Induction/Expanded Electric vs Propane What Would You Do?

[CatNewBee]

Originally Posted by skenn_ie

I wouldn't even try to provide a significant amount of heat from battery power

No problem, if you size your system for the task.

[warrior 90]

Originally Posted by CatNewBee

No problem, if you size your system for the task.

I agree and more so when You can store that heat in a good insulated tank in case of heating water.
Then You can decide the moment when You wanna produce that heat

[captain38]

Chotu,
Picture yourself in a quiet anchorage. There are 5 other boats there. It's 2:30 in the morning and you can't sleep so you get up, wander into the galley to make a cup of tea. The sky is overcast, and has been for five days! Your 440 ah battery bank only can safely deliver 220 ah whan fully charged, but they are down to 60% now. In order to make that tea, you'll have to start the generator - at 2:30 in the morning? Get real! Forget electric cooking... please.

[Paul_Carroll]

I just cruised on s/v Delos for a month and they are one of the boats that has gone full electric. The last comment about needing to fire up the genset just to make a kettle of tea is ridiculous.
First, the batteries pretty much have to be LiFePO4 so that they are not "depleted" at 50% state of charge. Secondly, just because it has been overcast for the last X number of days, does not mean that your batteries would be low. You would merely have had to run your genset during the daytime to charge the batteries.
On that point, I would put in the biggest genset practical so that the amount of time you need to run it to charge batteries and make water is at the bare mi imum.
Or, since you have a catamaran, you might want to consider two genset (need a combiner if they are going to have a common AC circuit), but that way you also have redundancy in case of a genset issue.
Now, all of this is a lot of money and systems to monitor. Propane is simple and common. There is something to be said for that. But if you want to be months away from civilization, then the electric route can be a good one.

[Jef & Marin, Netherlands]

On our cat we have 1760 W solar. LiFePO4 batteries, 12V 540 Ah.
We have a 4-burner LPG, a single cheap induction plate standing on top of the gas cooker, gas oven, gas BBQ.

Almost never we use gas for cooking. Almost always using induction. Cooking takes around 10-15% battery capacity.

You can put multiple smaller pans on a single induction plate; shifting the pans to have correct power for each.
At setting 5 of 10 of the induction plate it is around 1200W
We also boil water for tea in a 1800 tea kettle. It takes 2% of the battery to boil 1 liter.



We have a domestic fridge of 230 liters on 230V. Since a year. It takes 200 watt hours/24 hours, so 8-9 W average. This is at least 3-4 times more economic than the 2 marine fridges we had before.

The freezer (100liter) is using 3.5 A @ 12V day and night to bring the contens to -18C. I will go to a domestic one also.
And we are considering replacing the gas oven with an electric oven/microwave combination. Gas would then just be backup for cooking, and for the outside BBQ.


Very nice about an induction plate: you can cook your lobster outside, on deck or marina pontoon, to avoid the fishy smell inside!



With al the 230V equipment, it would be bad if our 2003 vintage Mastervolt inverter broke down. Therefore we have 2 2000W inverters, in case one fails.



I feel lead acid batteries are obsolete. Too heavy and big for a performance catamaran, limited life, high price per kWhour stored and used.

For a new catamaran I myself would always go for a LiFePO4 battery combined with an inbuilt 2-plate induction; use 2 inverters so that if one breaks down you still have 230V for the fridge.


You can also see the thread I started on the domestic refrigerator.
Good luck with your project,
Jef

[Chotu]

Originally Posted by captain38

Chotu,
Picture yourself in a quiet anchorage. There are 5 other boats there. It's 2:30 in the morning and you can't sleep so you get up, wander into the galley to make a cup of tea. The sky is overcast, and has been for five days! Your 440 ah battery bank only can safely deliver 220 ah whan fully charged, but they are down to 60% now. In order to make that tea, you'll have to start the generator - at 2:30 in the morning? Get real! Forget electric cooking... please.

If I can't sleep at 2:30AM, I invite the neighbors to shoot me to put me out of my misery. Ha ha ha.

[wingssail]

Originally Posted by Chotu

Lightweight, performance oriented sailing catamaran. I'd like to keep it that way. Ha ha.

We cook a lot. There are Indian/Desi meals being made a lot but I suppose we could pare it down to 2 burners...

Anyone who steps back a ways to look at the big picture can see that all-electric is the future.

For some that future is already here.

But if you are serious about keeping your boat a "Lightweight, performance oriented sailing catamaran" then I wouldn't be too keen to jump into that future quite yet. The simplest, lightest, most trouble free system is propane. Once you accept propane and get over the scare tactics of the propane-phobes there are several advantages.

