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Thread: 53kwh consumed in one charge

  1. #1
    smoothoperator
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    53kwh consumed in one charge

    I drove my Roadster in range mode yesterday and got back home with about 13 miles left. I have a digital sub-meter that displays load, total KWH & KWH consumed per session.

    To my surprise my Roadster consumed 53KWH in one charge! Has anyone else had s similar experience? Is there a problem with my meter or is this possible?
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  2. #2
    Roadster #1144 + Sig 114 dsm363's Avatar
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    I did the same thing yesterday (arrived with 20 miles) but only used 47 kWh. There is an overhead to charging so I think it is possible to use more energy to charge than your battery pack can hold.

  3. #3
    Senior Member W.Petefish's Avatar
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    Quote Originally Posted by dsm363 View Post
    There is an overhead to charging so I think it is possible to use more energy to charge than your battery pack can hold.
    Think cooling.
    If it is worth doing, it is worth OVER doing. - Mythbusters

    Debunking Pseudoscience is fun!

    Arctic White Roadster 2.5 #1200, S Sig Performance Vin# 227, HAM: KF5WDB

  4. #4
    Member Tommy's Avatar
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    Even the Model S with it's built-in charger's 92% efficiency would require about 62 kWh to fill a completely empty 53kWh battery. So not surprising that the roadster's internal charger, which is less efficient would consume 53 kWh to charge your nearly depleted battery.

  5. #5
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    Last month I had this one:
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  6. #6
    Roadster #1144 + Sig 114 dsm363's Avatar
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    Wow. 88 kWh. Can that be right? What were the circumstances behind that?

  7. #7
    mod squad bonnie's Avatar
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    I'm betting a very hot day & a very hot battery. Even if you're not charging until later (when rates are low), should probably at least cool down the battery (instead of letting it sit there hot).
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  8. #8
    Roadster #1144 + Sig 114 dsm363's Avatar
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    Do we having any guidelines on how many degrees is too warm? The OVMS lists the temps in Celcius so that would give some information.
    Do you just initiate a standard charge mode for half an hour when the battery is warm? Thanks.

  9. #9
    KWH-PWR#1349Sprt,S Sig#96 scott451's Avatar
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    Quote Originally Posted by dsm363 View Post
    Wow. 88 kWh. Can that be right?
    Yes, it is.

    Quote Originally Posted by bonnie1194 View Post
    I'm betting a very hot day & a very hot battery. Even if you're not charging until

    later (when rates are low), should probably at least cool down the battery (instead of letting it sit there

    hot).
    No. It is not caused by a hot battery

    I've seen this before on the roadsterVDS via the tattler charge reports. What I believe is happening is that the 88kWh and 15h:11m comes from two concatenated charges but with a drive in between. So the total energy used to charge is correct, but it represents two charges. Here is an example (as logged by the tattler):
    Name:  dual_charge.PNG
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    Notice in the above picture, I finished charging: 243 miles, 96%, 41kWh 8:20 hrs used. I then drove the car about 80 miles (not shown). I started a charge at 3:22pm. Notice the battery has dropped to 67% and 148 miles (from the 80 mile drive). Five minutes later, I sent the "charge?" command to the tattler and the roadster reported 42Kw (41kwh from the previous charge and 1kwh from current charge. 8:20+5min). Had the roadster reset the count at the start of the charge, it would have reported "1kwh used, 0:05hrs".

    So the accounting of charge energy of the VDS appears to be correct, but some of charge history records are the concatenation of two charge sessions with a drive in between.

    So if the OP adds up all charging energy reported by the VDS (including the 88kwh) it would correctly match the reading of a wall kWh meter.


    As far as the OT, I drove 222 miles from Goleta to San Diego on 95% charge. IIRC, the battery temp was 39C and the energy required to recharge was about 65kwh.
    Last edited by scott451; 2012-05-06 at 04:03 PM.

  10. #10
    I can confirm that some "bugs" related to CSH (Charge Session History) are still not fixed (in the 1.5 Roadster). And probably won't be ... Remember THIS ?

    And here's an additional photo from January 2010 ... notice the MANY things wrong with it back then. (The "Available Current" column was dropped shortly thereafter as part of some of the "bug fixes".)
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    Last edited by ChargeIt!; 2012-05-07 at 06:17 PM.

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