archie_b
Site Moderator
Posts: 126
Joined: Sun Dec 25, 2011 5:51 pm

Re: Best charging practices for battery longevity

Wed Jun 19, 2013 5:27 am

Tomrh:

I agree that cool temperatures are better for battery longevity, but slide 8 is showing the difference between 45C and 25C. This is 113F versus 77F, or very hot versus hot. Driving an EV, no matter what chemistry, at -10C to -20C (14F to -4F) or lower, does affect longevity. Just not to the degree that high temperatures (45C) do. Neither extreme is good for battery life.

Best would be 40F to 80F, like Seattle, WA. Rarely too cold and rarely too hot. Problem there is it rains, mists, is overcast, or foggy most of the time. Always green, but rarely sunny. Still, I enjoyed living there for 3 years.

tomrh
Posts: 33
Joined: Tue Jun 18, 2013 12:27 pm
Location: Norway

Re: Best charging practices for battery longevity

Wed Jun 19, 2013 7:08 am

MyNissanLeaf.com has an article about this. As far as I can understand, cold weather is optimal for battery life, and Rygge in Norway comes out with a very long battery life (~16,7 years estimated here for Leaf battery), only beaten by Juneau, Alaska, which is even colder! (cf. a table with cities further down in the article). I agree however that extremes are not good, there is a risk for lithium plating at a high SOC and very low temperatures. I assume that's why the cold weather package includes a battery heater.
Black 2012 i-MiEV, 70k miles.
Black 2012 Leaf.

MLucas
Posts: 833
Joined: Thu Jun 07, 2012 8:52 am
Location: Niagara on the Lake, Ontario, Canada

Re: Best charging practices for battery longevity

Wed Jun 19, 2013 7:20 am

archie_b wrote:...Neither extreme is good for battery life.


Many articles out on net about this, all say that low temps leave no permanent damage to lithium-ion batteries unlike extreme heat (e.g. SouthWest Leafs). While my batteries did not endure extreme cold as say in Montreal (-25c), my batteries did get down to -15c and I don't see any loss in range this summer. I'm doing the same commute I did last year and I usually make it to Buffalo on 5-6 bars just like I did last year.

Like Dylan...I went electric.

  • Purchased: June 29th, 2012
  • Mileage on June 29th, 2013 - 25,431 km / 15,802 miles
  • Mileage on June 29th, 2014 - 51,286 km / 32,616 miles

List of Oil Spills: http://en.wikipedia.org/wiki/List_of_oil_spills

tomrh
Posts: 33
Joined: Tue Jun 18, 2013 12:27 pm
Location: Norway

Re: Best charging practices for battery longevity

Wed Jun 19, 2013 11:28 pm

Here is a NASA report on the lithium plating effect: http://trs-new.jpl.nasa.gov/dspace/bits ... 8-0012.pdf

Slide 4 shows a typical lithium cell charged at -40C (-40F), and the plating effect is obvious. Plating is an effect where the battery cannot receive all of the charge current, and lithium ions are deposited as solid lithium causing short-circuits leaving permanent damage to the battery. While several different battery chemistries show this effect already at -20C (-4F), the most commonly used today show no such effect, like e.g. the lithium manganese oxide at slide 22, that is "our" chemistry. :) Thus our batteries are safe down to at least -4F with normal charging. Below that temperature the i-MiEV shuts off the charger. The battery is still ok, but you cannot charge it. Nothing to worry about. The battery heater is there (if equipped) only to heat up the battery such that it can begin receiving charge again. Fast charging increases the risk for plating at low temperatures since the current is much higher, thats why fast chargers significantly reduce power when temperatures are low.
Black 2012 i-MiEV, 70k miles.
Black 2012 Leaf.

