Eight Tips to Extend Battery Life of Your Electric Car

By · September 27, 2011

People considering a plug-in vehicle have a legitimate concern about how long EV batteries will last before they need to be replaced. The answer depends on how you use (or abuse) your vehicle’s batteries. With proper management—and following the tips in this article—the batteries in a modern EV could last decades, allowing plenty of time for the technology to go mainstream and for economies of scale to bring down the price. (Keep in mind: Nissan and General Motors and other carmakers currently provide EV battery warranties for eight years and 100,000 miles.)

Nissan LEAF battery pack

Nissan LEAF battery pack

Check out these tips—but of course, if your owner’s manual contradicts anything you read here, follow the instructions from the manufacturer.

1Avoid full charging when you can.

One reason that batteries in mobile devices only last a couple years is that they are being pushed to their maximum capacity—frequently getting fully charged and fully drained. Consumer products are advertised by their battery operation time, not their battery lifespan. This means that every possible electron will be shoved in there. Charging to maximum capacity might give you the most possible use for that one charge, but it is one of the worst things that you can do to lithium batteries.

In the 2011 Nissan LEAF, there is a Long Battery Life setting that tells the car to stop charging at 80 percent. This reduces the available range, but could greatly increase the lifespan of your battery pack. If your normal daily driving can be done with less than an 80 percent charge or you can charge mid-day, this simple setting is one of the easiest things that you can do to increase the battery’s lifespan.

One additional advantage of not charging up all the way is that it leaves room to store energy from regenerative braking. Often when the batteries are full or near full, regen will be disabled to avoid overcharging the batteries.

2For pure EVs, avoid deep discharging your battery pack.

Lithium-ion packs prefer a partial cycle rather than a deep discharge. Since lithium-ion chemistries do not have a memory effect, there is no harm using a partial discharge. Not only will this avoid excessive wear, it will also mean that—with a little planning—you will arrive at your destination with range to spare.

The Nissan LEAF has 12 “fuel bars” that tell you the charge level of the batteries. Just like you were taught to keep your hands on the wheel at 10 and 2, it is a good idea to keep your LEAF’s charge level within 10 and 2 bars of charge.

EV drivers are often asked, “How far can you go on a charge?” But if you can help it, avoid trying to personally find out for yourself by driving all the way down to an empty battery to test your electric car’s full range.

3For plug-in hybrids, consider “mountain-mode” or leaving EV-mode at key times.

In a plug-in hybrid like the Prius Plug-in Hybrid, or a range-extended electric vehicle such as the Chevy Volt, it’s more common to use all of the available battery capacity before switching to gasoline power. Fortunately, the vehicle’s battery management system knows when to stop drawing from the battery—to avoid deep cycling.

But if you know that your planned route includes a long hill climb, switch to Mountain Mode—which kicks on the gas engine and saves juice in the battery—at least 20 minutes before you start the climb. This will ensure that the batteries are not deep discharged during a long steep climb and you’ll have all the power you need to pass as you go up the mountain.

The Toyota Prius Plug-in Hybrid gives drivers the similar option of voluntarily pushing the car out of EV mode—and for a period of time use more gas and less battery.

4Use timers to minimize the time spent at a high state of charge.

You may have heard that, in many cases, it’s better for the grid, the environment, and your wallet if you charge your EV at night. (See our Top Five Rules for Electric Car Utility Rate Plans.) But careful timing of your charging schedule is also better for your batteries. Again, the idea is that lithium-ion batteries are most stable when they are about half charged—not too full and not too empty. However, a 50 percent charge may not provide adequate range for your daily driving—or may push your state of charge to the limit during your very next commute.

So how do you keep the batteries in their most stable state as long as possible while still ensuring that you have enough range when you leave in the morning? Many electric cars and charging equipment providers offer the ability to program the time of day the charging takes place. The best practice is to set the timer so the vehicle is at the charge level you need about 60 minutes before you plan to leave. Delaying the charge minimizes the time the batteries spend when the cell voltage is high.

The 60-minute buffer has two purposes. First, if something unexpected comes up, like an unscheduled meeting at work, you are not waiting for your car to charge in order to leave. Second, this time allows the batteries time to cool down after charging before they are used for driving. (This second reason is not as important during cold weather, since this warmth would help fight the cold.)

