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New confused owner here. How to balance battery?

Discussion in 'Roadster' started by Stewie26, Feb 19, 2018.

  1. Stewie26

    Stewie26 Supporting Member

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    I have done multiple searches on how to balance the battery and get even more confused with the more I read.
    I have a 2008 roaster, #466, with 36K on the odometer. I am not using the car as a daily driver and have been charging with the 110 volt charger. (My wife's S model has been hogging the 240 volt outlet in the garage).
    After charging in standard mode, my ideal mileage is consistently reading 170 miles. When I take to roadster out for a drive I am normally putting only 20 to 30 miles on it. When I get back home I plug it back in to top it off.
    Questions.
    Is it better to charge with the 240 volt charger or is it OK to use the 110v charger? Or does it make no difference at all regarding balancing the battery?
    Should I do a one time Range charge to help balance the battery?
    Not sure if this matters, but the previous original owner maintained the car like clockwork and did the annual service each year. He used it has his daily driver but his total commute was less than 15 miles a day.
    Any help would be appreciated.
    Thanks,
    Stewie 26
     
  2. AEdennis

    AEdennis Active Member

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    • Informative x 3
  3. DeedWest

    DeedWest 2010 Roadster 2.0 - VIN 523

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    #3 DeedWest, Feb 19, 2018
    Last edited: Feb 19, 2018
    The best way to keep it healthy and balanced daily is to continue what you have been doing - plug it in every night on Standard Mode and let it charge. The only known downside to constantly using the 110V yellow cable, is that it takes longer to charge and it keeps the coolant pump running longer. I've heard of some owners' pumps dying after just 3-4 years of exclusive 110V charging. For you, since it seems like just an interim charging fix, I wouldn't worry about long term effects. You can actually gain more miles charging from 110V since it's slower (maybe 3-5 more than 240V at higher amperage). When I charge using my UMC (240V Mobile Connector), I dial it down to 24A. This grants me at least 2-3 of those "slower" charging Ideal miles. Not to mention, it seems like the UMC is heating up less during use (which I'm hoping will extend its life).

    When I've gotten new Roadsters, I like to give the battery a nice reset cycling. If you'd like to do this, charge to full in Range Mode, let it balance for an hour, and then take it on a long drive. Plan a long drive until your pack gets below 20% (do not remove the key) before bringing it back home or elsewhere to charge. Then, let it charge all the way back to full on Standard Mode. I've heard of some owners blasting the heat or A/C to quicken the discharge of battery, and/or making a round-trip of highway miles only.

    Most of all, have fun with it! I find cycling to be exciting and a nice chance to plan out a long scenic round-trip on Google using the estimated range on the Roadster's VDS. Once you're finished, charge as normal for the next two days and you might see a change in Ideal Miles after charging. If your battery is balanced (which is more common on higher mileage cars like yours, since they've been driven often), you may not see much of a change at all.
     
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  4. hcsharp

    hcsharp Active Member

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    While this worked for AEdennis, it does not work for most people. Tesla has always recommended charging it every day. The reason for that is it has less impact on your cells to do a number of small charges than one big one given the same miles driven. Multiple battery studies have demonstrated this including Tesla's own testing.

    In addition, if you live in a warm-ish climate, charging every day helps maintain a cooler battery. If your pack is too warm it will cool it when you charge instead of letting it hot-soak for another day.

    As for balancing, some balancing occurs after a standard mode charge. The battery management system can do a better job of balancing after a range charge so if you think your cells are out of balance then it wouldn't hurt to perform a range charge. Contrary to intuition, you then have to let it sit for at least an hour afterwards for the cells to balance. As soon as you turn the key on it stops balancing until you charge it again.
     
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  5. gregd

    gregd Active Member

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    To add to this, I believe active battery cooling (using the A/C) needs a 240v charging circuit; you don't have enough power coming in to do that from a 120v outlet.
     
    • Informative x 2
  6. pharma5

    pharma5 Roadster F#25, Model 3 #36xx

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    On 120V 15A there is still active cooling of the pack, but it only does so after hitting a higher temperature threshold. This will go on periodically until the end of charging, when it goes through a final active cooling and stops charging.
     
  7. gregd

    gregd Active Member

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    Hmmpf. Didn't know it could do that. Must be using the pack's power to run the compressor, as I don't think 1.4kw is enough. Kind of defeats the purpose, but probably minimal because the pack cools pretty quickly (few minutes).

    Does it cool the pack enough for the coolant pump to turn off at the end of charging?
     
  8. Stewie26

    Stewie26 Supporting Member

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    Thanks everyone for all the help here.
    Can I do a range charge and still not drive the car for a few days or will that cause damage to the battery?
     
  9. gregd

    gregd Active Member

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    Not recommend. A few hours is fine; days would stress the battery.
     
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  10. AEdennis

    AEdennis Active Member

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    I ALWAYS drive off right after a range charge... Don't like it sitting there at 100%
     
  11. ion_1

    ion_1 Member

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    Highly dependent on ambient temperature. If it is a cold unheated garage or outside, I wouldn't worry about it even for a day or so. Most degradation that has been done is mostly completed. If it is mildly warm to hot, I would agree with the above two posts; charge and use within a couple of hours.

    100% Agree with @hcsharp: Numerous small standard charges always better the deep discharge.
     
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  12. hcsharp

    hcsharp Active Member

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    Heat is your biggest enemy. I agree with ion_1 that a range charge now and then has virtually no affect on battery life especially if it's kept cool. In addition, the coolant pump runs continuously after a range charge until the pack discharges almost down to a std charge level so it doesn't stay full very long. And if you're out of balance it will help with that.
     
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  13. AEdennis

    AEdennis Active Member

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    Please note that @Stewie26 is in Southern California... As such, "cool" and "hot" may be different temperatures than Vermont or New Jersey... ;)
     
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  14. sethr

    sethr CPO Roadster #1089

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    This has always perplexed me - If I look at the voltages of the bricks after balancing has completed after a standard charge, and the balancing grid is all 0's (or even hours after that), there's a 0.03 volt difference, which is within specs, but after a drive, the difference is 0.02 or even less. So my question is, if there's no balancing once you turn they key, how does that happen? I should note that brick #91 has always been lowest since I got my Roadster (no doubt because it apparently spent the first three years of it's life mostly in storage), if that could somehow be relevant.
     
  15. pharma5

    pharma5 Roadster F#25, Model 3 #36xx

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    @gregd, IIRC the coolant pump still flows for a bit at the end of charging before eventually shutting down. Esp. in summer. And I think you're right on the pack pausing momentarily to help get the heat out..
     

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