[rnumrich]

One week old Bolt owners, car has certainly exceeded all expectations and fully put to rest any reservations on if I did the right thing vs holding onto a 13 60K volt another year or two. Even in the Volt, I ran electric 98% of the time - normally 40-55 mi per day where I was partially able to recharge during the day.

So now in the Bolt, my driving will be similar. Might guess over 100 mi no more than once a month if that. Probably would take 2nd ICE vehicle on any long out of state trip. Still pondering if I want to get a level 2 charger, holding off for now on posting pros and cons for me.

But if I stay level I, would anyone have concerns if I essentially mimicked my charging behavior from the volt and simply plugged in every night when I return in the evening to charge say 40-55 mi to full charge? If so, I imagine I might force myself to drain to a 200 mi recharge say once every other month or so? Guessing this would be OK, but wanted to check with someone who might understand the Bolt battery structure to a more technical detail than myself.

Thanks.

Rich N

 

[Henry_FL]

Charge just like you did before, the lower the depth of discharges, the more cycles you get from a battery

 

[saghost]

With Lithium chemistries, there's no memory to worry about, and they are happiest near fifty percent - pushing them to the extremes on either end accelerates degradation.

There's certainly no problem charging every night, either on 120V or 240V; I think that's what most owners of EVs of any sort do.

Given your expected usage, you probably want to give careful consideration to turning on "hilltop reserve" mode. The official purpose of this is to leave you extra room to regenerate right after charging, but if you're not needing the whole range every day, stopping charging at ~90% like it does will reduce the wear on the pack.

 

[Slotracer577]

+1 on the hilltop reserve. I use it all the time as I don't use the full battery on my daily driving. Yesterday my wife forgot to plug it in and we only had to put in 30kwh for two days.
Go with the L2 charger. It will be nice on those days when you get home late and leave early. I would just put in an outlet, then use the evse from the car with an adapter. That alone will cut charging time in half. If at a later date you need the full 32a charging then buy a bigger evse.

 

[Barry]

I agree with saghost. Use the hilltop setting except for the rare long trip. Try to keep the "tank" somewhere around half full in general. The more time the battery spends full or nearly full, the faster it ages, so routinely charging short of that is good for the pack. But of course you have to balance that with your range anxiety. I don't think there is any need to intentionally fully discharge for the purposes of battery maintenance. These are not NiCD batteries.

 

[Ladogaboy]

Given your expected usage, you probably want to give careful consideration to turning on "hilltop reserve" mode. The official purpose of this is to leave you extra room to regenerate right after charging, but if you're not needing the whole range every day, stopping charging at ~90% like it does will reduce the wear on the pack.

My commute three to four days a week is ~140 miles, and I still am using Hilltop Reserve mode. I just don't need all of the 250-270 miles of range I normally see. And if I know I'm going on a long trip, I simply switch it off to get the extra 25 miles or so.

For the OP's purposes, I think Hilltop Reserve and 120 V charging are fine. Maximize battery life and save money on charging equipment.

 

[saghost]

My commute three to four days a week is ~140 miles, and I still am using Hilltop Reserve mode. I just don't need all of the 250-270 miles of range I normally see. And if I know I'm going on a long trip, I simply switch it off to get the extra 25 miles or so.

For the OP's purposes, I think Hilltop Reserve and 120 V charging are fine. Maximize battery life and save money on charging equipment.

Yeah. It's a pity GM couldn't give you a slider like Tesla (I usually keep the X at 80% for daily use - and after a year I'm down maybe 2 miles, far less than some other folks,) but at least they didn't force a 100% charge every time in response to the EPA rating rules like Nissan did.

 

[Ladogaboy]

Yeah. It's a pity GM couldn't give you a slider like Tesla (I usually keep the X at 80% for daily use - and after a year I'm down maybe 2 miles, far less than some other folks,) but at least they didn't force a 100% charge every time in response to the EPA rating rules like Nissan did.

I totally agree. I believe I already made that as a suggestion in an article I wrote about improvements GM should make to Bolt EV as soon as possible.

 

[MyBBolt]

Does anyone know how many cycles the batteries are rated for? I've been looking at Lithium Ion batteries for a tractor conversion and most are rated for 3000-5000 cycles. If the Bolts batteries are like the ones I've looked at, daily recharging with a 5k cycle rating says they'll last around 13-14 years. Recharging less than daily should extent their life. (The car we traded in was a 12 year old Honda Civic Hybrid.)