One exception to delaying the charge is if the batteries are almost completely drained. In that case, it’s best to begin charging as soon as possible.

Blink EV charger scheduling screen

Most electric vehicles, and many of the charging equipment systems, provide the ability to schedule charging at any time.

5On a hot day, try to park in the shade. During the winter, park in a garage, rather than on the street.

Many electric cars have thermal management—via air or liquid—that is great for keeping your batteries comfortable, but it comes at a price. Running fans and AC compressors use energy. On a hot day, if you were to park your car on a hot asphalt parking lot, you would not want the thermal management system to run continually. If it did, hours later when you came back, your batteries could be somewhat drained from cooling themselves. Alternatively, the car’s thermal management system could run for a few minutes after parking and then shutdown until the vehicle is restarted. That means that after that cool-down cycle completes, your batteries are slowly being heated by their surrounding. Neither of these solutions are ideal for battery longevity.

6Tip: If your EV has thermal management and the weather is extreme, plug in whenever you can.

This will, of course, charge your batteries, but more importantly, it will engage the thermal management system continuously without draining the batteries. Remember that lithium batteries like the same temperature ranges that you and I do. If you had to sit in the sun in a hot parking lot, would you want the AC turned on? Yes, you would and so would your vehicle’s batteries.

7Plan ahead for period of extended storage.

The Tesla Roadster has a “storage mode.” This makes it easy: plug in the car, set it to storage mode and the vehicle’s firmware takes care of the batteries. If your plug-in vehicle has a special storage mode, use it. If not, and you will not be driving your plug-in car for a month or more, here is what I recommend: (1) Store the vehicle in a cool, but not freezing, location; (2) Charge to 60 percent; (3) The batteries slowly self discharge; (4) When the charge is below 20 percent or 3 months later, whichever comes first, charge the vehicle back up to 60 percent.

With Internet-enabled EVs such as the LEAF and Volt, you can run a smartphone app and check the charge level. When the charge is below 20 percent, you can even initiate charging with these apps.

If you have your car in storage mode for a month or more, this can cause the batteries to become unbalanced. If the pack is unbalanced, your range will be greatly reduced. To alleviate this problem, simply fully charge your batteries before the next time you drive the car. Even if you generally use an 80 percent charge, the next two times you charge the car after a storage event, charge it all the way up. This will ensure the batteries are rebalanced.

8To maximize battery life, minimize use of DC quick charge.

I have saved the best for last. DC quick chargers can dump about 80 miles of range into the Nissan LEAF’s battery pack in 30 minutes. Fast charging is very useful if you need to drive more than the vehicle’s single-charge range in a single day. However, the batteries pay a price for this convenience.

Regular use of fast charging will cost you about 1 percent of capacity per year. For example, if you avoid fast charging, you may have 80 percent capacity after 10 years of normal use. However, if fast charging is your primary fueling method, then your capacity would be 70 percent after 10 years. While the cost to the battery’s lifespan may not be as much as you may think, fast charging still takes a toll that should be avoided when possible.

Conclusion

These tips can extend the life of an electric car’s batteries, but I’d like to make it clear that most are not absolutely necessary. With modern plug-in vehicles, you can simply plug them in anytime and drive it any way that you see fit and you should still have batteries that perform well in 10 years. The manufacturers already build in precautions so you cannot overcharge, over-discharge, or over heat. These are the biggest impacts to lifespan. Still, the tips can help wring a few more cycles out of your pack—and show you how to enjoy your EV while maximizing battery lifespan.

You can choose to be a battery-babier or a battery-abuser. That's up to you. For many of these tips, there is not extensive data that demonstrates exactly how much more life you can get. To quote Sammy Hagar, “Only time will tell if we stand the test of time.”

Comments

· · 2 years ago

Thanks Patrick. These may seem obvious to some of us that have either been driving or following EV's for some time, but to newcomers it's welcome advice.

On this topic, I recently did a blog post about my MINI-E's range. I have basically done everything that you advised against in my 27 months with the car. Since this is a limited, short term program (30 months) and the cars will be taken out of service when it is concluded, there was really no reason to pamper the battery packs in an effort to prolong their life span. In fact, I took it upon myself to be as abusive as possible to the battery in the effort to try to see how it would degrade in the time I had the car. Some of the things I have done are:

-I always charge to 100%, virtually every time I recharge, and have done so 1,235 times to date.

