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ELR charging theory question. I'm lucky in that my work is less than 5 miles from my home. The first few weeks I charged every day, then wondered if it would be better for the battery to be more discharged. I resisted charging, harder than I thought, until I was down to less than 10 miles. I can go 3-4 days without plugging in. I've looked for answers to what's better for my battery and charging system and see conflicting information. I hear fans and pumps running when I charge on my level 2 charger so I'm thinking it would be less wear on those parts to charge less frequently, but I'm more concerned with my battery. I've posted that I can easily drive 40 plus miles on the weekends on battery alone. I have a girlfriend 39 miles away. So will less frequent charging, keeping the battery in a state of 50 percent or less charge be an advantage or disadvantage to battery life? If it's inconsequential, then less charging would be less wear and tear on the fans and pumps that work during charging. Ideas? Screenshot_20181014-220328.jpg
 

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ELR charging theory question. I'm lucky in that my work is less than 5 miles from my home. The first few weeks I charged every day, then wondered if it would be better for the battery to be more discharged. I resisted charging, harder than I thought, until I was down to less than 10 miles. I can go 3-4 days without plugging in. I've looked for answers to what's better for my battery and charging system and see conflicting information. I hear fans and pumps running when I charge on my level 2 charger so I'm thinking it would be less wear on those parts to charge less frequently, but I'm more concerned with my battery. I've posted that I can easily drive 40 plus miles on the weekends on battery alone. I have a girlfriend 39 miles away. So will less frequent charging, keeping the battery in a state of 50 percent or less charge be an advantage or disadvantage to battery life? If it's inconsequential, then less charging would be less wear and tear on the fans and pumps that work during charging. Ideas? View attachment 155881
The engineers already made it so the battery is always within the Goldilocks zone; never too fully charged or too low. I will skip a few days between charging in the spring and fall but once it turns cold I plug in every evening so that I can precondition in the A.M. while plugged in. On the hottest days of summer I would plug in to recharge in the middle of the afternoon. As soon as charging was completed the AC would run to cool the battery. Eventually, depending on how long I own my 2017 Volt, the charging port may wear out and need to be replaced; it is fairly inexpensive. The AC compressor is an expensive component that is in almost constant use much of the year but essential to cooling the battery and the cabin. I'll deal with it when I have to.
 

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I guess your arm and the relay for the main contactor would be happy if your charge less :)

I have no data on the cycle life of those two parts.
 

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The fact that you have found conflicting information will also be reflected in this forum. You'll find opinions all over the map if the discussion takes off. In the end, you have to be comfortable with your own decision.
 

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The fact that you have found conflicting information will also be reflected in this forum. You'll find opinions all over the map if the discussion takes off. In the end, you have to be comfortable with your own decision.
Which conflicting information is that? I see cbsimons "wondering" (not being informed) if he could do something better and other people telling him to not worry about it.
 

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The engineers already made it so the battery is always within the Goldilocks zone; never too fully charged or too low.
Most lithium battery experts would say the 'Goldilocks Zone' is more like 20 to 30% SOC on the low end and 80 to 90% SOC on the high end and virtually every EV manufacturer exceeds those numbers - Their max range would be much lower if they didn't

Some advice for letting cars sit fully charged - Fully as in the max that the manufacturer allows, not the max allowable for the battery chemistry - from Teslarati

https://www.teslarati.com/top-5-tips-to-maintaining-ev-battery/

Tesla gives owners a choice of how 'full' to recharge depending on how far you need to go, so if you don't need the max range, they advise recharging to the lower percentage . . . . especially if the car is going to sit for 8 hours or more before it's going to be used. Unfortunately, GM didn't give us that option. Volts recharge to 'full' (which isn't the max allowable for the cells they're using, but it's still higher than 90%) which would put it above the 'Goldilocks Zone,' at least in my book

When we use the car for 5 or 10 miles per day, we go several days before we charge it again - Partly based on our experiences with our other BEV's gained over 6+ years of use

That said, it will last as long as GM designed it to last if you plug it in every night - If you want it to last longer than that, there are things you can do to improve battery life

Don
 

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Most lithium battery experts would say the 'Goldilocks Zone' is more like 20 to 30% SOC on the low end and 80 to 90% SOC on the high end and virtually every EV manufacturer exceeds those numbers - Their max range would be much lower if they didn't

Some advice for letting cars sit fully charged - Fully as in the max that the manufacturer allows, not the max allowable for the battery chemistry - from Teslarati

https://www.teslarati.com/top-5-tips-to-maintaining-ev-battery/

Tesla gives owners a choice of how 'full' to recharge depending on how far you need to go, so if you don't need the max range, they advise recharging to the lower percentage . . . . especially if the car is going to sit for 8 hours or more before it's going to be used. Unfortunately, GM didn't give us that option. Volts recharge to 'full' (which isn't the max allowable for the cells they're using, but it's still higher than 90%) which would put it above the 'Goldilocks Zone,' at least in my book

When we use the car for 5 or 10 miles per day, we go several days before we charge it again - Partly based on our experiences with our other BEV's gained over 6+ years of use

That said, it will last as long as GM designed it to last if you plug it in every night - If you want it to last longer than that, there are things you can do to improve battery life

Don
If the battery loses some of its capacity after 8+ years, it will still be usable for most purposes.
 

