Worst-case Scenario Range Estimates for each battery type

[Lynx]

I've spent a lot of time recently thinking about which battery option I should get, and that has led me down a rabbit hole of analyzing worst-case scenarios and thinking about what are my most realistic needs day-to-day. For a little bit of fun, I've gone ahead and drafted some worst-case scenario range estimates (these are just my own rough estimates) and I've included my considerations below. I'm interested to hear what everyone thinks about theses estimates, are these probably accurate or inaccurate? and what other further considerations am I missing? I'd love to hear everyone's thoughts on this!

For my hypothetical worst-case scenario thought experiment, let's include the following factors:
- Battery Aging (reduced maximum capacity over time)
- Healthy Battery Charging Habits (keeping the state-of-charge most of the time between 80% and 20% to reduce battery aging)
- Winter/Bad Weather Conditions (assume higher energy usage for battery management system and cabin heater)
- Possible SUV Kit and Possible Cargo/Passengers (more weight)

Battery Aging
As a broad generalization, let's assume 8% loss of battery capacity due to battery aging over the course of a few years (I'll leave it up to your interpretation how long 'a few years' is to keep this simple). I'm just choosing 8% for this hypothetical but we could assume less or more battery degradation if needed.

Healthy Battery Charging Habits
Let's assume you don't want to regularly discharge the battery all the way, in order to preserve your battery and reduce aging. You also don't want to regularly charge it up passed 80% for the same reason. If you're aiming to not charge above 80% and not drive below 20% then you're looking at ~60% of the battery's full capacity as actual usable range day-to-day excluding occasional long trips. If you want to take extra care of your battery you may not even want to let your charge get lower then 30-40%, but for this hypothetical I'll just assume a 60% spread (could be 80-20%, or 85-25%, etc...)

Winter/Bad Weather Conditions
For this hypothetical, I'll pull an estimate from another member on a different thread: -40mi for every 100mi of range on a really cold winter day (-40% range). As a disclaimer I have no idea the accuracy of this estimate, so I'll just let you interpret exactly how cold 'a cold day' is, and I'll note that Slate has said that on their initial vehicle they will use an energy-intensive resistor heater (cheaper for them) as opposed to a more energy efficient heat pump (more expensive part).

SUV Kit / Cargo / Passengers
This is perhaps the hardest factor to generalize/standardize for, simply because it will vary from person to person for each of our subjective day-to-day needs. Bearing this in mind, I will do initial estimates based on the blank Slate with no add-ons, no cargo, and just you the driver. After initial estimates I'll leave it up to you to subtract any additional range based on your plans for add-ons, cargo, and passengers.

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Worst-Case Scenario Estimates for Range:
Extended Range Battery, Blank Slate:
240 mi = Total battery range from 100% to 0%
220 mi = Max range assuming 8% loss with battery age (19.2 miles say 20) [-20 mi]
132 mi = Max range if you keep the battery state-of-charge (SOC) between 80% and 20% [-88 mi]
80 mi = Max range assuming cold battery and you're blasting the heat on a cold winter day. [-52 mi per 132mi (-40%)]

Standard Battery, Blank Slate:
150 mi = Total battery range from 100% to 0%
138 mi = Max range assuming 8% loss with battery age [-12 mi]
82 mi = Max range if you keep the battery state-of-charge (SOC) between 80% and 20% [-56 mi]
50 mi = Max range assuming cold battery and you're blasting the heat on a cold winter day. [-32 mi per 80mi (-40%)]

This leaves the worst-case scenario range for the base truck with no modifications or extra weight as:
Extended battery: 80 mi
Standard battery: 50 mi

BONUS: Let's say you have the SUV/Fastback kit installed (more weight) you might be looking at even shorter range. Also if you are hauling anything of significant weight, either cargo or more passengers, you would see even further range loss. Assuming you have SUV kit and 3 passengers + you the driver and possibly some light cargo, we could take off another ~10-20 mi from each and assume worst case range in that case would be ~65 mi and ~35 mi respectively.
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In either worst-case scenario on a winter day, the extended range should definitely still be enough for most people day-to-day, and for the standard range maybe you keep your battery SOC between 15% and 85% in the winter to just give you a slight range boost without significantly increasing your battery aging. In my case however, I happen to have a 50 mile commute to my job (thank you job market conditions right now) and a 50mi commute back to home every day, not including any errands. So in my situation, I would need at the very least 100mi of range bare minimum but 120-140 mi to not feel any range anxiety. So in my case, I'd either have to find a charger near my job and charge while I work or I'd have to take the hit to my battery aging/life long-term and just use it fully charged in the winters.

