The voltage will not change even if you lose capacity. You would have to actually put a load on it and measure how many amp hours you get. A battery in not an electrical device. It’s a chemical device. It’s materials expand and contract due to temperature and the ions move slower when cold because of increased viscosity of the liquid electrolyte. The ions are not easy to embed nor easy to get out and it’s difficult to get through the diaphragm. The battery will have higher resistance and reduced efficiency (actual lower capacity) and the faster you charge or discharge the faster the capacity loss. Some of this loss is irreversible and remains even when the battery is warmed. So yes, you have less capacity when cold.
Sent from AT&T Yahoo Mail for iPhone On Thursday, April 7, 2022, 4:43 PM, Cor van de Water via EV <ev@lists.evdl.org> wrote: Peri, The 1st gen Leafs have no regen when battery is deteriorated, so if you have steep hills then you will lose a *lot* of energy, friction-braking down, wasting all the potential energy you invested while climbing. So, unless you drive the *same* route later in warmer weather, it cannot be compared. I think the best way to *prove* that a cold battery is not lower capacity, even though it may lose a lot of *power*, increase *resistance* and other effects, is to take a warm battery (a single module from a Leaf pack should be sufficient), charge it fully to 4.12V per cell as the 1st gen Leaf has as max cell voltage, leave it sitting for a day to verify it is not self-discharging, then take the module and put it in a freezer for a couple hours. If the module has lower capacity when cold, then it should lose a lot of charge in the cold. Measure the cell voltage to see if it has changed (I expect it does not, but if capacity of the cells would be less, the voltage should rise as the cell will get over-charged due to its lowed capacity not being able to contain the same charge) Then put the battery back into a warm place, wait till it is warmed up and measure its voltage again. I expect that it will be the same as before, showing that the capacity of the cells was not affected by temperature. It also does not make sense that temp would affect capacity, since it is the material that gives a place to ions that make up the energy, and when temp changes the amount of places in the material is not changing. Hope this clarifies, Cor. On Thu, Apr 7, 2022 at 7:14 AM Peri Hartman <pe...@kotatko.com> wrote: > > - no heat. I needed the range, so heat and all accessories were off. > > - 2011 model > > - I did 4 trips of 2 miles and several shorter trips, over 2 days. This > was on residential streets, steep hills, speeds aroun 20-25 mph. When I > saw the charge state drop from 12 bars down to 2, it was clear I needed > to charge. After that, I plugged in the 120 V charge cable and kept it > on charge all the time while not driving. Temp was around 20F. > > The battery has only about 60% (or maybe 50%) of its original capacity; > it's pretty worn out at this point But the issue is the difference > between warm weather range and cold. Last week, I started with a full > charge and drove 30 miles RT with still 3 or 4 bars left when I > returned. Temp was 55F. Heat was off. This is partly on freeway, partly > on 40 mph highway, and some slower streets. > > Peri > > << Annoyed by leaf blowers ? https://quietcleanseattle.org/ >> > > ------ Original Message ------ > From: "Cor van de Water" <cor.vandewa...@gmail.com> > To: "Peri Hartman" <pe...@kotatko.com> > Cc: "Electric Vehicle Discussion List" <ev@lists.evdl.org> > Sent: 07-Apr-22 00:35:02 > Subject: Re: Re[2]: [EVDL] kWh versus charging temperature > > >Peri, > >Did you use the heater in the car when you were doing that 20 mile drive? > >How long did that trip take in minutes and which model year Leaf did you > >drive? > >I want to give some estimated nrs, so I can show how the distance can > >be so different. > >Cor. > > > >On Wed, Apr 6, 2022 at 8:52 PM Peri Hartman <pe...@kotatko.com> wrote: > >> > >> Cor, this just doesn't add up, for my case. Not the heaters, but the > >> difference in range between cold charging and warm charging. > >> > >> Let's say I have about 2/3 the original battery capacity, which would be > >> 16kWh. In warm weather, I'll guess I have a range of 50 miles, perhaps > >> 60 if I go 40 mph without many stoplights. But, as I mentioned, in our > >> december cold snap, I was getting about 20. I came very close to running > >> out of energy, so I think 20 is pretty accurate. That's less than half > >> the range. > >> > >> So, if the main culprit is internal resistance, then half the energy > >> would be going into warming up the battery. That's a hell of a lot of > >> energy. I would assume that one of two things would happen: the battery > >> would warm up and the resistance would drop (and range improve), or it > >> would become plasma. > >> > >> In reality, I don't think either happens. That's why I made this post in > >> the first place. I have searched on the Internet but haven't found > >> anything beyond people's speculation. But I would think this is heavily > >> researched within the battery industry. > >> > >> Peri > >> > _______________________________________________ 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/20220407/aa9844a2/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
