Educate me - the great range debate

[boltage]

I also agree. With adequate range, electric cars like the Bolt are great for commuting and local driving. But electric cars are miserable on road trips. I wouldn't even think about taking it on a trip beyond its range.

For a long road trip, an EV with fast charging would give about a 3:1 ratio of driving on the highway to recharging (probably 5:1 or 6:1 for the Teslas with the fastest charging provisions). Not exactly desirable for long road trips, but could be less of an issue for trips that would only need one or two recharges, since the ratio of driving to recharging would be better when the initial full charge leaving from home is considered.

 

[oilerlord]

For a long road trip, an EV with fast charging would give about a 3:1 ratio of driving on the highway to recharging (probably 5:1 or 6:1 for the Teslas with the fastest charging provisions). Not exactly desirable for long road trips, but could be less of an issue for trips that would only need one or two recharges, since the ratio of driving to recharging would be better when the initial full charge leaving from home is considered.

To your point, it's really about how fast you can charge your battery. At home, doesn't matter. Charge overnight. The Bolt supports 80kW "fast" charging but that's still at least an hour sitting there as most only support 50kWh. Sure, we can "make" that work, but really; it's still a waste of time. I'm hoping the next generation of EV's support 150kW charging and above.

 

[JHawk]

Electric cars are following a classic technology improvement curve. I am confident that a) The battery capacity/cost ratio will continue to rapidly increase and b) The availability and speed of fast chargers on the road will also dramatically increase over the coming years. Fifteen years from now no one will be discussing these issues. In the meantime each consumer will have their own thresholds for what is acceptable.

For me, the advantages and pleasantries of driving an EV are large enough that a 93 mile range Soul EV with no assumption of super chargers was enough for me to go EV. The Bolt of course is way better. No possibility of going back to ICE for me and my spouse.

 

[user 124]

...With adequate range, electric cars like the Bolt are great for commuting and local driving. But electric cars are miserable on road trips. I wouldn't even think about taking it on a trip beyond its range.

Doing a road trip in a non-Tesla EV is interesting and I think worth doing once or twice. I find it tolerable if you only have to charge once each way, and it gets old quickly if you have to charge twice or more. My RAV4EV has about ~130 mi range on the freeway and charging to >90% takes close to an hour, so my ratio of driving to charging is 2:1. OK for a 200 mi trip, but 300 mi each way is painful.

 

[oilerlord]

Doing a road trip in a non-Tesla EV is interesting and I think worth doing once or twice. I find it tolerable if you only have to charge once each way, and it gets old quickly if you have to charge twice or more. My RAV4EV has about ~130 mi range on the freeway and charging to >90% takes close to an hour, so my ratio of driving to charging is 2:1. OK for a 200 mi trip, but 300 mi each way is painful.

Your use of the word "tolerable" is a fair description. I think even with the Bolt, the 200 mile trip for me to visit family in Calgary would be "tolerable", as I might have to stop somewhere for an hour or two or so at a L2 charging station. We don't have any L3 chargers (except for Tesla's), and because it is 35F outside right now, and I'm not sure I'd make it with the Bolt's 9 kW heater using up to 27 kWh for the 3 hour trip.

So to your point, even with a 200-mile class EV, longer trips aren't necessarily enjoyable, but they are tolerable. We need to see continued expansion of the L3 infrastructure, bigger battery capacity, or both. Hopefully future improvements in battery density and weight savings allow a 90+ kWh pack to be a reality for the Bolt and other "affordable" EV's.

 

[LeftieBiker]

We don't have any L3 chargers (except for Tesla's), and because it is 35F outside right now, and I'm not sure I'd make it with the Bolt's 9 kW heater using up to 27 kWh for the 3 hour trip.

Does anyone know if the Bolts' Eco mode limits heater current draw? I would be surprised if it didn't. In the Leaf it's limited to 1500 watts (although I think I've seen 1750) in Eco, at least in the heat-pump-equipped models.

 

[GetOffYourGas]

it is 35F outside right now, and I'm not sure I'd make it with the Bolt's 9 kW heater using up to 27 kWh for the 3 hour trip.

This is a highly pessimistic calculation. Yes, it's true that the 9 kW heater would pull 27kWh in 3 hours at full-blast. But I highly doubt that it will stay at 9kW for more than 5-10 minutes.

Obviously every car is different, but my experience in the Leaf (with a 6kW resistance heater) is that at temps above freezing, it runs at 6kW for less than 10 minutes. Then it drops down to about 1-1.5kW to maintain the temperature. If the Bolt did the same thing, it would be more like 5kWh for the heater over your 3 hour trip.

 

[oilerlord]

This is a highly pessimistic calculation. Yes, it's true that the 9 kW heater would pull 27kWh in 3 hours at full-blast. But I highly doubt that it will stay at 9kW for more than 5-10 minutes.

No, it's only a calculation.