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Any lithium ion battery is in its lowest stress state at a medium level of charge, between about 40-60% state of charge. Any time it is within that zone, it is aging the most slowly. So I would say that if the battery is in that zone and you don't have to charge it to get the range you need, and especially if it is going to be unused for a while, then leaving it unplugged would technically be the best thing for the battery, assuming the active thermal management system is not needed. But you have to weigh that against the convenience of having a fully charged car ready to go whenever you need it.
 

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Discussion Starter #9
Information I hadn't found in my research. Thank you. I'm lucky that for where I live we have very little high or low temperature extremes.
 

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I tried this recently. Like you I have a short commute so I decided to experiment. It took about 5 days to discharge the battery enough for the ICE to come on. However, I only got about 32 EV miles total after those 5 days. I've gone back to charging it every night when I get home.
 

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One way to let the battery dwell at a lower state of charge for longer is to use the delayed charge feature of the car. That can let the car sit uncharged longer, and only begin charging when needed for your next planned departure. Other benefits include:
-This also lets the thermal management function because the car will be plugged in.
-The A/C thermal management may run less due to charging heat because charging will begin after the battery has had more time to cool down after driving.
-It can save you money if you have time of use billing, and/or it can be better for the grid to charge during low use times of the day.
 

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2014 ELR manual says to plug in when the car is not in use. Which is what I did with mine with zero issues in 50k miles. I never had any issues with the charge port on any of my plug-ins.

My drive cycle is not typical however. I discharge the battery nearly every day, so, I wouldn't get the tale-of-two-volts situation.

With all three (Volt, ELR, CT6), I plug in when the car is in the garage/driveway. My understanding is that the battery needs to cool/heat/cell-balance after/during charging. When it is really cold or really hot, I notice that the car uses line power periodically even if the battery is fully charged.

So, leaving them plugged in is the right move in my opinion.
 

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Any lithium ion battery is in its lowest stress state at a medium level of charge, between about 40-60% state of charge. Any time it is within that zone, it is aging the most slowly. So I would say that if the battery is in that zone and you don't have to charge it to get the range you need, and especially if it is going to be unused for a while, then leaving it unplugged would technically be the best thing for the battery, assuming the active thermal management system is not needed. But you have to weigh that against the convenience of having a fully charged car ready to go whenever you need it.
This is interesting information for me - I have a home office so won't be using my Volt daily - weekend errands will max my range, and there may be 2-3 mid-range trips during the week. I will try to play with this approach (particularly as my wall plugs are beyond a heavily trafficked part of the garage, above the washer/dryer + pet food storage area).
 

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Like Loboc, my Volt is plugged in whenever it is in the garage - but I do unplug during thunderstorms.

I'm retired, so there is no daily commute. (YEAH!) But I live on the SW edge of my community, so the grocery, library, shopping, doctor, etc. are all spread out about 6-7 miles away. This makes a typical "trip to town" anywhere from 18-22 miles round trip. In warm weather my estimated range is about 45 - 47 miles, so I could probably only recharge every other trip - but cold weather range drops to mid 30s. I find it simpler to just plug the car in when I get home and forget it. Let the car's programming take care of itself - and it is always ready to go anywhere without battery range questions.

A few months ago I ran across a web site that supposedly contained GM engineering info on the 2013 Volt battery pack and SOC limits:

16.5KW max capacity
18.5% SOC min = 3.05KW
83.5% SOC max = 13.77KW
Net usable KW = 10.72

Unfortunately I didn't make note of the site, so I can't submit this info as being absolutely accurate, but it seems to be credible. Whenever I use the battery to ICE start, the total battery usage is usually 10.6 or 10.7.

BTW - I recently met a guy with a spotless 2013 with 110K miles on it. His range and usage is the same as my car with only 32K. Seems like the battery maintenance programming is doing its job.
 

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BTW - I recently met a guy with a spotless 2013 with 110K miles on it. His range and usage is the same as my car with only 32K. Seems like the battery maintenance programming is doing its job.
. . . . . and ole 'Sparkie' has gone more than 300K on it's original battery, running it empty and fully recharging it twice each day, so GM's battery management program appears to be pretty conservative

I believe in the Gen 2 cars, they are using a larger percentage of the battery than the earlier cars. The battery isn't much larger, but it has significantly more usable capacity which gives the car a much greater range

In extreme climates (Arizona in the summer and any place where it regularly gets down near zero in the winter) it's probably best to leave the car plugged in 24/7 to allow the thermal management system to do it's thing - That's what it's there for

Don
 

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A few months ago I ran across a web site that supposedly contained GM engineering info on the 2013 Volt battery pack and SOC limits:

16.5KW max capacity
18.5% SOC min = 3.05KW
83.5% SOC max = 13.77KW
Net usable KW = 10.72
Seems reasonably close to the "goldilocks" range discussed upthread. Almost like someone engineered it that way.
 

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Occam's BATTERY POWERED razor at work :)
 

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Assuming that you are going to want your car fully charged when you start the day, you will get longer cycle life with shallow depth of discharge, charging every night than driving several days and resulting in a deeper depth of discharge. Li-Ion batteries have a number of degradation factors. Depth of discharge is one, as is calendar life, temperature, and storage SOC.
 
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