Pushing range: How far can you really go?

[ZeeDoktor]

@ICUDoc I shared the drive details in the link above. I drove to just past Taree and back. Left at 9:30pm so as to avoid causing too much disruption to others. I am however doing a P80 in a sense, so don't feel too bad about making the trucks pass me. The big surprise came on the way back between Newie in Sydney: Time was 3:15 - 4:30am and the highway was incredibly busy with both tradies and B-doubles flying past me doing 130. Yikes. I had to go past 80km/h on occasion and pretty much drove looking into the rearview mirror more than up front...

Next one I'll do down towards Hay. I have some more metrics to measure so I can create a range gauge in my app that gives me predictive range based on various speed scenarios (i.e. at 80 km/h your range is 400km, at 90 km/h it's 350km, you get the idea).

Also, as per above, I didn't log the minimum cell voltage which would have been the more important parameter to log than average cell voltage at ultra low SOC.

 

[ICUDoc]

Next one I'll do down towards Hay

I did some driving around Alice last year.
There is a trend for some of the locals to drive VERY slowly (like 40-50km/h) between stops out there- I think it's about saving fuel money.
I can't guess what the model S range would be in warm conditions at 50k....

 

[Backpacker42]

Your tolerance for risk is much higher than mine.

I lost my range anxiety after taking one trip the day after I got my car (it was only a 2 hour trip one way, but I miscalculated how far I could go on my charge). Ever since then I always make sure I have at least 15 - 20% charge as buffer left for the next charging stop so that I never have to go through what you had to experience above. I wonder if this behaviour is considered "range anxiety"?

Ofcourse this will not apply in places where there isn't a charger available to keep that buffer.

Not sure I would call it "range anxiety". I try not to drop below 15-20% on my ICE vehicles either. SInce I have older vehicles the fuel pickup is in the front of a flat tank. Guess what happens if you accelerate hard or go up a hill with less than that. I have taken my Tesla 3 down under 5%, but that is because I had to stop in an RV park to add 25 miles of range to make it to a supercharger and maintain my self-imposed margin. Should have added more but I was in a hurry. Took a wrong turn and was heavy on the pedal winding through the mountains so ate up most of my margin. At one point it told me I didn't have enough range to make it, but fortunately it was all downhill to the charger at that point and arrived with 10 miles to spare.

 

[Les236]

Mar 2018 MX100D MCU1, AP2.5, FSD
Thanks for the info. This is excellent data and I want to try the same with my MX at slower speed and hyper-miling. I have definitely seen that if I take it slow range is way more than advertised. I would do it over parts of Florida that are flat. I think the rated distance is based closed to 60mph, 100kph average. I typically go about 80mph. I have made a couple cross country treks (USA) and several Boston-Orlando-Boston trips. I have always relied on the car to project my percentage upon arrival, and is usually one or two percent higher upon arrival than what was projected at the start of the trip. Several times I did arrive at around 5-7%, but that was what the car predicted. There were a few times I had the message to stay below a certain speed, but found if I am at the beginning of a leg I can mostly ignore those as there will be natural things come up that force me to slow enough to eventually break even. Only once did I have an Oh S@#t moment. Last November going from Orlando to LA we were arriving late at a SC and decided we should eat first before places closed. We were at 7% and 2 miles from the SC. However the temperature was about freezing and when we came out 40 minutes later the car showed only 1% left. We took it very easy for the 2 miles to the SC with my wife saying "I'm not pushing". (Can you push a Tesla with a dead battery?). Now that I have heard going below 10% is not good I try to not go below that or at the most 9%.

So if suddenly you lose power when the car shows more than enough power to reach your destination, something has failed and I doubt a 12v battery. I hope they found and fixed the issue with that car so it doesn't strand someone else.

 

[KalJoMoS]

how can I balance the battery pack....do you run down to <20% and then charge to 100% and go drive? if you do that, how many times and at what intervals do you repeat the process and what do you look for to notice whether anything has changed

It’s been suggested here in the TMC that run the battery level to 5%, leave it for few hours, then charge to 100% and leave it there as well for few hours. Repeat this on the next day and you should get back to the original balanced battery level. It’s been noted that all the frequent small charging cycles have confused the BMS to be balanced.

