When testing a grid powered device such as an EV charging station itself, it is required to work for any grid voltage specified +/-10% so for an EVSE that can be used at a residential setting, which has 120/240V split phase as well as a commercial location which has 120/208 3-phase, the nominal spec for the EVSE is (for example) 208-240Vac and thus UL (or another test lab) will test the EVSE to work for voltages from 187 to 264Vac. That does not mean that cars will always successfully charge from this voltage range. In fact, a Tesla that sees the grid voltage drop to about 198V will reduce the current limit and warn that it noticed a drop in grid voltage, possibly due to a bad connection, and has therefore reduced charging speed (current), obviously in an attempt to avoid overloading an undersized or overloaded service and causing a fire. I typically see this problem in commercial locations where the 208V transformer is on one side of the building and the charging station at the other side. If you then also need a J1772 extension cord because the installed EVSE does not reach the parking spot of the EV, then it is easy to lose more than 10V in the wiring and get this warning.
Anyhow, 245V is not an unsafe voltage for an EV, in fact my Leaf has for years happily charged at 250V, because the location I could access was in the electrical room, right in front of the 480V transformer, so the 277V phase voltage was a bit "hot", about 282V and thus my little 32V transformer only reduced it to 250V but that was no problem for my 2011 Leaf at the time. I had modified a Leaf convenience charger so it could handle the 240V and 12A x 250V is 3kW so it was going at almost max charging rate from the convenience charger, very convenient. Cor. On Wed, Sep 4, 2024 at 3:28 AM Jay Summet via EV <ev@lists.evdl.org> wrote: > > I have a solar system on my house, and have seen my "240" volt circuit > jump as high as 245 when the solar system is adding 10 kw flowing back > into the grid, never had an issue charging my Nissan Leaf at that > slightly over spec range. > > I read somewhere that the national line voltage limits are 230V + 10% or > - 6% (253.3V-216.2V). > > Jay > > On 9/4/24 01:23, Rush via EV wrote: > > The J1772 Spec from the 2017 SAE Standard states - > > > > Table 9 - AC charging electrical ratings (North America) > > AC Level 2 208 to 240 V AC, 1-phase ≤ 80 A Per NEC 625 > > > > So your 245VAC may not be safe for some EV's > > > > Best, > > > > Rush Dougherty > > TucsonEV > > www.TucsonEV.com > > > >> -----Original Message----- > >> From: EV <ev-boun...@lists.evdl.org> On Behalf Of Cor van de Water via EV > >> Sent: Tuesday, September 3, 2024 6:24 PM > >> To: Electric Vehicle Discussion List <ev@lists.evdl.org> > >> Cc: Cor van de Water <cor.vandewa...@gmail.com> > >> Subject: Re: [EVDL] Are you NACS-charging a non-Tesla > >> > >> So, best to use a little step-down transformer on your TeslaTap... I have > >> a "dry > >> type" 240V to 32V 1kVA transformer and I wire the secondary in series with > >> the primary so that when putting 277V on the series connection, it drops > >> 32V > >> and delivers a safe 245V from the primary winding. > >> > >> On Tue, Sep 3, 2024 at 5:55 PM (-Phil-) <p...@ingineerix.com> wrote: > >>> > >>> Yes, I personally witnessed this happen at a Casino in Reno. Many Tesla > >> destination chargers are wired to 277VAC. > >>> > >>> On Tue, Sep 3, 2024 at 5:31 PM Cor van de Water via EV <ev@lists.evdl.org> > >> wrote: > >>>> > >>>> The only concern I would have with using a TeslaTap on an unknown > >>>> destination charger is that you are not guaranteed that the charger > >>>> won't damage your non-Tesla EV. > >>>> Because the Tesla charger is specifically specified to allow anything > >>>> between 100-277V so, while not common, some electrician may use a > >>>> commercial site's 277V parking lot lighting connection to wire up a > >>>> destination charger, making it very dangerous for any non-Tesla EV to > >>>> plug in... > >>>> > >>>> On Tue, Sep 3, 2024 at 2:15 PM Rush via EV <ev@lists.evdl.org> wrote: > >>>>> > >>>>> There are currently lots of versions of the 'teslatap'. It is just > >>>>> an adapter that changes one type of connection to another, Tesla > >>>>> inlet to J1772 plug. There are no resistors, diodes, PCB's or any > >>>>> electronic components in it. That is because the J1772 L1 and L2 > >>>>> protocols are used by Tesla and all the other J1772 EV's > >>>>> > >>>>> Years ago, in 2016, I tried to produce an injection molded Tesla to > >>>>> J1772 Adapter but found it way beyond my financial means. I did > >>>>> learn how the Tesla plug/inlet was able to accept both 120vac and > >>>>> HVDC using the same pin connector. Tesla uses BalSeal type coil > >>>>> springs in adjacent configurations to transfer the current from > >>>>> male to female connector so that there are lots of contact points > >>>>> for current transfer whereas the J1772 connector uses just a simple > >>>>> pin connector so that there are only 4 contact points for current flow. > >>>>> > >>>>> Best, > >>>>> > >>>>> Rush Dougherty > >>>>> TucsonEV > >>>>> www.TucsonEV.com > >>>>> > >>>>>> -----Original Message----- > >>>>>> From: EV <ev-boun...@lists.evdl.org> On Behalf Of Lawrence Rhodes > >>>>>> via EV > >>>>>> Sent: Tuesday, September 3, 2024 8:37 AM > >>>>>> To: ev@lists.evdl.org > >>>>>> Cc: Lawrence Rhodes <primobass...@sbcglobal.net> > >>>>>> Subject: Re: [EVDL] Are you NACS-charging a non-Tesla > >>>>>> > >>>>>> I have used a TeslaTap at destination chargers for years, on a Leaf. > >>>>> Lawrence > >>>>>> Rhodes > >>>>>> -------------- next part -------------- An HTML attachment was > >>>>>> scrubbed... > >>>>>> URL: <http://lists.evdl.org/private.cgi/ev- > >>>>>> evdl.org/attachments/20240903/2c3dbd75/attachment.htm> > >>>>>> _______________________________________________ > >>>>>> Address messages to ev@lists.evdl.org No other addresses in TO > >>>>>> and CC fields > >>>>>> HELP: http://www.evdl.org/help/ > >>>>> > >>>>> > >>>>> > >>>>> _______________________________________________ > >>>>> Address messages to ev@lists.evdl.org No other addresses in TO and > >>>>> CC fields > >>>>> HELP: http://www.evdl.org/help/ > >>>>> > >>>> _______________________________________________ > >>>> Address messages to ev@lists.evdl.org No other addresses in TO and CC > >>>> fields > >>>> HELP: http://www.evdl.org/help/ > >>>> > >> _______________________________________________ > >> Address messages to ev@lists.evdl.org > >> No other addresses in TO and CC fields > >> HELP: http://www.evdl.org/help/ > > > > > > > > _______________________________________________ > > Address messages to ev@lists.evdl.org > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > > _______________________________________________ > Address messages to ev@lists.evdl.org > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > _______________________________________________ Address messages to ev@lists.evdl.org No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