Anyways, for anyone whose made it this far through my rambling assumptions, I'd love to hear your thoughts on this, as well as your own range needs and estimates!

 

[ScooterAsheville]

A couple of inputs. First we don't even know what battery or battery chemistry Slate will use - because they recently announced they're trying to resource battery suppliers to remove cost. That's because some battery makers in the USA now have excess capacity as other OEMs take a knife to the BEV plans.

Every battery ages differently, but as a rule batteries have been aging suprisingly well. Way above 90% at a decade of use - and that's earlier batteries.

How you charge a battery at home depends on chemistry. If LFP, then 100% every night is actually recommended.

Every battery system behaves differently in the code. The thermal management. Heat pumps (which I don't think the Slate has), and preconditioning all affect cold performance. My guess, frankly, is that the Slate will suck in cold weather just because they don't have the capital or budget to do things like heat pumps, advanced "octobottles", etc. But I don't know that!

I don't personally worry much about battery degradation. Simply because ten years from now today's batteries will be so obsolete that everyone will be swapping them out for solid state with double the range, half the cost, and half the weight. For me personally, longevity is a non issue.

One argument for the smaller battery is simply that it makes for a lighter vehicle. Arguments against are if you have the money, don't care, or want that comfy feeling - it's always nice to have.

Oh, another factor to consider. Does your employer have chargers? If not, would they be open to installing a few inexpensive Level 2 chargers in the parking lot? Sometimes all you have to do is ask. You'd be surprised what an employer will do to keep a good employee happy.

 

[Dorbiman]

40% is feasible in winter, but not the norm, even with resistive heater equipped EVs.

Here is an interesting study that looks at winter EV range for a variety of models, including resistive heaters vs heat pumps. The Ioniq 5 is interesting, as it was equipped with a resistive heater or a heat pump depending on the trim level. One thing to note is that the data seems to stop at 30°F, which is unfortunate. But also of note is that resistive heaters (in some cases) end up being more efficient (and capable) than heat pumps in extremely cold temps.

One other thing to note is that if you preheat the cabin before leaving while still plugged in, the range difference is much lower. It's much easier to maintain a cabin's temp than it is to make the big sweeping change when you first get in and try to bring it up to temp. This is why many people are hoping that the Slate's fob will support preheating from the "2X" button.

 

[zipn]

I really wonder if they'll even go to market with the smaller battery. The LEAF, BOLT, Hyundai/KIAs and the upcoming FORD ev will all probably be in the 250-300 mile range. Hard to compete if you're an a similar price point with 1/2 the range and minimal features.

Seems to me SLATE would be better off scaling for just the larger battery and offer one model with no options. Keep it simple and competitive.

For anyone looking at the SLATE as a low cost / commuter EV (and not just an electric pickup), the Slate is going to go up against some compelling competition. We're in the group. We want a low cost simple around-town EV. It doesn't HAVE to be a pickup... anything with 2 seats and someplace to stow groceries is fine. SLATE was a good choice at $20K... at $25-$30K we're going to look at all the options.

 

[cadblu]

Oh, another factor to consider. Does your employer have chargers? If not, would they be open to installing a few inexpensive Level 2 chargers in the parking lot? Sometimes all you have to do is ask. You'd be surprised what an employer will do to keep a good employee happy.

As a facility manager in a former life, I once proposed a CAPEX project to install Level 2 chargers in the employee parking lot. Surprisingly, it was met with a lot of resistance and even sarcasm. Even though the local utility PSEG was offering attractive rebates, owners of ICE vehicles remained defiant. "If you put EV chargers in the parking lot, where's my Shell 93 octane gasoline pump " LOL

Regarding cost, while the chargers are relatively inexpensive, the labor and materials portion is heavily dependent on the proximity to the 220V panel feed. Hopefully, the conditions at the plant where the OP works are more favorable for EV chargers.

Subsequently, I was advised the project needed to be expensed since there is zero return on investment and a zero-payback period. Resubmitted the project as an expense, and it was again voted down because it was deemed it would only benefit employees with EVs, not ALL employees as a general plant improvement. In addition to the 'free' charging, EV owners would also get closer preferred parking as a benefit. Definitely a nice perk with a parking lot nearly 22 acres. Then the endless questions... Who would manage the charging? Who would be supervising the lots to make sure users are not overstaying their time slot? Why should EV owners get a free benefit, and ICE vehicles park 1/2 mile away? Etc. Etc. Since we couldn't agree on the logistics and management / employees were divided, the project was cancelled. Yes, tough crowd! I miss those days...

