Bye bye ICE

[begreen]

A reference:

Impact of Precipitation Drag on a Road Vehicle

Road vehicles in the real world experience aerodynamic conditions that might be unappreciated and omitted in wind-tunnel experiments or in numerical simulations. Precipitation can potentially have an impact on the aerodynamics of road vehicles. An experimental study was devised to measure, in a wind

www.sae.org

And from the high mileage truckers:
"Rain, snow, or slush on the road increases the vehicle’s rolling resistance, because in addition to moving the vehicle, the tires must also push their way through the precipitation on the roadway. The precipitation cools the tires, transmission oil and axle oils. These components operate less efficiently at lower temperatures. The increased rolling resistance and drive-train friction in just a light rain can increase fuel consumption by 0.2 to 0.3 mpg."

How Adverse Weather Affects Fuel Economy

For every 10º F drop in temperature, aerodynamic drag increases by 2%. Every 2% increase in aerodynamic drag results in a 1% decrease in fuel economy.

www.freightliner.com

 

[Highbeam]

These cars have an 800v system

Wow, 800 volts DC. Way higher than I expected.

I love ICE but I would also love to experience an EV someday.

 

[gthomas785]

I love ICE but I would also love to experience an EV someday.

Go test drive one!

 

[begreen]

Wow, 800 volts DC. Way higher than I expected.

I love ICE but I would also love to experience an EV someday.

The quiet engineering is really nice. We run it in ECO mode so far. In Sport mode the acceleration is eyewatering.

 

[woodgeek]

Wow, 800 volts DC. Way higher than I expected.

I love ICE but I would also love to experience an EV someday.

Usually the onboard electronics like the motor and DC-DC are still 400V rating, but the battery has two identical 400V strings. During DCFC a contactor places these two strings in series to make a 800V battery temporarily. This speeds up DCFC by 2X, given that the current carrying capacity of the DCFC connector is the limiting factor (usually around 450 amps, with a water cooled jacket, or 60 amp when the water cooling is offline). 800V x 450A = '350 kW' rating DCFC.

The 400/800V are nominal maximum, real voltages are 10-20% lower.

My 'old tech' Bolt has a 400V platform and 125A max charging current.

 

[gthomas785]

Usually the onboard electronics like the motor and DC-DC are still 400V rating, but the battery has two identical 400V strings. During DCFC a contactor places these two strings in series to make a 800V battery temporarily. This speeds up DCFC by 2X, given that the current carrying capacity of the DCFC connector is the limiting factor (usually around 450 amps, with a water cooled jacket, or 60 amp when the water cooling is offline). 800V x 450A = '350 kW' rating DCFC.

The 400/800V are nominal maximum, real voltages are 10-20% lower.

My 'old tech' Bolt has a 400V platform and 125A max charging current.

Always thought it was clever how you can replace amps with volts by putting things in series (DC) or using transformers (AC).

 

[DBoon]

I just recall a friend owning one that said he had to charge mostly on L2 chargers on a trip and thought that was a limitation like our Volt.

Early Bolt's offered the DCFC as an option, so unless you bought that you were limited to Level 2 charging. Most dealers stocked the Bolts with the DCFC option, so most have them, but it wasn't standard in the early years.

The quiet engineering is really nice.

There really is nothing like a BEV with a really nice sound system if you love listening to music in your car. That Bolt with the Bose sound system, along with Spotify, has improved my in-car music listening more than I can describe in words.

 

[begreen]

Just did my first 100% charge. The guess-o-meter claimed 332 mi range based on our local rural driving. I took the car over the weekend up north, a 125 mile trip and the car still claimed 216 miles left on the charge. No need to recharge coming home. The ACC is really nice. It is amazing to have the car handle 65mph to 0mph in stop and go traffic without missing a beat. The lane keeping takes a bit of getting used to though it functioned well. I am driving in ECO mode which switches off the front motor.

 

[s0ulP@tch]

the wife and I bought a ‘22 Kia Niro EV in February and absolutely love it. It was JUST BARELY eligible for the $4000 tax credit on used EVs. Installed a charger myself in the garage, and since we have solar and net metering, our fuel is paid for.

