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Charging frequency and battery life

Discussion in 'Model X: Battery & Charging' started by rainforest, Jun 11, 2017.

  1. rainforest

    rainforest Member

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    I charge my X60D every day. Does charging frequency affect the health of the battery? Should I be charging every other day instead?
     
  2. JHWJR

    JHWJR Member

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    "A plugged in battery is a happy battery." -- Elon Musk
     
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  3. BigD0g

    BigD0g Member

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    #3 BigD0g, Jun 12, 2017
    Last edited: Jun 12, 2017
    --- Comment Deleted -- I was providing information that I thought to be true, and appears to not be thanks to TexasEV. I apologize for any confusion it might have caused.
     
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  4. jbcarioca

    jbcarioca Active Member

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    I leave mine plugged in 100% of the time when I am at home, and always when I have a L2 connection available. I use DC Fast (CHAdeMO, Supercharger) only when I need it for trips.
    My car has 30,000 miles and still has zero degradation, with 100% at 251 miles, exactly what it was when I took delivery.
    Tesla has had constantly improving battery technology, but the basic idea of charging to somewhere between 40-90% indicated SOC remains the preferred tactic, except for software-constrained batteries, in which case 100% is a fine upper limit.
    All the evidence suggests that it is difficult to damage any Tesla battery from high or low charging limits in actual fact, but I still behave conservatively.
    Remaining plugged in at 50% is my typical daily choice.
     
  5. TexasEV

    TexasEV Well-Known Member

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    Absolutely incorrect. Are you confusing level 2 with CHAdeMO or supercharging? Level 2 is 240V charging, whether by J1772 or HPWC, or 14-50 outlet. This is how Tesla recommends charging the car, and it recommends plugging in when possible and letting the battery management system manage the battery. It says so IN UPPER CASE in the owners manual, so Tesla must think it's important, and we used to get these cards in the car at delivery:
    A connected Model S is a happy Model S

    With so many questions about this recently, I really fault the Tesla delivery process in not explaining this to new owners and not including the cards any more. (I know it's too much to expect them to RTFM as us early adopters did).
     
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  6. BigD0g

    BigD0g Member

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    Hey TexasEV, now I think i'm completely confused, and yes, I guess I am confusing the two, I'm knew to the whole EV thing only had my model S for 4 months or so. So, can you point me to something that explains the different chargers and I guess the good chargers vs the bad? For example my work has ChargePoint chargers that are 30 AMP and I use the CP adapter, is that the good charger for everyday? Is CHadeMO a non 240 volt charge? So confused, I'll start googling, but any help is greatly appreciated. I'll also try to delete / mark up my other post as I did not mean to spread fud, clearly I just don't understand the different types.
     
  7. Ugliest1

    Ugliest1 S85: "Sparky"

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    Go to evtripplanner.com and check out the various pages; one of them describes all the power options and approximately how quick they charge.

    As a quick layman's explanation, 30A is fine. Any chargers with the J1772 adapter port will be either 208V or 240V and depending on the supply equipment could be 30A, 40A, 60A, 70A, 80A, 90A, or 100A. Why the volt difference? Well I don't know the technical reason but at least in Canada household (private) systems are 240V but commercial are required by code to be 208V. Note if you're looking at the actual draw the volts could be slightly lower when your car is actually charging (e.g. 202V); depends on the other load on the overall system is my understanding.

    Also don't be concerned when you see your car is only drawing 24A on that 30A Chargepoint: by code, they're limited to 80% of the breaker max for safety.
     
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  8. TexasEV

    TexasEV Well-Known Member

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    A very basic explanation:
    level 1- 120V AC charging (usually 15A at home, 20A outlets at commercial locations)

    level 2- 240V charging (or 208V at commercial locations as noted above). These can be outlets such as the 50A called NEMA 14-50, or 30A called NEMA 14-30 (a dryer outlet), or J1772 charging stations which can be anything but most commonly 30A, or Tesla HPWCs. Note the electrical code requires the car to pull only 80% of whatever amps the circuit is rated for because it is a continuous load. So you get 40A from a 50A circuit, etc.

    level 3- DC charging. For Tesla this means supercharging or CHAdeMO with the adapter.

    You have no concerns whatsoever about frequency of charging with level 1 and level 2, as long as you charge to 100% only if you need it for a trip and don't let it sit there. The only issue is with frequent DC charging and the latest battery- it slows down the initial charging rate if it's been done frequently (like if it's been used almost exclusively). Some people are freaked out about this, but really it just extends a supercharging session for a few minutes for those cars affected by it. Don't worry about it.

    Bottom line don't worry about the battery. Keep your car plugged in when you can and let the battery management system manage the battery.
     
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  9. SureValla

    SureValla Member

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    I plan on getting the 3LR. I drive the equivalent of 300 miles per week so my first thought was to basically charge it once per week until I saw this thread and realized I would be better off charging nightly.

    My followup question: Does it matter what % I charge to nightly or more that its plugged in? i.e. can I set my charge rate equal to my current battery % everyday (therefore not really charging, just plugging in) until I hit say 20% and then go back to 90% and expect no worse degradation than charging to 90% each night?

    The reason I ask is I'm trying to reduce my charging costs. I can charge 1/week for free so I'm trying to minimize my energy use at home.
     