• It is a light weight, simple, approach.
• You have absolute cooking flexibility: 1,2,3,4 burners plus Oven plus BBQ
• No special pots and pans
• No special batteries, gensets, huge solar arrays, etc. Light, simple, easy.
• Lowest cost
• The 2:00AM cuppa is easy, no need to look at the battery meter.
• You have a simple system of spares, so a genset or BMS failure is not going to take you down to cold cans of beans.
• Your refer should be electric, it's more appropriate on a moving boat than household or camper propane.
• You retain the simplistic, performance, aspect of your boat. it does not need to be a heavy, technological wonder.
• There is no HOB to put away when you want to go sailing. The stove and refer and water heater works exactly the same, always, sailing, anchored, in port, hove-to in a storm, any time.
• Even though you only cook during the day, you are not stuck by that restriction. In the tropics we cook in the evening when it is cooler outside because we BBQ a lot. But big complex, Asian, meals are no problem, day or night. You just take the consideration of the stove OUT of the equation and focus on the meal you are preparing.

We've used a simple propane based system on our boat for cooking and hot water (instant) for 34 years. WE TAKE IT FOR GRANTED THAT THE GALLEY JUST WORKS, EVERY TIME, WITHOUT A THOUGHT. Keep yourself out of technology and into cooking.

In 34 years, 35 countries, we have NEVER had a problem getting propane. We use 9 gallon bottles. They are smaller and lighter. Each one lasts about 21 days. (that includes cooking washing with hot water, and showers). We have two aluminum tanks.

So Chotu. don't be rushed into bleeding edge. Go simple, go light, stay performance. Go propane.

[Dockhead]

Originally Posted by captain38

Chotu,
Picture yourself in a quiet anchorage. There are 5 other boats there. It's 2:30 in the morning and you can't sleep so you get up, wander into the galley to make a cup of tea. The sky is overcast, and has been for five days! Your 440 ah battery bank only can safely deliver 220 ah whan fully charged, but they are down to 60% now. In order to make that tea, you'll have to start the generator - at 2:30 in the morning? Get real! Forget electric cooking... please.

This is ridiculous. You haven't done any numbers on this and have thus reached a flawed conclusion.


It's all in the numbers -- how many amp hours of power does it take boil 250ml of water? You've got 44 amp hours of usable power when your batts are at 60% in the given case. So how many cups or dozens of cups of coffee can you still make without starting the generator, in the given case?


Depending on how cold the water was to begin with, you need about 100 seconds at 800 watts to boil 250ml of water. 4.2 (joules per gram of water per degree) * 250 (ml of water) * 75 (delta T to boiling) = about 79 kilojoules. 79kj is all of 0.0219 kwh. Let's say you need a bit more power, to heat the kettle itself, so call it 100 kj. That's 0.0277 kwh, or all of 28 watt hours. At 12v, that's 2.33 amp hours. So the answer is you could make 10 cups of tea in the given case and your battery bank would still be at 54%, plenty to run the anchor light for the rest of the night.



I have gone over to electric cooking only gradually, but I stopped boiling water for tea or coffee as soon as I bought my first inverter back in the 90's. You will never start a generator to make one cup of tea, I can tell you from experience.

[Dockhead]

Originally Posted by wingssail

. . . In 34 years, 35 countries, we have NEVER had a problem getting propane. . .

Well, I don't think anyone said that propane is not a workable solution. Certainly gas cooking works and is well proven and used by 90% of cruisers.



But you have sure been luckier than most of the cruisers I know with sourcing propane. I have a gas stove and oven and getting gas has been a big PITA for me on many of my cruises. In Northern Europe despite the EU almost every country has a different bottle standard so you have to either get an illegal field pour (I had to travel halfway across Gotland to get the last one of those I did), or you have to buy the regulator and fittings specific to that country's system, convert the whole thing over, pay a deposit on a bottle which you will then have to throw away later -- bleh!


On top of that, gas systems are maintenance intense things if you maintain a reasonable standard of safety. I have some kind of problem with my gas system almost every year, and in fact it's inoperable right now.


There are great reasons for going electric, and especially if it is part of an overall electrical system design like what CatNewBee did which includes lots of solar power and lithium batteries, but not only in a case like that. Electric cooking is not "bleeding edge" any more -- it's being used by more and more cruisers we encounter out there, and every one of them delighted with it, in my experience.


And in any case, as has been stated by several people, it need not be a question of either/or. If the OP already has a gas system and gas stove, he can leave that in place and supplement that with induction and use whichever one he feels like using on any given day. Best of both worlds actually, and that's what I have. Whether or not he will gradually abandon the gas cooking like I did, because the induction cooking is so much better and more convenient, I don't know, but that will be his own choice which he can make as he gradually accumulates experience.

[Dockhead]

Originally Posted by Chotu

If I can't sleep at 2:30AM, I invite the neighbors to shoot me to put me out of my misery. Ha ha ha.

A nice cup of camomille tea can be a good thing in such a case, although a stiff glass of whiskey might be better, and requires no cooking . . .

[Jef & Marin, Netherlands]

Several posts mention gensets to charge the batteries when there is not enough sun.
Unless you love cold places, prolonged insufficient charging on a catamaran does not occur often. Meaning you only need the generator for short periods.
Like we did recently, when last southern winter we sailed from New Zealand eastwards to Rapa Iti in Polynesia. The generator ran 1 hour per day, for charging and cooking and also to run the electric fan heater. But this was just for 4 weeks, so maybe 30 generator hours. Did not need the generator since then.