-Park it in my parking lot where there is no shade during the summer. (This wasn't really done on purpose because there isn't much shade anywhere)

-Parked it outside over night when it's freezing outside and snowing.

-Frequently do deep discharges. I have driven it to the point where it just about stops dozens of times.

-Charge it at the highest charge rate all the time. The MINI-E can charge at 12, 32 or 50amps. I always charge at 50amps. It can charge the car from dead to full in 3 hours and is very useful. It's allowed me to drive it well over 200 miles on single days many, many times.

I didn't mistreat it because I'm a jerk and want to damage BMW's property, I really wanted to see if it would degrade faster than the other cars that may have been treated better. BMW is well aware of how I charge/recharge as I document my travels with the car very well. I actually think they like what I'm doing. I do however treat the car itself very well and it still looks like new.

Now to what I'm getting at. I have over 65,000 miles on it and even with the way I have treated the battery the car still has the same range as it did when it was new so whatever damage I've done hasn't shown yet. I'm sure at some point the battery will degrade to the point where I would notice it, and if I actually owned this car I would have treated the battery better and followed most of Patrick's suggestions so I definitely suggest following them.

There are people out there like Darell that have been driving an EV with NiMH batteries for a long time and have experienced the point where the batteries begin to show their age and need to be replaced. However the latest crop of EV's with newer battery chemistry haven't been out long enough for us to really know how long they will be useful. Will they last 100,000 miles with proper treatment? How about 150,000? How much will frequent quick charging degrade them? If you do everything that Patrick suggests will it add 5,000 miles to the life of the battery or 20,000? The manufacturers can tell us how long they think the batteries will last, but until we have thousands of cars on the roads for 7 or 8 years driving 100,000 miles plus, I think the jury is out.

However I'm very encouraged by the results of my personal experience. By now I would have definitely thought I'd be seeing some signs of degradation but the data I've complied doesn't lie.

· · 2 years ago

Patrick,
Excellent job on this entry! I'm going to save it for future reference :-)

· · 2 years ago

Thanks Tom. You bring up a great example of a situation where you do not need to coddle the batteries. You are helping them collect data on an accelerated timeline. Like Darell, I had a NiMH vehicle, mine was a Chevy S10. When the batteries were 9 years old, the range was halved. At 13 year old, the range was down to about 25 miles. I sold it in May when I bought my Leaf and the batteries are currently being replaced in the S10 by the new owner.

My goal with the Leaf is to make the batteries last long enough that my daughter (now 6), can drive it when she is 16. I don't want her going too far from home anyway :)

· · 2 years ago

Thank you Christof.

· · 2 years ago

Patrick,

I wonder how much the physical age effects the batteries as compared to the use. I'm sure both play a role, but how much does each contribute to the ultimate demise of the battery.

My pack has only been in service for 27 months so you would naturally say that it should still be performing at a high level, just as if it were new. But then you look at the use I've put it through, over 1,200 charging cycles and 65,000 miles. That's about 70 miles and 1.5 recharges every single day I've had it. Now obviously there were many day's I didn't drive it, so I'm probably closer to 90 miles average every day I have used it. This is possible because I can recharge quickly at work.

If I were to keep the car, I'd hit 100,000 miles in about 3 1/2 years. Would the pack act like an EV that had 100,000 miles on it and was showing signs of age, or an EV that was only 3 1/2 years old? I suppose a combination of both.

· · 2 years ago

Patrick,

I've been trying to follow as many of those recommendations as possible with my LEAF, and have found this to be relatively easy. My only question is, why are you recommending garaging EVs in winter weather? I understand that this would be optimal from a range perspective, since batteries are less effective at storing and delivering energy in the cold. But are there any known battery life consequences to leaving an EV parked in subfreezing temperatures? I am curious because I do not have a garage. Thanks.

· Matt J (not verified) · 2 years ago

Has Nissan said anything about Battery upgrade for the Leaf. I get mine in December and would like to think that in time I could extend it's range with new technology. Seems like this would put people at ease about making the leap. I have Demo driven it twice and the car is very well thought out. Can not wait for my Xmas present.

