How does it compare to direct solar cooking?
How to build a solar powered electric oven
21–30 of 55 posts
Re: How to build a solar powered electric oven
#22Great project and build. I wonder if using a small fan would not help energy transmission, which is eventually the goal of cooking. It may also make the oven work like it’s at higher température while not consuming much energy. It would discharge energy from the walls faster using convection in addition to radiation.
Plus, you can experiment with tray materials depending on what you want to cook.
Suggestions inspired by my experience with convection/classic oven and copper pizza plates
https://www.italiancookshop.com/products/hammered-copper-rou...
Re: How to build a solar powered electric oven
#23>lower cooking temperature of about 120°C
At what point is it easier to just use a microwave? For all the effort to biuld an insulated box, a small microwave consumes maybe 600w, easily doable with batteries and an inverter. Microwaves also get hotter (useful if you want to do more than poach food at 120c).
Actually, forget the inverters. It turns out loads of 12v/24/48v microwave ovens exist for the RV market.
Re: How to build a solar powered electric oven
#24This is fun, I'm curious to try it. An alternative that I experimented with and found to be very usable is one solar panel, a small camping battery ("portable power station"), and an Instant Pot. The total cost is not super high. The Instant Pot is power efficient and can cook a lot of food at once. Since it's battery powered you can start any time the battery is charged.
There are now commercial ovens with LiFeO4 batteries in then that do basically just that. Except they're stupid expensive.
I don’t understand why people go this direction when propane-powered appliances are so much more appropriate. Much cheaper, readily available fuel, a few minutes to “reload” vs multiple hours to recharge the battery.
Similarly, I think there’s a niche market for a propane-powered espresso machine.
Re: How to build a solar powered electric oven
#25>lower cooking temperature of about 120°C At what point is it easier to just use a microwave? For all the effort to biuld an insulated box, a small microwave consumes maybe 600w, easily doable with batteries and an inverter. Microwaves also get hotter (useful if you want to do more than poach food at 120c). Actually, forget the inverters. It turns out loads of 12v/24/48v microwave ovens exist for the RV market.
>useful if you want to do more than poach food at 120c
Slow cooking almost always gives you excellent results with vegetables, meat or fish. There is already a market of crokpots, sous vide and steamers, that I wouldn't dismiss as "poach food".
And for things like a pizza or crispiness in general, that need higher temperatures, I doubt you can get decent results with a microwave.
The usual 180°C / 350°F set has more to do with convenience (highest temperatures that doesn't burn the outside before the core is cooked) for cooking things as quick as possible, than tastiness of the food.
Re: How to build a solar powered electric oven
#26This article references a 2023 article about lithium battery costs with price at 750 EUR per kWh (approx 12V 100Ah) for 30 years life couting 3 replacements if I read correctly note 5:
https://solar.lowtechmagazine.com/2023/08/direct-solar-power...
These days 1 kWh of LFP battery is 70-150 EUR depending on the brand, so far lower than referenced. And LFP cell lifetime is probably 20 to 30 years.
In a system it means that 1 kW of solar PV panels is about the same price as 1 kWh of battery, and similar lifetime.
Re: How to build a solar powered electric oven
#27Earlier quoted context omitted.
There are now commercial ovens with LiFeO4 batteries in then that do basically just that. Except they're stupid expensive.
I don’t understand why people go this direction when propane-powered appliances are so much more appropriate. Much cheaper, readily available fuel, a few minutes to “reload” vs multiple hours to recharge the battery. Similarly, I think there’s a niche market for a propane-powered espresso machine.
I can charge any battery powered appliances like that at home. Propane is only sold per bottle, not every petrol station has them(in fact - majority don't), you have to rent the bottle each time, the thing is stupidly heavy and has various restrictions on storage(can't park a car with it in an underground garage for instance, my insurance does not allow me to keep it inside my garage etc). Battery powered is just so much easier unless you're using it commercially and go through a lot of gas I guess.
Re: How to build a solar powered electric oven
#28Even if insulated, isn’t this setup always heating the home? The insulation slows down the heat transfer but if I’m following correctly it’s basically running the heat element anytime the sun is up. I think this would be counterproductive in my climate as I’m cooling the home most of the year which is an even more energy intensive process
Stick it in the balcony then?
Re: How to build a solar powered electric oven
#29Very neat. I guess what you cant do is cook a lot of food. The food needs to be in there a while and adding cold food takes energy out of the system which is say 0.8kwh per day. So like 20 minutes of microwaving a day of power. You probably need 2 or 3 for a family.
Re: How to build a solar powered electric oven
#30Why do the images look like someone took pictures of dotmatrix printer output? --- Update: for whatever it's worth, I just asked the Magic 8 Ball (Perplexity): Low-tech Magazine uses the option to display images as dithered primarily to reduce the energy consumption and data load of their website. Dithering is an old image compression technique that reduces the number of colors in images to just a few shades of gray…
This feels (needlessly) performative. I get the idea, but the low quality images make it harder to understand what they are showing in the photos, which makes it harder to then reproduce their work.
I suppose the vast majority of users will not need the higher resolution, so perhaps have it be a toggle to get the higher-resolution when needed.