Yes, but if you wanted to make your own CCS or Tesla jumper "suitcase", you wouldn't be able to do that without cooperation from the vehicle BMS. I'm talking about what's possible to make this operate without hacking into at least one of the cars.
For example, I could hack my Tesla (with a f**kton of work) to build working mobile supercharger or CCS that would charge other vehicles, but it would require hacking the BMS to omit isolation detection as well as preventing the circuit from causing an ISO fault on the other vehicle. Most isolation circuits pull the chassis alternately from one side of the HV to the other and look at the current. (aka Delta V across the "pull" resistors) -Phil https://youtube.com/ingineerix/ On Tue, Oct 26, 2021 at 1:47 AM Cor van de Water via EV <[email protected]> wrote: > Since the charging sequence has a fixed order of control, it should be > possible to avoid one vehicle's isolation check to fault the other > one. > The "sending" vehicle can do the isolation check before the charging > is started, while contactors are still open, then the connection is > made, then the receiving EV does the isolation check at a moment that > the sending EV is not checking and since both packs are isolated, all > should check out fine, no? > Cor. > > On Mon, Oct 25, 2021 at 3:54 PM (-Phil-) via EV <[email protected]> wrote: > > > > Thanks Lee, But keep in mind without galvanic isolation on this, (or > > vehicle support from the manufacturers) it would likely instantly trip > the > > HV isolation detection on one or both EVs. So the magnetics have to > handle > > the full power being transferred, not just the difference. > > > > Basically the isolation check circuitry on one vehicle is going to > trigger > > the opposite's. I have also run into this when paralleling 2 EV packs > > (Tesla). > > > > -Phil > > https://youtube.com/ingineerix/ > > > > > > On Mon, Oct 25, 2021 at 10:01 AM Lee Hart <[email protected]> > wrote: > > > > > (-Phil-) via EV wrote: > > > > Don't believe everything you read! Definitely not possible to do > this > > > > without some sort of high-power buck/boost converter in-between the > EVs. > > > > Even a 50kW capable unit is going to probably weigh 50lbs minimum > even if > > > > built very well. > > > > > > Hi Phil, > > > > > > Forgive me for butting in, but that's not quite the case. The > > > power-handling ability of the DC/DC is determined by the *difference* > in > > > voltage between the two packs, times the current being transferred. > > > > > > It works the same as a buck-boost transformer. Suppose you want to buck > > > 240vac down to 220vac at 50 amps. The transformer doesn't need to be > > > 240v x 50a = 12KW -- it only needs a 240vac primary, and a (240-220) = > > > 20vac x 50a secondary. This secondary is connected in series with the > > > primary, and phased to "buck" the voltage down 20 volts. That's only > 1KW > > > -- 12 times smaller. > > > > > > Similarly, the DC/DC needed to transfer power between two EV packs that > > > are nominally the same voltage only needs to handle the *difference* in > > > voltage between them, times the current. > > > > > > Of course, the real challenge is to handle the battery management > needed > > > during such a charge. The EV already has the necessary fans, fusing, > > > balancing, and state-of-charge controls; but convincing the EV's > > > computers to help do this would be a bigger problem than the charging > > > itself. > > > > > > Best wishes, > > > Lee Hart > > > > > > -- > > > A designer knows he has achieved perfection not when there is > > > nothing left to add, but when there is nothing left to take away. > > > -- Antoine de Saint Exupery > > > -- > > > Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com > > > > > > -- > > > This email has been checked for viruses by Avast antivirus software. > > > https://www.avast.com/antivirus > > > > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20211025/b53fbb91/attachment.html > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > > ARCHIVE: http://www.evdl.org/archive/ > > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/ > LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20211026/c9848579/attachment.html> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/ LIST INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org
