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Top off Function

Discussion in 'Roadster: Technical' started by Tomihly, Nov 30, 2013.

  1. Tomihly

    Tomihly Rdstr #350; S #13833

    Joined:
    Aug 14, 2010
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    Location:
    Switzerland
    #1 Tomihly, Nov 30, 2013
    Last edited: Nov 30, 2013
    I already placed this question in the forum 3 years ago, but got no reply, so I try again with a new thread :smile:: Can anyone explain what should happen when you press the "Top off" button on the 2.5-Roadster screen? Back then our sales rep in Zurich told me that this would allow to charge the battery to the absolute maximum possible (100% capacity), while a range mode charge would only go to about 96% capacity. He recommended not to use the function if not absolutely necessary.
    I have followed this advice for more than 3 years.
    A couple of weeks ago, following a range mode charge, I decided to hit the "Top off" button for the first time to see what 100% means after 3+ years and 66'000 km of driving (for info: It seems I have now a standard range oscillating between 268 km in winter and 282 km back in summer - i.e. the lower the ambient temp., the lower the capacity of my battery). What happened was that the loading process resumed for about 2 minutes, then stopped again. Similar to what happens when you disconnect and re-connect the charging cable after a full charge. The battery-charge status indicator kept indicating about 96% afterwards.
     
  2. wiztecy

    wiztecy Active Member

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    From my experience "Top Off" does just that, tops off your charge. Mostly in Range mode you'd use it. Its where you charged in RM, fiddled around packing 1-4 hours have passed after the charge finished and the pack's been bleeding down the charge. You'd hit Top Off to get back most of the miles you've lost. Its a silly button in my opinion that just causes confusion. If I wanted miles back in my pack I'd re-initiate the charge again. I haven't seen the Charge climb any higher than what the original charge had yielded.
     
  3. Doug_G

    Doug_G Lead Moderator

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    I agree with wiztecy. I've pressed it shortly after a Range mode charge, and the car started charging, added a grand total of 0 km of extra range, then stopped again.

    It appears to be useful if you've left the car sitting for more than an hour after Range mode charging, and the balancing process has bled off some range and you want it back again.
     
  4. ViperDoc

    ViperDoc Roadster 1305

    Joined:
    Jun 24, 2011
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    Location:
    Vermont
    Top off works



    I have used it to push about 5 miles or so into my battery after I did a range charge overnight and wanted to get a couple extra miles in the morning before going on a long trip. I think the max range I saw was something like 248 miles.
     
  5. Tomihly

    Tomihly Rdstr #350; S #13833

    Joined:
    Aug 14, 2010
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    Location:
    Switzerland
    Impressive numbers... 248 miles, equivalent to 397 km!! Not even when I got my brand new roadster in 2010 did I get this much from a RM charge. I think, something around 365 km (228 mi) was the maximum. Now, it's down to some 335-345 km.

    Thanks for the info!
     

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