  10. TexasEV

    TexasEV Well-Known Member

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    The lowest charge level you can set the slider to is 50%.
     
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  11. SureValla

    SureValla Member

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    interesting, so then my revised options are as follows:

    1) Set slider to 50% 6 of 7 days of the week, 90% on day 7
    2) Set slider to 90% every night

    Which is better for the battery health?
     
  12. Ugliest1

    Ugliest1 S85: "Sparky"

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    Don't overthink it. Pick your favourite number. Tesla doesn't release information at that granular level of detail.

    I just leave the slider at 90%. Occasionally for road trips may charge to 100% if leaving soon after charge completes. After 3.5 years, 85,000km, and a hundred or so supercharges, my 100% charge has gone from 425km to between 406 and 413km. So, 3-5% loss, and the loss stopped after about 1.5 years (2 years ago).

    Remember we are all comparing EVs to what we are used to: all the extraneous systems an ICE needs to keep it from blowing itself up. We have to realize our old habits of measuring every temperature (engine oil, transmission oil, coolant) to give us early warning ... they aren't needed. Tesla is designing these battery packs with longevity in mind.

    After a few months of vehicle ownership, I made a choice to not sweat the details, to trust that Tesla did their homework and the battery was going to last. I've been very comfortable ever since.
     
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  13. SureValla

    SureValla Member

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    Not sure if you saw my post above but i can charge 1/week for free so doing my option 1 above will save me some "fuel" costs. The point of my question was to ensure I wasn't doing so at the expense of my battery health.

    I'm mainly questioning the statement of a plugged in battery is a happy battery. Is the battery happy b/c its charging up to a higher SOC or b/c its just plugged in and possibly not charging. I'm trying to differentiate between the two to save money and b/c I'm genuinely curious at the answer for knowledge sake.
     
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  14. Ugliest1

    Ugliest1 S85: "Sparky"

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    Sorry, didn't put 2+2 together. Maybe a few more details from me will help.

    I don't plug in at all unless it's to charge. Yes a plugged in battery is a happy battery, but I live in a condo and the two charging spots are communal (so I only park there when I'm charging). With our driving we probably average plugging in once or maybe twice a week, when the car gets to 40-50% or so. It does not seem to be having any adverse impact.

    Instead of setting your charging percentage to your car's current SOC, I'd just leave it unplugged. My advice would be to charge based on tomorrow's needs, not based on how healthy the car will be (I believe it will be healthy, no matter what you do within your stated scenarios). So charge to 90% on your free night, then don't charge again until your comfort zone needs it for next day's travel. At that point, you have two choices: plug in and charge to the SOC you think you'll need for the next day (i.e., have 30%, want 40%) and do that every day until the next free 90% night (5 minutes of thinking per day). Or, (my preferred), for a couple of months just charge to 90% when you reach your low comfort zone no matter what day it is, and see how the car and your needs behave. You can then adjust -- and I'll bet it will be easier, and may only cost you a few dollars more a month, to just charge to 90% once you hit the low comfort point.

    Again because of the shared charging spots, I actually have a spreadsheet to record the kWh my car uses, and that also gives me an estimate of what I owe the condo each year. I record starting SOC, starting RKm (rated 'miles'), ending SOC, ending RKm, and total kWh used. I can then multiply the kWh by the utility's rate of charge and voila. If you do that, it will quickly show over those couple of months where you could trim some costs.

    Even if you happen across the absolute healthiest set of processes around charging for your car's battery, you won't know it because Tesla won't tell you. They don't want to make worrying about all that "a thing".
     
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  15. David99

    David99 Active Member

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    According to Jeff Dahn, it makes almost no difference if you have more frequent, small charge cycles or less frequent but deeper cycles. What matters (in terms of battery degradation) is the amount of energy charged and discharged in total. In other words, it's fine to charge 40 miles every day or wait three days and charge 120 miles. Makes no difference to the battery.
     
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  16. jdw

    jdw Supporting Member

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    In general, the battery life and capacity will be improved by using shallow charging cycles. 80->90% five or six days a week is likely better for the battery than one charging cycle from 30->90%. That is likely where the “a plugged in Tesla is a happy Tesla” mantra originates - multiple short charging sessions vs one big one.

    edit: too funny the timing of the above post and mine …goes to show that there are many opinions about this.
     
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  17. TexasEV

    TexasEV Well-Known Member

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    It's not going to be a meaningful difference. I've plugged in set at 90% every night for 4 years and have only lost 4% range (most of that in the first year as is typical). If you want to save money option #1 would be fine. If you want the convenience of never thinking about it, option #2 would be fine. Really for the amount you drive the cost to charge the car is so little that I wouldn't think about it.
     
  18. SureValla

    SureValla Member

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    I appreciate the tips thank you. I think my savings could be ~$400/year by using my method.
     
  19. thisisnew

    thisisnew Member

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    60D MX, 11K miles, 192 miles at 100% charge, steeper than what I was expecting...

    -90% of the charges with level 2 chargers, charges to 100%
    -10% of the charges with super charger, charges to 100%

    Read somewhere the rated miles not an indication of kWh retained, but an estimate based on previous 30 - 100 miles of driving? Wish there was a more transparent diagnostic output of our car's battery life...
     
  20. TexasEV

    TexasEV Well-Known Member

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    You read wrong.
     

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