Super Gizmo, You shouldn't wait until your range drops to a certain level before you plug in to your 14-50. Remember, "a connected Model S is a happy Model S". It's all over the owners manual-- plug in when you can. That means every night if you have a 14-50 at home. Let the battery management system manage the battery.
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What should my ideal charge percentage be?
- Thread starter Al Sherman
- Start date
Yes I did reboot both screens to no avail. I think this did start after a firmware upgrade but doesn't everyone get the same firmware?
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I used to do that but it resulted in an unbalanced pack. My Rated 90% max range went down to about 213. After several months of charging at 90% it has gone back up to 225-226.
Sort of. I believe the firmware is customized for each car during install (that is, for example, a Signature doesn't get all the same firmware that an S70D would). Also, many don't have it set that high and the alert doesn't happen until the third charge (at least that's how it used to be). I've had the alert when doing RV Park trips where you always range charge. I haven't had it at max-daily, but I also haven't charged three times in a row at max-daily with the latest firmware.
That doesn't mean the pack is unbalanced or that the car wouldn't correct it if it was unbalanced. The rated range is an estimate and may be more or less accurate at times, but doesn't necessarily mean a real loss in range. Also rated range changes as the algorithm changes in different firmware versions. If Tesla recommends staying plugged in when you can, I'm going with that rather than assuming any games about how long to wait to charge is better for the battery than letting Tesla's own software manage it.
Am I bad to do the opposite...
I was going to only charge at work (thanks Charles Schwab) M - Th to 50% set to start around 2 PM (we have empty chargers all day), F to 80%. And not charge at home unless needed (It's an 'old' 3.3 KWh charger). Round trip to/from work is 40. I'm averaging 1100 - 1200 miles/month now...
I was going to only charge at work (thanks Charles Schwab) M - Th to 50% set to start around 2 PM (we have empty chargers all day), F to 80%. And not charge at home unless needed (It's an 'old' 3.3 KWh charger). Round trip to/from work is 40. I'm averaging 1100 - 1200 miles/month now...
It's easy to get confused reading this thread, but I think I can be confident that keeping the battery in the 50% +/- 10% range is ideal. How you achieve this is down to your daily requirements.
As an example, I use 30% of charge for my daily driving (65 miles) so I settled on 80% for my nightly charging. The car will wake up and charge to 80% shortly before I leave for work, and will then sit for 8 hours at 65%. Then it will sit at 50% for a further 10-12 hours before the charging starts again in the early hours of the morning, starting the whole cycle again.
As an example, I use 30% of charge for my daily driving (65 miles) so I settled on 80% for my nightly charging. The car will wake up and charge to 80% shortly before I leave for work, and will then sit for 8 hours at 65%. Then it will sit at 50% for a further 10-12 hours before the charging starts again in the early hours of the morning, starting the whole cycle again.
Roadrunner13
Member
THIS ^^ is a great summary that takes into consideration three important 'derived' rules from roadster experience:
1. Pack balancing occurs at 90% and up
2. Pack balancing regularly is important to keep your range up for moments when you need a range charge
3. Keeping the SOC high in high temperatures is the worst combo and must be avoided at all cost when possible
It probably also is the method that is the closest match to Tesla direct's instruction so it should appeal to the non-tinkerer crowd in this thread.
fsch
Member
The 2nd link in post #2 does not work, but the paper can be found here: http://www.dtic.mil/get-tr-doc/pdf?AD=ADA527711
Mike Tuccelli
Member
I picked up my 90D a few days ago and asked them about this. They say leave it at 90, period. I said what about crystal formation compromising integrity of the cells and they said it wouldn't happen and even not to worry about 100% if I had to maximize my range.
Tesla would never officially recommend to charge a lower level. If Tesla would officially say that it's really better to not charge your car more than 70% it would make potential buys have doubts about the car and battery. It's just something no car manufacturer does. Porsche would never officially recommend to drive slow and defensive otherwise the car will have much more wear and tear and break down much quicker. We all know that is true, but you won't hear any official recommendation from any performance car company in that direction. Same with Tesla, they will not make any official recommendations that make you feel bad about using the range of the car.
It is undoubtedly better to charge to 70% rather than 90%.
It is undoubtedly better to charge to 70% rather than 90%.
bancroftc
Member
Why would Tesla make a firm recommendation that would potentially compromise the batteries? That would not make financial sense considering they offer an 8 year warranty on the battery. Or from a long term PR perspective, if batteries are crapping out due to a knowingly incorrect recommendation. There is a great YouTube video posted somewhere on this forum of a Canadian professor discussing battery chemistry and technology. Very minor changes to lithium ion battery chemistry - particularly the electrolytes - made dramatic impacts on the longevity of various batteries over a range of conditions. The video was made in 2013 I believe, and presumably battery technology has advanced considerably in that time frame. IIRC one of the guys that worked with said professor is now with Tesla. The right chemistry with the appropriate anode/cathode and proper cell management and the degradation of some these cells over long periods of time was negligible.
While I think your firm comment about 70% vs 90% may apply to some specific types of lithium ion batteries, from what I've learned that's not necessarily the case with ALL types of lithium ion batteries.
50-70 percent daily. I now charge mine at 50 percent unless going on long road trips. Again based upon reading U.S. Army lithium study and talking to Tyson's Tesla store folks.
Toyota seems to follow the same strategy in the Prius. I have a Prius with a scan gauge. The car strives to get the battery to 60% and it stays there while cruising on the highway. The highest I have ever seen is 80%, and that is only on a long downhill stretch. As soon as the battery falls below 40%, it fires up the engine and does not shut it down until it gets back to 50%. The lowest I have ever seen the battery is 35%.
The Prius is not comparable to the Tesla the Prius is using a different type of battery.
The ideal charge is whatever you want the fact there is an 8 year unlimited mile warranty tells me the car is in control of the batteries safety. With that type of warranty the battery degradation is minutely small or they could not offer this warranty.
chriSharek
Member
I'm astonished that Nissan didn't put a thermal management system in their Leaf. I realize they probably did it to save money, but their approach isn't good for EVs long-term.
The 8 year battery warranty does not cover degradation. Tesla will not give you a new battery if yours shows more degradation than someone that took care of their battery better and has less degradation. It is a well known fact that Lithium batteries age (degrade) faster the higher the state of charge is.
The only way it can be determined with reasonable accuracy is to first balance the battery, then drain and fully charge the battery. Unfortunately, the drain and fully charge process causes battery degradation, so the only time it's done is when there is already a problem and data is required for proof (e.g. the Leaf battery problem). Anything else is an estimate, sometimes a good estimate and sometimes not.
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