Induction vs Gas Cooking

[paul2884]

Originally Posted by mvweebles

Try a single hobb induction hot plate. Most cooking will be 300W-600W (approx 20-40 amps at 12vdc). 1-2 batteries and a decent sized solar panel will suffice as long as you're not doing a full Sunday dinner with braised brisket, etc.

Peter

300watts load, inverter say 90% efficient (seems average) so this is more like 330watts. On a 12v battery bank will draw something like 27.5 amps.

600watt load, inverter say 90% efficient (seems average) so this is more like 660watts. On a 12v battery bank will draw something like 55 amps.
Also no gas means boiling the kettle for tea/coffee, 2KW kettle 3 minutes to boil draw on batteries 2000w inverter 90% efficiency 2200watts - 183amps on 12 v battery bank

Great with a big lithium battery bank, not so good for us with a lead acid bank that copes with normal use – (fridge running, instruments/PC charging etc.) but with not too much to spare and what will that do to our battery life span?

We can carry a spare gas bottle, swap it at many places. To use electric cooking we would need a generator/lots of solar (and sun shine – not usually much in the UK), carry petrol for the generator – extra noise in the anchorage, big boat in good climate it might be great but for sub 40’ with lead acid batteries and not wanting to have to run a generator to cook it’s not really practical at the moment.

[Dockhead]

Originally Posted by paul2884

300watts load, inverter say 90% efficient (seems average) so this is more like 330watts. On a 12v battery bank will draw something like 27.5 amps.

600watt load, inverter say 90% efficient (seems average) so this is more like 660watts. On a 12v battery bank will draw something like 55 amps.
Also no gas means boiling the kettle for tea/coffee, 2KW kettle 3 minutes to boil draw on batteries 2000w inverter 90% efficiency 2200watts - 183amps on 12 v battery bank

Great with a big lithium battery bank, not so good for us with a lead acid bank that copes with normal use – (fridge running, instruments/PC charging etc.) but with not too much to spare and what will that do to our battery life span?

We can carry a spare gas bottle, swap it at many places. To use electric cooking we would need a generator/lots of solar (and sun shine – not usually much in the UK), carry petrol for the generator – extra noise in the anchorage, big boat in good climate it might be great but for sub 40’ with lead acid batteries and not wanting to have to run a generator to cook it’s not really practical at the moment.

I think most people would agree with this.



Without a generator, or else a mongo solar array, ideally with lithium (like CatNewBee), it would be a drag coming up with the power to feed electric cooking. God invented gas cooking for this use case.

[noelex 77]

If you want to replace propane cooking with electric cooking away from shore power you need to be able to produce considerable amounts of power. It is easy to do with a marine generator, but with solar it requires a very large solar array. Even then it is not feasible in all locations and seasons.

If contemplating the solar option, the restricted cruising area need not be a limitation if it suits your plans, but using a mixture of electric and propane cooking removes the restrictions and provides redundancy.

[Van Der Beek]

I might add an induction cooktop as redundancy myself running it off the genset, but gas will be primary.

Right now debating between Cummins Onan and Northern Lights.

The Amel has a Cummin Onan as standard, however, the new ones uses circuits boards whereas the Northern Lights uses relays. I like relays more, thing is though that the Northern Lights is a bit heavier.

[slug]

Originally Posted by Van Der Beek

I might add an induction cooktop as redundancy myself running it off the genset, but gas will be primary.

Right now debating between Cummins Onan and Northern Lights.

The Amel has a Cummin Onan as standard, however, the new ones uses circuits boards whereas the Northern Lights uses relays. I like relays more, thing is though that the Northern Lights is a bit heavier.

The Cummins is a good unit

I just changed out from a Cummins to a northern lights

The old Cummins had 25 000 hours, very reliable ,never missed a beat

It was condemned due to a worn flywheel from thousands of starter motor engagements

The cost to repair plus the 25000 hours of age was too much

The northern light has run well so far

As you say it’s a simple piece of equipment

The northern lights has a separate alternator to charge the start battery
This alternator gets very hot ... you might consider an up grade

The onan had a winding on the generator to charge batteries

The sound enclosure on the northern lights is fragile and overly complicated , it may not stand the test of time

The onan sound box was rugged and simple

Both gens have a good reputation

Your choice

[Adelie]

Originally Posted by paul2884

300watts load, inverter say 90% efficient (seems average) so this is more like 330watts. On a 12v battery bank will draw something like 27.5 amps.



600watt load, inverter say 90% efficient (seems average) so this is more like 660watts. On a 12v battery bank will draw something like 55 amps.

Also no gas means boiling the kettle for tea/coffee, 2KW kettle 3 minutes to boil draw on batteries 2000w inverter 90% efficiency 2200watts - 183amps on 12 v battery bank



Great with a big lithium battery bank, not so good for us with a lead acid bank that copes with normal use – (fridge running, instruments/PC charging etc.) but with not too much to spare and what will that do to our battery life span?



....

Battery load is not 10% more than cooking load, it’s 11% more.

Cooking load / efficiency = battery load.

