how far would a tesla go with a generator in the trunk and a full tank of gas? Answer: a long way

Sure, but get rid of the electric motors and giant battery pack and it would go even further.

[ranchero76]

Originally Posted by valhalla360

4. We have nothing close to that. 130w solar and a single deep cycle battery, no shore charging... never been an issue. Not to mention, by the time you buy the system you propose, you could just buy a generator and fuel for the next 10yrs.

You see, I'm talking about newer boats, when +/— $30-40k to the price is not a big deal. And in this case I see advantages of having hybrid and powerful solar/battery. I'd rather spend money once and then have free power for everything on boat and free, silent maneuring/short runs. As we discussed before - say I spend a month on remote island and spend zero $ on charging batteries, cooking, scuba compressor, AC, fridge, freezer, and everything else on boat, including boat moving here and there. Nice.

[cwjohm]

You see, I'm talking about newer boats, when +/— $30-40k to the price is not a big deal. And in this case I see advantages of having hybrid and powerful solar/battery. I'd rather spend money once and then have free power for everything on boat and free, silent maneuring/short runs. As we discussed before - say I spend a month on remote island and spend zero $ on charging batteries, cooking, scuba compressor, AC, fridge, freezer, and everything else on boat, including boat moving here and there. Nice.

You are talking a requirement of up to 240KW emergency and 800Kw long term motoring provision, so you would need to spend at least $100K and require carrying capacity of a couple of metric tons in terms of batteries and generator.

Sure, $30-$40K will allow you to spend a month at an island fully covered but you will need a big boat with large diesels to tow you to that island and back again.

[44'cruisingcat]

Originally Posted by ranchero76

You see, I'm talking about newer boats, when +/— $30-40k to the price is not a big deal. And in this case I see advantages of having hybrid and powerful solar/battery. I'd rather spend money once and then have free power for everything on boat and free, silent maneuring/short runs. As we discussed before - say I spend a month on remote island and spend zero $ on charging batteries, cooking, scuba compressor, AC, fridge, freezer, and everything else on boat, including boat moving here and there. Nice.

Running all that stuff on solar will require a huge solar array and a LOT of sunshine.