· · 2 years ago

Great article. I am a bit like Tom, I would not worry too much about coddling the battery. But it is different when you own the car and don't lease it.

And if I recall, I think Tom posted something recently about getting the dead battery icon?

And about melting the wire on the power transformer out on the telephone pole, like maybe more than once?

To be fair, the Mini E has a lot more safety built into the pack, 100% is far below the maximum capacity of the pack and does not cut off regenerative braking like it does in the Leaf and the Think, which can charge far higher into the upper limit of the smaller pack.

The Tesla has a normal mode which is like the Mini E, where it is practically impossible to stress the battery by over charging or over discharging it. But the Tesla also has an extended range (250 miles) mode which lets you use more pack capacity after you acknowledge the risk of accelerated pack wear. This extended range mode is similar to the only mode the Leaf and Think have, and which the Mini E does not have at all (without modification at least, ask AutoPort of Delaware or ACP about that).

So it depends on what you are driving. This article is accurate for "affordable" EVs that you can purchase today.

· · 2 years ago

@jamcl3: The LEAF does have a "long life mode" for charging on a timer. In this mode, it stops charging at 80% rather than "100%".

· · 2 years ago

abasile, you asked "are there any known battery life consequences to leaving an EV parked in subfreezing temperatures? I am curious because I do not have a garage."

It depends on where you live and how cold the winters are. As long as it is not 40°F below, you should be fine. See if your owners manual has anything to say. As you noted, the capacity is reduced with cold weather, this can result in deeper cycling. Deep cycles are the bigger concern, IMHO. I think this is what accelerated the decline in my truck's batteries.

There are things you can do to combat the cold, other than park inside. I just mentioned avoiding deep cycles, another one is to time your charging so you leave soon after charging is complete. This way the batteries are warm before you place the demand of driving on them.

With any of these, I suggest that you first make the car fit your needs. Then consider how you can help the car. If you don't have a garage, I would not worry about it.

· · 2 years ago

My understanding is that the Nissan warranty is for cell failure and specifically excludes the gradual decline in capacity, so the "eight years, 100,000 miles" isn't intended to imply that the battery will hold a particular capacity for that period. And numbers from Nissan are all over the map, including "20% reduction in five years" from one rep. It will be interesting to see how their battery chemistry holds up over the next decade or so.

I am hopeful that by the time it is necessary to replace the battery there will be improved cells that could fit in an old car and that they will be more affordable than the current cells are today. We shall see.

· Norbert (not verified) · 2 years ago

> "Regular use of fast charging will cost you about 1 percent of capacity per year."

What exactly means "regular use"? Does it imply not using Level 2 at all? What is the source for the number 1%, and was there more information about it?

· · 2 years ago

The 2011 LEAF owner's manual instructs us not to "store a vehicle in temperatures below −13 F (−25 C) for over seven days", as the battery could freeze. It also indicates that motor power could be limited ("turtle mode") if the battery temperature drops below -4 F.

Considering that our wintertime low temperatures here in the Southern California mountains (elev. 6100') are usually above 20 F, and only rarely below 10 F, it seems that we don't have anything to worry about except avoiding deep discharges.

Further, the 2012 LEAF comes standard with a "cold weather package" that is supposed to keep the battery temperature from becoming excessively low. If anyone from a place like Minnesota is planning to buy a 2011 LEAF, however, then garaging it during the winter really would be best for the battery pack.

· · 2 years ago

Norbert, "fast charge" refers to DC charging via CHΛdeMO, not level 2. Level 2 is no problem, it is the way that the car is expected to charge. Level 2 is no better or worse than Level 1.

There are 3 levels of charging:
Level 1: 120V AC 12A, aka trickle charging
Level 2: 240V AC 16A (or more), aka Level 2 :)
DC Quick Charge, aka DC Fast Charge, aka CHΛdeMO: up to 500V DC A 125A. This is sometimes called Level 3, but that is not correct. The "Level" names are 'owned' by the SAE and they have not yet defined their Level 3.

You second question: What is "regular use"?
I could not find a more specific reference than just that. Some of that specific content is from a discussion with Prof. Dan Hammerstrom of Portland State and some of it is from this question that I submitted last year when HybridCars.com asked for questions for an interview with Nissan's Mark Perry:

Q: Will the DC fast chargers degrade the battery faster?