300W / 90% = 333W

Minor error when efficiency is around 90%, error gets much bigger very quickly as efficiency drops. At 50% battery load is not 450W, it’s 600w.

Why can’t an LA bank cope?
Yes, there is Peukert, but unless you are trying to cook a Thanksgiving feast for 10 high demand will not go on for that long before throttling back, 10min maybe. So that not really going to affect battery capacity that much.

I can see that a high C (C/3) draw might present a problem for a Gel bank but a FLA bank will probably be fine and an AGM bank should have no problem at all.

More to the point if you go electric cooking you would add to your battery capacity. Going cruising with gas you wouldn’t leave with the single propane tank the boat came with you would upgrade with at least 1 extra tank. Same applies to solar panels and or wind generation.

I get that if you already have a gas system upgrading that is much easier and cheaper than installing a new electric system and that’s fine.

But saying electric can’t be practical without some special equipment (LiFePo) seems like confirmation bias at play.

[Pelagic]

Originally Posted by noelex 77

If you want to replace propane cooking with electric cooking away from shore power you need to be able to produce considerable amounts of power. It is easy to do with a marine generator, but with solar it requires a very large solar array. Even then it is not feasible in all locations and seasons.

If contemplating the solar option, the restricted cruising area need not be a limitation if it suits your plans, but using a mixture of electric and propane cooking removes the restrictions and provides redundancy.

There is an alternate way of looking at this if you don't like propane gas lines below decks.

A small diesel generator is used sparingly to supplement solar charging

To maximize life span, run at proper operating load by harmonizing battery charging while using induction cooking and electric appliances..

This will gives you many years of reliable service using a fuel source already on board.

So propane cooking is relegated to outside social BBQs and refills in foreign lands are less critical.

[Dockhead]

Originally Posted by Adelie

. . . But saying electric can’t be practical without some special equipment (LiFePo) seems like confirmation bias at play.

I think, as others have said, that the batteries are less important than the means of production of power. If you have a ton of solar, then lead batteries will work ok. If you have a diesel generator, then electric cooking is fine, as I have experienced myself. If you have solar but not a ton of it, then batteries become more important. Lithium helps a lot in that case. Not just for the charge efficiency, but for not being a slave to the bulk-absorption charge cycle.

[noelex 77]

Originally Posted by Pelagic

This will gives you many years of reliable service frustration using a fuel source already on board.

I fixed your post .

Propane does have its limitations, but it is a simple system with few moving parts and minimal service requirements.

We use diesel cooking a great deal in winter. The diesel drip heater is a simpler, more reliable method of cooking and utilises our main diesel fuel source far more efficiently than a generator.

In summer or warmer climates there is plenty of power for induction cooking via our solar panels.

Consequently, we use little propane. On current usage patterns we have about 5+ years (full time cruising) before we need to consider replacing or refilling our three bottles. We have room for eight gas bottles in our vented locker should our usage increase in the future. So the main frustration of propane, which is replacing/refilling bottles is minimised.

Despite the relatively small usage, the propane system provides redundancy and versatility. To try and achieve the same goals with a diesel generator would require more service, repairs and periodically running the generator just to ensure its long term health. The fuel consumption would be higher, the cost greater as well as potential noise and vibration issues.

There are many alternatives and no perfect solution, but our system has worked very well in practice. It fulfils our goals of simplicity, reliability, and redundancy with very little ongoing maintenance, so we have plenty of free time to enjoy the cruising life.

[Dockhead]

Originally Posted by noelex 77

. . . Despite the relatively small usage, the propane system provides redundancy and versatility. To try and achieve the same goals with a diesel generator would require more service, repairs and periodically running the generator just to ensure its long term health. The fuel consumption would be higher, the cost greater as well as potential noise and vibration issues.. . .

It would be crazy to have a generator only to service electric cooking. A generator makes sense only if you have an electric-intensive boat and use it for multiple tasks, preferably many of them.

A school bus alternator on the main might be enough, however. Especially if you have a really efficient way to store power produced that way, like lithium batts. Lithium batts with a really big alternator would allow you to use the main for quite short intervals, compared to lead, limited by absorption rate and needing absorption charges. Much less need for a generator in that case, even if you have multiple large loads on board.

Huge advantage of propane vs. generator is that the system itself is cheap and doesn't care if it's not being used.

So I actually like your system. The safety issue is almost non-existent while you're not using the system and have the gas shut off at the bottle. Your system makes a lot of sense on a boat without a generator.

Only one comment is that I wouldn't say that the maintenance is "minimal". You need to pay attention to gas systems to keep them safe, even if they are not being used.

[Van Der Beek]

Originally Posted by slug

The Cummins is a good unit

I just changed out from a Cummins to a northern lights

The old Cummins had 25 000 hours, very reliable ,never missed a beat

It was condemned due to a worn flywheel from thousands of starter motor engagements

The cost to repair plus the 25000 hours of age was too much

The northern light has run well so far

As you say it’s a simple piece of equipment

The northern lights has a separate alternator to charge the start battery
This alternator gets very hot ... you might consider an up grade

The onan had a winding on the generator to charge batteries

The sound enclosure on the northern lights is fragile and overly complicated , it may not stand the test of time

The onan sound box was rugged and simple

Both gens have a good reputation

Your choice

I appreciate the feedback, good info on the heat and the sound box, two things I haven't seen mentioned when researching these units.

