What do you need to run a 1800w oven?

[johnny b]

Yes you can draw down lithium to 10 -20%, so maybe reduce the system size a bit.
But you're still looking at a 'non portable' scenario with say 600 watts on the roof.
But if that oven draws 1800 watts, that is 165 amps at 12 volts (150 + 10% inverter loss).
You're still looking at a difficult system to build and maintain (as your first).

That's why most folks on the road in small vehicles cook and heat with propane; and use solar for the lesser power needs.

 

[John61CT]

No portable power pack you can recharge at the coffeeshop has enough AH to power the kind of loads you're talking about.

And a quality LFP bank costs more than 4x, you're talking thousands.

Get away from using electricity as much as possible.

Just running a fridge in a city you should have a couple hundred pounds of lead, maybe $400 is cheapest.

You'll want a little quiet genny as well as solar.

 

[kllcbosmetris]

No portable power pack you can recharge at the coffeeshop has enough AH to power the kind of loads you're talking about.

Agreed. I think those portable battery packs are capped at 1000w or 1500w max. One of the reviews said Kodiak Inergy was expandable and able to serial or parallel (can't remember which one) added to an existing system. [I figure cheaper Chinese version of those could do the same]  so I thought I can charge the stationary system as much as I could (from solar) and then make up the difference with the extra plug-in-at-office battery I carry around during the day. Is that feasible you think? It is like charging the battery with solar + vehicle driving around via battery isolator or alternator switch + plug-in-portable battery pack.

 

[tx2sturgis]

P.S. Why do we need double the solar panels? Do they have 50% efficiency in charging or something?

Since terrestrial solar panels only put out the rated power, more or less, for a few hours a day, unless they are movable, you get a lot less power for the other daylight hours and of course none at night. Even movable panels that track the sun produce a lot less power during shading and cloudy days.

So in your calculations, you have to account for less total power produced in the course of a 24 hour day.

Think of the power rating of a panel in a similar way that we think of horsepower ratings of engines. You can get all of it for a little while, but only in specific and rare cases can you get ALL of that power ALL of the time.

 

[John61CT]

And with the shading conditions of most *cities*, I think probably lucky to get even 10AH/day per 100w of panels.

Driving around needs to be for 6+ hours a day with a lead bank. Another big point for a LFP bank, but man, we really are talking thousands for even a small bank.

Nope, little gennie + solar.

Or find places let you plug your van into mains power overnight.

Paid parking?

Otherwise, lowering consumption will be the key to making this work.

You want a 12V fridge right?

 

[highdesertranger]

here's my pat answer, I always say this. heating anything with electricity is very inefficient, no matter the voltage. highdesertranger

 

[tx2sturgis]

HDR, we need to be on the same page when this topic comes up.

Electrical heating elements are almost always 100% efficient. 1000 watts of electrical power in to the element will always yield 1000 watts of heat energy produced. Unless they emit light also, then the efficiency does drop just a tiny bit, maybe less than 1% for most heating elements. This a fundamental principle of physics, not something I just made up.

The inefficiency in electrical heating is always at the source and/or in the transmission from the source. And, like any stove or burner, in the case of an oven, there will normally be a loss of heat to the surrounding environment.

Heating with electricity is not only 100% efficient at the load, but things like electric water heaters are MUCH more efficient than gas water heaters, since 100% of the energy input is conducted to the water in the tank. Gas water heaters lose a fair amount of heat energy in the flue pipe and the standby losses are much greater than an electric water heater.

Now, depending on the cost to produce that energy, the cost-effectiveness is a much better way to look at this.

How much will it COST to get the desired amount of heating?

In the case of this 1800 watt convection oven, on solar power, the cost is WAY too much.

 

[John61CT]

All the inefficiency of electricity may be eliminated at the consuming device, but the upstream production, delivery and (in our case) storage has plenty.

Efficiency is not so relevant to me.

What is important is, my system's capacity to produce, not at peak but average/poor conditions

and capacity to store/carry,

as opposed to my consumption **needs**.


People coming from unlimited S&B are usually completely unaware of just how limited the former is, and how often we need to compromise on the latter.

Wants are not needs.

Yes you *can* set up a system that allows you to cook or heat your space with solar electricity.

Jusy like using battery powered A/C, once the factors required to do so are made clear, most people realize it is not practical, not in line with their other priorities once they've learned and accepted the harsh realities.

Yes sometimes efficiencies play a part, like my preference to avoid using an inverter whenever possible.

