[obermd]

Given that electric house wiring pretty much limits you to 100KWh battery packs because larger packs simply won't able to fully charge overnight (Tesla Models X & S 100D take 8.5 hours at 100 amps). Most home wiring is 240v 100 amp or 200 amp although older homes may only be 110v 100 or 200 amp. This means there is a physical size limit to EV batteries.

So now the question, given that DC motors are already 90% or more efficient, where else in the vehicle can we find efficiency improvements? This will be critical to continue extending the range of EVs. On the flip side of this if Chevy were to put a 100KWh battery into the Bolt simple arithmetic results in a 400 mile range on a single charge. This is on par with gas for range but still falls short of diesel for range.

 

[rhodomel]

Something big is missing... Home Storage Batteries... Somebody should design home battery storage that we would be able to charge directly from it into our cars. The home storage batteries can be charged by solar, off-peak rates, and then the energy can be downloaded into the car efficiently using direct DC to DC connection plus the power available for the overnight as well. In effect you can still use the existing circuit plus the direct line to the battery storage.

 

[ClarksonCote]

Why does a home's electrical wiring limit EVs to having only 100kWh battery packs?

I can't really think of many scenarios where a person will need to use a full 100kWh in one day, then charge to full and repeat that entire trip the next day. For the very tiny minority that do have a 300+ mile commute daily, I think they'd be better off with a gasser.

For the rest of the population, even a 200kWh battery can be charged at home, they get their super long trips done on EV, and even if it takes them a couple days to charge back to full, they have way more than enough range for their daily commuting after one night of charging.

 

[Barry]

I think future efficiency improvements will have to come from lighter battery technology along with car design that puts more emphasis on streamlined aerodynamics, lightweight materials, and smaller frontal area. There really is no reason why the average personal vehicle on the road has to weigh close to 5,000 lbs and is big enough to carry more than half the soccer team. We could gain huge amounts of range by just re-imagining what a vehicle should be. The problem here is that you can't put a 2,000 lb car on the road today and expect it to be safe in a collision with an SUV. Maybe when autonomous driving has taken over, we can end the arms race toward tank-like vehicles.

 

[obermd]

Why does a home's electrical wiring limit EVs to having only 100kWh battery packs?

I can't really think of many scenarios where a person will need to use a full 100kWh in one day, then charge to full and repeat that entire trip the next day. For the very tiny minority that do have a 300+ mile commute daily, I think they'd be better off with a gasser.

For the rest of the population, even a 200kWh battery can be charged at home, they get their super long trips done on EV, and even if it takes them a couple days to charge back to full, they have way more than enough range for their daily commuting after one night of charging.

If the building main is limited to 240v 100a then you cannot charge more than a 100KWh battery overnight. (ClipperCreek shows this is an 8.5 hour charge.) If it's limited to 240v 200a then you could theoretically charge a 200KWh battery overnight. Both of these assume that you aren't running anything else such as your refrigerator or air conditioner.

 

[llninja]

My house has two 200amp breaker boxes in the garage. But with the onset of big battery electric cars, it seems like one should be able to run a whole new electrical feed to the house for the EV. Also, maybe there's a way to get commercial 480V to the house.

 

[realdb2]

Something big is missing... Home Storage Batteries... Somebody should design home battery storage that we would be able to charge directly from it into our cars. The home storage batteries can be charged by solar, off-peak rates, and then the energy can be downloaded into the car efficiently using direct DC to DC connection plus the power available for the overnight as well. In effect you can still use the existing circuit plus the direct line to the battery storage.

This. If battery prices continue to plummet that could make this scenario very feasible.

Charge your battery slowly over several hours and then charge from battery to battery (with proper power management of course) in a matter of minutes.

 

[flyingsherpa]

If the building main is limited to 240v 100a then you cannot charge more than a 100KWh battery overnight. (ClipperCreek shows this is an 8.5 hour charge.) If it's limited to 240v 200a then you could theoretically charge a 200KWh battery overnight. Both of these assume that you aren't running anything else such as your refrigerator or air conditioner.

