12v electric stove OR Rice Cooker in a Minivan with a 12v freezer & 12v fridge for a healthy diet power requirements?

[maki2]

My research consists of Amazon searches. There are induction cookers which adjust by wattage, but I have not purchased or used.

With my 600 watt inverter I’d imagine that level would best be used for low and slow cooking, during good solar conditions.

Sorry for the bad news but you can’t get by with a smaller inverter for Induction cook tops by cooking on lower heat settings. The induction cookers do not create lower cooking temperatures the same as an electric burner stove. They still require the same rating of power at low as they do at high. They work with pulses of energy and the strength of the draw of power to create the pulse does not vary. The temperature is controlled with fewer pulses per minute on low and more pulses on high. So that means you will need an inverter that can handle what the induction burner is rated for. There are a few induction cooktops being sold that are less than the typical 1,500 watt rating. Take a look on Amazon for them.

 

[wayne49]

This induction cooktop claims to have three wattage settings. Are they lying or misdirecting?

https://www.amazon.com/dp/B08YJ6ZPFJ

"NUWAVE Flex Precision Induction Cooktop, Portable, Large 6.5” Heating Coil, Temperature from 100F to 500F, 3 Wattage Settings 600, 900, and 1300w"

 

[laura anne]

Right now I have 200watts of solar and a 200ah battery. My only draw right now is my 12v fridge.

I'm interested in electric cooking. be it a stove top or a rice cooker.

I recently discovered I can toss in a frozen bag of broccoli with my rice and they both cook up wonderfully! Next week I want to try cooking my frozen peppers and meatballs with three fresh eggs. If that is a success to then no doubt I can cook my frozen carrots bag with some cheese on top and have pretty much all my healthy meals done right from the rice cooker! Although I still want to have a stove top for cooking meat and chicken but I don't think I would need to use it very often. Plus I could freeze it for long term usage as well.

I think I could upgrade my minivan to have 400watts of solar (maybe more if I see about panels that are more efficient per inch of space ie 180watts instead of 100) Plus I would build my system to support two 100watt pannels to be plugged in during emergencies thought I rarely park off gride so there value wouldn't be so realistic but it be an option for durations of extreme clouds or bad weather. I don't have more space on the roof but I would just mount a frame where I can mount the panels directly too.

I don't have space for more batteries so 200ah might have to be the max. I regularly maintain a USB power banks rotation system. I rotate between six power banks and charge them up when needed. That gives me great flexibility. Essentially only draw at night is the fridge and would be a potential freezer. Plus a USB fan I typically plug into the USB outlet on the fridge which draws directly from the battery. I ony seen my batter as low as some 77% before sunrise.

I don't live in the minivan full time anymore but I would like to figure out how to live in it again but in a means that allows me to maintain a very healthy diet on the cheap.

any help in the numbers or advice in a better method would be much appreciated. When I lived in the van last time I used a butane cooktop. I just rather invest more into my van now to build something that is safer.

check out the cheap rv youtube channel about the istant pot

 

[townline]

I am following this conversation because i am looking for a rice cooker 110v that is less than 300 watts. I have seen some 250watt cookers. It dos'nt need to be fast. I have 300w solar with an iffy 100amp agm. Am sure to upgrade battery to 150 to 200amps soon and will try a cooker on next trip. I also want ceramic rather than teflon type coating.

 

[abnorm]

^ With what size inverter ?

 

[frodo2222]

This product from that Road Truckers site is a perfect illustration of why electric cooking in off-grid applications is very limiting:

https://www.roadtrucker.com/12-volt-appliance/roadpro-12-volt-20oz-smart-car-pot.htm

8A draw, 600mL capacity, 1 hour to boil water. For an 200Ah AGM setup you're looking at over 10% of your battery capacity just to heat some water. Might work if you're a trucker burning diesel all day every day, not so much if you need to charge off solar.

I've got a Travel Buddy and it almost works as a proper oven but the power draw is very high (the marketing says 10A but real-world it pulls more like 13-15A). Preheating to 300F+ takes 30-45 minutes if you need to actually cook something with it. Its alright for warming up rolls/bread or prepackaged frozen food but objectively speaking it is a terrible oven. I tried to make both brownies and biscuits in it, while they eventually cooked it took hours and flattened my batteries. These days I don't use it unless I'm driving and can afford the massive power draw. Having said all that, it's amazing to just toss something frozen in there and have a hot meal right when I get to camp with zero effort.

IMO battery capacity and tech is going to need to improve by an order of magnitude before electric cooking will be a truly viable option all around. Until then its going to be an exercise in managing expectations, if all you want is to warm stuff it'll be fine. If you're expecting to make thanksgiving dinner you will be disappointed. In that regard I think a rice cooker makes a good deal of sense - you're not trying to brown anything, they're generally well insulated and thermally efficient, and won't need to run for hours to make a meal.

there is 2 ways to go..1. have enought battery amps to run what you want or 2 have enough solar power to use the battery as a pass through really...I can run my 8000 BTU AC on just 1000 watts solar and have the batteries be full from 10 am to about 2 hours B4 nighfall on my van build i..solar is $50 for a 250 watt from San tan Solar..great deal

 

[wayne49]

Unpacked the induction cooktop, that I mentioned above, I used lowest setting for 600W and the Kill-A-Watt showed 620 some watts.
Amazing to see bubbles forming quickly, with very little residual heat after shutting it off.