I hadn't heard about the 50% "happy" level that Saghost wrote about. We've owned our Bolt for 3 months and drive 25-50 miles a day. Most days I was plugging in as soon as we got back to keep the battery "topped-off". Now, I'm looking at only plugging in once to twice a week. I also need to use the hilltop setting as we live on a hill and no room left to regen on the way down has been an issue. I guess I need to finish reading the manual...

 

[hellsop]

Does anyone know how many cycles the batteries are rated for? I've been looking at Lithium Ion batteries for a tractor conversion and most are rated for 3000-5000 cycles. If the Bolts batteries are like the ones I've looked at, daily recharging with a 5k cycle rating says they'll last around 13-14 years. Recharging less than daily should extent their life. (The car we traded in was a 12 year old Honda Civic Hybrid.)

I hadn't heard about the 50% "happy" level that Saghost wrote about. We've owned our Bolt for 3 months and drive 25-50 miles a day. Most days I was plugging in as soon as we got back to keep the battery "topped-off". Now, I'm looking at only plugging in once to twice a week. I also need to use the hilltop setting as we live on a hill and no room left to regen on the way down has been an issue. I guess I need to finish reading the manual...

With properly managed batteries, the number of cycles a "full charge" is ends up being about the proportional fraction. If you use 200 miles a week, one once-weekly charge is one charge cycle. But nightly charges of the 30-40 miles used during the day for a whole week are ALSO one charge cycle, because each one is only adding 20% of a charge. "Proper management" is really key, though. GM gets the capacity cycles it does by rigorous thermal management of the battery pack (It stays between 50 and 90F any time it's being used or charged, and it will use "plugged in but not actually charging" available power to keep the pack there even when not doing much), and avoiding the ends of the charge range (the 100% and 0% charge) like they're Ebola hot zones. A Bolt pack is likely to be able to cycle 300 MWh through before it starts losing capacity, and drive substantially over a million miles with that power. The odds of the battery pack outlasting the rest of the car are very very high.

 

[saghost]

Does anyone know how many cycles the batteries are rated for? I've been looking at Lithium Ion batteries for a tractor conversion and most are rated for 3000-5000 cycles. If the Bolts batteries are like the ones I've looked at, daily recharging with a 5k cycle rating says they'll last around 13-14 years. Recharging less than daily should extent their life. (The car we traded in was a 12 year old Honda Civic Hybrid.)

I hadn't heard about the 50% "happy" level that Saghost wrote about. We've owned our Bolt for 3 months and drive 25-50 miles a day. Most days I was plugging in as soon as we got back to keep the battery "topped-off". Now, I'm looking at only plugging in once to twice a week. I also need to use the hilltop setting as we live on a hill and no room left to regen on the way down has been an issue. I guess I need to finish reading the manual...

Two points to remember here, one of which hellsop touched on somewhat:

First, a cycle isn't "any time you recharge the battery." For these ratings, a cycle is usually when you charge and discharge the battery it's full capacity rating, however many fractional cycles you do to get there. It can get a little muddy when they say X cycles at 80% depth of discharge - is that X 80% cycles or X equivalent cycles of 80% DoD (hence 1.25 times as many actual cycles) - but either way, the average 12k mile per year driver should only be putting on around fifty equivalent cycles per year.

Second, the battery doesn't suddenly stop working after that many cycles. The industry standard is to rate the cycles until the pack reaches 80% capacity. It will continue to operate normally for a long time thereafter, just with progressively less capacity.

 

[Upper5Percent]

With Lithium chemistries, there's no memory to worry about, and they are happiest near fifty percent - pushing them to the extremes on either end accelerates degradation.

There's certainly no problem charging every night, either on 120V or 240V; I think that's what most owners of EVs of any sort do.

Given your expected usage, you probably want to give careful consideration to turning on "hilltop reserve" mode. The official purpose of this is to leave you extra room to regenerate right after charging, but if you're not needing the whole range every day, stopping charging at ~90% like it does will reduce the wear on the pack.

Well, actually...

http://www.nature.com/nmat/journal/v12/n6/full/nmat3623.html

https://www.psi.ch/media/memory-effect-now-also-found-in-lithium-ion-batteries

For the future use of lithium-ion batteries in vehicles however, this recent discovery is not the final word. It is indeed absolutely possible that the effect could be detected and taken into account through clever adaptation of the software in battery management systems, Novak pointed out. Should that prove successful, the memory effect would not stand in the way of a reliable and safe use of lithium-ion batteries in electric vehicles. So now, engineers face the challenge of finding the correct way of handling the peculiar memory of batteries.

