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Driving (not charging) in Range Mode + 24-hour 270 mile Road Trip Review

Discussion in 'Roadster' started by JohnnyLounge21, Jul 30, 2013.

  1. JohnnyLounge21

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    We know CHARGING in Range mode isn’t the best for the battery and shouldn't be done very often.

    What is the downside to using Range Mode to DRIVE as far as battery longevity?

    I recently needed to squeeze as much mileage out of the Roadster as possible to get to and from South Haven, MI and Chicago (~125 miles each way) in about 24 hours (add on 20 miles for stops and a little tooling around). My biggest problem, I knew when arriving in South Haven, I only had a 110V 15A to charge with. And it was just a quick overnight so I was only going to have ~14 hours to charge. Those with their spreadsheets out already know I had a tall order in front of me!

    So I charged to absolute maximum before leaving Chicago (including about 2 hours of “top off”) and had ~230 ideal miles (on my 26K #1190) in Range mode. It was a little spooky taking off b/c regen was deactivated (for obvious reasons). That car will REALLY roll with no regen. Anywho, We arrived in South Haven just fine with about 70 miles ideal left in “Range” (we made a couple stops and I drove non-conservatively, but NOT aggressively). Again, the whole trip was done in Range (and very little no drafting). I switched to “Regular” mode to charge the vehicle and ideal miles plummeted to around 40 or so (don’t remember exactly). Then charged for 14 hours. In the morning, it said I only had 110 miles on the charge. I was obviously a little perturbed (again, trip back with no stops is 125 miles). I clicked it into Range mode to drive and that went up to 145 – feeling a little better. But on the dash, it said I had 120 miles. Very WORRIED again (do you tell the GF and freak her out? I mentioned it softly and she took it OK and said that if I wasn't worried, she wasn't worried. OK - cool!). So I drove very conservatively including drafting on the way back. As the ideal miles on the console began to bleed, the dash stayed at 120 for about 20 mins! I was delighted. My GF had the GPS going and kept reading down the lower and lower mileage home as my dash continued to sit at 120. Finally, the console started catching up with the dash and they both started to bleed. We made it home with zero issues (I drafted about 90% of the time behind a truck and went about 65 MPH the whole way). When we arrived home, the console and dash said 25 ideal miles left. I was thrilled! I dropped of the GF at the foot of my building to walk the pooch (who came with us for the trip) and clicked the console monitor to change it back to “Normal” range. The fan BURST into action behind me and I get this warning on the console that I have 2 miles to go and the car is going to shut off! I was pretty darn scared! I still needed to get the car up to the 5[SUP]th[/SUP] floor of the parking garage in my building and obviously, this is all uphill! That’d be ALL I’d need is a flatbed right on front of my condo building with my pretty toy sitting on it for the neighbors to laugh at! I switched it back to “Range” and the fan settled down and I quickly zipped it up the ramp and to my space and stared charging immediately. Crisis averted! I’m now charging in “Storage” mode b/c I’m going to be away from the car for the next 17 days **sniffle** and I hope it’s not too upset with me when I get back (at which point I’m going to bump it up to “Normal” and let it fully charge and I’ll take it out about 48 hours later).

    So, again, did driving in Range mode for this sequence put a hurt on my battery – at all?
     
  2. wiztecy

    wiztecy Active Member

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    Driving the battery above 85% or below 15% is what typically is bad for the pack... also worse with temperature. That's why Tesla charges to 85% in Standard mode and you can access the lower 15% using Range mode. I wouldn't be scared of using it... I typically use it as a reserve tank on a need be basis.
     
  3. augkuo

    augkuo Member

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    What decreases your battery life is the time it spends less than 20% and greater than 80% of capacity (less than ~48 miles and greater than ~192 miles in range mode) and also above 30C and less than 0C. So charging in range mode and immediately taking off on a long drive won't do too much and it was also good you charged after you got home so that the fans turn on to cool the battery. You'll need to charge occasionally in range mode to balance the batteries and once it reaches the maximum amount, do a long drive to bring the state of change (SOC) below 80%. Glad you made your trip with no problems! The trick is to drive slow on the freeways which is hard to do in a roadster ;(
     
  4. wiztecy

    wiztecy Active Member

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    Also if you're going to leave the car in Storage Mode for 17 Days I'd at least have the pack charged up to 50% in case of a power outage or a technical problem with the charger.
     
  5. Doug_G

    Doug_G Lead Moderator

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    What Range mode does on the Roadster, aside from charging to 100% and draining to 0%, is this:

    1. Runs the HVAC harder during charging to precool the battery. So charging will actually take a little longer (want the fastest charge? Use Performance mode. It does the opposite.)

    2. Runs the HVAC as little as possible during driving to conserve power. This is probably a bit "bad" for the battery as it allows the pack to get warmer. I doubt it matters in cool conditions, but it might affect battery life slightly in extreme heat.
     
  6. djp

    djp Roadster 2.0 VIN939

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    Driving in Range mode also reduces the power available for acceleration.