JoeS
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Location: Los Altos Hills, California

Re: Best charging practices for battery longevity

Thu Jun 20, 2013 12:50 pm

tomrh, thank you very much for sharing these links with us and adding to our body of knowledge about batteries. In my case, I'm happy that my iMiEV rarely even gets down to 32degF (0degC) and extreme high temperatures are rare since I live in a coastal area.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

tomrh
Posts: 33
Joined: Tue Jun 18, 2013 12:27 pm
Location: Norway

Re: Best charging practices for battery longevity

Thu Jun 20, 2013 2:34 pm

No problem, I'm just happy to be of any help. :) I have been active in a norwegian EV forum, but I have occationally been reading this forum as well because there's a lot of helpful advice to be found here! But a few days ago I noticed a post in this old thread about battery life worries. So I decided to register to share my thoughts. No need to worry when there's no reason to. In Norway, battery life worries is one of the main reasons why people won't buy an EV. It didn't exactly help that previous EV generations (lead-acid, NiCd, NiMH etc.) suffered from severe battery trouble every now and then, and had escalating expenses.
Black 2012 i-MiEV, 70k miles.
Black 2012 Leaf.

RobbW
Posts: 395
Joined: Mon Jul 08, 2013 1:23 pm
Location: Elgin, IL

Re: Best charging practices for battery longevity

Thu Jul 18, 2013 7:50 pm

Being a new EV owner, I've never really had to worry about battery longevity before. However, I've had plenty of hobbies where a hardcore niche of hobbyists get really OCD about trying to eek every last bit out of whatever it is they do in their hobby. Is there truly a real concern about battery longevity in EVs? Or is all this talk another case of a core group of uber-geeks trying to push the envelope as far as possible? (**I hope I'm not offending anyone by using the term geek. I'm considered among the geekiest by friends and family.) Is using optimal charging strategies really going to have THAT big of an impact on the longevity and usefulness of my MiEV's batteries? Or is it only going to provide a minimum of improvement that is championed by us geeks but would never be noticed, recognized, and/or appreciated by the vast majority of the population?

My concern is that I don't want to give myself an anxiety attack worrying over whether I'm charging my car, not simply properly, but to its maximum efficiency. Normally, I would love to take a lot of time studying my charging habits and the effects thereof. But truthfully, I don't really have time for all that right now. My life has gotten really busy this past year since my second daughter arrived and my wife went back to work. These days it is more important that I actually make it to and from childcare, dropping my wife off at the train, and work each day than trying to maximize the optimal charge level in my EV. I don't want to have to worry every morning if there is enough charge to get me there and back based on my charging strategy. It would be most convenient to simply plug my i into the L2 charger every night and know that I will wake up in the morning with a full "tank" that will take me everywhere I need to go and then some.

With all that being said, if charging strategy truly has a significant impact on battery life and capacity, I'd prefer to make a little bit of time in my busy day to address my charging habits and avoid any premature and costly battery replacement expenses.
Clear Skies,
Robb

EV: 2012 Mitsubishi i-MiEV SE, Raspberry Metallic, Premium Package - Purchased 07/11/13
PHEV: 2017 Chrysler Pacifica eHybrid, Bright White, Platinum Package - Purchased 05/01/17

Don
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Location: Biloxi MS

Re: Best charging practices for battery longevity

Fri Jul 19, 2013 7:12 am

Robb - I think the jury is still out. There are users who are fully recharging everyday and some who fully recharge more often than once per day. There are also some who make regular use of the ChaDeMo Quick Charge process . . . . and then there are some of us who only fully recharge the pack once every 2 or 3 weeks. I suspect after some period of time, we'll begin to see how the battery pack fares depending on how it's been treated. Hopefully, nobody will begin to see any adverse effects for several years

But, it's certainly a fact that the overall economy of driving this car is a factor of what a new pack will cost when the time comes to replace it and how many miles you got out of the pack. If you really can drive it for 100,000 miles and the new pack costs $10,000, then your average mileage expense just went up by ten cents a mile . . . . plus whatever you paid for electricity. Consider that a 40 mpg ICE burning $3.50 a gallon gas is using less than 9 cents of fuel per mile

If you need it fully charged to make the trip you're headed out on, by all means, fully charge it but if you can get where you need to go on only 10 bars of juice, then leaving home with 12 or 13 showing is probably better for the battery - It SHOULD last longer doing this

I just wish Mitsu had given us the 80% charge option like Nissan did for the Leaf - I would use that nearly every time. It would be much less time consuming than manually stopping the charge process at about 80% which is what I do now

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1994 Miata 60K miles - Soon to be sold
1979 Honda CBX six into six

RobbW
Posts: 395
Joined: Mon Jul 08, 2013 1:23 pm
Location: Elgin, IL

Re: Best charging practices for battery longevity

Fri Jul 19, 2013 7:57 am

Don wrote:I just wish Mitsu had given us the 80% charge option like Nissan did for the Leaf - I would use that nearly every time. It would be much less time consuming than manually stopping the charge process at about 80% which is what I do now.