Some time ago I visited a catamaran with a great setup. Were I building a catamaran, I would copy that system.
This cat has 24V LiFePO4 batteries, and on each engine a massive 24V 175A alternator, watercooled, connected to the engine cooling system. These were 2nd alternators, he kept the original small 12V alternators to charge the start batteries.

That is 2 times 4 kW! Thus he saves the weight penalty plus cost plus maintenance of a 3rd diesel engine. And you have a backup.

Cheaper, lighter, less maintenance, simpler.

I know it is not great to run the 40hp engines only having an alternator load of maybe 6-8 hp, but if it is only for 50 hours per year, it is not going to kill them; just need to let them work hard now and then to decoke.

[Adelie]

Originally Posted by Mike Cunningham

....
They say Induction is 90% efficiant compared to 65% for electric and 40% for gas/propane...
....

From personal testing.
Boiling water:
Induction is 76-77% efficient
Butane is 45-50% efficient
Microwave is 46-47% efficient.
I have not tested resistive heating elements. If I can find a $5-10 countertop job I’ll test that too but don’t see a great need to.

Ways to increase efficiency/decrease energy use would be to use a pot cozy or Wonderbag. Possibly you could even use them while heating since there is no exposed flame or heating element.

For baking I have yet to acquire a convection oven. But will post results whenever I do. 2021 maybe.

I have tested induction cooking for various items and concluded that for a couple an extra 150a-hr battery and 100-160w solar panel would make day to day induction cooking use reasonable. No great need to LiFePo batteries or regular use of a generator needed.

On demand electric water heating is also possible, especially if the water is preheated by solar means.

All this assumes you aren’t going high latitude off season.

[Dockhead]

Originally Posted by Adelie

From personal testing.
Boiling water:
Induction is 76-77% efficient
Butane is 45-50% efficient
Microwave is 46-47% efficient.
I have not tested resistive heating elements. If I can find a $5-10 countertop job I’ll test that too but don’t see a great need to. . . .

We should all be grateful when people take the trouble to do actual testing


Based on this, it looks like induction is considerably less efficient for boiling water, than an electric kettle, which must be nearly 100% efficient.


I've been through a number of different electric kettles on board. I got rid of the standard 2.3kW one because it just drew too much power. An 800 watt travel kettle was too slow and couldn't be separated from its cord. I eventually settled on one which draws about 1.3kW and is separable, and am well pleased with that. It's a little slow to boil a whole liter of water, but for a couple of cups it's fine.


I covet a convection oven very much but I have not yet found one which will fit in the place of the built-in Panasonic microwave my boat was built with. I hate the gas oven on my boat, which is terribly inefficient, doesn't get quite hot enough, doesn't bake evenly.

[Adelie]

I would expect that an electric kettle is 85-95% efficient. It does lose some energy to the environment while heating but the biggest loss is going to be heating the materials in kettle itself.

When I get around to it I’ll make a kettle cozy and redo the test with the cozy on the pot while it’s heating.

The willingness to have a single use item on a boat is going to depend on your priorities and how big the boat it.

I for instance wouldn’t carry an electric kettle unless I had a really big boat, a regular kettle on an induction burner will be almost as efficient.

On the other hand I’m a big fan of bread, especially fresh baked. I got a garage sale bread maker and tested the energy consumption. It was about 25a-hr for a 2lb loaf. This was about what I expected, because only a small volume and a small mass is heated energy requirements are greatly reduced compared to an oven. For me 25a-hr every 3-4days is worth having a single use item, it saves so much energy compared to a regular oven (electric or propane) and on top of that I don’t have to do anything more than add the ingredients and wash up after.

[Dockhead]

Originally Posted by Adelie

I would expect that an electric kettle is 85-95% efficient. It does lose some energy to the environment while heating but the biggest loss is going to be heating the materials in kettle itself.

When I get around to it I’ll make a kettle cozy and redo the test with the cozy on the pot while it’s heating.

The willingness to have a single use item on a boat is going to depend on your priorities and how big the boat it.

I for instance wouldn’t carry an electric kettle unless I had a really big boat, a regular kettle on an induction burner will be almost as efficient.

On the other hand I’m a big fan of bread, especially fresh baked. I got a garage sale bread maker and tested the energy consumption. It was about 25a-hr for a 2lb loaf. This was about what I expected, because only a small volume and a small mass is heated energy requirements are greatly reduced compared to an oven. For me 25a-hr every 3-4days is worth having a single use item, it saves so much energy compared to a regular oven (electric or propane) and on top of that I don’t have to do anything more than add the ingredients and wash up after.

To each his own, but I can't recall having been on a cruising boat WITHOUT an electric kettle in many years. On my boat the kettle is used more than the stove, maybe 10x more, so I hardly can think of it as a "single use item". We sail in cold places and therefore consume mass quantities of hot drinks, so YMMV, but for us the electric kettle is a basic necessity. The economy with energy is just a bonus and not at all the main point -- the main point is quick and easy production of boiling water.


Even better than this might be one of those boiling water taps -- something I would love to have on board. But the ones I looked at needed huge amounts of power.