All things considered, you have to drive with an efficiency of at least 3.33 miles per kWh to make a 200 mile trip with a 60kWh battery. Temperature, speed / aerodynamic drag, and power loads still apply. I mentioned the heater would use "up to" 27kWh on a 3 hour trip. You highly doubt it will stay at 9kW for more than 5-10 minutes - which may be highly optimistic given how cold it is outside, and that we don't know if the heater has variable power consumption.

So, anything less than 3.33 miles per kWh, and you don't make it without stopping for a charge (if one is available), or having to make choices such as driving X MPH under the highway speed limit, managing the use of the heater, or driving on a warmer day. It really is that simple.

tgreene summed it up perfectly: The trip may be tolerable. How tolerable is akin to comparing an individual's tolerance for pain. Most have different thresholds.

 

[GetOffYourGas]

No need to get defensive here. If you read the second sentence, you see that I agree with your numbers. And if you really want to mince words, fine. You have some highly pessimistic assumptions in that calculation.

I'm pointing this out more for others' benefit. This type of calculation will overestimate your heater's energy consumption almost every time. There is no need to scare people that the heater will consume half of your battery charge on a long trip. It might if you do a lot of short trips, letting the car cool off in between. This is what I do during the week - short commute, rest, daughter to gymnastics, rest, son to martial arts, rest, run to the grocery store, rest... Each "rest" lets the car cool and the heater has to overcome the difference. Very different use case to a 3-hour drive.

BTW, For someone who lives in Alberta, I'm shocked to hear you claim that 35F is particularly cold. I can't see the heater running at 9kW for 3 hours unless you set the car temperature to something like 90F. I guess I assumed you would set it to a more reasonable mid-60s level.

 

[oilerlord]

No need to get defensive here. If you read the second sentence, you see that I agree with your numbers. And if you really want to mince words, fine. You have some highly pessimistic assumptions in that calculation.

I'm pointing this out more for others' benefit. This type of calculation will overestimate your heater's energy consumption almost every time. There is no need to scare people that the heater will consume half of your battery charge on a long trip. It might if you do a lot of short trips, letting the car cool off in between. This is what I do during the week - short commute, rest, daughter to gymnastics, rest, son to martial arts, rest, run to the grocery store, rest... Each "rest" lets the car cool and the heater has to overcome the difference. Very different use case to a 3-hour drive.

BTW, For someone who lives in Alberta, I'm shocked to hear you claim that 35F is particularly cold. I can't see the heater running at 9kW for 3 hours unless you set the car temperature to something like 90F. I guess I assumed you would set it to a more reasonable mid-60s level.

Whoa...Brian, who's getting defensive?

Simply stated, on a 200 mile trip with a 60 kWh battery, unless you drive with an efficiency of 3.33 miles per kWh - you're not going to make it without some deliberate power saving / efficiency choices. You might set your temperature at "reasonable" 65F while others might set it at a "reasonable" 75F. There's no right or wrong, and again, we don't know how much power the heater draws as part of normal operation (I'm going to "Ask Amber" if she knows this).

There are Bolt owners on this forum that live in California that have reported they are getting under 3 miles per kWh driving on the highway. There are other Bolt owners reporting they get over 4 miles per kWh on the highway, but the common thread is not using the heater or AC, and driving ~60 MPH.

I'm also pointing things out for others' benefit so they have realistic range expectations.

 

[GetOffYourGas]

Whoa...Brian, who's getting defensive?

Not me! :lol:

I guess this just proves that we're both horrible at reading people via the internet!

 

[SeanNelson]

You highly doubt it will stay at 9kW for more than 5-10 minutes - which may be highly optimistic given how cold it is outside, and that we don't know if the heater has variable power consumption.

It seems highly unlikely that the power consumption would be fixed at a constant 9KW. What if you're driving in merely cool weather and want a little heat - pumping out the same amount of heat that would be required to keep the cabin warm in subzero weather would be obviously crazy. And just as crazy would be running the heater at 9KW and dumping most of the heated air overboard in those conditions.

So the heater output must surely be variable. Either the HVAC system varies the power delivered to the heating element, or it varies the duty cycle of the heating element, which amounts to the same thing.

 

[powersurge]

In regard to the original article about battery size, I do not agree that a 200+ mile battery is that desirable. No one drives that much in one trip. Paying per KW for a battery you will be dragging around if you do not use its capacity is a waste of money at both ends... Once when you buy the car, and then when you let the unused capacity or the battery deteriorate over time. I am not interested in driving long distances in an EV because I do not see that we have the charging infrastructure developed at this time... I also don't want to walk in the desert and hope that I will find water before my canteen is empty....

Also, I in terms of the health of the battery, I know some facts.. 1) you don't want to keep the battery charged to a high level (e.g., 90-100%) for long periods. 2) The battery safely stores for the longest life-time at the 50% mark. Example #1 - I drive a 24kw Nissan Leaf. I would say that I drive a lot.. 50 miles per day. I start at 100% every morning, and charge the car when it is about 45-50% (the battery sweet spot). Example #2 - A 200 mile EV would need to drive 100 miles per day to reach the "sweet spot" of 50%.

