I seem to recall being told to charge my Model S at every chance I got, regardless of how many miles I drove in a day. (Up to the 85% level unless going on a road trip...) A friend of mine taking delivery this week was told to NOT charge it until it got low on remaining charge...like your phone. Which is correct?
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To always charge or not?
- Thread starter Cowboyjinx
- Start date
ucmndd
Well-Known Member
This card used to be inside every Model S at delivery. I wish Tesla still did that, it would avoid a lot of these questions.
A connected Model S is a happy Model S
A connected Model S is a happy Model S
By keeping it plugged in you reduce battery discharge cycles, the refresh models can charge the 12volt off of AC current and all models can use AC connection for heater, and AC.
The "should run it down" I do not believe applies at all to lithium batteries believe that was OLD NiCad and NiMHydride used in toy remote control cars.
The "should run it down" I do not believe applies at all to lithium batteries believe that was OLD NiCad and NiMHydride used in toy remote control cars.
ucmndd
Well-Known Member
Anyone ever try this? I imagine it's plausible if you do a full power-down from the MCU. Obviously not if you just lock the doors and walk away.
.jg.
Member
We've covered the car, but the same rule actually applies as well to your phone, or laptop, or any Li-Ion battery. Your friend is wrong on all counts. Li-Ion batteries are healthiest and last longest if used in small cycles centered around 50% state of charge. 10 charge/discharge cycles between 45% and 55% is better for the battery than one deep discharge/recharge from 100% to 0% and back to 100%.
Storing a Li-Ion near 0% or 100% is bad for the battery. Plugging in a phone or laptop before bed and letting it sit overnight fully charged for hours is damaging to the battery. Many new laptops have BIOS settings to set custom charge profiles. You can set the max charge to something less than 100% to trade shorter run times for long-term battery health.
The conventional wisdom of "run down a NiCd to 0% before recharging" isn't necessarily good either. If the cells in a pack are out of balance, a deep discharge runs the risk of running a cell below 0% and reversing polarity. On the next charge cycle, you're reverse-charging the cell (bad). Conventional wisdom states deep cycling a NiCd is necessary to avoid "memory effect." Most of the damage attributed to "memory effect" in consumer NiCd's is permanent capacity loss/cell damage due to chronic overcharging on cheap trickle chargers that don't shut off when the battery is full. A good charger that uses -deltaV cutoff avoids much of the risk. Memory effect - Wikipedia
I always love this argument. There are so many people who believe that this is a completely cut and dry question, when I believe that the answer is far from cut and dry.
For example, Let's take a driver that drive 150 miles per day and leaves their car plugged in at night. (Oh, by the way, shouldn't they keep it plugged in during the day?)
And then let's compare that to a driver that drives 20 miles per day and over 5 days and then plugs in, using the same amount of battery drain as the 150 mile per day driver.
So, over a month period, the first driver uses 30 charge cycles and the other uses maybe 5.
Which is better and which is worse?
I believe that the reality here is that you want to keep things in the middle. Stay away from 80%+ and 20%-. But, if needed, you can go into these areas, just don't go there by default. No, you don't want to run the car down to 10 miles every time. No, you don't want to leave it sitting at 95%+.
For example, Let's take a driver that drive 150 miles per day and leaves their car plugged in at night. (Oh, by the way, shouldn't they keep it plugged in during the day?)
And then let's compare that to a driver that drives 20 miles per day and over 5 days and then plugs in, using the same amount of battery drain as the 150 mile per day driver.
So, over a month period, the first driver uses 30 charge cycles and the other uses maybe 5.
Which is better and which is worse?
I believe that the reality here is that you want to keep things in the middle. Stay away from 80%+ and 20%-. But, if needed, you can go into these areas, just don't go there by default. No, you don't want to run the car down to 10 miles every time. No, you don't want to leave it sitting at 95%+.
Please lookup and understand what a charge cycle is. From the link, "using half the charge of a fully charged battery, charging it, and then using the same amount of charge again count as a single charge cycle".
Another issue is that when talking about bringing the charge down to 0 some don't seem to understand this isn't voltage down to zero. Nor does bringing the Tesla up to 100% mean 4.2 volts per cell. Most equipement that use a single 18650 battery charges it up and sometimes over 4.2 volts on the cheaper style charges. The Tesla doesn't do this, from my observation the battery CV stops just shy of 4.2 at around 4.190-4.195volts. This is only during the charge state, once the charge is completed it drops to around 4.180-4.190 If you don't need the full use of the battery pack then there is no reason to charge above 70-85% Still not enough data to state for sure what will happen if you charge 100% everyday.
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ucmndd
Well-Known Member
I mean, believe what you want, but the facts and Tesla's own advice really do make it very cut and dry. Plug the car in when you can. Full stop.
Tesla continues to recommend in the Owners Manual to plug the car in for charging whenever possible.
They used to have a warning about charging above 90%, except when needed for trips - and that has been removed in the later versions of the Owners Manual.
Long-term studies have shown Tesla battery usually lose a relatively small amount of charge over time - and that's based on owners using a wide range of different charging strategies.
For us (and many others), we usually charge to 90% every night, using a 14-50 connector (at 40A) or an HPWC (at 48 to 80A, depending upon the vehicle), and only charge above 90% infrequently when leaving for a road trip where we may be able to use the extra charge to skip over a supercharger. And using that strategy, the long-term battery degradation hasn't been significant.
Others spend more time worrying about charge management - charging less often, charging to 50% or 80%, … Doing that may or may not help, not sure if there have been any studies on Tesla battery packs on the impact of these different charging strategies on battery degradation.
Though, my recommendation would be to keep it simple - follow the Owners Manual recommendations - charge to 90% every night - and not worry about it - enjoy the car...
They used to have a warning about charging above 90%, except when needed for trips - and that has been removed in the later versions of the Owners Manual.
Long-term studies have shown Tesla battery usually lose a relatively small amount of charge over time - and that's based on owners using a wide range of different charging strategies.
For us (and many others), we usually charge to 90% every night, using a 14-50 connector (at 40A) or an HPWC (at 48 to 80A, depending upon the vehicle), and only charge above 90% infrequently when leaving for a road trip where we may be able to use the extra charge to skip over a supercharger. And using that strategy, the long-term battery degradation hasn't been significant.
Others spend more time worrying about charge management - charging less often, charging to 50% or 80%, … Doing that may or may not help, not sure if there have been any studies on Tesla battery packs on the impact of these different charging strategies on battery degradation.
Though, my recommendation would be to keep it simple - follow the Owners Manual recommendations - charge to 90% every night - and not worry about it - enjoy the car...
I agree completely with @bob_p. When I sold my Model S 60 after five years of charging to 90% every night, and to 100% several dozen times on trips, I had only lost 5% of range. You’re not going to do any better than that with the various “babying the battery” strategies people are suggesting here. You don’t need to obsess over the battery. Just keep it plugged in as Tesla recommends, enjoy the car, and let the battery management system manage the battery.
As long as you keep the battery charge between 10-90%, you don't have to re-charge the car overnight or keep it plugged when parked. Not everyone has access to overnight charging - and have to rely on less frequent charging.
Depending upon settings and temperature, you will always get some vampire drain when parked. Keeping the car plugged in (including on a 110 outlet) will avoid losing any charge. Though if you can't, then don't worry about it - just try to keep enough charge in the car to avoid allow the charge level to get too low.
Depending upon settings and temperature, you will always get some vampire drain when parked. Keeping the car plugged in (including on a 110 outlet) will avoid losing any charge. Though if you can't, then don't worry about it - just try to keep enough charge in the car to avoid allow the charge level to get too low.
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