Pushing the limits of electric cooking

[Na Mara]

Originally Posted by sailcrazy

The mentioned idea of a gimbaled box- with a cooktop on top and a m/w below is a great idea!

Sailing Delos got there first (though the microwave is my own addition).

[tdgaffney]

Mustang Sally, my Olson 40 which I purchased in 2016, was built in 1983 with little upgrade through the years to any of the electrical system. Most notably, the “early automotive” electrical power wiring, the five wet-cell batteries, the non-working Force 10 stove and the propane bottle locker consuming the starboard half of the lazarette all begged for attention. I removed all of that and started over.

To your issue – I removed all the propane system (100lbs) and converted to an induction cooktop with a convection microwave cooker (60lbs), all 120vac, powered by a 2kw inverter. Actually, my inverter powers my six 120 vac GFI outlets, one dedicated to the cooker (so, yes, power management will be important).

My upgraded battery bank is AGM, one start and five house, about 500AH for the house. I upgraded the alternator to a Balmar 150Amp with serpentine belt for backup. I have solar provisions, but will put that in later.

I designed/built gimbal straps and bolted them to the microwave cover shell. I added brackets for the induction cooktop. I hung a utensil drawer under the microwave. I installed new gimbal retainers and hung the cooker system, adding releasable hooks to prevent rotation when desired. See photos.

I also installed a Real Time power consumption gauge positioned at eye level above the cooker installation – please moderate you usage to that the inverter can accomplish.

Doing all this has been a work of love and patience. As a design/engineer/builder, I enjoy the project and anticipate happy sailing some time soon. Some day …

[SV Tom Crean]

Originally Posted by Na Mara

Sailing Delos got there first (though the microwave is my own addition).

We have a combo microwave and convection oven under the hob as part of the gimbal. Same space but more flexible - if you don’t have the juice to run the oven just use the microwave until your power reserves are good. We also have a tabletop induction as a standby if the primary built-in unit fails and then a bbq if the power is gone (but that means we have bigger probs anyway).

Now there is 1400 watts of solar, 14Kwh lithium and an Onan (but it’s only used maybe once a week).

[s/v Jedi]

Originally Posted by Andypids

While induction hobs etc can work very well on boats, my point would be that you are putting all your eggs in one basket. If your electrical system goes down you even loose the ability to make a cup of tea!
There are plenty of more deserving uses for your limited electrical supply on board than turning it into heat although I do support the use of a good coffeemaker!

So explain how you can continue cooking when your propane system fails? How is propane more redundant?

[s/v Jedi]

This project is on my list too. I plan to make something more like a heavy duty tray that I gimbal below countertop height so that portable induction cookers come flush with the countertop.
Then under the tray mount a countertop model microwave with stainless vertical straps.

[goboatingnow]

I prefer gas cooking , I also have a gas cook top at home

[fxykty]

Originally Posted by Na Mara

5% drop in charge from what if I may ask? Also I’m very surprised that you can’t keep up with domestic loads with 2.4kW of solar panels (surely you are a catamaran?). Even in midwinter in Europe you should be averaging about 2kWh of charge a day. In the summer you should be averaging 10kWh. That latter figure is 4 times my daily consumption.

Reread what I wrote, if you are referring to the 0.3V voltage drop that I see at our battery when pulling large current at mid to low SOC.

Reread what I wrote, if you are referring to the 1-4 kWhs solar production that we see on the East Coast of Australia in winter. I’m so happy for you that Europe has amazing solar conditions all year round, but we do not see anything like the figures you and others quote for solar production. Lucky you.

[Na Mara]

No 1-4kWH midwinter is about what you would see in the med mid winter from 2.4kWh. What you claim tracks, it’s just I could meet my daily needs off that so I was a bit surprised that you claim not to have sufficient solar at 2.4kW of panels.

[Jef & Marin, Netherlands]

I fear the bottleneck might be your solar power. But maybe you can spare 0.6 kWh, and that is enough in our experience.



