What's your realistic "worst case scenario" for CT range/efficiency concerns?

WildhavenMI

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So I've been going through the process of "worst case scenario" planning for my personal field work applications for my CT, and I've think I've figured out my not-exactly-uncommon "worst" scenario.

There are a few days a year where I'm in-the-field, ~100-120 miles from home in the bush, on COLD days (sub-zero Fahrenheit), with ~500-600lbs of stuff in the bed. Assuming I start from home on a full charge with a conditioned battery, drive the 100 flat miles to the site, then the truck sits outside in the subzero weather all day until I get done, and then I gotta drive the 100 miles back. I'm trying to figure out just how much range loss to expect not just in the cold driving, but in the super-cold start after a day in the open air.

IMO, these days are "cutting it close" on a 400 mile range CT. And charging en-route home is...well, in the part of MI I'm taking about travelling to there are no superchargers (Tesla or otherwise). While these are not common days for me, they do happen once or twice a year at a minimum.

What's your personal, realistic, "worst case scenario" range day?





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egandalf

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So I've been going through the process of "worst case scenario" planning for my personal field work applications for my CT, and I've think I've figured out my not-exactly-uncommon "worst" scenario.

There are a few days a year where I'm in-the-field, ~100-120 miles from home in the bush, on COLD days (sub-zero Fahrenheit), with ~500-600lbs of stuff in the bed. Assuming I start from home on a full charge with a conditioned battery, drive the 100 flat miles to the site, then the truck sits outside in the subzero weather all day until I get done, and then I gotta drive the 100 miles back. I'm trying to figure out just how much range loss to expect not just in the cold driving, but in the super-cold start after a day in the open air.

IMO, these days are "cutting it close" on a 400 mile range CT. And charging en-route home is...well, in the part of MI I'm taking about travelling to there are no superchargers (Tesla or otherwise). While these are not common days for me, they do happen once or twice a year at a minimum.

What's your personal, realistic, "worst case scenario" range day?
My worst cases would all be pretty survivable, generally. Nothing like yours. Most of my concerns would be around driving 100 miles to an airport, leaving the vehicle in Sentry mode for 4-5 days, and then needing to drive home (in freezing temps half the year, but nothing like the northern US).

Since I've ordered the Dual CT, I would wonder how close I was cutting it if there are no available/working charging stalls. The cities I would go to have only one Supercharger each.

I have found more charging options using PlugShare, though, so in a pinch it could supply the necessary range boost to get home.
 

ajdelange

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Your 500 mile CT goes about 5 miles on 1% of a full battery and has a working range of approximately 400 miles (90% to 10% SoC region). With the mission you mention you would probably leave the house with a 90% charge and use 20 - 24% of its charge in getting you out 100 - 120 miles so you should arrive at your destination with 66 - 70% SoC remaining. You will, after having driven the truck for a while, learn how realistic that consumption level is for your style and driving conditions. Thus if you are on open roads with a heavy foot you might only get 4 miles per percent and use 25 - 30% in getting there leaving 60 - 65% to get you home. You will also be aware that there are weather related conditions that can increase your consumption even more. So you monitor your usage as you drive outbound. It's probably pretty clear that if you arrive at the site with more than half the battery (meaning that you used 40%) you can probably get home on the remaining 50% but this isn't always the case. If you used 40% to get going down hill with with a howling tail wind you probably won't get back driving uphill into that wind on 50%. Conversely arrive with 50% after driving uphill into a stiff crosswind you should be able to get home without problem.

The message is that you must be cognizant of what head winds, uphill and rain/snow can do to you and you must monitor consumption as you go.

Extra weight and cold weather are not the huge bete noir that the popular chatter makes them out to be, especially with the new heat pump systems in the later Teslas. For example, in driving 120 miles with a 2 kWh heater load at 60 mph you will use 4 kWh of battery energy. That is 2% of the generally suposed 200 kWh battery in the TriMotor CT.
 
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WildhavenMI

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Your 500 mile CT goes about 5 miles on 1% of a full battery and has a working range of approximately 400 miles (90% to 10% SoC region). With the mission you mention you would probably leave the house with a 90% charge and use 20 - 24% of its charge in getting you out 100 - 120 miles so you should arrive at your destination with 66 - 70% SoC remaining. You will, after having driven the truck for a while, learn how realistic that consumption level is for your style and driving conditions. Thus if you are on open roads with a heavy foot you might only get 4 miles per percent and use 25 - 30% in getting there leaving 60 - 65% to get you home. You will also be aware that there are weather related conditions that can increase your consumption even more. So you monitor your usage as you drive outbound. It's probably pretty clear that if you arrive at the site with more than half the battery (meaning that you used 40%) you can probably get home on the remaining 50% but this isn't always the case. If you used 40% to get going down hill with with a howling tail wind you probably won't get back driving uphill into that wind on 50%. Conversely arrive with 50% after driving uphill into a stiff crosswind you should be able to get home without problem.

