Electric Vehicles

[Capricio]

Originally Posted by Martinjlm

Two thoughts on this...

1. Batteries tend to have their own thermal management systems.
2. In the picture, right around the blue card that says "02"...you can see the engine's exhaust routed right alongside the battery.

In the absence of shore power, in my freezing airport parking lot scenario, is battery heat generated heat from an already low condition (hypothetically lets say it was 55% charge when I parked, and now it's maybe 35% charge because it's so cold when I arrived back) effective at raising my available charge level?

In other words, what's the approximate net gain? Can I get back over 50% total charge? I know there are a lot of variables, battery size, temperatures, etc. Just a general idea on the thermal energy effectiveness of getting some juice back to make it home without help.

Or are self contained heaters only effective at "conditioning" the battery, warming it up, so it can take a charge from shore power better?

[Martinjlm]

Originally Posted by Capricio

In the absence of shore power, in my freezing airport parking lot scenario, is battery heat generated heat from an already low condition (hypothetically lets say it was 55% charge when I parked, and now it's maybe 35% charge because it's so cold when I arrived back) effective at raising my available charge level?

In other words, what's the approximate net gain? Can I get back over 50% total charge? I know there are a lot of variables, battery size, temperatures, etc. Just a general idea on the thermal energy effectiveness of getting some juice back to make it home without help.

Or are self contained heaters only effective at "conditioning" the battery, warming it up, so it can take a charge from shore power better?

Great question. I don’t really know how to answer that one. I’ll have to “phone a friend”

[Capricio]

Originally Posted by Martinjlm

Great question. I don’t really know how to answer that one. I’ll have to “phone a friend”

I know it's apples and oranges, comparison-wise... but for reference, my home HVAC is a heat pump system with a two stage heat mode. If it gets below around 20 F outside, its not effective to just run the compressor in reverse anymore. So, it has to resort to "emergency heat", which is basicially some toaster wires/resistors, which makes the meter spin significantly faster.

So i'm inclined to believe that asking a battery source to provide heat via the same type of resistive load is very draining, and only useful to activate for a few minutes prior to charging. But if some (sustained in exteme cold outside temps) warming can drasitically improve the chemical reactivity enough to overcome that sustained loss, then I don't know?

It seems silly if these Range Extender EV configurations don't use the heat biproduct from the ICE component to help with this. Without it, I think BEVs are going to continue to suck in cold conditions.

[genxer]

Originally Posted by Capricio

I know it's apples and oranges, comparison-wise... but for reference, my home HVAC is a heat pump system with a two stage heat mode. If it gets below around 20 F outside, its not effective to just run the compressor in reverse anymore. So, it has to resort to "emergency heat", which is basicially some toaster wires/resistors, which makes the meter spin significantly faster.

So i'm inclined to believe that asking a battery source to provide heat via the same type of resistive load is very draining, and only useful to activate for a few minutes prior to charging. But if some (sustained in exteme cold outside temps) warming can drasitically improve the chemical reactivity enough to overcome that sustained loss, then I don't know?

It seems silly if these Range Extender EV configurations don't use the heat biproduct from the ICE component to help with this. Without it, I think BEVs are going to continue to suck in cold conditions.

It's silly enough not using engine heat that I be shocked if they didn't. The right tool for the job thing. LFPs are known to perform worse in cold than other Li cells. Sodium cells are reported as less cold affected, but they're not really energy dense enough to be more than hybrid packs, which hasn't happened yet to my knowledge. ariZona28 mentioned locomotives, there's no buffer battery.

[Capricio]

This showed up in my newsfeed, prob because Google was spying on my searches. Which, privacy issues aside, was kind of timely.



https://gmauthority.com/blog/2025/01...testing-shows/


I'm not an HVAC expert, but from my experience with a heat pump at home and from talking to HVAC techs:

• Air coming out my vents doesn't feel warm on my skin, even though it keeps the house at the set temp. (Be prepared for your wife/gf to complain)
• You want your system scaled as small as possible for efficiency, it's better to run constantly with fewer stops/starts. Its also easier on the equipment, kind of like "highway miles".
• Newer refrigerants are more effective down to lower outside temps. Some of new ones go down to 0 F but are quite expensive.
• Because of (thanks EPA!) stricter efficiency standards, the cost of a system comparable to the one I had installed 5 years ago has risen about 50%.

In a recent report, Recurrent published cold-weather testing results for more than 20 new EV models. Notably, the Chevy Equinox EV retained just 74 percent of its normal range in winter conditions, while the Cadillac Lyriq fared slightly worse at 72 percent.

Yikes! 25-30% loss, with the heatpump!



Oh well, just another reason to wait a few years while they sort the bugs out. I used to live in northern MN and ND, and I'd never consider a pure BEV up there, or even a heat pump HVAC for that matter. The heat pump is fine for where I live now, however.