 

[Zoomyn]

Years back I test ran a $400 Panasonic inverter type microwave against a $50 induction portable cook plate - the plate boiled a liter of water about 10% faster using 400w less draw.. .

When I summered in my van three years ago I unpacked the then 7 or 8 year old induction cook plate from camping supplies and it is still humming along nicely on its third season.

One thing I discovered is the same magnetic fields heating a pans iron insert will lift & rattle smaller pans out of the active hearing zones if the plate isn't near level - at the closest dimension to glass tops edge there usually is not a spill hazard where the pan creeps all the way off since the induction coils are centered and the pan quits coupling with the strongest magnetic flux as it has gone off center - BUT food location and a handle hanging ten can set it up so a nudge will topple it.. . Easy to say oh I always level the van but in practice having some shims to lift one side of the plate works very well, just don't block the cooling airflow much.

 

[BlueMarkOhio]

Most considerations about electric cooking in vehicles focus on the wattage available from the power bank, but that is mainly a matter of the inverter and maximum discharge rate of the batteries, not power usage.

I'm interested in knowing the most efficient way to cook so that your battery charge lasts longer. I would think that a microwave would be much more efficient than a range despite high wattage during the shorter cooker time. We know that induction ranges are much more efficient than regular electric ranges. I also suspect that direct contact appliances like George Forman grills and rice cookers are better than ranges. My guess is that a slow cooker is very inefficient.

Has anyone ever seen an examination of the most electricity-efficient ways to cook?

 

[bullfrog !]

Bob Wells has a few videos I believe on his small microwave he used in his van. There may be some information on electric usage in the discussions on solar as well. Big problem is having to use an inverter (inefficient use of power)instead of direct 12 volt current for many appliances. Heating anything with electricity is usually more efficiently done with propane unless you are on grid power.

 

[abnorm]

My guess is that a slow cooker is very inefficient.

WHY ? For Us.......a Slow Cooker is a perfect match............................

 

[rruff]

Has anyone ever seen an examination of the most electricity-efficient ways to cook?

No, but I like your thinking! I bet the microwave would come out on top. It directs the heat right where you want it rather than heating up metal and ceramic things. Just need to figure out how efficient microwave itself is (probably need to experiment and measure input vs output), and also take the efficiency of your inverter into account.

I don't know if they make them lower powered, but usually they are about 1000W heating. Saw one where 1300W input was listed. You'd need a couple 100ah 12v batteries for that much power and a 2,000W inverter.

 

[wayne49]

Microwave ovens need an inverter that has twice the wattage of the microwave according to the instructions from the microwave manufacturers.

It's a trap, where lower wattage means longer cooking times, higher wattage, shorter cooking times. In the end it uses up a lot of AH, either way.

I switched to having hot meals in midday, when there is enough solar still available to replace the energy.

 

[jasper]

This is directed at those that don't already know this.

Watts gets almost all the attention. Amps (current flow) is much easier for me, and amp flow is the basis for most all other electrical measurements. Anyone using solar, battery, and inverter (120VAC), needs the capability to measure amps, and notice on a device's label how many amps are required. If amps aren't shown, use watts divided by 120v equals amps required.

However many amps your 120vac load requires, your inverter to change the 12vdc to 120vac requires more than 10 times that amount of current (amps) from the battery to power your AC device. 120v divided by 12v equals the 10x multiplier.

A 2000 watt inverter will power things that don't require heavy start-up surges about the same as a 15 amp residential wall outlet.

Multiplying that 15 amps times 10 results in 150+ dc amps from the battery to provide that 2000 watts. How long can your battery provide 150 amps? How big are the wires feeding your inverter from the battery?

Time flies. I bought my first 2000 watt inverter over twenty-five years ago, to power 120vac power tools from a vehicle's battery. It still works.

After about ten years experimenting with toaster ovens, microwaves, electric skillets, short term air conditioning, etc, I basically gave up on large ac loads, even with 400 watts of solar, deep cycle and lithium batteries. It takes effort, skills and dedication to develop and maintain your own miniature power grid. Large amounts of DC current can really tax your system and create problems.

In my case, it's also about space saving. Giving up those electrical things provided more space in my van. Using a fuel based stove for me is more efficient, allows for inside heating while cooking, and outside cooking when possible. I use two small pressure cookers as energy savers.

An induction hot plate is next on my list to try. Thanks for the above info on them.

 

[bullfrog !]

