Electric Range without a Generator?

[OldMan]

Originally Posted by a64pilot

Efficiency is sort of irrelevant when comparing fossil fuel items on a boat as compared to electric.
It’s what the electric propulsion people love to bring up.
Reason it’s irrelevant is that a kilowatt of solar panels harvesting power all day can’t likely come up with the power in a cup full of Propane.
Now I have not run those numbers, that is purely made up, but tries to illustrate my point.

It would take ~1800 watts of solar and 5 hours of sunlight @ 80% efficiency to equal the 7.1KWh of power in a liter of propane.


When it comes to heating, propane is fit for purpose, no conversions required, hence very high efficiency. As nice as induction is, it can't come close to matching efficiency of propane for heating/cooking.

[Suijin]

Originally Posted by RonSwanson

I plan on cruising in the near future, so I would not be relying on shore power to use this sucker. It sounds as if it would need to plug into an inverter if offshore? Or is it wired straight to the battery bank? Only other charging is the alternator. Engine is brand new. Clearly I do not have enough energy to support this but I do not know what I need to do to get closer.

Do you have refrigeration and have you spent an extended period away from shore power? If yes and no you’re going to need all the capacity and solar you have to keep up with your current needs. In fact you’ll find the 200 watts solar inadequate if you don’t want to run the engine every day.

[a64pilot]

Originally Posted by Sand crab

I think a large portion of the gas fired BTUs are wasted due to heat loss around the pot. I suspect more of the induction's energy gets right to the job at hand.

Of course, your correct a whole lot of heat is lost with propane.
However it’s more than that, I suspect that use of an induction cooktop requires cookware that contains iron, likely not an insignificant amount.
If I’m correct then using the same kettle to show how much quicker induction will bring something to boil is skewed to induction.
If a much thinner copper bottomed kettle were used on the propane it’s likely the water would have boiled much faster.

However if you want induction cooking and have the power generation and storage to feed it, your boat, do as you like.

However very, very few do, average cruiser is murdering their banks as it is, I hear almost every day on the net about someone wanting help with why their bank drains down so fast during the night, and they want to borrow a battery tester etc.
Give them an inverter big enough to feed an induction cooktop and said cooktop and their bank will be stone dead in a week or less.

[seandepagnier]

Both me and the guy anchored next to me cook using solar power from just a few small panels. He has only 80 watts. My cooker draws 5 amps at 12 volts, but it takes 45 minutes to cook.

I met someone on 26ft boat running microwave using solar power. Since it runs only 5 minutes it is not a lot. You don't need lithium batteries.

The standard electric range, or gas stove is incredibly wasteful. Do you notice it can heat a room? This is all wasted energy. It would not make much sense to do this with solar power. It is unfortunate that delios or whoever is promoting this concept. It make a lot of pollution to make all those panels and lithium batteries compared to much better alternatives:

Many ways to cook much more efficiently, most people on boats make no attempts past a pressure cooker. For example, a flame should never ever touch the cooking pot, to be efficient it needs to be a good distance below and centered under the pot. This is proven for industrial uses, but it seems most people when cooking would rather burn 10x the fuel and get only 3-4x the heat. The heat is limited at maximum efficiency because the stove is designed to be more compact and other trade offs that are mostly sacrificing efficiency.

The stove if made of metal will sink a lot of heat away. I found origo stove consumed 2x more fuel than just using a can stove to cook exactly the same. A lot of ovens on boats are not well insulated. They should be vacuum insulated.

Today we have something called "solar tube" you can just put your food in and put in the sun. This is a very small area compared to how many solar panels you would need to power it. If you want to run on electricity from battery to buffer clouds or work at night, you can put an electric heating element inside since it's vacuum insulated.

I also have a solar furnace. It is a parabolic mirror that tracks the sun at anchor. It is very dangerous because the heat is concentrated 500W of solar into few sq cm. It makes metal glow red. So by moving out of the absolute focus point I achieve safer heat in a larger area. It is comparable to a regular stove but it requires full sun, and the wind cools the cooking pot a lot more since it is outside, so insulation is needed.

[a64pilot]

Originally Posted by boat_alexandra

Both me and the guy anchored next to me cook using solar power from just a few small panels. He has only 80 watts. My cooker draws 5 amps at 12 volts, but it takes 45 minutes to cook.

As a kid growing up all the little girls had the same thing, it was called an easy bake oven.
60 watts.
Using Solar power as a heat source is far more efficient and productive than using it to make electricity, then storing that electricity and using stored electricity to make heat.

Me, I’ll just pay $10 or so and have the propane bottle filled once a month, I carry four, so I can go four months if needed.

[john61ct]

Originally Posted by Adelie

So I just saw something that give one an idea of how efficient induction cooktops are.
YT video where a cook put his home gas stove up against a $69 countertop unit he'd just bought at Costco. Gas burner used was the big 18,000BTU pot boiler. The induction unit was 1800w max since it was cord powered.
Same teakettle, same 2cups of water.
Burner took 2m30s to start whistling,
Induction took 1m30s.

There are different measures of efficiency.

But that is a demonstration more of effectiveness.

Time efficiency I suppose.

But off grid, smaller boat, solar being the main energy input, compromises are the order of the day.

