Background: Emergency preparedness.
I’m in the middle of repurposing some old backpacking equipment into a set of bug-out bags (Post #1620). To me, the big surprise is that mass evacuations in the U.S. almost always generate horrendous, days-long traffic jams.
You can pretty much bet on it. Which means that you ought to be prepared for it. Which I was not. As a result, my most pressing need wasn’t for camping gear per se. It was for the supplies that would allow me to live in my car for a day or two.
Basically, to be prepared to bug out, in an urban area, I need a mini-#vanlife kit. Ideally, without spending a fortune, and without having to replace critical supplies every year. (Because I’m not that organized, and I’ll forget to do it.)
It’s not rocket science. You need to take care of water, food, warmth (maybe), and sanitation (maybe).
In my last post, when I looked at options for the critical sanitation category, I found plenty of good choices for #1, but not such great options for handling #2. In both cases, I’ve gone with some version of special-purpose plastic bag lined with super-absorbent gel. I picked this and this, for starters, both of which I expect to last indefinitely and be once-in-a-lifetime purchases.
Research reveals some constraints on food choices for an emergency kit kept in the car, driven by the harsh environment of the car’s interior. Some mainstays of camping (e.g., chocolate bars) are obviously inappropriate. Less obviously, experts frown on most canned foods and high-fat foods because the heat and freeze/thaw lead to rapid deterioration. Even foods packaged for stability, like MREs. In particular, the “best used by dates” of those foods cannot be trusted, if kept in a car, because those dates assume the foods were kept at normal room temperature, not at the often blistering-hot temperature of a car interior.
So I’m putting together a little kit of dried foods. Starting with a brick of true emergency rations and some emergency food bars. Both of those ought to last five years, even if kept in a car. And then I’m adding things any camper would consider, and that have exceptional shelf life. Or at least won’t kill you, even if they don’t taste so hot after a decade in the car. These include ramen noodles, oatmeal, dried potato flakes, maybe some tea, and coffee, hot chocolate, and other dry foods.
But this brings up a new need. My ability to eat anything tasty, out of that emergency stash, depends on my ability to boil water in the car. I expect that the emergency ration bars taste awful, and while you can, in theory, just cold-soak ramen noodles and potato flakes, nobody claims that the results are palatable.
And that’s when I started running into the tyranny of physics.
Pick an option for boiling water in the car: Asphyxiate, spend tons of money, electrocute, void your new car warranty, or wait a really long time.
The task is to come up with a modest amount of boiling-hot water, on demand, as the car is creeping along the freeway.
Seriously, how hard can that be?
Asphyxiate. First, I’m going to rule out any traditional flame-based camp stove. Even clean-burning fuels like butane. Burning anything in an enclosed space is just a bad idea. Couple that with notion that a) you’re going to be doing this while in dense traffic, and b) whatever fuel you use, it’s going to get stored long-term in the car. Aside from Esbit — of which I am a fan — I can’t think of a refined stove fuel that I’d even consider keeping in a hot car in the summer.
Spend tons of money. Second, there are cooking systems that rely on exothermic chemical reactions. You chuck a packet of chemicals into water or salt water, and the resulting chemical reaction generates the heat to cook your meal. These include Army MRE heaters as well as commercial systems such as Barocook. The only downside here is the expense. Near as I can tell, it would cost me a $2 disposable every time I wanted to heat up a cup of water for tea. And you should ideally buy the right equipment first, the sole use for which is to heat foods with these chemical heaters.
So, those would work, and those will keep indefinitely. But there’s a lot of dedicated equipment and expense, and I would never get any utility out of them except as a component of this car emergency pack.
Third, seriously, it’s an electric car. The motor/generators can put out tens of thousands of watts of power. Why not just plug in an electric kettle/coffee pot and be done with it? That’s where the choices boil down to electrocution, voiding the warranty, or waiting a long time.