 

[highdesertranger]

in the chain does it really matter where the inefficiencies lie. you are correct that the heating element itself is ALMOST 100% efficient but making the power and getting it to the element is where the loses are. a lot of people don't realize this because they don't realize how much electricity they are actually using in a house. highdesertranger

 

[Weight]

There is no debate to ring true. The 1500 watt appliances can only operate for a few minutes on the inverter. Then you need a large battery bank for even that. My two slice toaster takes 3 minutes for my morning bread. Coffee pot takes about the same for my pint of coffee. The microwave is less than 15 minutes on a long day. My 690 amp hour bank is the smallest I would recommend for this load. The portable butane stove is very convenient for cooking everything else. At home we have the convection counter top oven. The least time cooking is 30 minutes for most anything except toast. 30 minutes at 100 plus amps would send my battery bank into heart failure.

 

[John61CT]

Very few vandwellers use any kind of stove.

 

[Trebor English]

If I use a Goal Zero Yeti or Kodiak Inergy type of compact lithium battery pack (instead of a full stationary solar set up w/ inverters) there won't be any (10-30%) loss, correct? Though I am not sure if they would power 1800w appliance. Probably not.

The battery pack devices are a battery and an inverter in the same box.  The common box does not grant them immunity from physics.  The battery must be charged.  The charge / discharge cycle is less than 100% efficient.  The conversion of low voltage DC from the battery to 120 volts AC is less than 100% efficient.  

Lithium can be more efficient than lead.  Inverters are not all equal.  A 2 kilobuck price could yield an improved system.  The price does nothing in the recharging department.  Each watt hour taken out must be preceded by a watt hour plus some put in.  That means you need a gasoline engine turning a generator or a solar panel.

 

[jimindenver]

Y'all are soooo funny.

Is it easy? No

Is it cheap? No

Does it take a lot of real estate? Yes

Does any of that mean it is not possible? Not a chance.

To the OP

If you want to talk big solar and see what it can do on a day to day basis, stop on by my rig in Quartzsite or Ehrenberg, I will show you what is possible in real life. Is it inefficient to heat with electricity? That depends on how you look at it. I have power coming out my ying yang most days and it would be inefficient if not stupid to burn propane don't ya think?

The difference between now and when I started is that were no voices saying it is possible at all, There were only the naysayer's that didn't understand enough about solar or could not conceive how to do it because no one told them it could be done or there was no place on the net to read and regurgitate it. So it could not be done and don't even try it. Some, possibly most didn't even have solar at all and really had no practical experience to be saying what they do. Five years down the road things have changed a bit because of people like me that didn't listen. We are self taught because there was no one to even say it was possible much less explain how to do it.

So don't fall into the trap of OMG it can't be done. You want to run a oven then work out the numbers, price out the gear and see for yourself if it works for you. You want help, ask someone that has done it because if no one pushes the boundaries, nothing ever changes.

 

[tx2sturgis]

Is it easy? No

Is it cheap? No

Does it take a lot of real estate? Yes

Does any of that mean it is not possible? Not a chance.

To the OP

If you want to talk big solar and see what it can do on a day to day basis, stop on by my rig in Quartzsite or Ehrenberg, I will show you what is possible in real life.  Is it inefficient to heat with electricity? That depends on how you look at it. I have power coming out my ying yang  most days and it would be inefficient if not stupid to burn propane don't ya think?

But also: is it practical compared to the alternatives.

There are few cheap alternatives to cooling the inside of an RV in the middle of nowhere. But there ARE good alternatives for heating a piece of toast or a frozen pizza.

Any yes, my point about inefficiency is: it depends on a lot of things, and low efficiency is NOT a reason to not do something.

Solar panels are terribly inefficient, around 20% but we use them anyway.

Internal combustion engines are terribly inefficient, around 25%, but we use them anyway.

Incandescent bulbs are terribly inefficient 10-30%, but we use them anyway.

COST is what matters. (and weight)

I would not put together a $10,000 solar system just to cook pizza or heat frozen dinners twice a day. A lot of cheaper alternatives are better for that job.

I certainly MIGHT spend the same money to keep me comfortable in my home 9 hours a day in mid-summer heat. And then I might have surplus, as you do, to run a coffee maker or a toaster for a few minutes per day. Easy peezey.

As far as efficiency, who really cares if the efficiency is low, if the price for the incoming fuel or energy is cheap or free?

That's why we didn't care when our 1965 Buick got 9 miles per gallon in the late 60's since gas was only 30 cents per gallon...remember those days?

But today, gas is nowhere near that cheap here in the USA. Again, cost matters.

One note to be aware of: The OP is trying to do all of this in a Metris, I believe, not an RV with lots of real estate for panels.

