Maybe for vehicles with close enough voltages, all that's necessary is to connect the packs together to equalize them?
I know it sounds crude, but really having a big enough resistance in the charging/jumping cable could work to an advantage here, because you canstill transfer a lot of energy and only waste a portion of it. The amount of energy you are transferring is Bat volt * amps and the amount of energy you are losing is Cable Volt * amps. So connecting a 400 volt car to a 360 volt car means you are wasting 10%...that means your 100 kw cable has to disappate 10kw, which is a lot, but for an emergency jump situation probably do-able and maybe it's just instantaneous, because the voltage sag and charge increase, so maybe the 400 goes to 380 during the heavy discharge and the charge side goes up to 380 and all the sudden the cable works just fine. I know diddly about Tesla's and what the voltage characteristics are during charge and discharge, but I'm 100% sure you could make a jumpercable that would work (obviously a high resistor would work....just very slowly). So the question would be in optimizing it to equalize to packsand still stay cool enough and fast enough to be useful. On Thursday, March 20, 2025 at 01:03:33 PM PDT, Cor van de Water <cor.vandewa...@gmail.com> wrote: Lawrence,That will work, provided that you supply DC, else you are limited to the onboard charging speed of the receiving car, which will typically be in the 6 to 11kW range, for the overnight fill.The only way commercial EVs would be able to exchange high power, is when both vehicles connect to a boost charger, which uses one (V2X) DC connection as power source, changes the voltage to the level required by the second car and performs a normal DC Fast Charge into that car, while doing the normal station things like adjusting voltage to meet the requested current or limits it to the available power from the source car, keeping in mind limits like minimum remaining charge configured for the source, so it can still get where it needs to after the charge. Note that input and output voltage levels will likely cross over during the charge, so it will likely require a special architecture or a sequence of for example a boost converter to take the source voltage and create >500V, then a buck converter to generate the ~400V for the receiving EV.Cor. On Thu, Mar 20, 2025, 12:26 PM Lawrence Winiarski via EV <ev@lists.evdl.org> wrote: Yeah, the pack swap has lots of prob if you aren't swapping your own pack, but it got me thinking..... Maybe there might be a merit for something like this idea : Charging a stranded EV You need a gimongous generatorto charge an EV in 5 min and a little generator would take hours or even days, but perhaps a way of using an 2nd EV to "recharge" a stranded EV you could do it super fast also On Thursday, March 20, 2025 at 12:04:56 PM PDT, (-Phil-) via EV <ev@lists.evdl.org> wrote: This has been tried before, even by Tesla. People don't want to risk getting a pack swapped in that has been abused, has high degradation, etc. The only way it can work is if you lease the pack, and while that model has had success in China and the EU, it's not worked here at all. I think Tesla only ever had a handful of takers willing to pay the extra premium over supercharging (which was then free), and it was only used in the LA <--> SF corridor and Tesla promised to give your original pack back when you returned! It's been tried also by others, and it's always failed in the US and EU, only in China has it had any success whatsoever, and I bet it won't last. On Thu, Mar 20, 2025 at 11:55 AM John Lussmyer via EV <ev@lists.evdl.org> wrote: > On 3/20/2025 11:10 AM, Lee Hart via EV wrote: > > But it would (gasp! choke!) require EV manufacturers to standardize > their batteries. > And have all "charge" stations have large, mechanical, complex stations > that are likely to need lots of maintenance, and possibly attendants. > AND still have huge power requirements to recharge all the swapped packs. > _______________________________________________ > Address messages to ev@lists.evdl.org > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > > -------------- next part -------------- An HTML attachment was scrubbed... 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