The simpler the genset is the better, it's just there to provide electricity.

Simplicity is a bit a problem these days in general, same thing with choice of engine.

[CatNewBee]

Corrosion and degrading hoses are a big issue on propane installations. I need every 2..3 years new hoses and regulators for my BBQ. hidden installations behind galley furniture are hard to inspect on a regular base.

I do really prefer wires over hoses.

[Dockhead]

Originally Posted by Van Der Beek

. . . The simpler the genset is the better, it's just there to provide electricity.

Simplicity is a bit a problem these days in general, same thing with choice of engine.

I agree about gensets.


I like the NexGen ones made in the U.S. -- dead simple, very compact, inexpensive.


I think all the main heavy duty low speed ones are ok -- Cummins, Kohler, Northern Lights. Plus minus this or that weak spot, but I love my Kohler 6.5EFOZ. Really simple and bulletproof. Driven by a Yanmar 3 cylinder tractor motor, at 1500 RPM


If you REALLY want simple, then why not build your own, DC generator? Why not drive a giant alternator with the smallest marine propulsion engine you can find? Then you can keep a complete spare generator head in spares -- can't get more reliable than that, and any fault can be repaired in any third world port without the need of any proprietary parts, circuit boards, sensors, etc.

[noelex 77]

Originally Posted by Dockhead

A school bus alternator on the main might be enough, however. Especially if you have a really efficient way to store power produced that way, like lithium batts. Lithium batts with a really big alternator would allow you to use the main for quite short intervals.

We have a large frame alternator (175A @24v derated to about 100A), but given our reasonable solar array and minimal engine hours, it does not see much work.

It does provide enough power to run an electric kettle or induction system while the main engine is running. This is fine if the engine is also being used for propulsion, but running the main engine just to cook, is not a very satisfactory backup.

If the primary cooking system was to develop a fault, this backup would only be acceptable for a short time. Lithium would be a help in this situation, but only when doing more engine hours than our typical usage pattern. When running the engine for cooking the majority of the alternator output is taken up by the cooking or hot water heating process so there is not a great deal of power left over to store in the battery bank. The high acceptance rate of Lithium is not really a help.

When designing boat systems to provide redundancy, the quality and performance of the back up system is important. One criterion I like to consider is “would you alter your cruising plans to repair the main system, or is the back up good enough that this could be delayed until a repair was convenient.”

Our case is a little usual, as we only tie to shore or call into a marina every two years, so backups have to be very functional, as they may be needed for long periods. Ideally the primary system or systems are also both reliable and easy to troubleshoot and repair, so situations where a repair needs specialist intervention or delays are rare.

[Dockhead]

Originally Posted by noelex 77

We have a large frame alternator (175A @24v derated to about 100A), but given our reasonable solar array and minimal engine hours, it does not see much work.

It does provide enough power to run an electric kettle or induction system while the main engine is running. This is fine if the engine is also being used for propulsion, but running the main engine just to cook, is not a very satisfactory backup.

If the primary cooking system was to develop a fault, this backup would only be acceptable for a short time. Lithium would be a help in this situation, but only when doing more engine hours than our typical usage pattern. When running the engine for cooking the majority of the alternator output is taken up by the cooking or hot water heating process so there is not a great deal of power left over to store in the battery bank. The high acceptance rate of Lithium is not really a help.

When designing boat systems to provide redundancy, the quality and performance of the back up system is important. One criterion I like to consider is “would you alter your cruising plans to repair the main system, or is the back up good enough that this could be delayed until a repair was convenient.”

Our case is a little usual, as we only tie to shore or call into a marina every two years, so backups have to be very functional, as they may be needed for long periods. Ideally the primary system or systems are also both reliable and easy to troubleshoot and repair, so situations where a repair needs specialist intervention or delays are rare.

That seems all quite reasonable to me.


For an electric intensive boat, it's good to have redundant power sources. Maybe essential. I have heavy duty generator plus main and big alternator. Either of these is adequate for electric cooking. You have solar plus main and big alternator. Solar is enough for you in season, but not otherwise, which would leave you without redundancy. So it's logical that the gas system plays an important role in the architecture of your system, even if you rarely use it.


I use gas more than you, but that's because my electric cooking is more limited than it would be in a boat which I had designed for it. If I had two induction eyes on a gimbal, the gas would probably go back to pure backup, or I might even remove it. As it is, I use gas anytime the system is working () and I'm at sea at sail, or anytime I need to have two or three pots going at the same time, or anytime I'm on battery power. I even use gas and electric at the same time -- there's no law against it.



But I do get the value of having gas back there, with the gas tured off at the bottle, ready for use at any moment in case of any kind of need, even if it's rarely used in real life.