Disaster Strikes! How to Use an EV To Keep The Lights On

When I bought my chest freezer, I started to accumulate a lot of frozen meats and other things that began to add up in value. The total stock of just our chest freezer frequently exceeds $1,000. More if you include precious breast milk (shout out to you moms and dads out there who get it). A long term power outage, in our area, seems to be one of the worst case scenarios that could affect our refrigerables. So, I set out to figure out a way to mitigate this issue…

The Pure Sine Wave Inverter

Enter, the pure sine wave inverter. This nifty little device takes direct current (DC) power and converts it to alternating current (AC) power. Why is this such a big deal? It’s not just the name of the band. To start with, DC power, like the power that comes from your car, cannot power normal household devices, which run on AC current. I am not an electrical engineer, but I will still paste the following graphic into my post to make you think I know what I’m talking about:

What I’m trying to distill for you, my dear reader, is that DC power (the top graph) is different than AC power (the bottom graph). There are converters out there that change one to the other. Importantly from my perspective, there are converters out there that change one to the other better than others.

There are regular sine wave inverters, and then there are pure sine wave inverters. The difference is mostly apparent if you’re trying to power a something that requires a motor or other sensitive electronics (like a refrigerator, microwave, newer TV, or medical equipment like a CPAP) versus trying to power non-motored or non-sensitive equipment (like phone chargers, laptop chargers, lights, etc). Regular sine wave inverters can damage these sensitive devices, whereas pure sine wave inverters produce a cleaner current that allows them to function without issue.

Since I wanted to ensure we could power anything our little hearts desired during a power outage, I opted to purchase a pure sine wave inverter. Better to cast your net too wide than not, right? I also knew I specifically wanted to be able to power the three fridges/freezers in our last house, so a pure sine wave was the way to go.

Some Background Considerations

So, what did I get, and what should you get if you’re thinking about implementing this to boost your resiliency? One consideration I read about was the ability of my old electric vehicle (EV), and any car, for that matter, to produce the current necessary to power the inverter. It read as if the 12V accessory battery (your normal old car battery, even if you have a non-EV) might have its fuses tripped if you stress it over 2000 watts. If this happens, apparently it’s not terribly easy to replace them. They are fuses, after all, not breakers like you have in your house. If blown, they require replacements. Yuck.

We’ve now established that your pure sine wave inverter must not exceed 2000W. I’ll now tell you that inverters are typically rated to provide two different currents: constant load and surge load. Take a refrigerator as an example: A normal household fridge might run normally at 750 watts. However, when the compressor kicks on, momentarily the wattage might surge to 1500 watts. Strangely, at least to me, this only lasts a split second. If you purchased an inverter that was only rated to 1000 watts, however, it would shut off when the compressor kicked on. Womp womp!

This shows that you need a pure sine wave inverter that has a base load that covers your needs but will “surge” to allow you to not blow your inverter when your appliance kicks on. I went with a 1000W/2000W inverter, which provides 1,000 continuous watts and will surge to 2000W without shutting off. This accommodates all of my fridges, freezers, and normal household appliances if necessary.

My Setup

The inverter I bought years ago, which is available for much less money today (~$150), is this one (<—AFFILIATE LINK). It is a 1000W continuous, 2000W peak. Additionally, (and I know this is a pain in the ass), you have to buy cables to accompany it because the ones that it comes with are big pieces of crap and super short.

I bought these beauties (<—AFFILIATE LINK), which are massive-gauged wires with alligator clamps. The alligator clamps are important because they will fit onto any car battery configuration your car might have. If you’ve not seen a lot of car battery terminal hook-ups, please trust me when I tell you there are some weird ones out there and that these badass alligator clamps will accommodate most anything on the road.

How-To

Hooking this system up is relatively easy and can be done to pretty much any car out there that has a 12V battery. With your car off, simply attach the cables to the inverter, then alligator clamp them onto your 12V battery [Red (positive) first, then black (negative), ALWAYS IN THIS ORDER; when disconnecting, reverse the order]. Start your car’s engine (or drivetrain battery if you have an EV), then turn on the inverter switch.

From there, you can run an extension cord to whatever appliance you want to power, so long as it falls within the wattage range of 1000W (this is almost everything). You can also power multiple appliances at once (lights, chargers, TV, internet modem and router, etc.). When I first got this setup, I ran our household fridges for an hour and only used up about 1 percent of my old EV battery, which was only 24KW!

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Benefits of Using an EV for Backup Power

A really beautiful aspect of owning an EV is that I can hook this inverter system up to my car in the garage with no sound and no emissions whatsoever and power what I need to in the house. There are a lot of rural preppers out there who are fine to just fire up their generators, but I’m in the suburbs. This kind of thing gets noticed if your car is sitting out in your driveway idling with wires running into your house! It also helps in the event there is inclement weather and I can have my car turned on in the nice dry garage without having to worry about fumes or noise. 

Beyond the obvious increase in household resiliency, this setup could also be helpful for tailgating or camping. However, for most of those applications you can get a much cheaper, simpler, lower-wattage solution. I bought this 300W inverter (<— AFFILIATE LINK) years ago to use for lighting, blowing up an air mattress, charging my laptop, and charging tools while camping. Your needs may vary, but it has been great for us and was less than $40. If you want to go bigger and power a TV or something similar, the pure sine wave inverter is the way to go.

Final Thoughts

As I’ve written or alluded to many times before, resiliency and preparedness are good things. This nifty setup helps harness your car for use as a generator. If you have an EV, it leverages a giant battery asset that you already have, which is much larger than what you could easily afford through battery banks from Jackery or GoalZero. 

Hopefully, in the future most EVs will be sold with Vehicle-to-Grid (V2G) capabilities (which is kind of what I outlined here, only much better).* Imagine plugging your car in to charge in your garage and your battery could power your entire house in the event of a power outage. That would include your A/C, heat, water heater, oven/range, everything. Ford’s introduction of the new EV F-150 included a smaller backup capability like this, which is heartening. Hopefully manufacturers will start to equip their vehicles with options like this even more in the future. Then, this whole charade I’ve gone through will be obsolete!

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*For more about V2G, check this out.