A: If [DC] fast charging is the primary way that a Leaf owner recharges, then the gradual capacity loss is about 10 percent more than 220-volt charging. In other words, it will bring the capacity loss closer to 70 percent after 10 years. http://goo.gl/tDwyu

· · 2 years ago

abasile, thanks for following up. That is great information. I think it is a good idea for the 2011 Leafs without thermal management to stay in the parts of the world where the weather is "battery friendly."

· · 2 years ago

dgpcolorado, you are correct. And some battery degradation will happen just from ageing, even if you were not using the batteries. I, however, expect to have far better than 80% in 5 years.

· Priusmaniac (not verified) · 2 years ago

The tips are interesting but aren’t they generating unnecessary stress to potential EV buyers?

In a sense if I was an EV buyer IO would rather like to know that my battery will be OK if I leave it outside at minus 10°C, if I leave the car in Death Valley at 40°C, if I charge it full and drive it dead for a whole week and if I charge it slowly or fast what's however. That would make me more confident than a long list of precautions to take not to damage the so fragile battery.

· Norbert (not verified) · 2 years ago

Patrick, thanks for the link. I would think "primary way" means to use DC instead of Level 2 (no home charging), but the quote isn't very specific and seems to be a shortened and inexact version of what Mark Perry said elsewhere:

http://www.bnet.com/blog/electric-cars/rockin-down-the-electric-highway-...

Jim Motavalli: "Nissan’s Mark Perry told me it won’t be an issue unless cars are heavy users of fast-charge ports — more than once or twice a day."

http://reviews.cnet.com/8301-13746_7-20011094-48.html

Liane Yvkoff: "The life expectancy of the Leaf's battery is about 70-80 percent of capacity after 10 years of normal use. Frequent fast chargers--more than once or twice per day--can expect performance on the lower end of that range, according to Perry."

In both cases Mark Perry was talking about using a fast charger more than once or twice a day... which would be 2 or 3 times, each day for 10 years.

According to a "leaf fan" on the MyNissanLeaf forum, Brendan Jones, Nissan VP of Sales, went even further:

http://www.mynissanleaf.com/viewtopic.php?f=38&t=3705&start=20

"The other day I talked with Brendan Jones, Nissan VP of Sales, and he told me that charging to 100% EVERY day (topping off) will not degrade the battery pack. Also, he told me that using DC fast chargers less than 7 times a day will NOT degrade the pack. He said that these particular batteries have been extensively tested with a simulator that equals 8 years of use."

· · 2 years ago

Has anyone worked up a list like this re. extending the life of the NiMH battery pack in a standard Prius? If so, please post a link. Thx!

· · 2 years ago

> Has anyone worked up a list like this re. extending the life of the NiMH battery pack in a standard Prius? If so, please post a link. Thx! <

There is really not much you can do in a standard Prius. The car babies the battery considerably - keeping it in the sweet spot of charge constantly. When you see "full" and "empty" on the display, that's only the small portion of SOC that the car allows you to use.

· · 2 years ago

> There are people out there like Darell that have been driving an EV with NiMH batteries for a long time and have experienced the point where the batteries begin to show their age and need to be replaced. <

I've certainly not needed to replace the pack, but yes I have seen a bit of range reduction after nine years of daily use and abuse. Really, the only problem I see with "protecting" the battery at all costs, is the amount that it reduces the utility of the car. If I want to "save" my battery from deep discharges, it means that I can't use it for long distances. So while the car might last me longer, why have it if I can't use it? I have used the HELL out of our Rav4EV. I have driven it until it wouldn't move any more. Then turned it off. Turned it back on and drove home. I have packed it full in the heat of summer because I needed the range. And today, after nine years of daily driving, the range is reduced such that we can only use the car for about 95% of the trips we used it for when new. I'm still a far way from complaining!

