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cooking with excess electrical power
Cooking and heating water with electricity off-grid is usually impractical but there are exceptions. In some cases the relatively large power loads can be used without affecting house battery1) state of charge:
gear
In general DC power3) is used for warming or very slow cooking. Part of this is due to the limits of cigarette lighter outputs, typically 120w (10A x 12v). The “catch-22” is that most people don't drive their vehicle sufficient hours to do real cooking off DC.
Higher power is common with AC devices but one must have the power to run it, and to recharge the battery bank afterwards.
DC
heated mugs can be used to keep beverages hot, or heat small amounts of water for tea, coffee. Warm canned soup, etc. Example:
Wagan heated mug (12v/
24w).
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AC (inverter)
[personal note from secessus: Electrical appliances like crockpots are plentiful and cheap at thrift stores. Check the wattage on the bottom/label. Removable crocks are somewhat less important in a vehicle context since we have no dishwasher to remove the crock to.]
Note: instant pots typically require more power than vehicle-dwellers have on tap, but it can be done if one understands the issues.
. See below for alternatives.
Normal sized
crock pots typically take 125w-200w on HI and half that value on LO. Example: Example:
Maximatic slow cooker (
170w) and
Courant 1.5qt slow cooker (
120w) with WARM/LO/HI settings.
Some
mini crocks have only one setting around 60-75W. Example: Tru stainless 0.65qt mini crock (
40W).
Large
5) domestic crocks can take 300w+ and also a lot of space.
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crockpot vs instant pot
Instant Pot advantages:
much faster cooking times possible
temperature control (heating element runs as needed)for more accurate cooking and reduce power consumption
better insulation will likely reduce power consumption
pressurized modes will result in consistent cooking at high altitude
Crockpot advantages:
much lower cost, particularly if bought used at thrift stores
much lower current demand (150w vs 1000w), which means a crock can run on components that cost 1/6th as much
analog crocks (physical controls, no digital components) run happily on inexpensive
MSW inverters
also see this post
breaking the 10A barrier
Ciggy outlet power is typically limited to 10A (~120w).
If you wanted to extract more power from the alternator you could wire in an isolator (plain solenoid or VSR). Instead of feeding an auxilliary battery this isolator would be used to pull more current into the living area. You could run 12v loads directly, or attach an inverter's input wires to the isolator's outputs.7)
further info
techniques
Power/time saving
Preheating water on the dash or elsewhere
heating only the required amount of water
reducing power level after reaching a boils (ie, reduce power to simmer)
covering pots while heating
pre-soaking beans (overnight) rice (up to an hour), etc
Cleaning
use parchment paper, foil to line crocks
lightly oil crocks before cooking to reduce sticking
immersion heaters might best be used for heating plain water, as the loops can be difficult to clean
resources