[Martinjlm]

Originally Posted by Capricio

This showed up in my newsfeed, prob because Google was spying on my searches. Which, privacy issues aside, was kind of timely.



https://gmauthority.com/blog/2025/01...testing-shows/


I'm not an HVAC expert, but from my experience with a heat pump at home and from talking to HVAC techs:

• Air coming out my vents doesn't feel warm on my skin, even though it keeps the house at the set temp. (Be prepared for your wife/gf to complain)
• You want your system scaled as small as possible for efficiency, it's better to run constantly with fewer stops/starts. Its also easier on the equipment, kind of like "highway miles".
• Newer refrigerants are more effective down to lower outside temps. Some of new ones go down to 0 F but are quite expensive.
• Because of (thanks EPA!) stricter efficiency standards, the cost of a system comparable to the one I had installed 5 years ago has risen about 50%.

Yikes! 25-30% loss, with the heatpump!



Oh well, just another reason to wait a few years while they sort the bugs out. I used to live in northern MN and ND, and I'd never consider a pure BEV up there, or even a heat pump HVAC for that matter. The heat pump is fine for where I live now, however.

Also not an HVAC expert. Not by a long shot. I can only provide my real world experience after 14 months with a Tesla Model Y and 4 months with an Equinox EV.

• Both have diminished efficiency in cold weather. I'm defining cold as under 30 degrees.
• How much the efficiency is diminished depends on a few things. Most important of this is where the drive starts. Both cars can be pre-conditioned from grid energy if they are plugged in at the start of the trip. So if I'm at home and I'm taking either car out on a drive, I precondition it. Same as remote starting my Camaro. But instead of burning E85 at $2.59/gallon, I'm using grid electricity at $0.17/kWh. Both EVs get around 3 - 3.5 mile/kWh.
• If I am leaving from somewhere that I am not plugged in, either car will have poor efficiency until the battery is at an appropriate operating temperature. So for short drives it might never get to the right temperature. For longer drives it will eventually get back to normal operating temperature.
• Long drives using cabin heat (who wouldn't?) will also diminish efficiency, but pretty much at about the same rate as running AC in an ICE car. I compare to AC in an ICE car because heat in an ICE car does not typically have the same level of efficiency reduction. Heat is mostly drawn from the engine and is "free". It doesn't cause the engine to work any harder than it already is.
• The Tesla is the easier comparison since we've had it more than a year and this is its second winter. When I look at energy efficiency, most of the year it averages around 3.5 miles/kWh. More in city driving, less in highway driving. Complete opposite of an ICE car. In the winter it averages around 2.9 miles/kWh. More in city driving, less in highway driving.
• We have never had an "omigod I'm gonna run out of range" moment, even in the winter. Other than long trips (250 miles+) I don't think either car has ever been under 50% charge.
• Both cars will draw more energy from our grid during the winter, but at $0.17/kWh it means each car will add about $30 - 35 / month to our electric bill most months, $40 - 45 in winter months.

***EDIT*** I'm about to head out in the Tesla. So I screenshot my phone to show how I'm able to precondition the battery and the cabin so that when I'm ready to unplug from my home charger, it's operating as if it's a 70 degree day (for the most part). Reduces the energy draw needed to heat the battery and the cabin while I'm driving.

[Martinjlm]

So I returned from the drive. Roundtrip was 57 miles mostly highway, 55 - 78 mph. Used 17 kWh of electricity (22% of capacity). That amounts to 3.35 mi/kWh in 31 degree weather. Compared to an average 3.5 mi/kWh during warmer months. That's the value of pre-conditioning the cabin while it's plugged in at home. Car is plugged in and will be back to full charge (80% from a current 58%) in 2 hours 25 minutes. Until then I still have at least 190 miles of range if I need to go anywhere.

[Capricio]

So, we're still at "good for commuting from single family home structures in cold climates"?

[genxer]

Originally Posted by Capricio

So, we're still at "good for commuting from single family home structures in cold climates"?

https://www.rivianforums.com/forum/t...eeze-up.39249/

Some relevant deep freeze experiences posted.

[Martinjlm]

Originally Posted by genxer

https://www.rivianforums.com/forum/t...eeze-up.39249/

Some relevant deep freeze experiences posted.

Different cars, different experiences. Forgot to plug the Equinox in last night after a short trip to the grocery store. When I parked it in the driveway it was at 79% charge. It sat outside (Camaro and Tesla in the garage) in -5F temps. Now it’s at 74%. Meh.

[snizzle]

Lyriq V production starts early '25 (maybe..)

https://pressroom.cadillac.com/gmbx/...3-lyriq-v.html

[Martinjlm]

A lot of GM stuff in the news the past few days:

• GM hourly employees will receive the largest ever bonus, based on company profits from last year. $14,500 per employee.
• GM announces that they are now making a variable cost profit on all EVs they produce.
• Cadillac will end the XT5 and XT6 in the US at the end of 2025. XT4 has already ended production. They will be replaced by Optiq (XT4), Lyriq (XT5) and Vistiq (XT6).

As it stands, Lyriq already outsells XT5 (28,402 in 2024 vs 26,432). Sales for Optiq have already started but I haven’t been able to find confirmed sales numbers yet. Vistiq is about to start selling.

[kevint]

I'm honestly surprised this thread wasn't bombarded after the president signed his EO to cancel the electric car mandate.

[Martinjlm]

Originally Posted by kevint

I'm honestly surprised this thread wasn't bombarded after the president signed his EO to cancel the electric car mandate.

Can you link to the EO and/or the "mandate" that it cancels?