· AnonymousDmitry (not verified) · 2 years ago

Great post and discussion
We need to wait to really know how well batteries last in Leaf
He said/she said doesnt worth much if it is not spelled out in warranty book

· · 2 years ago

My warranty expired six years back, so that's certainly not a worry of mine! ;)

· Intel_Jim (not verified) · 2 years ago

One comment wrt using Nissan's CarWings on-line or smartphone app to turn charging on if you have your car plugged in: (mentioned in the long term storage section.)
While you can turn your charging on you CANNOT turn the charging off. The result is that your recommended 60% charge level cannot be accomplished via CarWings. You'd need someone to physically disconnect the cable from your Leaf. I think it would stop at 80% charge IF you had that setting enabled, though I'm not sure. Best to check in case it runs to 100% instead.

One other challenge:
My Leaf has some anomaly where even at the 80% charge level it often charges to a displayed 93% level. Nissan says "don't worry" but offers no solution or path to correction.

· · 2 years ago

@Intel_Jim,
Those are definitely some missed features in the Leaf that I'd like to see in order to take better care of the battery. It would also be nice if it told you when the car is scheduled to begin charging if it is on a timer. That way one could relax better at night, knowing it was set to charge after you go to sleep.
All this is stuff for the future but Nissan does not appear to be ready for improvements yet.

· Eric Geisler (not verified) · 2 years ago

Thanks Pat for the concise list of tips in one place. I hadn't considered the need for storage planning, and extreme weather advice is good with winter coming. I've set the Leaf timer for 6am and 80%, and I've been glad it charges just before that time.

· · 2 years ago

ex-EV1 driver - Your phone ap will send you a text when the LEAF starts charging.

· · 2 years ago

@Red Leaf,
That feature doesn't really help me if I want it to start at 2:00 am but hope to be asleep at the time so I don't want to have the wake up at 2:00 each night, just to verify.
If it told me it was set to begin charging to 80% at 2:00 am, I'd feel a lot better and I could sleep too.

· · 2 years ago

darelldd made the point better than I ever could have. The point of these vehicles is to use them.

I attempted to say just that in the conclusion but as Priusmaniac points out, the bulk of the article sounds like a list of things not to do or you may hurt your batteries. Putting a couple lines in the conclusion hardly makes up for it.

Please don't look at any of these are MUST do things. Rather think of them suggestions to consider if they fit how you use your vehicle.

· · 2 years ago

Well done, Patrick! For the record, I think your list is well done. I also know that the EV-inexperienced use this sort of information to dump on EVs somewhat regularly.

· · 2 years ago

@Intel_Jim, you are correct that the Leaf smartphone app does not currently allow you to stop charging but it does allow you to check the charge level and you may be able to use the EVSE's remote interface to stop charging. If you don't have that capability, then I would just recommend unplugging it. Every 3 months does not seem like too often to have to visit your stored EV for a couple hours.

· · 2 years ago

Thanks darelldd. I certainly was not attempting to arm EV-bashers. On the other side, I didn't want to sugarcoat the reality. There will be some range degradation over time, and how the batteries are treated will be a factor in determining the extent.

I am a firm believer that the perfect should not be the enemy of the good. Will we eventually have ultra-capacitors that a charge in seconds and last tens of thousands of cycles with little to no degradation? Maybe.

However, today we have Li-ion and I think if you were to compare this list to all the things that have to be done to an ICE, this list would be insignificant in comparison.

· · 2 years ago

> However, today we have Li-ion and I think if you were to compare this list to all the things that have to be done to an ICE, this list would be insignificant in comparison. <

Indeed. Yet that typically gets swept under the rug (right along with the upstream emissions of gasoline production and such). It is odd that when something new comes along, that it is so rarely compared to the traditional method - it is only compared to the author's perfect view of how things "could be" if we lived in an alternate reality.

Anyway - we've obviously on the same page here! The users of the new technology are expected to spell out all the negatives of the new technology so the general public can fairy compare it to the hidden negatives of the old technology. ;)

· BlueLeaf (not verified) · 2 years ago

Thanks Patrick, Tom, Darell, et. al. for the excellent information.

I currently drive to and from work, which is a round trip of approximately 70 miles, with a hill in the way that reduces my range somewhat. I therefore have two choices - charge to 100% in the morning and get back home on a single charge (usually 10-15 miles of range left), or charge to 80% in the morning and then trickle charge at work (at 110V) to make it back home.

My question is, is it better to have effectively 2x the number of charges with 80% overnight + tricke charging or is it better to have just 1x the number of charges with 100% overnight charging?