 

[Letas]

For anyone looking at the SLATE as a low cost / commuter EV (and not just an electric pickup), the Slate is going to go up against some compelling competition. We're in the group. We want a low cost simple around-town EV. It doesn't HAVE to be a pickup... anything with 2 seats and someplace to stow groceries is fine. SLATE was a good choice at $20K... at $25-$30K we're going to look at all the options.

I'm sure you will get varying opinions on the first part (which I deleted)- but I think you nailed it here, something I've been trying to articulate.
There is a MASSIVE segment of people who just.... drive their car.
Nothing crazy. Rarely more than 1 person in it, even more rare that 2+ are in it.
At 20k, Slate is a massive hit for that market, with the added benefit of the bed for those who like it.

Final price point will be critical to the success of the company.

 

[Doug T]

As a facility manager in a former life, I once proposed a CAPEX project to install Level 2 chargers in the employee parking lot. Surprisingly, it was met with a lot of resistance and even sarcasm. Even though the local utility PSEG was offering attractive rebates, owners of ICE vehicles remained defiant. "If you put EV chargers in the parking lot, where's my Shell 93 octane gasoline pump " LOL

Regarding cost, while the chargers are relatively inexpensive, the labor and materials portion is heavily dependent on the proximity to the 220V panel feed. Hopefully, the conditions at the plant where the OP works are more favorable for EV chargers.

Subsequently, I was advised the project needed to be expensed since there is zero return on investment and a zero-payback period. Resubmitted the project as an expense, and it was again voted down because it was deemed it would only benefit employees with EVs, not ALL employees as a general plant improvement. In addition to the 'free' charging, EV owners would also get closer preferred parking as a benefit. Definitely a nice perk with a parking lot nearly 22 acres. Then the endless questions... Who would manage the charging? Who would be supervising the lots to make sure users are not overstaying their time slot? Why should EV owners get a free benefit, and ICE vehicles park 1/2 mile away? Etc. Etc. Since we couldn't agree on the logistics and management / employees were divided, the project was cancelled. Yes, tough crowd! I miss those days...

This probably does not scale well, but a year or so ago a friend of mine and a couple of his co-workers talked their facilities manager into installing 120V outlets, one for each EV driving employee. They provide their own Level 1 charger and are always charging while at work. The outlets are not shared because you cannot realistically shave a Level 1 outlet

A Level 1 charge over the course of an average 9-hour day covers my friend's one-way commute. This is likely true for most employees. A few more outlets have been added over the last year to support new employee-driven EVs. The arrangement is not managed or supervised since the outlets are dedicated.

This is clearly a much smaller facility than described above and this certainly does not solve objections from non-EV employees. But it works at this company.

 

[cadblu]

This probably does not scale well, but a year or so ago a friend of mine and a couple of his co-workers talked their facilities manager into installing 120V outlets, one for each EV driving employee. They provide their own Level 1 charger and are always charging while at work. The outlets are not shared because you cannot realistically shave a Level 1 outlet

Of course, I allowed EV owners to use outside 120V outlets on a case-by-case basis.
To me, it's the same scenario as jump charging an ICE vehicle stuck in the lot.
And yes, there were plenty of those cases, especially during the winter months...

 

[zipn]

A Level 1 charge over the course of an average 9-hour day covers my friend's one-way commute. This is likely true for most employees. A few more outlets have been added over the last year to support new employee-driven EVs. The arrangement is not managed or supervised since the outlets are dedicated.

.. this is the way.

Airport parking should also feature this.. level-1 outlets, or just free level-1 charge cables. No need to level 2 or higher if your car is parked for a few days!

 

[atreis]

50% is a good planning number if you have very cold winters. While my car has a heat pump, it blends in resistance heating once temperatures fall below freezing, and that increases as temperatures continue to get lower. IME, it's been closer to 70% of summer range for my car when temperatures are around 0 F. On one occasion when I was driving into a stiff wind in temperatures more than 10 degrees below zero F, I saw range about 60% of what I get in the summer for the same drive.

This was all, for me, interstate drives at relatively constant (and similar) speed on relatively flat ground. I do a lot of road trips. I personally wouldn't consider or recommend the small battery Slate for anyone that lives somewhere with significant cold winter weather.