In my opinion, very few people would drive 100 miles daily to use 50% of the 200 mile car's capacity. So really, a 100 mile car can safely (for battery longevity) drive 50 miles daily, while a 200 mile car can safely drive 100 miles daily. I prefer to NOT BUY the extra capacity of the 200 mile car from the start.. When my 100 mile range Leaf battery goes, then I will rather buy another 100 mile range battery in the future.

SO, IMO I don't see that 100 mile range EVs will disappear unless the battery prices drop to a ridiculously low level.. What I would LOVE is a battery as reliable as the Hybrid cars (Prius, Ford Escape) that last 10-15 years, or the life of the car.

 

[boltage]

What I would LOVE is a battery as reliable as the Hybrid cars (Prius, Ford Escape) that last 10-15 years, or the life of the car.

A large battery has two advantages in this area:

a. It needs fewer charging cycles. If you drive 50 miles per day, then you will recharge a 238 mile Bolt every 3-4 days of driving, or every 150-200 miles. But you will charge an 84 mile Leaf every day, or every 50 miles, so you will be putting the battery through 3-4 times as many charge cycles, likely increasing battery degradation.

b. Even in the case of battery degradation, a 238 mile Bolt that has degraded to 190 miles is still very usable, while an 84 mile Leaf that has degraded to 67 miles may be more restricting on daily drives.

 

[michael]

What I would LOVE is a battery as reliable as the Hybrid cars (Prius, Ford Escape) that last 10-15 years, or the life of the car.

A large battery has two advantages in this area:

a. It needs fewer charging cycles. If you drive 50 miles per day, then you will recharge a 238 mile Bolt every 3-4 days of driving, or every 150-200 miles. But you will charge an 84 mile Leaf every day, or every 50 miles, so you will be putting the battery through 3-4 times as many charge cycles, likely increasing battery degradation.

b. Even in the case of battery degradation, a 238 mile Bolt that has degraded to 190 miles is still very usable, while an 84 mile Leaf that has degraded to 67 miles may be more restricting on daily drives.

What you are saying is true but an even better plan is to charge the battery daily but never anywhere near full.

Shallow cycles at low states of charge are much easier on the battery than full cycles.

 

[boltage]

What you are saying is true but an even better plan is to charge the battery daily but never anywhere near full.

Shallow cycles at low states of charge are much easier on the battery than full cycles.

For a Bolt with 50 mile daily drives, would 4 charges from 20-41% be better or worse than 1 charge from 16-100% or 6-90% in terms of battery life? Or compare 3 charges from 20-41% to 1 charge at 27-90% (for a larger buffer against range anxiety)?

In comparison, a short range EV like an 84 mile Leaf would likely mean daily charging from 40-100%, or as low as 1-61%, depending on how much buffer against range anxiety you want (but even the 40% level at 34 miles is less than 16% of a Bolt's battery at 38 miles). So it seems that either Bolt scenario is better for battery life than the Leaf scenario.

Now, if you charge your Bolt daily from 79-100%, that may be worse for battery life.

 

[michael]

The four shallow charges would be better.

Based in my research I believe your 20-40 scenario is great. Others will tell you to stay mid range, like 40/60. This is a matter of debate. Clearly the 40/60 plan gives more safety net and even I agree it's very healthy for the battery

 

[oilerlord]

It seems highly unlikely that the power consumption would be fixed at a constant 9KW. What if you're driving in merely cool weather and want a little heat - pumping out the same amount of heat that would be required to keep the cabin warm in subzero weather would be obviously crazy. And just as crazy would be running the heater at 9KW and dumping most of the heated air overboard in those conditions.

So the heater output must surely be variable. Either the HVAC system varies the power delivered to the heating element, or it varies the duty cycle of the heating element, which amounts to the same thing.

I'll say it (yet) again - We don't know. Someone else started a thread about the heater using 9kW, which sounds high but may not be. That's why I started a thread in the Ask Chevrolet section. Hopefully, we'll get some answers.

 

[SeanNelson]

It seems highly unlikely that the power consumption would be fixed at a constant 9KW.

I'll say it (yet) again - We don't know. Someone else started a thread about the heater using 9kW, which sounds high but may not be. That's why I started a thread in the Ask Chevrolet section. Hopefully, we'll get some answers.

Of course you could just ask some Bolt owners to report what the power meter shows for various settings of the HVAC system.

 

[oilerlord]

Of course you could just ask some Bolt owners to report what the power meter shows for various settings of the HVAC system.

Are your fingers broken, Sean? Fill your boots.

Instead of another 5 pages of debate in the Heater = 9kW thread, I figured everyone would benefit getting answers from the source.