I think you missed his point... he's saying you're not limited to to 100kWh because almost no one needs to be completely full overnight with batteries that big (or larger). Even if the average house can only fully charge a Model S70, that's still like 250 miles of range. Who cares if you had a hypothetical Model S140 but could only halfway fill it overnight, you still have 250 miles! After your daily driving, you'll come close to filling it the next night. Or the one after that, it doesn't usually matter for most usage scenarios. If you're going on a roadtrip, well 250 miles will definitely get you to the next DCFC stop.

If you daily drive 400 miles and need overnight charging to full and have no nearby convenient DCFC... well, that's a .01% usage case for passenger cars, and EV won't work for you, get an ICE for now.

To answer your original question: better aero, lighter cars (composite materials), slower speeds. Those are the other efficiency knobs to twist. Composites aren't cheap, though, and ideal aero often makes an ugly car that no one wants or are too small and dangerous (Aptera), so it's not easy. I have heard that allowing the removal of side mirrors and using small cameras instead would several percent more range, but current regs don't allow it. I wouldn't expect any big overall efficiency improvements anytime soon, things are pretty efficient already, but maybe a few percent here and there from motors/inverters/batteries and aero tweaks.

 

[jsmay311]

Given that electric house wiring pretty much limits you to 100KWh battery packs because larger packs simply won't able to fully charge overnight (Tesla Models X & S 100D take 8.5 hours at 100 amps). Most home wiring is 240v 100 amp or 200 amp although older homes may only be 110v 100 or 200 amp. This means there is a physical size limit to EV batteries.

Why does a home's electrical wiring limit EVs to having only 100kWh battery packs?

I can't really think of many scenarios where a person will need to use a full 100kWh in one day, then charge to full and repeat that entire trip the next day. For the very tiny minority that do have a 300+ mile commute daily, I think they'd be better off with a gasser.

Exactly. The entire premise of this thread is silly.

If someone with a 300-mile EV arrives at home with a near-depleted battery and needs to leave again the following morning for another long-distance drive (a pretty uncommon scenario to begin with) before the car has finished charging, they can just stop at a DCFC charging station part way through their next trip. No big deal as long as there are DCFC stations available -- and if there aren't, then long-distance BEV driving isn't practical anyway.

I'm probably going to end up getting either the 220-mile or 310-mile Model 3, and more than likely I'll stick with the existing 12AWG wiring going to my existing EVSE in my detached garage, which would mean a max charge rate of 16 amps or 3.8kW and would only charge ~170 miles in 12 hours. That would be more than sufficient for 99.9% of my driving.

In fact, I could probably even get by with 120V 16A charging 99% of the time. And on those 1% of days when it's not sufficient, I could just hit up a DCFC.

The actual limits on EV battery pack capacity are cost, weight, and size.

 

[ewiggins]

Something big is missing... Home Storage Batteries... Somebody should design home battery storage that we would be able to charge directly from it into our cars. The home storage batteries can be charged by solar, off

You are so correct. If a home had a battery that could slow charge then when you get home the battery can quick charge to your car.

 

[llninja]

Exactly. The entire premise of this thread is silly.

If someone with a 300-mile EV arrives at home with a near-depleted battery and needs to leave again the following morning for another long-distance drive (a pretty uncommon scenario to begin with) before the car has finished charging, they can just stop at a DCFC charging station part way through their next trip. No big deal as long as there are DCFC stations available -- and if there aren't, then long-distance BEV driving isn't practical anyway.

I'm probably going to end up getting either the 220-mile or 310-mile Model 3, and more than likely I'll stick with the existing 12AWG wiring going to my existing EVSE in my detached garage, which would mean a max charge rate of 16 amps or 3.8kW and would only charge ~170 miles in 12 hours. That would be more than sufficient for 99.9% of my driving.

In fact, I could probably even get by with 120V 16A charging 99% of the time. And on those 1% of days when it's not sufficient, I could just hit up a DCFC.

The actual limits on EV battery pack capacity are cost, weight, and size.

If I hade a 140 KWH battery, my 50 mile per day commute would mean I would only need to charge once in awhile. The need to fill the battery nightly like I do with the Volt would be diminished.

 

[Barry]

One of the things that makes electric vehicles relatively easy and cheap for society to convert to is the fact that our electric grid has a tremendous amount of untapped capacity at night. However, that same grid is already stretched to its max during daytime peak hours. Solutions that require more charging during the day, such as home storage batteries, or that require dropping lots of new 100A connections to lots of homes, might tend to tax the grid more instead of taking advantage of its off-peak potential.