Read more at: https://phys.org/news/2013-04-memory-effect-lithium-ion-batteries.html#jCp

 

[saghost]

Well, actually...

http://www.nature.com/nmat/journal/v12/n6/full/nmat3623.html

https://www.psi.ch/media/memory-effect-now-also-found-in-lithium-ion-batteries

For the future use of lithium-ion batteries in vehicles however, this recent discovery is not the final word. It is indeed absolutely possible that the effect could be detected and taken into account through clever adaptation of the software in battery management systems, Novak pointed out. Should that prove successful, the memory effect would not stand in the way of a reliable and safe use of lithium-ion batteries in electric vehicles. So now, engineers face the challenge of finding the correct way of handling the peculiar memory of batteries.

Read more at: https://phys.org/news/2013-04-memory-effect-lithium-ion-batteries.html#jCp

Interesting. I hadn't seen that before, just the endless assertions that lithium packs don't have memory. Those articles all seem to be about lithium iron phosphate batteries - and the effect is said to be from the anode that's specific to those batteries only.

Since I believe the Volt is using a variation of the same NMC chemistry that all the other GM EVs have used, the effect described by the articles doesn't seem to apply to them.

 

[summit]

I haven't heard of the 50% happy SOC neither, can someone point to a source/doc ? Thanks

 

[saghost]

I haven't heard of the 50% happy SOC neither, can someone point to a source/doc ? Thanks

https://arstechnica.com/gadgets/2011/02/ask-ars-what-is-the-best-way-to-use-an-li-ion-battery/

http://batteryuniversity.com/learn/article/how_to_store_batteries

https://www.tesla.com/blog/bit-about-batteries

https://zeusbatteryproducts.wordpre...an-of-lithium-ion-batteries-in-home-business/

From the first half dozen hits on a google search for Lithium ion battery best state of charge. I thought it was common knowledge - though some of these say 40% or 40-50% instead of 50%.

 

[hellsop]

From the first half dozen hits on a google search for Lithium ion battery best state of charge. I thought it was common knowledge - though some of these say 40% or 40-50% instead of 50%.

Based on conversations with People Who Should Know, the difference between 40 and 50 and even 70% is vanishingly small. It's a thing you can measure using fancy battery-testing equipment, but in practical use, anything that isn't "full" or "drained" is so much better for storage that "how much is your partial charge" almost isn't worth working for. Just "someplace towards the middle" is plenty better, and beyond that, put your effort into storing batteries in a place that's cool instead of hot or freezing instead. (Smart boat owners, for example, take the lithium battery banks OUT when the boat is going to winter over on a stand in a marina, and store the batteries in their basement, and put them back for Splash Day.)

 

[michaellax]

With properly managed batteries...

I always plug in every night: L2, no hilltop reserve, lease 3 years. Could you give me your opinion.

 

[saghost]

I always plug in every night: L2, no hilltop reserve, lease 3 years. Could you give me your opinion.

Is there a reason you aren't using hilltop reserve? How far do you drive every day?

 

[Steverino]

Is there a reason you aren't using hilltop reserve? How far do you drive every day?

I interpreted his answer as, "The car is a rental, I don't care if a future owner may encounter premature battery decline because of my actions". Or, maybe they have a 230 mile round trip commute. Or maybe they don't know how to set Hilltop Reserve. Or maybe they think Hilltop Reserve is fake news? Or...?

I set mine to Hilltop reserve. My commute is 60 miles so there is plenty or anxiety-free range left over. plus I want to maximize the battery life.

 

[saghost]

I interpreted his answer as, "The car is a rental, I don't care if a future owner may encounter premature battery decline because of my actions". Or, maybe they have a 230 mile round trip commute. Or maybe they don't know how to set Hilltop Reserve. Or maybe they think Hilltop Reserve is fake news? Or...?

I set mine to Hilltop reserve. My commute is 60 miles so there is plenty or anxiety-free range left over. plus I want to maximize the battery life.

Lots we don't know about the Bolt yet, and GM's instrumentation approach makes it harder to see, but I don't think it'll be just future owners of the car that experience degradation in that scenario. It likely won't be as bad as the Leaf fiasco, but I'd be surprised if his car doesn't experience measurable degradation over the three years...