Engineering a DC-DC that can handle the full peak load as well as accept the load dumps can be done, but the cost exceeds that of a small basic DC-DC and a lead acid battery (so far). That's the real reason.
EU also now has an Ecall requirement that mandates the system still work after an accident. Most EVs cut the HV system as soon as a crash is detected for obvious reasons. So you'd need to add a backup battery for that. On Wed, Dec 16, 2020 at 3:44 PM John Lussmyer <[email protected]> wrote: > Really the ONLY reason to have a 12v battery is for Emergency power. > Building a DC-DC that can handle the load is a solved problem. > You could easily have 2 DC-DC units. 1 tiny one that just handles the > parasitic loads and can power the "start" relays. (efficient, very little > lost power) > and a larger one that can handle all the normal operations of the vehicle. > > > On Wed Dec 16 15:21:42 PST 2020 [email protected] said: > >You cannot run on DC-DC alone, You still need a 12v battery to stiffen the > >12v bus, provide load dump capability, and emergency power for > >braking/steering should the HV system fault. > > > -- > > Bobcats and Cougars, oh my! http://john.casadelgato.com/Pets -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20201216/fe254ace/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