The range is over 300mi in the warmer weather. 95% of our driving is around town. We absolutely love having an EV. The Niro is not the sporty car the EV6 was billed to be, but in sport mode it’s still a lot of fun even with front wheel drive.

The great thing about EVs is that you don’t need a gas station or a charging infrastructure if you also own a home. Recharge at home overnight and have a full tank each morning. Longer trips do require planning, but we just plug in at mealtimes on the road. The Niro goes from 0-80% in an hour. I wouldn’t go across the country in it, but weekend trips are very doable.

 

[gthomas785]

Longer trips do require planning, but we just plug in at mealtimes on the road. The Niro goes from 0-80% in an hour. I wouldn’t go across the country in it, but weekend trips are very doable.

Honestly, this is the same as my Bolt. People told me the 55 kW would be a dealbreaker but I have not found the charging stops to be a hassle at all. It takes 45 mins. 99% of the time I charge at home and can only see myself using DCFC a handful of times a year. And if I've been driving long enough to need a charge, I'm ready for a break anyway.

 

[DBoon]

People told me the 55 kW would be a dealbreaker but I have not found the charging stops to be a hassle at all.

I'm also a Bolt owner, and while I wouldn't buy another EV that could only charge at 50 kWh/hour rate, I don't find it terrible even for long trips. It's about an hour (less in the summer, longer in the winter) to go from ~ 15% state of charge to 75% or 80% state of charge. In winter, DCFC charge rates can be stubbornly stuck at 25 kWh/h until the battery is warmed up (which might be an entire DCFC charging sessions). The 2nd DCFC charging sessions a few hours later generally goes faster.

One trick I have learned is that I can pre-condition the Bolt battery to warm up (and accept a faster charge rate in the deep winter) by charging to 100% state of charge at my time of departure. I don't like doing this, but for just long road trips and also just in winter I think the risk of battery degradation is pretty minimal.

 

[gthomas785]

I'm also a Bolt owner, and while I wouldn't buy another EV that could only charge at 50 kWh/hour rate, I don't find it terrible even for long trips. It's about an hour (less in the summer, longer in the winter) to go from ~ 15% state of charge to 75% or 80% state of charge. In winter, DCFC charge rates can be stubbornly stuck at 25 kWh/h until the battery is warmed up (which might be an entire DCFC charging sessions). The 2nd DCFC charging sessions a few hours later generally goes faster.

One trick I have learned is that I can pre-condition the Bolt battery to warm up (and accept a faster charge rate in the deep winter) by charging to 100% state of charge at my time of departure. I don't like doing this, but for just long road trips and also just in winter I think the risk of battery degradation is pretty minimal.

I always charge to 100% if I know I'm going to need the range. That's what it's there for. The amount of degradation from having the battery at 100% for a few hours is not significant.

Routinely charging to 100% and letting it sit there for days at a time might lead to a noticeable increase in battery degradation over the life of the battery. Hard to say how much though.

 

[s0ulP@tch]

One of the things I specifically looked for in my Kia Niro EV was the cold weather package. It includes a heat pump instead of the typical AC & resistive heater. It also comes with a battery warmer that makes charging and long trips more consistent in the winter.

My wife also loves the heated steering wheel and heated/cooled seats ♨️

 

[gthomas785]

One of the things I specifically looked for in my Kia Niro EV was the cold weather package. It includes a heat pump instead of the typical AC & resistive heater. It also comes with a battery warmer that makes charging and long trips more consistent in the winter.

No such package for the Bolt, unfortunately. (Edit: the 2LT does come with heated seats and steering wheel, but no heat pump or battery conditioning). It's pretty clear that GM was pinching pennies and even removed some features from the '22-23 EV that had been available previously, just to make the EUV 'special' without spending a single dollar more.
Too bad really because a few more features (faster DC charging, heat pump, and apparently CarPlay?) and the Bolt EV would have been perfectly poised to become the default choice for the entire subcompact EV market, but GM decided to throw it all down the drain instead.