Yep, this is the part I'd like to figure out; only charging up to about 80% give or take. I would prefer to take measures that will extend the life of the battery pack and give me the biggest bang for my buck, but it would be nice if the process could be automated. Being a new i owner, I have NO idea how long to charge given a current SOC in order to reach that just-under-full charge. As has been mentioned in many other threads, I'm sure I will learn my car's charging needs as time goes on.

I used the remote timer for the first time last night to take advantage of lower rates in the wee hours of the night. Let me tell you, THAT was a confusing fiasco! It was VERY difficult to determine if the car was currently charging or properly set on a timed setting. The "Charging" light on the L2 EVSE kept going on and off, and I frequently got lots of beeping and errors on the remote. Anyway, I set the beginning time a certain number of hours from the current time (9pm) that would certainly be within the lower rate period. However, I did not set the end timer because I have no idea how many hours to go to reach a SOC that will get me everywhere I need to go throughout the day, but less than a full charge. I'm still too timid to risk not having enough charge when I leave in the morning. So, I let it continue to a full charge.

Speaking of the remote timer, that thing is confusing as heck and has a rather steep learning curve for such a "simple" device. The need to set the charging to manual using the remote before you can set the timer is annoying. Even more annoying is having to press the "comm link" between each command. But most annoying of all is the actual setting of the charging time! Why did MM make it based on hours from current time for a certain number of hours? This would have been MUCH simpler to use if I could just set it to start charging at 1am every night and stop charging at 6am. That way I could be certain it is charging at exactly the same time each night. A truly plug-and-play process. As it is now, I will either need to manually reset the remote timer every night based on the current time or wait until the same specific time every night before I plug in the i and start the remote timer.

I have another question about the remote timer. I know the remote retains the timer settings from the previous session so that you don't have to re-set it up every night. What I want to know is if those charging settings are stored in the i's memory somehow? For example, if at 9pm last night I had plugged in my i and set the remote to start charging in 4 hours and stop charging after 5 hours, will the i remember those settings? So, tonight would I be able to go out to the garage and simply plug the i in at 9pm and it will automatically adhere to the previous remote settings without me taking any other steps? Or do I have to go out at 9pm, plug the i in, transmit a manual charging signal to the i using the remote to stop the auto charging that started when I plugged in, and THEN go through the remote charging steps on the remote?
Clear Skies,
Robb

EV: 2012 Mitsubishi i-MiEV SE, Raspberry Metallic, Premium Package - Purchased 07/11/13
PHEV: 2017 Chrysler Pacifica eHybrid, Bright White, Platinum Package - Purchased 05/01/17

olagon
Posts: 133
Joined: Fri May 03, 2013 5:54 pm

Re: Best charging practices for battery longevity

Fri Jul 19, 2013 12:42 pm

RobbW wrote:I used the remote timer for the first time last night to take advantage of lower rates in the wee hours of the night. Let me tell you, THAT was a confusing fiasco! It was VERY difficult to determine if the car was currently charging or properly set on a timed setting. The "Charging" light on the L2 EVSE kept going on and off, and I frequently got lots of beeping and errors on the remote. Anyway, I set the beginning time a certain number of hours from the current time (9pm) that would certainly be within the lower rate period. However, I did not set the end timer because I have no idea how many hours to go to reach a SOC that will get me everywhere I need to go throughout the day, but less than a full charge. I'm still too timid to risk not having enough charge when I leave in the morning. So, I let it continue to a full charge.


What about using a light timer? You can buy one at a local hardware store for $5. They have some rated for 15 amps so good enough at the 110 charging level. Easy to set start and stop time mechanically.
2012 iMiev SE
Last two cars were both '95 biodiesel benz
Home & now car 100% PV powered since '09
Other car 2003 Forester...waiting to upgrade when Outlander PHEV is out :-)

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