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Jumper Siphon Cables for Electric Vehicles

Beta V

Author, Dad, Mentor, Technology Critic
Nov 8, 2017
Redmond, WA USA
I carried jumper cables in every car I've owned since my first--a 1930 Model A Ford--until now. Sure, I still carry a portable "jump and carry" battery/compressor/USB power source to use for others (in ICE vehicles) and to recharge my Model X's 12VDC battery in case it runs down. But why hasn't the industry created an apparatus that would let one EV charge another? When we're stuck on a freeway for 22 hours in freezing weather, our batteries can run down too. When we misjudge the available charge remaining (or the car does), we can be stranded in the middle of the freeway with no power to get to safety or to a third-party recharge point a few miles away. But what if we had a "Jumper Siphon" cable that would let us connect to any EV willing to share a bit of their charge? We could call a friend to come help and twenty minutes later, we're back on the road.

Yes, I expect that would take a bit of thinking as the battery systems in our Teslas are probably not designed to let power flow OUT of the charge port. But that's just technology and foresight. Any entrepreneurs out there who need funding to make this happen? Does such an apparatus exist?
Rivian may allow vehicle to vehicle charging with their vehicles in the future.

Rivian CEO R.J. Scaringe interviewed by 'The Drive'

A portable "rescue" DC charger

Charged EVs | Sparkcharge launches a portable and scalable DC fast charging unit

It has been done in the past, but it was expensive and required a huge external box to control the current flow between the two vehicles. I can't think of the one that I recall from the past. The box filled half of the trunk of a Nissan Leaf but allowed CHAdeMO to CHAdeMO charging.
Apple was coming out with a feature that allowed one phone charge another, but it didn't make it into the latest phone.

Seemed like a pretty stupid idea to me. iPhone users are ALWAYS looking for a plug to charge their phone. Why would anyone ever give some of their charge away?

Sure, it can be done, but it's not just hooking the two batteries together. Hooking a charged and empty battery together tends to create sparks because of the huge inrush of current that would occur. Variable resistors that can handle 100's of amps aren't small, nor cheap.

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