 

[lenny flank]

If you want to talk big solar and see what it can do on a day to day basis, stop on by my rig in Quartzsite or Ehrenberg, I will show you what is possible in real life.  

Somebody told me that you haul a nuclear reactor around with you....?   

 

[John61CT]

Yes, a **small van** parked **in a big city** was the context I was working with.

Not to mention the "portable powerpak I can charge while having a coffee at Starbucks."

I did not notice anyone saying anything's impossible, just in order to have X you may need to do Y.

Just giving the various constraining factors that make things difficult and perhaps more expensive than OP is willing to spend.

Assuming solar doesn't work for a moment, is using electric to cook worth carrying a genny and using it in a big city?

Only the OP can answer that.

 

[kllcbosmetris]

Y'all are soooo funny.

Is it easy? No

Is it cheap? No

Does it take a lot of real estate? Yes

Does any of that mean it is not possible? Not a chance.

To the OP

If you want to talk big solar and see what it can do on a day to day basis, stop on by my rig in Quartzsite or Ehrenberg, I will show you what is possible in real life.  Is it inefficient to heat with electricity? That depends on how you look at it. I have power coming out my ying yang  most days and it would be inefficient if not stupid to burn propane don't ya think?

The difference between now and when I started is that were no voices saying it is possible at all, There were only the naysayer's that didn't understand enough about solar or could not conceive how to do it because no one told them it could be done or there was no place on the net to read and regurgitate it. So it could not be done and don't even try it. Some, possibly most didn't even have solar at all and really had no practical experience to be saying what they do.   Five years down the road things have changed a bit because of people like me that didn't listen. We are self taught because there was no one to even say it was possible much less explain how to do it.

So don't fall into the trap of OMG it can't be done. You want to run a oven then work out the numbers, price out the gear and see for yourself if it works for you. You want help, ask someone that has done it because if no one pushes the boundaries, nothing ever changes.

Thank you for your encouraging words. One of the most common things a newbie DIYer experiences is to realize it is too complicated or hard or nearly impossible to build a sustainable set up like you originally imagined. I'd hate to give away this multipurpose machine just because I can't power it in the van.  At this point, I'll buy a Kilawatt and see what it draws I guess. I'm looking to maximize the roof to see if I can have max solar possible. Even looking to find that new technology people talk about where thin tint like film used on windows producing solar. I'll keep you updated.

 

[jimindenver]

That is why I said check it out, run the numbers and see if it is possible. It is also a good idea to look at all the possibilities including generators or alternate methods of cooking. I could run a lower watt oven a good portion of the day, then again if it is that sunny I will have solar ovens taking advantage of it.

I like to use my system to teach what is possible. It may not be practical or cost effective but it is possible. That is what is important.

Oh and a Metris, I had to look that up. The only way it will be possible is to store the panels in the van until you stop and then pull them out and set them up as portables. I use to do it with 1, 2 and even three big panels. What a pain in the butt and it kept the rig from being usable on the road.

 

[kllcbosmetris]

COST is what matters. (and weight)

I would not put together a $10,000 solar system just to cook pizza or heat frozen dinners twice a day. A lot of cheaper alternatives are better for that job.

Just to clarify, I would not be putting a solar just for this mini oven. I'm trying to see if I can do a full-time so there needs to be some type of solar set up regardless - for charging laptop/phone, electrical needs of Webasto heater, possibly a 30/40 Dometic fridge, etc. I figured why not do everything electrical - just skip the propane and everything else. So, cost of the solar will be a sunk cost here. Is it expensive? Most likely. Can I afford it? Not sure. But I know if I am keeping a van for 10+ years that will be the way to go. That was my mindset. Do it right the first time and have a bit of comfort. Like some suggested I may have to buy a Yamaha/Honda generator as well but I wanted to understand whether I can run this appliance (or anything like this that draws 1500w-1800w) and if so, what do I have to have.

Just as a side note, I do like to keep appliances A/C if I can help it. Why? Let's say you got sick and had to get a hotel for a day or two (or a room/house/airbnb for a month or two). You just move this thing into your room and it works. Health food. Easy transition.

 

[tx2sturgis]

Sure, I understand.

My point was a bit extreme, to make the point.

As far as keeping the oven, most of us here can relate to things and devices that we want to keep. In the case of this power-hungry oven, the cost is going to be high.

Keep in mind that you could sell it, or store it, and in the possible situation of an exended stay at a BnB or whatever, Amazon can deliver a small toaster oven for $50 right to the door of your room. 

There are always options.