 

[begreen]

I opted for the Wind AWD in order to get the heat pump. Charged today returning on a trip from 36-87% in 20 minutes on a 150kW charger, that I note peaked at 176kW.

 

[EbS-P]

Why would anyone be selling an EV without a heat pump??? Boggles my mind.

 

[gthomas785]

Why would anyone be selling an EV without a heat pump??? Boggles my mind.

Well if you're GM and you want to make the cheapest EV possible while supporting your position that EVs aren't really that good anyway you use resistive heat.

 

[s0ulP@tch]

Why would anyone be selling an EV without a heat pump??? Boggles my mind.

Because heat pumps are more expensive and so are EVs in general. At the end of the day all companies need to turn a profit, and if GM can’t sell EVs with expensive heat pumps, they’ll go with toaster elements and smile when you pay more for the upgrade (if available).

I’m not knocking the auto industry here - just pointing out that profits have to be made otherwise companies can’t afford to make products or afford employees. It’s the way of things.

 

[EbS-P]

Well if you're GM and you want to make the cheapest EV possible while supporting your position that EVs aren't really that good anyway you use resistive heat.

Because heat pumps are more expensive and so are EVs in general. At the end of the day all companies need to turn a profit, and if GM can’t sell EVs with expensive heat pumps, they’ll go with toaster elements and smile when you pay more for the upgrade (if available).

I’m not knocking the auto industry here - just pointing out that profits have to be made otherwise companies can’t afford to make products or afford employees. It’s the way of things.

From a materials/parts perspective it’s not that much more expensive. It’s a reversing valve, but a whole thermal system integration is expensive. I’m not sure that is has to be a whole thermal system though.

 

[stoveliker]

Huh, a heat pump not having more materials than a wire...?

 

[EbS-P]

Huh, a heat pump not having more materials than a wire...?

You already have the compressor for as and two coils. Add the reversing valve.

 

[begreen]

Why would anyone be selling an EV without a heat pump??? Boggles my mind.

Cost

You already have the compressor for as and two coils. Add the reversing valve.

It's not that simple. Remember that the battery system also needs conditioning, sometime different from the car cabin. The Tesla heat pump went under several redesigns. The final implementation is an impressive piece of engineering.

 

[EbS-P]

Cost

It's not that simple. Remember that the battery system also needs conditioning, sometime different from the car cabin. The Tesla heat pump went under several redesigns. The final implementation is an impressive piece of engineering.

It doesn’t have to be. The could keep the same resistive heaters in the battery. I would like to know for winter use heat loads cabin heat vs battery heat. One of the manufacturers has three separate cooling/heating loops. Cabin, battery and motor/voltage regulators. I forget who??

 

[begreen]

It took a lot of engineering and design work to refine a solution. The model Y heatpump is an exceptional piece of engineering that took years to develop. The early model 3s didn't have a heat pump for cost and so that they could get the cars to market. To quote EM:

Model Y heat pump is some of the best engineering I’ve seen in a while. Team did next-level work.
PCB design techniques applied to create a heat exchanger that is physically impossible by normal means. Heat pump also has a local heating loop to spool up fast & extend usable temperature range. Octavalve is pretty special, too. Team did great work.

How Tesla’s Heat Pump was Designed, Explained by its Engineers VIDEO] | TeslaNorth.com

Tesla uploaded a new video on Thursday evening, titled "Tesla Heat Pump”, noting it offers "More Range in Cold Weather." Heat pump systems are not new technology, but they are far more efficient than resistive heaters found in traditional cars. Tesla engineers reimagined the heat pump that first...

teslanorth.com

An automotive heat pump must not only function under a large range of conditions, satisfying different needs; it also needs to be rugged. Putting one in adds hundreds of dollars cost to the build.

What is a heat pump and how do they benefit electric cars? | Move Electric

www.moveelectric.com

 

[woodgeek]

Why would anyone be selling an EV without a heat pump??? Boggles my mind.

The heat pump only helps at modest cold. And in modest cold, the hit to heating is not that bad. In extreme cold, you still need to switch to resistive anyway.

IOW, I doubt that heat pumps are a panacea for all range losses in very cold weather.