The message is that you must be cognizant of what head winds, uphill and rain/snow can do to you and you must monitor consumption as you go.

Extra weight and cold weather are not the huge bete noir that the popular chatter makes them out to be, especially with the new heat pump systems in the later Teslas. For example, in driving 120 miles with a 2 kWh heater load at 60 mph you will use 4 kWh of battery energy. That is 2% of the generally suposed 200 kWh battery in the TriMotor CT.
I'm wondering if my efficiency loss related to cold weather is less on heating the cabin (which, I'm dressed for subzero field work already so NBD for a cold cabin) and more on how the battery is going to act at that temp. I've seen YT videos and the recent Model Y vid on cold starts, but they're "cold weather starting" at 30 degrees. I'm not sure how much more severe the drop is at zero vs 30.
 

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As the temperature drops the COP (ratio of heat produced to heat consumed) drops so that while it may be over 3 at 30 it could be down to 2 or even less at 0. But as noted above even if you are using 2 kW for heat that's only 2000/60 = 33 Wh/mi at 60 mph and your other loads are going to be around 450. You can, of course, save some of that 33 Wh/mi by using the seat heaters instead of cabin heat.

Keep in mind that the battery is less efficient when it is cold soaked but the innefficiency goes to provide energy to heat the battery. Losses in the inverters and motors also heat the battery and, in the later cars, heat is taken from the outside air to heat the battery even more. Once it is warm it is not inefficient.

We won't know exactly how this is going to play out until the trucks are in our hands. The message remains the same as in my previous post. Once you have your truck learn how it behaves under various driving conditions and learn how to use the instrumentation it provides you for managing energy. If you do this you will not have trouble. It is only fair to point out that if you are blessed with, for example, my wife's level of intuition about technical things this is all going to be a great mystery to you.
 

egandalf

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I'm wondering if my efficiency loss related to cold weather is less on heating the cabin (which, I'm dressed for subzero field work already so NBD for a cold cabin) and more on how the battery is going to act at that temp. I've seen YT videos and the recent Model Y vid on cold starts, but they're "cold weather starting" at 30 degrees. I'm not sure how much more severe the drop is at zero vs 30.
The biggest battery concerns in cold weather, from what I've read, seem to be present *until the battery reaches peak temperature.* Meaning, while the battery is cold, your efficiency is awful but once the battery itself warms up through the octovalve magic and just plain movement of electrons through metal things should get back to (relatively) normal efficiency.

Something I'd like to know is whether you might get better daily efficiency by letting the vehicle just keep the battery warm for those 8 hours you're working versus letting it get super cold and warming it up again during the drive home.

Anyone have this type of experience?
 

ajdelange

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I don't, happy to say, have the experience but can reason that it doesn't matter whether the energy lost by the battery due to cold is replenished slowly or all at once. The key to being more battery efficient is to get the energy that keeps it warm from somewhere else. Following this reasoning it is often advised that one schedule his home charging such that it completes just prior to planned departure. Charging warms the battery thus in this case the warming energy comes from the mains. In the field sheltering from wind (minimizing the loss to cold) might help as, of course, would parking in a heated Quonset or other shelter. For the case discussed I don't see a problem but I am not privy to all the details.
 

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So I've been going through the process of "worst case scenario" planning for my personal field work applications for my CT, and I've think I've figured out my not-exactly-uncommon "worst" scenario.

There are a few days a year where I'm in-the-field, ~100-120 miles from home in the bush, on COLD days (sub-zero Fahrenheit), with ~500-600lbs of stuff in the bed. Assuming I start from home on a full charge with a conditioned battery, drive the 100 flat miles to the site, then the truck sits outside in the subzero weather all day until I get done, and then I gotta drive the 100 miles back. I'm trying to figure out just how much range loss to expect not just in the cold driving, but in the super-cold start after a day in the open air.

IMO, these days are "cutting it close" on a 400 mile range CT. And charging en-route home is...well, in the part of MI I'm taking about travelling to there are no superchargers (Tesla or otherwise). While these are not common days for me, they do happen once or twice a year at a minimum.

What's your personal, realistic, "worst case scenario" range day?
You mentioned that you will need to drive out to the bush for work. Question: Is there a 110v power source nearby the job site where you can plug in your travel charger via extension cord?
 