    Driving below 20% SOC isn't bad for the battery as long as you don't punch it - a high current draw at low voltage is hard on the pack. The car will protect itself by going into power limit mode at low SOC and you can help by driving conservatively.

    The biggest risk of low SOC is dropping to absolute zero and irreversibly damaging the pack, which you've successfully avoided. Close call but at least you've now got a better feel for the limits of the car.
     
  7. wiztecy

    wiztecy Active Member

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    #7 wiztecy, Jul 30, 2013
    Last edited: Jul 30, 2013
    The depth of discharge *is* a key factor to a lithium battery's life. Same goes with full charges...:
    How to Prolong Lithium-based Batteries - Battery University

    Again, my rule of thumb (given there's no bugs in the pack or firmware) for battery longevity is to keep the Temps at 26C or below when possible and SOC hovering on AVG at 50%. When doing full charges I drive it down like Augie said ASAP and try to push it at least to 85%. Anytime I drive it below 50% I'm easy on the accelerator and not throwing burst into the pedal. I'm not afraid to drive it down to 20% or even 10% but I don't want to make it a habit and I don't ever let it sit there for any standing time if I can prevent it... again I try to shoot it to 50%. Short discharges is what the Lithium battery likes. My daily commute I Std charge to have the Roadster ready 1/2 before I leave so it can properly balance... So from 50-60% SOC I'm now at 85% SOC. I then drive 35 miles one way where the roadster would sit. SOC is now at 70%. At the end of the workday I commute back home 35 miles with my SOC at 55%. I then do an immediate cool down of the pack with the 240V charger to drop the Battery temps from 32+C down to 21-26C. I then let the Roadster sleep at 55% SOC with a cooled pack until morning where my charge begins and ends 1/2 hour before I leave work. Some people say its lots of work... it really isn't. It's just being conscience of the pack and what environment it prefers.

    I've worked with Lithium Batteries, been close to battery engineers who test them, and have seen the test data. Also when doing a google search you can come up with your own results hence where I re-enforced mine.
     
  8. JohnnyLounge21

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    Such great thoughts all around. Really appreciate the help, team!

    "I then do an immediate cool down of the pack with the 240V charger to drop the Battery temps from 32+C down to 21-26C. I then let the Roadster sleep at 55% SOC with a cooled pack until morning where my charge begins and ends 1/2 hour before I leave work."

    How do you do this entire sequence? Meaning - you initiate all of this yourself? Or can you set something up with the OVMS or on your charger or within the car to do all this for you?
     
  9. wiztecy

    wiztecy Active Member

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    Mark is implementing this "cool down" feature as we speak for the OVMS. My guess is that in the next release he'll have it. Keep following the OVMS threads for updates... I currently do the cool down manually when I get home each day.

     
  10. JohnnyLounge21

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    Great to know! I think Mark is a little overwhelmed at the moment with all that he's got going on. I asked him a couple questions via PM and haven't heard back just yet. I know he's also on opposite time as the US - so that may be causing a little delay also.

    Is "cool down" something that is an actual charger setting? Can it be done with a 110V?
     
  11. wiztecy

    wiztecy Active Member

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    Won't work under 110v, I tried to do this at work and the HVAC failed to kick on. Don't know the outcome on a 20AMP but it may be the same. Talked to Tesla and they said the system under 110v will begin cooling down when the pack is really hot, 38C-40C... but that's when the HVAC system will kick on anyways without AC current flowing through it. So the answer would be no. If you have any more questions on the OVMS/Cool down I'd start asking them under the OVMS threads to keep this tread on topic.

    OVMS Installation - Page 19

    Yes, Mark can be pretty busy so it may take some time for a response.
     
  12. rgjones

    rgjones Member

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    #12 rgjones, Aug 29, 2013
    Last edited: Aug 29, 2013
    I've been doing something similar with Tattler V2 for some time now, in a manner that lets me just plug in and walk away.
    Here are the typical settings;

    charge mode range
    charge target 60
    charge limit 33
    cool 25
    per
    1: daily home 0545 <charge target 180. charge start>

    My car is set to charge at 1am. When I plug in, instead of stewing with a hot battery, cool down runs immediately with a target of 25C (can use F if prefer). This typically uses only 1-3KW.
    The car then sits with a nice cool battery till 1am where it starts charge.
    The charge parameters are over ridden with range mode (more cooling), a nice gentle 33A current limit and '60' means stop at 60% SOC.
    The daily periodic, home location command kicks in at 5:45am, temporarily sets the charge target to 180 (miles, but can set it for km) and starts charge.
    The start time can be tweaked to ensure 30mins or so of balancing before the car is driven.

    When not at home (e.g. 'away') there are a different set of charge & monitor params which optimize for opportunity charging;
    charge mode range. charge limit off. charge target 200. mon 5 min. mon end. mon cool on
    Here the car charges immediately in range mode (for better cooling) using max available current, stopping at 200mi of range (more than standard, but not enough to lose regen), with more frequent monitoring sms messages including nerdy alerts when the car starts & stops cooling the battery.
     

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