Induction cooktop, battery bank required?

[GoingMobile]

Wondering what size battery bank would be required to be able to use an induction cooktop to cook most meals?

 

[PlethoraOfGuns]

That depends. I think the answers that might help you are how many amp hours it takes to cook certain foods. For example, for me to cook 1lb of shrimp scampi, I need about 55 amp hours of power to do it. That includes boiling the pasta and cooking the shrimp and sauce in a cast iron skillet. Induction draws lots of power, but it is usually quick, like with boiling water. 100 amp hour lithium, it will be enough. 100 amp hour lead acid, not gonna work so good.

 

[travelaround]

When I use my induction cook top in my travel trailer I have to turn off everything else: air conditioning, microwave, electric tea kettle, etc. However the cooking goes very fast. I like that there's a timer on the cook top. Works great for me.

 

[travelaround]

I should add that I'm on 30amp RV park power right now. I'm watching this thread because I'd like to know if others are using a cook top in a van with solar power... which is what I'm hoping to do in the future.

 

[GoingMobile]

I'm more likely to be using solar panels (400W), and a DC to DC charger to charge batteries and run the Induction Cooktop off of the battery bank. I have 340 Amp Hours of LiFePo4 Lithium Batteries. It appears Induction Cooktops all run off of 110V AC so it looks like I'd need a larger Inverter than the 1000W one I have already.

 

[PlethoraOfGuns]

Oh yea, with that electrical setup you'll be able to use the induction cooktop for breakfast and dinner everyday! Just need to get at least 2000 watt inverter.

 

[Knit]

The important thing is being able to make coffee the next morning. At least to me. My van has 300ah of lithium batteries. When fully charged at end of the travel day, this is about the right amount to be able to run the van overnight, make dinner, and start the next day with coffee and breakfast.

 

[jimindenver]

I have at least one customer that uses a induction cook top with 200 Ah of lithium and 345 watts of solar. I can't say that she uses it for three squares a day or long term meals like frying chicken. I do know that normal quick meals do not take huge amounts of reserve. It isn't that much different than my electric cook top that is not induction except mine uses lower power levels for longer time to get up to temp.

Having seen both in action I can tell you the differences.

I do not remember the brand of her induction cook top except that I do know it is not the as seen on TV NuWave. Hers can use 1800 watts if turned on high or the 10 setting. Turned on a lower setting it uses fewer watts.

Mine is a Elite two burner electric cook top. The larger burner uses 1030 watts and the smaller uses 470 watts. It uses that amount of watts no matter the setting.

Both cook tops turn on and off once the pan is brought up to temperature. So they both use the same amount of power to do the same job, it's just that the induction cooker uses more watts to get the pot up to temp quicker.

So that means that if your batteries can handle the initial high draw of bringing the pot up to temp and your solar can cover the low draw of keeping it there that you should be able to cook during the peak of the day without worry. With my large solar system I can turn the small burner on high late morning and leave it on until around 4 or 5 pm and never touch the batteries.

So a induction cooker is like a microwave in the beginning. It uses a lot of power to do the job quickly. While your system has to be able to provide the level of power, it doesn't mean it is a lot of power in the end. Without using a induction burner I can not tell you how much personally but I can give you examples from my cook top or other devices that people assume use a lot of power.

I make coffee in a Moka pot in the morning. It's wasteful because the pot does not cover the burner as it heats up. Still it's not terrible. The burner is on high at 470 watts for 12 minutes. 470 watts a hour divided by 60 minutes is 7.83 watts a minute for 12 minutes or less than 10 amps out of the battery including inverter losses.

My toaster uses 700 watts for 3 minutes. That's 35 watts total or 4 amps including the inverter.

My microwave uses 1070 watts. two frozen burritos take 4 minutes or less than 6 amps. Two good sized potatoes for 9 minutes is a little more than 13 amps. A pot pie takes around 7 amps. Warming up a cup of water for tea is less than 2 amps.