[Cheechako]

"Cap'n, I think we're gonna need a bigger boat"

[zboss]

We run a 1500 watt plug-in induction cooktop alongside our existing propane system. We use iron skillets and most of the time we use the cooktop on medium or low which is surprisingly hot and probably only draws half that 1500 watts. We use AGM batteries and have a high output alternator (165) that quickly charges up the AGM’s. This is very effective and as a bonus it makes sure we regularly start the engine. Between our solar, the wind gen, and the high output alt we produce all the power we need BUT we also keep a Honda gen on board, which is faster at heating the hot water on the boat but not nearly as efficient at charging our batteries as the high output alt because our shore charger is only 50 amps.

Conceivably you could also run an electric stove but you better have an alt that can put out 200 or more amps continuously and lithium’s that will take all that 200 amps.

[StuM]

Originally Posted by Sand crab

I think a large portion of the gas fired BTUs are wasted due to heat loss around the pot. I suspect more of the induction's energy gets right to the job at hand.

That's the situation exactly. It's all about efficiency of transfer of energy from the source to destination and how much is lost to heating up the surroundings.

[wtmf]

if the stove amps is less than the inverter amps you are OK . if not get an 8000 amp inverter, better to have bigger and more than not enough, just ask any woman.
i have 8 deep cycle, maintenance free, Marine batteries and I am happy with them. I have four solar panels that measure 5'5" by 3'3" on a manual gimball that I turn directly into the sun during high usage and I have no problems.

[Sailor 99]

Originally Posted by OldMan

It would take ~1800 watts of solar and 5 hours of sunlight @ 80% efficiency to equal the 7.1KWh of power in a liter of propane.


When it comes to heating, propane is fit for purpose, no conversions required, hence very high efficiency. As nice as induction is, it can't come close to matching efficiency of propane for heating/cooking.

Yup diesel and propane are very energy dense. Have to burn a lot of wood to measure up to 100 litres of diesel. We will have plenty of solar and a generator AND we will have diesel heat and propane cooking. While a Go Sun looks very cool and attractive, when your on an over nighter and you need some food, the Go Sun is not going to cut it.

[Sailor 99]

Originally Posted by a64pilot

Just like all the electric propulsion threads don’t seem to realize best way to harness Solar power for propulsion, is Sails.

I simply don't understand the electric propulsion thing. To me its not a workable solution. Great. I can electric motor for 3 hrs and then my $5K batteries are dead. To bad I needed to power for 3.5 hrs and as a result of running out of power I got run over by a freighter.



What is wrong with that picture besides everything.

[Sailor 99]

Originally Posted by zboss

This is very effective and as a bonus it makes sure we regularly start the engine.

I am pretty sure that the economics of running a $12,000 diesel engine ( only if you replace yourself) to charge your batteries are very poor. Just on a litre per hr basis it must just kill. Add in the damage to the motor from sitting at best on a high idle and its painful to even think about.


Don't take my word for it ask around. Using a 40 to 50 hp diesel to charge the batteries is just terrible for the engine.

[a64pilot]

Ah, but an electric motor is way more efficient than an internal combustion motor.

To me it’s the same as cooking with electricity, for most that don’t have a lithium bank and or a Solar farm, it’s going to mean burning Diesel to make electricity, to make heat, as opposed to burning propane to make heat.
I say that cause after having been cruising for awhile, the average cruiser has a battery bank that is chronically undercharged as it is, adding a cooking load is likely way more than another fridge, and the system just can’t support it, they will be replacing banks way more often.

Most it seems think they can crank their motor for an hour a day, so long as they keep the bank at 12V they are OK, right? It is a 12v battery.

Cooking with electric power continuously is going to require a graduate level of understanding of charge sources and the battery bank, and I’ve not met very many Cruisers that truly understand what is going on, most are sure if they have Solar that they are charged by noon, cause the little green light comes on.

It can be done of course, just not by the average person, with the average electrical system.

Heck, electric propulsion can be done, has been done. Just not with the average boat, by the average cruiser.

[zboss]

Originally Posted by Dark Horse

I am pretty sure that the economics of running a $12,000 diesel engine ( only if you replace yourself) to charge your batteries are very poor. Just on a litre per hr basis it must just kill. Add in the damage to the motor from sitting at best on a high idle and its painful to even think about.


Don't take my word for it ask around. Using a 40 to 50 hp diesel to charge the batteries is just terrible for the engine.

Yeah I know but the poster asked if it were possible to do all electric without a generators and it is... we do it.

We use our electric induction probably every other day when we are cruising and it uses surprising little power on medium setting. It heats up the skillet very quickly and we almost never run it full output unless boiling water for coffee... which takes 4 or 5 minutes on high setting... using about 10 Ah. Cooking breakfast on medium setting takes 10-15 minutes using another 10ish Ah. Dinner is maybe another 30 amps. So for us... a very high use day would be 100 Ah for the induction (guests) but our average is about 40-60 Ah every other day. I really do think we should use it more and if we didn’t need an oven then I could definitely see going with an gimbaled induction cooktop and getting rid of the propane. We won’t starve if the electric cooktop fails for some reason.

The trick to making it work on a small boat is that high output alternator.

We are starting the engine for 20-30 minutes anyhow when we up anchor or need to move the boat under power so we might as well enjoy the power we would otherwise be wasting. At worst you end up motor sailing for an hour.