We use a single induction plate of 2000W since 2014. A single plate is OK if you have small pans; you can put up to 3 pans on a single induction hob. Shift them around for power distribution.
Pasta and so goes in a wool isolating bag after a few minutes of boiling and stays there until ready.
We rarely set it higher than 1000W.

Cooking for the 2 of us takes around 0.6 kWh on average.
We have 1800Wp of solar and consume a lot. Production is around 300 Ah at 12V. Freezer takes 1.2 kWh/day, will be replaced. Tea water is boiled in an electric cooker. Oven is still gas.
Inverter nr.1 is a 2kW Mass Sine from Mastervolt, 220V.
Battery is a worn-out set of LFP 540Ah @ 12V. Down to 70% capacity after 7 years and around 2500 cycles.

We have used 1/2 a gas bottle in 4 years for the oven, BBQ and gas cooking when there is not enough sun.



I can recommend the Ikea Valbildad 2-burner flush induction cooker. It is 3500W but it is one of the rare ones that can be set to a maximum available power level (during installation). In our case 2000W. Power is automatically split over the 2 burners.
220V, don't know if there is a 110V version.

And it is cheap, 199 euro, and quiet, and has 5 years warranty. You can buy a double gas burner in equal footprint and similar styling.


We have purchased 2 of these double induction cookers, one for each inverter. Will be installed flush in the kitchen top. We are also purchasing a Miele electric oven / microwave which is very economical (200W) but quite expensive. Everything will be installed when we get to New Zealand in a few months.
After that we will retain the gas bottles for the BBQ. When the gas bottles are empty, many years from now, we might buy a charcoal BBQ. Then we are rid of gas.


A disadvantage is that when it is very cloudy, in the future we can not fall back to gas anymore but will have to start the generator. Also a worry in case of a mid-ocean lightning strike. We might buy a camping-type single-burner for emergency use. Also good for heating smelly stuff in the cockpit.



The problem with gas for long-distance cruising is not only the danger; also the different fittings, ordering and filling bottles, transferring the gas to your own bottles, returning bottles...... rusting bottles..... As you are all aware. Plus, solar is free and good for the planet.

[Shaneesprit]

I have induction hob at home and I hate it.
You so much as touch the pan lift the pan it can’t put heat, spill something try and wipe down while on it simply turns off - really difficult to cook a steak 🥩
so for me that’s not cooking it’s heating food. Likewise we don’t have a microwave at home either.
Like the gas on the boat ( yes I am aware of the risks and I even take samples of the air in the bottom of the hull and test)

[Na Mara]

Jef and Marin, thank you for the really great tip on the ikea cook top. I will research it tomorrow. I already have the camping stove and barbecue as backups. It would be great to limit the cooktop to 2.2kW and that way know that we are always well within the inverters limits.

I just made a curry with rice today using thermal cooking. Both curry and rice were subjected to the treatment in lue of simmering time. The rice saved 10 mins of simmering at 400W, the curry saved 30mins of simmering at 600W. Together it saved in the ballpark of of 0.4kW on the meal for 3 people. The result actually tasted better than usual. The rice was perfectly cooked after 20mins in the thermos and the curry was both crispy and sweet. Seriously, why aren’t we taught to cook like this from the egg. If so much easier and efficient both in terms of time and energy. I reckon I can save about 60-70% of the energy I normally use cooking like this. Anything that simmers, it’s a no brainer.

[noelex 77]

For those thinking of electric cooking via solar, here is a summary from this thread of actual user experiences:


Wholybee:
0.7kw solar.
Propane retained.
Engine charging to supplement solar if cooking more than every other day.

Fxykty:
2.6kw solar.
Electric cooking. Solar not enough on grey or rainy days.

Noelex:
1kw solar.
Propane retained.
Partial electric cooking.