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WildhavenMI

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You mentioned that you will need to drive out to the bush for work. Question: Is there a 110v power source nearby the job site where you can plug in your travel charger via extension cord?
Unless I bring a generator, no. It's not construction work, it's habitat work and there's rarely if ever outbuildings or electricity.

I did consider some sort of suitcase solar strictly for warm up, but IDK if it'd be robust enough to make a difference -and would the additional weight being carried offset that gain at all anyway.
 

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On my bike, which has no way to heat the battery, loses up to 50% range and can get power-limited to 50mph.

A Tesla has a heated battery and thermal management, so your losses are limited to heating the pack and the cabin.


35% loss at no pre-charging (which you described) at ~10F. So alot less than my bike! (And somewhere near what my car gets in that sort of weather...)

As has been pointed out, weight isn't so much the issue as bulk, so if you have a solar trickle, it would counter-act a little of your lost range. Remember, your Cybertruck will try to keep itself ready for you, so will consume energy now so more power is available later.

-Crissa
 
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rr6013

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Global warming is the new Armageddon.

After Eta then Iota storms, back to back, here in Panama, days apart, they symbolize my worst case scenario. Nicaragua took the brunt of the storm system twice. That happens in Panama, Texas, Louisiana or Florida it would cause similar infrastructure havoc.

Expecting the apocalypse from that vector reflects my history with back to back 100 year snows living in the Wasatch. Back to back firestorms late eighties and nineties in So. Cal. And it dovetails my wedding driving back 200 miles in 12 in. snowstorm that even the Iowa DOT had pulled plows off the roads. I had my three other best men caravaned and chained up to get back.

Weather has always been the unplanned event that my trusted wheels need to get me through and out of harms way. My biggest fail was -30F driving across NE I-80 where the heating system couldn’t clear the side windows from icing over.
 

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I reserved a 2 motor ct and worst case acceptable for me is 300 miles but i'd love to see 350. Anything under 300 isn't of use to me. Good news is that with the recent stock run i think i might opt for the 3 motor.
 

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Some things to keep in mind:
  • You will want to max charge to 90% daily. Typically anything 70-90% is recommended.
  • You’ll start off by warming up your vehicle 20-30 min before you leave for the site, which will help condition your cabin, and the battery pack. If it’s like the Model 3 and Model Y, it won’t have a dedicated battery pack heater.
  • Your efficiency will typically drop 30-40% in below freezing, and down to subzero.
  • I have driven my model 3 in subzero temps, and a dual motor would cut it close..especially with pre-conditioning of the cabin again before you leave the site. 20-30 min again.
  • Tri-Motor will be able to handle the range no problem.
  • The battery in app and on the vehicle will show a snow symbol, and show you the % you don’t have access to at that moment until the battery is warm enough. This is where pre-conditioning the cabin, helps.
 

CostcoSamples

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Here's my worst-cast-scenario. This is a trip I make maybe once every year, but similar trips (slightly less extreme) would be frequent.

Out of town trip in Canadian winter, at -35 C, driving between Saskatoon and Edmonton. The trip is about 550 km across northern prairie, cold AF. There are very few stops along the way, and charging is virtually out of the question. Best you could hope for is a 15 amp 110V.

Charge the night before up to 95% because it is a rare occurrence and as such, damage to the battery should be minimal.

500 miles = 800 km
800 km x 95% = 760 km
760 km x 60% (40% winter reduction) = 456 km!

Therefore, the trip is not possible without special measures. If I charge to 100%, winter reduces range to 480 km, still not enough. Only solution is going to be a reduction of speed and/or attempt a reduction in cabin heat.

Please note: a reduction in cabin heat might not be possible. Travelling in such extreme cold means you need constant heat on the windshield or it frosts up very quickly. BUT, if you reduce the speed you could likely also reduce the heat. Perhaps at 90km/hr the trip would be possible.

As you can see, range is king if you live in Canada. Our distances between cities are vast, and only major routes have superchargers. I really don't need a tri-motor setup, but the largest battery is the only one that makes sense. I would already own a Tesla if they offered larger batteries.
 

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When you're going on a long trip, charge to 100%. You can tell it to precondition, and even without a dedicated heater, it will heat the pack while plugged in. Doing that and you'll lose less range than the guy in the video.

Damage from charging to 100% is about sitting up there... not just getting there at all. And this would definitely be it!

If you have access to a 15a 110v, that's what the granny cable is for. It will keep it from losing charge from the cold, and allow it to heat the cabin. And after all that, it will gain a few miles per hour.

-Crissa
 

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