Electrocution: Although the Prius Prime can literally run on electricity, Toyota didn’t think to bring much of that inside the cabin. The power sockets (“cigarette lighter sockets”) on the Prius interior are rated for a maximum of 120 watts. The upshot is that if you plug in an inverter and a typical home electric kettle, you’ll instantly blow the blow the fuse on the power socket. A typical US home electric kettle draws 1500 watts.
In fact, that’s so little power than you can’t even run this device:
Source: Ebay.
The Kenner Easy-Bake toy oven above draws way too much wattage to be used inside a Prius Prime. “The original Kenner Easy-Bake Oven was heated by two 100-watt incandescent light bulbs, …” (source: Wikipedia).
Heck, I already own one of these little immersion heaters:
And even the lowest-power version of that device draws far too much power for the Prius power outlets to handle.
Void your warranty. There’s an obvious way around this, which is to wire up a socket or an inverter directly to the battery (fused, of course). That way you could use much heavier wire, draw more current, and use an electric kettle capable of heating a pint of water in a reasonable amount of time. Even then, as discussed in Post #1020, you probably wouldn’t want to exceed 1000 watts. That’s the size of inverter I hook up, when I used my older Prius as an emergency generator.
That said, on an almost-new car, still under warranty, with a rather delicate 12V electrical system, I’m not sure I want to attach cables to the battery. Let alone try to find a way to get them through the firewall. For fear that if something goes wrong in the 12V electrical system, the deal will point to the modifications as an excuse not to fix it under warranty.
So while I have no problem hooking up a 1000-watt inverter to our long-out-of-warranty 2005 Prius, I’m not quite comfortable doing that with my wife’s 2021 Prius Prime. Particularly not as a permanent install, to be ready in case of emergency evacuation.
Wait a really long time. At this point, all remaining electrical solutions fall under the tyranny of physics. If you input few watts, the water heats slowly. And there’s no way around that. That’s just basic physics.
If you want to heat a pint of water from room temperature to boiling, using the limit of 120 watts, assume zero losses, and assuming you don’t blow the fuse on the power socket, that will take you 22 minutes.
That said, of all the ways I could heat water in the car, a little low-powered cup-sized electrical heater seems to make the most sense. For one thing, if I’m using it while stuck in a traffic jam, I’ll have nothing but time. For another, I can actually use that on normal road trips to make a fresh cup of coffee or tea. So I will get some utility out of it, beyond its value in an emergency. For a third, they are designed to fit in a car’s cup holders, which would be handy if I’m going to use one while stuck in traffic.
When all was said and done, I ordered one of these:
Source: Amazon.
This is an 80-watt device that should be able to bring 12 ounces of water to a boil in about 25 minutes. That’s far enough below the power socket’s limit that I don’t risk blowing a fuse. That’s enough boiling water to cook at least a single serving of ramen noodles. And if I’m stuck in the car for 24 hours, the 25 minute wait will just give me something to look forward to.
Conclusion
For emergency rations to be kept in the car, experts say that a lot of your normal choices for emergency food are off-limits. Canned foods, high-fat foods (including nuts), and MREs are all poor choices due to their rapid and unpredictable spoilage rates when subject to high temperatures and freeze-thaw cycles.
For my car kit, I am going with some ultra-stable commercial emergency foods, and a selection of dried foods and beverages. The latter require me to boil water, in the car, possibly while moving in extended stop-and-go traffic. After looking over my options, to boil water I’ve decided to go with the simplest plug-and-play setup I could find. For the Prius Prime, that’s a small (12 ounce) low-wattage (80W) water heater built to sit securely in a cup holder. The sole downside is that, assuming it works perfectly, it’s going to take roughly half-an-hour to bring 12 ounces of water to boiling.
Seems like a lousy choice. Until you realize that all the other choices involved significant risks (flame-based cookers), expensive disposables (MRE heaters and similar), or blown fuses or possibly a blown warranty for higher-powered electrical devices.
