Imeasured my Prius and got somewhere between 10 to 25 mA always-on load while parked. That is a LOT! Bob
On Wed, Apr 21, 2021 at 12:46 AM Glenn Brooks via EV <ev@lists.evdl.org> wrote: > > Hmm, Phil’s comment about battery drain is very interesting. Up until last > year, My daughter had an older Lexus SUV hybrid . She worked in San Francisco > and walked to work, so the car stayed parked for weeks sometimes. When parked > for a week, the battery pack and the lead acid battery always went dead from > some mysterious , undetectable current draw. Neither the dealer or Lexus > ever traced ( or admitted a design flaw) in the supposed stray current, when > parked. We never figured it out. Finally talked her into selling the d#%n > thing. Wondering if something to do with cell monitoring was killing the > batteries. > > It’s gone out of our life, ( dad’s are the 24 hr on call emergency fixit > guys), but still curious. > > Thanks , > Glenn > > Sent from my iPhone > > > On Apr 20, 2021, at 9:29 PM, (-Phil-) via EV <ev@lists.evdl.org> wrote: > > > > The problem most people are seeing is the high quiescent drain. IMO, this > > started with the Prius with the smart-key option. It was exacerbated with > > the introduction of telematics, which means there's a cell modem always on > > in your car now. Most modern cars now have both. So if you drive every > > day, and long enough to get your absorption phase completed, likely not > > going to be much of a problem, but if your car isn't used as often, you are > > in trouble. > > > > Ultracaps (or any capacitors) have a linear Dv/dt plot, which means voltage > > falls immediately on discharge. This means to get the capacity anywhere > > CLOSE to what you get with lead-acid, you'd need a ludicrously large cap > > array. > > > >> On Tue, Apr 20, 2021 at 8:36 PM George Tyler via EV <ev@lists.evdl.org> > >> wrote: > >> > >> The leaf battery behaves much like the 12V Prius battery in my experience. > >> They both seem to fail earlier than they should, but when should they fail? > >> That is "opinion". The failure mode is different, probably because they > >> don't fail by not turning a started motor? So you don't know capacity is > >> almost zero. > >> I don't think a lithium is good for this application. To get > >> voltages that are close enough you have to use LiPo4 litiums, with a very > >> flat discharge curve. This means that the charging voltage is not optimal, > >> although they do work in this application in ice cars with 14.7V charging. > >> 4 > >> cells at 13V is 3.25/cell, that's totally flat for these batteries! 14.7V > >> in > >> an ICE is 3.675V per cell which is about right. Temperature compensation > >> for > >> a lead acid may be way off. How about a supercap "battery", much less > >> critical. Seeing that we don't notice the leaf battery losing capacity > >> until > >> it's dead, maybe we don't actually need much capacity? > >> GWT > >> > >> -----Original Message----- > >> From: EV On Behalf Of Lee Hart via EV > >> Sent: Wednesday, 21 April 2021 2:14 pm > >> To: Lawrence Rhodes via EV <ev@lists.evdl.org> > >> Cc: Lee Hart <leeah...@earthlink.net> > >> Subject: Re: [EVDL] From my nissan leaf .com: Why the Leaf 12v system > >> undercharges the 12v battery. > >> > >> Lawrence Rhodes via EV wrote: > >>> https://mynissanleaf.com/viewtopic.php?t=22752 According to these guys > >>> a lead battery is not what a Leaf needs. Seems a lithium of some sort > >>> would do great. Another site said the DC/DC converter can put out as > >>> much as 120amps. The brakes and other systems that run on the 12v > >>> system might need a boost if the battery fails and braking is very > >>> important. After finding out that the lead battery is under charged I > >>> suspect an undercharged lithium battery might fair much better and for > >>> longer. Lawrence Rhodes > >> > >> I don't "buy" it, Lawrence. Too many of his comments are just opinions; not > >> facts. Just a few glaring points: > >> > >> - A 12v battery *will* reach full charge at 13.0v; it just takes a long > >> time > >> (like a week or so). > >> - He ignores temperature compensation. The Leaf does temperature compensate > >> its charging. > >> - He ignores aging. The older the battery, the lower its basic charging > >> voltage. > >> - 14.4v will easily fully charge a 12v battery. Remember, if it's holding > >> the battery at around 13.0v, it's already close to full; so it takes very > >> little time at 14.4v to finish the job. > >> > >> Lee > >> > >> _______________________________________________ > >> Address messages to ev@lists.evdl.org > >> 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/20210420/bc2bc0ee/attachment.html> > > _______________________________________________ > > Address messages to ev@lists.evdl.org > > 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 ev@lists.evdl.org > 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 ev@lists.evdl.org 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
