Can your EV share a battery capacity with your home battery system?

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This was an idea that I briefly mentioned in another episode, but which I now feel deserves its own video.

Most people drive less than 50 miles per day.

However, we are super concerned with Range for EVs and people are afraid to get an EV with a range of less than 300 miles, even though that range is rarely needed. We are mining rare elements to make a battery capacity that is rarely needed for those that have a convenient place to charge at home or at work. Is a waste of materials, and damaging to the planet for little real benefit. I drive a plugin hybrid with a small 26-mile battery, and I rarely need to use the gas engine. If we only need to drive further a couple times a month, or even just a few times a year, why pay to have that huge extra capacity sitting around unused for the other 99% of the time?

People also are getting battery backup systems for their homes to store the excess energy that their solar/wind systems generate, for when their use is higher than what is being generated.

Why not combine these capacities together so that each household would need less overall capacity, but could utilize the capacity where it is needed?  The vast majority of the time the capacity isn’t needed for the vehicle, and so it would be in the house, but when extra capacity is needed in the vehicle for a longer trip the capacity can be transferred to the vehicle. Once the trip is over the capacity can be transferred back to the home energy storage system.

How could this work? For example, an EV maker could make a vehicle with a smaller 75 mile onboard battery. This vehicle would come bundled with a home battery storage system which has multiple battery modules which can be detached. The vehicle would also have expansion slots where extra battery packs/modules could be connected in. When the vehicle is going to be driven further the user can tell the system the day before to make sure that the packs are fully charged up, and then the packs can be disconnected from the home battery system and plugged into the expansion slots of the vehicle. Let’s say, for example, that each module added an extra 50 miles of capacity and there are 4 of them. That would add 200 miles of range to the vehicle for a total of 275 miles. When the owner is away on a trip less power is going to be needed for the home anyway, and the house is still connected up to the grid in any case. When out on the road the expanded capacity can be charged up at any charging station just like any normal EV. Once the trip is over, the battery modules can be removed from the vehicle and transferred back to the home battery system. This would allow for a greater amount of the battery capacity to be utilized a much higher percentage of the time. This would also be far cheaper as the batteries are the most expensive parts of a vehicle and rather than buying a large capacity in a vehicle and a large capacity for the home, the capacity can be shared.

If someone doesn’t really have the need of a home battery backup system there could be the option of simply buying the vehicle without any extra battery modules. This would make the vehicle considerably cheaper than current electric vehicles, as the battery is so small. If a longer trip will be taken, battery modules could just be rented by ordering from an app and the user can have them shipped to their home, or just stop by a dealership and pick them up, just as they’d normally stop by a gas station to fill up before getting on the highway. This would also provide the dealerships or car companies an ongoing source of income even after the vehicle is purchased. That could be especially beneficial for the dealerships as a way to make up for the fact that EVs tend to require less maintenance than their internal combustion counterparts.

As I mention in my other video on electric cars, there could eventually develop a whole network and system of stations where users could swap out spent batteries for freshly charged ones, but that is much more long-term, and not really required to make use of this model.

Overall this idea is a way to make much better use of the battery capacity we have, as well as a way to make the transition to electric vehicles and home energy storage much less of an upfront investment. Buy one battery capacity, and share it between home and vehicle, transferring it to the vehicle only when really needed. Or, don’t buy a large battery capacity at all and just get a vehicle with a realistic daily range and pay to temporarily add capacity only when you really need it. And this model could be done right now. It doesn’t depend on some future technology. It only requires an electric vehicle maker to give it a try.

by Eric Sparks, 2024