The Leaf most definitely has HV Isolation detection. I got one of the first 2011's, and I tested it. Not sure where it's located, but I would guess inside the BMS. I am not aware of any non-isolated charging happening. The Leaf's OBC is definitely isolated, as are all modern production EVs.
On Tue, Oct 26, 2021 at 2:44 PM Cor van de Water via EV <[email protected]> wrote: > Phil, > The Leaf has a self-contained BMS that does not care about isolation, > it simply works and is readable from CAN bus. > Sure, before the Leaf will accept a connection to its battery, it is > likely that the inverter does a ground fault check but typically > during charging it cannot (to allow non-isolated charging). So, I > suspect that as long as the Leaf thinks it is charging (even > "negative" charging, which has already been possible through the > CHAdeMO plug for quite a while) then there is no error. > How do I know for sure? I have worked on a prototype CHAdeMO charger > that was non-isolated and we had no problem charging Leafs (and even > Teslas) from it... > Sooo - if you can create a box with the proper charging interface (CCS > or CHAdeMO) for V2G on one side, a small fixed boost converter and a > buck to regulate the charging of the 2nd EV and the charging control > interface on that side (CCS or CHAdeMO again) then you have a vehicle > to vehicle DC Fast Charger for production EVs. > Cor. > > On Tue, Oct 26, 2021 at 11:51 AM (-Phil-) <[email protected]> wrote: > > > > 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 > _______________________________________________ > 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... 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