But charging at a lower voltage appears to be less efficient.

 

The inverter is less efficient at the lower voltages and power levels. This is a fact re,aged to system voktages and the components they use. A simple example is the linear region of a transistor. It dissipates more power compares to what it carries than a fully saturated one carrying more current. You can google those terms if you do not understand them.

Also, if the bolt needs to do battery conditioning due to extreme heat or cold, there isn’t enough power to do so and charge the car at the same time. The straw is too small.
Earlier charging to be ”ready’ for something that may never happen is what the 40% priority charging is. If you come home with a low charge, it will immediately start charging to reach 40% and then stop, tailoring the remaining charge time to be close to the set departure time. This prevents you from being caught with the battery low in case something comes up and you are unable to finish charging later in the night.

The power company doesn’t care about your power draw during off-peak hours ( at night). They wish their grid was drawing 10% of its maximum capacity all the time instead of at a few points of the day. They hate that we don’t use all of the available capacity all the time.

 

The inverter is less efficient at the lower voltages and power levels.

Also, if the bolt needs to do battery conditioning due to extreme heat or cold, there isn’t enough power to do so and charge the car at the same time.

The power company doesn’t care about your power draw during off-peak hours ( at night).

1) Since we are using AC to charge and storing as DC, should this not be a rectifier rather than an inverter?

2) The hot or cold would have to be VERY extreme. This would never be while charging in a garage. {In 29 months, I have only detected battery conditioning once - during DCFC on a very hot day. I did not even see its use when parked outdoors for 4-5,hours in 25-30 degree weather.} In fact, even in cold climes, airport long-term (> 72 hours) parking lots will use 120 VAC outdoor outlets to both charge and keep the batteries a little warmer.

3) Agreed.

 

I expect some combination V2G (vehicle to grid) capability in the future, and as a stepping stone, voluntary programs that allow the utility to regulate charge rate and/or time. You would opt in and be given some incentive to participate. You would provide the time that the vehicle must be done charging, and the utility would determine how it achieves that goal. SF utility and BMW piloted a program that was similar in that participants were asked to delay charging during certain infrequent peak demand times when the grid was particularly strained.

 

Would love to see V2G and also a larger battery in the car that can go 500 miles... bigger battery, lower % cycling, longer life.

 

I have not gone through a SW winter with the Bolt, so will have to see if I need higher charging speed.

 

Do you run out of time when charging? Do you charge at home and need more time? My average charge is about 2 hours.

 

I'd charge at a rate lower than the full 32A if I knew it would extend battery life. But I surmise it does not. 32A is still way less than CCS can do, and people who do a ton of fast charging (NewsCoulomb) seem to be OK.

I take a couple of measures that ought to keep the battery happy. I plug in only when the SOC is below 50%, or if I've planned a longer trip so that the SOC averages 75% or less. And I unplug soon after its full.

 

Some charging related degradation in li-ion batteries is related to the time spent charging. Thus charging slowly can actually be more harmful than charging more quickly.

In practice, on a Bolt, I suspect it makes no measurable difference, just like most of the other superstitious rituals people use to try to make sure their Bolt's battery will be good for 500,000 miles, never mind that the average life expectancy of a new vehicle is around 8 years or 150,000 miles, and most people who buy new sell way before that.

 

32A is already very slow. You are using about 7000 watts to charge 288 cells, so each cell is being charged at about 24 watts. Imagine your cell phone or laptop taking 9 hours to fully charge.

Mike

 

It's nice to see these esoteric discussions on the board. It means that there are no major problems to be addressed by somewhat bored but enthusiastic Bolt owners. In S. California, I keep the Bolt fully charged during fire season when the possibility of electric cut-off by the power company is high. I plan to use a small inverter to power my fridge and freezer during an emergency.

 

I find it both humorous and tragic that EV fora members are still discussing their wants and desires with V2G. This was also a hot topic on the EV-1 forum (RIP) in...1997.

 

Change takes time. We probably need, what, like 40% of all vehicles to be EV before utilities get serious about integrating load shifting strategies? They might be thinking seriously about it in 15 years, and then it will take how many years to implement, another 5? Until then all we can do is speculate as to what strategies are easiest to implement and how things will progress.

 

Yup. Just like fusion energy that's been "only 20 years away!" for at least 40 years.

 

I bought my (for my grandfather) first SSD drive in 2009 and experienced how vastly superior they were in performance and proclaimed that they would represent 50% of drive sales in 2 years. I figured it would be way cheaper to manufacture too since there are no moving parts; simply print circuits on silicon... well here it is a decade later and we might just now be at 50% sales. I'm now pessimistic about how quickly technology can be developed, mass produced, and then adopted by the market.

BTW, we're approaching a decade since the original Nissan Leaf was introduced, and we're at something like 2% of vehicle sales being EV. My current estimate is 2035 before we hit 50% of sales.

 

sigh

Did no one read “DC Fast Changing” or “current trends rectified” and realize the nature of my post?

 

sigh

Did no one read “DC Fast Changing” or “current trends rectified” and realize the nature of my post?

Yes, I understood the humor of your post. I got a good chuckle out of it. I stand by my response, though. That last part just doesn't make sense.