 

[RichNot]

Thanks. Even though your conditions (speed, most level surface, no HVAC, etc.) are beyond what I would consider normal driving, your test gives a good indication of what contributes to battery drain. The list might be useful when I fond myself with an unexpectedly low battery and too many miles.

 

[r1200gs4ok]

It’s been suggested here in the TMC that run the battery level to 5%, leave it for few hours, then charge to 100% and leave it there as well for few hours. Repeat this on the next day and you should get back to the original balanced battery level. It’s been noted that all the frequent small charging cycles have confused the BMS to be balanced.

we dont go too far or drive much....therefore, we charge about every 7-12 days.....when you say repeat the next day, does that mean I need to drive the car down to 5% and then charge back to 100%

 

[KalJoMoS]

Model S and X have shorter BMS monitoring period than Model 3 so to get it balanced again it’s advisable to repeat this in a row, so yes it’s quite demanding to achieve. I was able to do this on a road trip, but it was a year ago...

 

[serpico007]

I find it hard not to accelerate with my car but knowing I have that long range helps if I need it.

 

[ZeeDoktor]

@Les236 did you notice the yellow dashed arc on the energy meter on the dash? You're really only near empty when this arc starts to show limiting available power so the battery voltage doesn't drop to damaging levels under load.

 

[A-Wimoweh]

Not anymore. lol

I had what I consider to be "range anxiety" when we bought our first EV/Tesla but this was slowly eroded by reading posts on forums from owners about some "mystery reserve" BS and other anecdotal experiences that made me feel like if we did get down that low it wouldn't be a big deal. I helped me to relax a little bit more about that zero number even though I was previously the type who also wouldn't go to 15-20% predicted much like yourself. It's not always that easy depending on what model Tesla you're driving, the conditions and spacing of the Superchargers though. I forced me to take a slightly "riskier" chance than I otherwise would have.

Interesting though that from the moment we left one Supercharger headed for the next my estimated range was always right about 2x what the distance was needed for the next Supercharger stop. This would lead the average human to think you had plenty when you left and question or second guess it once the entire way. The car agreed with me and never once did it warn me to decrease my speed to reach my destination. Nothing at all. Just... dead. First time I've ever run out of "go forward juice" in any vehicle in several decades of driving. Lots of people with cameras taking pictures of the Tesla on the side of the highway as they went by isn't a good look for the brand either as I'm sure whatever they tell their friends won't be good and will further perpetuate the false narratives of the "Tesla experience" as a whole.

I've read on here in the past that your HV battery periodically recharges your 12v battery, but this doesn't happen when your HV battery gets below a certain %, I want to say that was 20%? So it is entirely possible that if you were pushing the range and had a questionable 12v battery, and were running lights, AC, radio, etc. that the 12v battery ran out of juice before the HV battery, and caused what you described.

 

[Les236]

@Les236 did you notice the yellow dashed arc on the energy meter on the dash? You're really only near empty when this arc starts to show limiting available power so the battery voltage doesn't drop to damaging levels under load.

Yes, definitely saw that and new I had limited acceleration available, but it was all along the highway access road and not going very fast.

 

[r1200gs4ok]

It’s been suggested here in the TMC that run the battery level to 5%, leave it for few hours, then charge to 100% and leave it there as well for few hours. Repeat this on the next day and you should get back to the original balanced battery level. It’s been noted that all the frequent small charging cycles have confused the BMS to be balanced.

I am at 7% now....time here is 1015pm....will be charging at 0115am and when complete will allow to sit for 3 hrs then take a trip.....hopefully, I can run down to 5-7 per cent and do it again.....then I will be able to see what's going on

 

[KalJoMoS]

It’s all to the individual battery condition, don’t expect instant recover. For me it took one or two months to see it on battery range. It was app. 8% gained, around 25km, I have 70kWh battery. I did not noticed it until I had to charge again to 100%. Now year later the battery rage have started to drop again, being 1% lower.
There are several discussions here about this BMS and the voltage of individual cells and how it’s been balanced both on Model S and Model 3.