So you need a battery bank that and inverter that can puke out that kind of power and enough solar to produce it be it directly or replacing what you take out of the bank. A single Lithium battery limited to a 100 amp draw or a pair of 6 volt batteries with high resistance are not going to be able to handle it.

 

[jimindenver]

The ways I work out what a device uses are the formula above if I only know the watts it pulls in a hour

watts used per hour divided by 60 minutes times the number of minutes used divided by the voltage of the bank at the time equals actual amps out of the battery. We generalize it's 12 volts but that's misleading since our banks are higher than 12 volts especially while charging during the day. I use 13.1 volts as a base for lithium at night. !2.7 is a fully charged lead acid not being charged. The other way to look at it is by using the lower 12 volts you are roughly automatically adding in the inverter loss.

watts per hour / 60 minutes x minutes used/ voltage of the battery = actual total amps used from battery

The other way if you can find the specs and they say the draw is 6 amp at 120 volts, simply move the decimal point one space to the right.

My 5000 Btu is rated for 3.9 amps at 120 volt which is 39 amps a hour at 12 volts.

People think that small residential refrigerators use a lot of power compared to the more efficient 12 volt units. A energy star rated 3.1 cf 2 door refrigerator with a square foot of freezer space uses .6 amps at 120 volt while the compressor runs. That's 6 amps at 12 volts which isn't bad compared to the larger dual compartment 12 volt units.

I apologize for getting of topic but this is always the answer to the question of can it be run off of solar. Anything can be run off of solar if it has a system that can support it. Know what kind of power you want to use and build your system around it. I built my trailers system to be able to run the A/C.

 

[tx2sturgis]

Wondering what size battery bank would be required to be able to use an induction cooktop to cook most meals?

If you want to cook 'most' of your meals with an induction cooktop (or any electric powered cooking appliance) you will need a large, expensive system. 

You did not mention solar panels, or a generator, but you gotta have a way to put back in the batteries what you take out...preferably daily.

You need to figure in battery bank size AND solar array wattage, or at least, have a generator as a back up. 

Typical van roofs don't provide enough useable 'real estate' for a large array, but if you have an RV with a large spacious roof for panels, or you will deploy several portable panels, or you have a generator in mind, then you are heading in the right direction.

 

[PeterPiper]

I pack an induction cooktop in my travel / camper Caravan.

I have 200watts of solar on top and another 100 stored below for use as needed that can be quick connected to my system.
200Ah of Lithium batteries.
That said, I also have a small propane gas burner.
That said, I also carry a small 2000watt gasoline powered inverter generator.

The induction cooktop at anything above 300watts really sucks down the power.

I think it all boils down to being prepared and having options on board. Wait...was that an unintentional pun ?

 

[Weight]

If you want to use 120V household appliances you plan on 15A 120V outlet. I have a 1000W microwave. Powered by (recommended) 2000W inverter. When cooking steam-in-bag frozen vegetables on high I use 150 amps of battery amperes. Some frozen Stouffers dinners can take 10 minutes. 10 minutes at 150 amperes equals 900 amp hours. My 350 available ah bank can do this twice a day and recover 100% in one day of sun shine on my 400 watts solar panels.
My induction set on 2 out of 10, cycles on off. It still needs 120V 15A outlet. The induction is much more efficient as it only heats the pan, directly with magnetic pulses. Any other type radiant energy source wastes more energy than is used in the pan.

 

[tx2sturgis]

Some frozen Stouffers dinners can take 10 minutes. 10 minutes at 150 amperes equals 900 amp hours.

Your math is off a bit.

150 amps pulled for one hour, would be 150 amp-hours.

10 minutes is one sixth of an hour.

So 1/6th of 150 would be 25 amp-hours.

Which is easily recoverable with a mid-sized solar array and a decent battery bank.

 

[Weight]

Thank you. My bad. I didn't have my morning wake up beer. 150 amperes times 10 minutes divided by 60 minutes per hour.
When I went to school that was college prep level math. Today it might be 4th grade.

 

[tx2sturgis]

Yep...stuff happens.

'Ciphering' is not my best subject either.