🔋 The Extended Battery Decision (Poll: Which battery option suits you best?)

[ElectricShitbox]

There's another factor in the small/big battery decision for me that I just realized. New York has an EV tax credit still, and it's $1k for an EV with 40-199 miles of range, $2k for 200+ mi. So I would theoretically get a net $1k off whatever the big battery upgrade costs.

 

[metroshot]

With a super long battery warranty (8 years), I do not worry about longevity or battery degradation.

I charge mine to 100% on L2 and DCFC and never worry about reaching 8 years.

EVs I plan on keeping it at least 5 years.

 

[beatle]

While most of the miles I plan to do in a day will be well within the capability of the standard battery, only having 150 miles of range really changes your road trips, sometimes forcing DCFC targets over 80% which is a real drag. Experimental route planning with ABRP on a 339 mile trip I routinely take shows that I'd be stopping every 45 minutes to charge in the winter with the standard pack, adding 1h 45m to a trip with 5h 45m of driving. The extended pack drops an hour off the charging time.

I guess it's not insurmountable to road trip with the standard pack, but it's still pretty restrictive. This is also assuming I don't have a motorcycle in the bed cutting range down further. I think the 240 miles of range with the extended pack will be plenty. I had that with my old 2015 Model S that charged slow as can be by modern standards, and I still thought it was plenty fine for almost all road trips.

 

[Driven5]

Modules are designed to operate at the architecture voltage and bussed (connected in series) within the vehicle battery pack.

This is a completely self-contradicting statement. With more than one module in series, module voltage cannot be architecture voltage. Modules must either be low-voltage (operating at a 1/#modules fraction of pack voltage) connected in series, or they are operating at full pack voltage connected in parallel. I am not aware of any EV's operating pack voltage modules in parallel, only low-voltage modules in series.

Slate is designing around 10.5 kWh 400V modules

Source? Sure the math dictates 10.54kWh modules, but there is zero available on the actual voltage beyond being 400V charger compatible... But that does not mean 400V pack voltage, as noted below.

Number of modules will have no effect on architecture voltage.

Manufacturers creating unique battery modules for each different kWh pack capacity could make both packs the same voltage, but manufacturers that use common modules across the different pack capacities are actually running at different pack voltages.

Blazer EV Standard: 10x 8.5kwh 28.8V modules = 85kWh 288V pack
Blazer EV Extended: 12x 8.5kwh 28.8V modules = 102kWh 345V pack

So of all the vehicles advertising their 400V charging compatibility, many (most?) are not actually running a true 400V pack thanks to the system ability to automatically adjust the charging voltage to the specific pack need... They're just not advertising that part of it.

 

[Tom Sawyer]

This stub post will be used to accumulate the scintillating insights revealed in the thread. With any luck it will become a short, helpful, single document that someone can read before deciding and eventually, if all goes the way it should, they'll be happy that they made the right decision.

Updates! What's the summary so far?

 

[AZFox]

Updates! What's the summary so far?

https://www.slateforums.com/forum/t...ttery-option-suits-you-best.13395/post-189479

 

[metroshot]

While most of the miles I plan to do in a day will be well within the capability of the standard battery, only having 150 miles of range really changes your road trips, sometimes forcing DCFC targets over 80% which is a real drag. Experimental route planning with ABRP on a 339 mile trip I routinely take shows that I'd be stopping every 45 minutes to charge in the winter with the standard pack, adding 1h 45m to a trip with 5h 45m of driving. The extended pack drops an hour off the charging time.

I guess it's not insurmountable to road trip with the standard pack, but it's still pretty restrictive. This is also assuming I don't have a motorcycle in the bed cutting range down further. I think the 240 miles of range with the extended pack will be plenty. I had that with my old 2015 Model S that charged slow as can be by modern standards, and I still thought it was plenty fine for almost all road trips.

For long distance driving, consider using an EREV or PHEV.

I have both a PHEV and BEV - different tools for the job.

While my PHEV can go almost 400 miles on a full 17kW BEV and 7 gallon full gas tank; my BEV goes 230 miles on a full charge, the infrastructure (gas stations vs EV fast chargers) and weather/terrain will be the restrictive issues.

 

[E90400K]

For no real good reason I have been trying to understand the California CARB Advanced Clean Cars II (AAC II) regulations/mandates and I think Slate has a problem with its standard 150-mile battery. As I understand the CARB ACC II regs, any BEV needs to have a minimum range of 200 miles to account for credits ("vehicle value") towards compliance of meeting ACC II regulations.

The legislation states (cribbed from RMI - Rocky Mountain Institute ACC II summary)):

ACC II (enforceable between 2026 and 2035) uses a vehicle “value” accounting system that awards roughly one value for the sale of a ZEV and a portion of a value for the sale of a PHEV. A value is closely correlated to the sale of actual vehicles and so the vehicle value percentage targets outlined in ACC II can reasonably be considered a representation of ZEV sale share percentage.

Who must comply?
OEMs that sell more than 4,500 light- and medium-duty vehicles per year must comply with ACC II. Small-volume OEMs that sell fewer than 4,500 light- and medium-duty vehicles annually in California are exempt until 2035, when the state’s 100 percent ZEV mandate comes into effect.

