on the possibility of all electric cooking
I’ve been experimenting with cooking everything from excess solar power
the numbers
Since I moved into the van in 2018 my solar harvest1 has been about 1.76kWh/day, which included use of crockpots and other forms of cooking opportunity loads.
When I installed the new controller I observed improved performance under marginal conditions. This led me to be a little less careful with power and average consumption went up to ~1.9kWh/day. Less careful might mean leaving lights on, tv on, not being aggressive about putting the laptop into suspend, etc.
For the past weeks I’ve been experimenting with doing as much cooking as possible off solar power rather than propane. The biggest change for me was early morning use: coffee, breakfast, heating water for spongebaths. My consumption in this mode has increased to ~2.5kWh/day and the solar is still loafing.
In bad weather mode I reduce power consumption to the essentials and only require 1.0kWh/day.
how much insolation does 2.5kWh require?
Since my system is 750w (0.75kW) and my overall efficiency is ~0.85 we can back into the hours of Full Sun Equivalent required:
2.5kWh / 0.75kW / 0.85 efficiency = 3.92 hours of FSE
3.92 is easy to get everywhere I camp in spring, summer, and fall. Only winter is iffy.
when it will be possible
On the right is a charge of average insolation in my winter base, by month. We can compare this against requirements to see in which months on average I will be able to get away with all-electric cooking.
| demand | FSE required | months available |
|---|---|---|
| 1.0kWh | 1.57 | all year |
| 1.76kWh | 2.76 | all year |
| 1.9kWh | 2.98 | all year |
| 2.5kWh | 3.92 | January - November |
| 3.7kWh2 | 5.8 | March -September |
I plan to be at winter base November - March; my next post will be about this plan. I’ve included the other months in the graphic and table for completeness, but it would be too hot to be there from late spring to early fall.
There’s also the possibility I might prefer to cook over propane in cold months for the warming effect in the van.
my previous array
My original array was 570w, which would require 5.16 hours of FSE to make 2.5kWh/day. so March-September.
follow-up
March 2024
After almost a year of data collection it appears it only requires 2.25kWh for me to do all cooking off solar (including brewing coffee), not 2.5kWh as I previously ballparked. So let’s adjust the numbers.
ok, how much insolation does 2.25kWh require?
Since my system is 750w (0.75kW) and my overall efficiency is ~0.85 we can back into the hours of Full Sun Equivalent required:
2.25kWh / 0.75kW / 0.85 efficiency = 3.53 hours of FSE
The end result is still the same: 3.53 is more than the 3.34 available in my wintering spot, but it’s closer. The shortfall is 190Wh
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