Rslifkin:
Generator powered electric cooking

Bolbliksem:
Unknown amount of solar.
All electric cooking

Alctel:
Unknown amount of solar.
Propane retained

Jedi:
Unknown amount of solar.
Suggests a minimum of 1.5 kw of solar for electric cooking.

Pete7:
0.3kw solar
Easter: Electric cooking created a shortfall of 0.3kw day.
August: 50/50 gas and electric. Some engine charging.

Zboss:
1.1 kw solar.
5kw generator.
Summer OK on solar. Winter two hour run with the gen every two or three days.

Jimellifritt:
2.4kw solar.
Just enough for electric cooking?

Jabberwock:
0.2kw solar.
Some engine use, but enough for electric cooking for one.

Sailcrazy:
All electric cooking with diesel 6/5kva genset.

Tom Crean:
1.4kw solar.
Diesel generator used once per week.

Jef & marin:
1.8kw solar.
Partial electric cooking. Future all electric cooking with gas BBQ back up, but anticipates some generator use needed.
.

[pnw2022]

This is an interesting thread for me. I also tend to dislike having to use hydrocarbons and in particular dislike different sources of fuel for them.

One interesting things about boat life, is that even the simple things often involve compromise?

I have been looking at replacing the propane galley stove. It still works fine but sometimes I wonder when it will eventually bite the dust and e. As a liveaboard it is definitely an important even though not critical item.

I have found that (as others have mentioned) the combination of the microwave, the rice cooker and the bread machine can do a lot.

In my case, with additional loads like separate refrigerator and freezer units - plus the general power consumption for other items like laptops/internet (I work from home even when underway or anchored) the amount of power consumed is already up around ~7amps 24x7 at 12-volts => ~2kw daily.

Once underway and under sail (no wind vane) add on a few more amps for the autopilot, AIS, VHF, nav lights, etc.

I am currently upgrading from a 300w => 600w solar system for improvements and figure I can do up to about 900w with currently technology and some Flexi-panels on top of the main dodger area in another year or two. I also have a 100w 'kick out' panel that I can move around and flip on the life lines here and there.

Overall my point here, and my I did not read the thread in full detail, is whether realistic base loads are under consideration above and beyond adding in electric cooking. I like the idea, but for us in more northern climates (Pacific NW USA and farther North) the solar is just not there as much as we would like it to be.

Conversely - many years ago I took a 30' boat over to Hawaii on the Vic-Maui and back. We ran everything off a single 30w solar panel. Only goal then was to be able to keep the nav lights on as much as we could, and the batteries topped 'enough' to be able to use the SSB half hour a day

Side topic - there is a safety at sea issue involved as well? When that unexpected cascading chain of small failures results in a serious situation - and all the electrics are out. How does one warm one's self or somebody that might have fallen overboard and been retrieved?

[s/v Jedi]

Originally Posted by noelex 77

For those thinking of electric cooking via solar, here is a summary from this thread of actual user experiences:
Jedi:
Unknown amount of solar.
Suggests a minimum of 1.5 kw of solar for electric cooking.
.

We have 1,875W of solar. We do 100% electric cooking except for the cockpit grill which is still propane, using the little 1lb tanks. Looking into making that electric too

Our solar is enough to also run the 40gph watermaker and even the A/C now and then, but this is in the Bahamas so pretty good solar conditions. Our record production recorded is 2,200W.
A year ago we spent a month in a marina in Nassau and didn’t need shore power.

[Jdege]

Originally Posted by tdgaffney

I designed/built gimbal straps and bolted them to the microwave cover shell. I added brackets for the induction cooktop. I hung a utensil drawer under the microwave. I installed new gimbal retainers and hung the cooker system, adding releasable hooks to prevent rotation when desired. See photos.

Thank you for that. I've been planning a microwave/air-fryer+induction-cooktop replacement for my existing gimballed marine propane oven/range. And seeing your design made me realize that I was looking at the problem too narrowly.