What is required for compliance?
To comply with ACC II, OEMs must submit an annual compliance report from 2026 onward. A manufacturer is in compliance when it can show that their sale of ZEVs and PHEVs resulted in enough total vehicle value to meet their ACC II ZEV and PHEV target for a given model year. The Total ZEV fleet milestone is calculated by taking the ZEV percentage target and multiplying that by the number of vehicles sold. The result is the number of ZEV values that an OEM obtains to comply with ACC II.

Understanding how values are defined and accounted for can help OEMs comply with ACC II requirements. This information will also help OEMs estimate how ACC II will impact ZEV sales, the retirement of internal combustion engine vehicles, and transportation-related emissions reductions.

ACC II provides OEMs with the flexibility to accrue vehicle value in four ways:

1. The sale of PHEVs: The value of a PHEV sale is less than one vehicle value, dependent on vehicle range.
   • Value stipulations: PHEVs must meet minimum range criteria: 43 miles through 2028; after 2028 the minimum range requirement increases to 70 miles. The partial vehicle value credit ranging from 0.63 to 1 is based on vehicle range.
   • Compliance cap: OEMs are permitted to count PHEV sales and values for up to 20 percent of their annual value requirements.
2. The sale of ZEVs: The value of a ZEV sale is equal to one vehicle value.
   • Value stipulations: BEVs must be all-electric and have a range of at least 200 miles. FCEVs can also count toward ZEV value requirements through 2031 but are subject to proportional value requirements based on the FCEV sales percentage share.
   • Compliance cap: No cap; OEMs can earn values for 100 percent of their ZEV sales.

I wonder if this means Slate will be forced to only sell the 84kWh battery models to California residents and the residents to the other 14 states that have adopted CARB emission standards.

 

[KevinRS]

For no real good reason I have been trying to understand the California CARB Advanced Clean Cars II (AAC II) regulations/mandates and I think Slate has a problem with its standard 150-mile battery. As I understand the CARB ACC II regs, any BEV needs to have a minimum range of 200 miles to account for credits ("vehicle value") towards compliance of meeting ACC II regulations.

The legislation states (cribbed from RMI - Rocky Mountain Institute ACC II summary)):

ACC II (enforceable between 2026 and 2035) uses a vehicle “value” accounting system that awards roughly one value for the sale of a ZEV and a portion of a value for the sale of a PHEV. A value is closely correlated to the sale of actual vehicles and so the vehicle value percentage targets outlined in ACC II can reasonably be considered a representation of ZEV sale share percentage.

Who must comply?
OEMs that sell more than 4,500 light- and medium-duty vehicles per year must comply with ACC II. Small-volume OEMs that sell fewer than 4,500 light- and medium-duty vehicles annually in California are exempt until 2035, when the state’s 100 percent ZEV mandate comes into effect.

What is required for compliance?
To comply with ACC II, OEMs must submit an annual compliance report from 2026 onward. A manufacturer is in compliance when it can show that their sale of ZEVs and PHEVs resulted in enough total vehicle value to meet their ACC II ZEV and PHEV target for a given model year. The Total ZEV fleet milestone is calculated by taking the ZEV percentage target and multiplying that by the number of vehicles sold. The result is the number of ZEV values that an OEM obtains to comply with ACC II.

Understanding how values are defined and accounted for can help OEMs comply with ACC II requirements. This information will also help OEMs estimate how ACC II will impact ZEV sales, the retirement of internal combustion engine vehicles, and transportation-related emissions reductions.

ACC II provides OEMs with the flexibility to accrue vehicle value in four ways:

1. The sale of PHEVs: The value of a PHEV sale is less than one vehicle value, dependent on vehicle range.
   • Value stipulations: PHEVs must meet minimum range criteria: 43 miles through 2028; after 2028 the minimum range requirement increases to 70 miles. The partial vehicle value credit ranging from 0.63 to 1 is based on vehicle range.
   • Compliance cap: OEMs are permitted to count PHEV sales and values for up to 20 percent of their annual value requirements.
2. The sale of ZEVs: The value of a ZEV sale is equal to one vehicle value.
   • Value stipulations: BEVs must be all-electric and have a range of at least 200 miles. FCEVs can also count toward ZEV value requirements through 2031 but are subject to proportional value requirements based on the FCEV sales percentage share.
   • Compliance cap: No cap; OEMs can earn values for 100 percent of their ZEV sales.

I wonder if this means Slate will be forced to only sell the 84kWh battery models to California residents and the residents to the other 14 states that have adopted CARB emission standards.

My read of page 4 of https://theicct.org/wp-content/uploads/2022/11/accii-zev-lez-reg-update-nov22.pdf seems to indicate that lower range vehicles don't earn credits, but also are not counted towards a manufacturer's requirement. Even if they were, for 2026 the requirement is only a 35% credit percentage. Anyway, it looks like Slate, like Tesla will have a surplus of credits and will be trading them to other manufacturers. I am also noting on page 6 of that document, there is an additional 0.1 credit per truck sold with MSRP at or under $26,670, so that may well be a price limit Slate wants to stay under if possible.

 

[sodamo]

About 99% sure with my decision. I can live with the standard battery. Only a handful of trips/year that exceed the 150 range.
we don’t have a definite cost for the extended yet, but it has been suggested in the $4-5k range. Appears for that money I can add about 8kw PV to my current offgrid system. Not only would that support Level 2 charging of my Slate, but additional capability for whole house system. Seems like a beneficial tradeoff.