Adding distributed solar to the mix might seem like a solution to the grid limitation, and I think it could help, but by the time you add solar and home storage batteries to the cost of getting an electric car, it starts to seem too costly. Plus solar generation depends on weather and season, which may not match driving needs. We all know we use more energy to drive during the coldest, darkest months. So you still need something for when solar generation is in a slump.

I think the most practical source of widespread charging in the near future is at home overnight charging based on the electrical supply already installed in homes. That's the easy, cheap, efficient resource that can be scaled up.

 

[srmarti]

Given that electric house wiring pretty much limits you to 100KWh battery packs because larger packs simply won't able to fully charge overnight (Tesla Models X & S 100D take 8.5 hours at 100 amps). Most home wiring is 240v 100 amp or 200 amp although older homes may only be 110v 100 or 200 amp. This means there is a physical size limit to EV batteries.

So now the question, given that DC motors are already 90% or more efficient, where else in the vehicle can we find efficiency improvements? This will be critical to continue extending the range of EVs. On the flip side of this if Chevy were to put a 100KWh battery into the Bolt simple arithmetic results in a 400 mile range on a single charge. This is on par with gas for range but still falls short of diesel for range.

The electrical service of your house will limit the energy capacity (KWhrs) of the battery that can be charged overnight, NOT THE PHYSICAL SIZE of the battery. Doesn't matter if the 100WKh battery is the size of a semi-trailer or a cell phone. 100KWh is still 100KWh. Electrical limit yes, physical size limit no.

 

[obermd]

The electrical service of your house will limit the energy capacity (KWhrs) of the battery that can be charged overnight, NOT THE PHYSICAL SIZE of the battery. Doesn't matter if the 100WKh battery is the size of a semi-trailer or a cell phone. 100KWh is still 100KWh. Electrical limit yes, physical size limit no.

That's what I was trying to say. Thanks for a definitely clearer way of saying it.

 

[Mister Dave]

LCAC Fans to offset weight and increase thrust.

Oh wait, this isn't my hovercraft forum is it? Well, maybe then.....

 

[srmarti]

That's what I was trying to say. Thanks for a definitely clearer way of saying it.

It's still sort of a non-issue unless you nearly deplete the battery every day. So unless someone is a travelling salesman or something they aren't going to burn on the order of 300 miles and 100KWh per day. One doesn't top off their gas tank in an ICE car every day because of the range left in the and the low recharge time. Topping off to full charge overnight at home can be less critical if the capacity/range is higher or fast charging is more available for road tripping. Still in favor of EREV for the foreseeable future. Sidesteps the whole issue nicely.

 

[Upper5Percent]

Given that electric house wiring pretty much limits you to 100KWh battery packs because larger packs simply won't able to fully charge overnight (Tesla Models X & S 100D take 8.5 hours at 100 amps). Most home wiring is 240v 100 amp or 200 amp although older homes may only be 110v 100 or 200 amp. This means there is a physical size limit to EV batteries.

So now the question, given that DC motors are already 90% or more efficient, where else in the vehicle can we find efficiency improvements? This will be critical to continue extending the range of EVs. On the flip side of this if Chevy were to put a 100KWh battery into the Bolt simple arithmetic results in a 400 mile range on a single charge. This is on par with gas for range but still falls short of diesel for range.

You can have another 200 amp service meter added to your home for that Tesla...Electric Companies love to add wire from the pole to new meters "for free"...

 

[Mister Dave]

You can have another 200 amp service meter added to your home for that Tesla...Electric Companies love to add wire from the pole to new meters "for free"...

What if it's underground?

 

[ClarksonCote]

The electrical service of your house will limit the energy capacity (KWhrs) of the battery that can be charged overnight, NOT THE PHYSICAL SIZE of the battery. Doesn't matter if the 100WKh battery is the size of a semi-trailer or a cell phone. 100KWh is still 100KWh. Electrical limit yes, physical size limit no.

That's what I was trying to say. Thanks for a definitely clearer way of saying it.

Right, but my point is it doesn't matter. The home's electrical service doesn't need to be beefed up, and batteries don't need to be limited by this lack of service to 100kWh, because nobody makes back-to-back 300 mile trips requiring a full charge at their home overnight.