In my opinion the technology just isn’t quite there yet as most just don’t have enough roof space for the amount of solar required or the money for batteries. The EcoFlo Delta 2 did solve some of my electrical needs this past year by decreasing the amount of time I run my generator by half as well as extend the life of my old lead acid batteries probably at about the same cost as replacing my old system with new less the labor to install the new. All I had to do was simply connect it to my system. Much easier than redoing everything with new technologies. The more room you have for solar the better but unless you have new technology batteries or a generator you will eventually run down the batteries too much too often and end up prematurely replacing them which gets expensive. Even if you can afford the new technologies you still need the roof space for panels or you will occasionally find times you just can’t get enough solar for large loads.

 

[rruff]

Watts gets almost all the attention. Amps (current flow) is much easier for me, and amp flow is the basis for most all other electrical measurements.

It's true that amps are most important if you are looking at wire capacity, but if power and energy are your concern, then the units for that are watts (power), and watt-hrs (energy). An amp or amp-hr is neither power nor energy.

P=V*I ...so you can always covert from current to power if you know voltage.

In this case, a typical LiFePo4 12v 100ah battery will have a 100a max discharge rating, which is 1200W at 12V. Two in parallel would be 200a at 12v, or 2400W. Two in series would be 100a at 24v which is still 2400W.

In my opinion the technology just isn’t quite there yet as most just don’t have enough roof space for the amount of solar required or the money for batteries.

Microwave ovens need an inverter that has twice the wattage of the microwave according to the instructions from the microwave manufacturers.
It's a trap, where lower wattage means longer cooking times, higher wattage, shorter cooking times. In the end it uses up a lot of AH, either way.

Solar on a small rig is certainly precious electricity, but running a microwave isn't a big hit. A couple 12v 100ah batteries is enough. The main thing that could be unusual is the 2000W+ inverter. Good pure sine wave models are ~$250. That's a good chunk of money if you don't need it for anything else. If you use 1400W at the batteries for 5 minutes, that is 125W-hr or only 5% of your battery capacity of 2400W-hr.

That's only warming something up though, not cooking. Here is a test of an Instant Pot: https://www.techradar.com/news/does-an-instant-pot-use-a-lot-of-electricity

"First, we prepared two racks of baby back ribs in the Instant Pot on high for 25 minutes. The pressure cooker took seven minutes to preheat so the total cook time was actually 32 minutes. It used 0.26Kwh of electricity and gave us beautifully succulent and tender ribs falling off the bone."

That's 260W-hr/.9 (inverter eff)/2400, is 12% of your battery capacity. Doesn't seem too bad.

"Alongside pressure cooking, slow cooking is another of the Instant Pot’s multitude of cooking methods. We whipped up a beef chili to find out.
The chili was bubbling away on the high setting in the Instant Pot for six hours and used just 0.31kwh of electricity."

310W-hr/.9/2400 is 14%. Again, not that bad.

 

[BlueMarkOhio]

WHY ? For Us.......a Slow Cooker is a perfect match............................

A slow cooker, especially on low setting, draws a relatively small amount of electricity (watts or whatever) but it does so for a loooooooong time, resulting in a high total energy usage. I'm guessing it is among the least efficient ways to cook per kilowatt-hour.

But it doesn't have to be. If you insulate it really well, it shouldn't need much power to maintain temperature (assuming it actually uses a thermostat). There are many insulated carry bags for slow cookers, which provide a modicum of insulation but probably not a lot.

There are also high insulation covers that are designed to slow cook without slow cooker - You bring the pot up to a boil, then put it into the ultra-insulated bag and it cooks for hours with no added heat. Link follows as an example, not an endorsement as I've never used this particular item. This would be a great DIY project.

https://www.amazon.com/Hungry-Fan-F...ilgating/dp/B01N3LQOQV/ref=asc_df_B01N3LQOQV/

 

[abnorm]

A slow cooker, especially on low setting, draws a relatively small amount of electricity (watts or whatever) but it does so for a loooooooong time, resulting in a high total energy usage. I'm guessing it is among the least efficient ways to cook per kilowatt-hour.

................ low setting,..................loooooooong time,


Low and Slow........Hmmmmmmm......Sounds just like Solar Charging.......Charge/Discharge

Paulette asks:
"What do you do with the excess power after your batteries 'charge'......sell watts to your nomad neighbor ?"

We COOK......


Our favorite 350 watt (120V) slow cooker............use it or lose it

 

[CampingOdyssey]

I was planning on getting a 12v, 200ah or 400ah lithium battery and charging it from my van using a 60a dc-to-dc charger, as well as solar (100watts at the moment but would like to add more).

I was thinking about cooking with my slow cooker. Its 120v and uses 250w of power (that's what it says on the bottom). At my house on the grid, I typically have it on for about 7 hours and it is enough food to last me 3+ days. It seems like the slow cooker would use about 1750 watts of electricity, which would be doable. I'm not sure if my calculations are true to its actual power usage though. Has anyone ever tested one to see how many watts are used while it's on?

 

[Happy Camper]

You can get a kill a watt meter to check consumption. Someone mentioned that some libraries have them to lend out.

They aren't expensive, and are on sale for the weekend apparently.
https://www.harborfreight.com/search?q=kill a watt
Looks like Amazon has similar devices for less. But I hear kill a watt recommended here almost exclusively. Others will have more experience with them