The Leaf manual also suggests that it preferrable to do level 2 charging instead of trickle charging. Any thoughts on why that may be the case?

· · 2 years ago

@BlueLeaf,
You're probably better off charging to 80% at home and trickle charging at work. Partial charging on a Li-ion battery doesn't affect its life. What hurts Li-ion batteries is being in a high or low state of charge. This will allow you to keep your state of charge in the mid-range - which is good.

I don't know what the mechanism is in Li-ion that prefers reasonable charging currents. With old Lead-Acid, slow charging can cause build up on the electrodes.

· · 2 years ago

Honestly, I think you're splitting hairs here. The LEAF, even at level 2 charges very slowly and the battery shouldn't really be effected one way or another by charging level 1 vs level 2. Perhaps there is something to charging to 100% all the time though so if you really want to be excessively conservative than perhaps charging it to 80% daily would be better, but again, I think it's splitting hairs.

· · 2 years ago

Blue Leaf -

One thing to understand is that charge cycles is NOT how many times you plug the car in. IN that regard, it is for sure better to plug the car in more often and not use the extremes (high or low) of the pack. The best you can do for your pack is to stay between about 30 and 80% SOC. So the easy answer to your question is to charge at both ends without going all the way.

The only problem I know of with the trickle charge is the overhead losses means that it is a bit less efficient (about the same losses as charging twice as fast... but you experience those losses for twice as long). I can't imagine that charging the way you suggest would negatively affect your battery pack.

And for Tom: I like splitting hairs! I'm just getting too old to do it without a magnifying glass.

· · 2 years ago

I agree with ex-EV1 that I would definitely charge at work if that allowed me to stay in the middle of the charge range (below 80%). On MyNissanLeaf.com, there been multiple discussions on L1 versus L2 charging. I am not aware of any reason that L1 could be at all detrimental to the battery pack; as Tom mentioned, even L2 is very slow with the LEAF. With L1, besides the obvious fact that it is way slow, the main negative is that it is at least 10% less energy efficient due to greater overall overhead associated with the long charge duration.

· Blue Leaf (not verified) · 2 years ago

Thanks everyone for the suggestions. I'll go with charging to 80% at home and trickle charging at work. A bonus is that my empolyer allows me to charge my Leaf for free and some day may even install a Level 2 charging station. Thanks again for all your help and expert advice.

· Brad Horton (not verified) · 2 years ago

Great article! I must say though, you cannot monitor your Volt if you aren't around as the vehicle deactivates the on-star connection after 2 days of no activity. I presume to prevent the discharge of the 12v battery. I don't know. There are way sto work around it, such as remote starting once per day or something. The other other thing is, I know you can start a remote charge, but I don't think you can stop one. So keeping the float at 60% may prove to be difficult. I think that simply plugging it in should be fine as it won't be at the battery's maximum charge level, so the voltage shouldn't be too dangerously high.

· SoonToOwn (not verified) · 2 years ago

I read through the article and it's a great one. Does anyone know what impact hot weather has? I know it's recommended to park in the shade but trying to find shade in Kansas in the summer is like trying to find an honest man in Congress. So what will the impact be on the battery for 100*F air temp and 120*F + internal car temp?

· · 2 years ago

@SoonToOwn, The folks with LEAFs in Phoenix don't seem to be having much trouble, but it is hard to know just how battery packs are holding up in the heat.

However, even if the car has an internal temperature of 120º it is likely that the battery pack temperature will be lower because it has a lot of mass and takes time to warm up. But doing a quick charge on a hot day or driving aggressively could heat the battery up. The LEAF is designed to lower power output and even shut down ("turtle") if the battery temp gets too high. I believe that the lower power protocols start to kick in at temp bar 9: 52.5º C (126º F). If the car started out moderately cool in the morning just parking in the sun on a 100º day shouldn't get the pack under the floor of the car anywhere close to that temperature.

That said, if it really concerns you I suggest that you lease the car. It is true that the battery pack should show more degradation at high temperatures than if kept at lower temperatures (like where I live). To be safe you can just return the leased car after three or so years and buy whatever the current EV market then offers.

Another option would be to buy a Ford Focus Electric, which reportedly has a thermally managed battery pack. However the roll-out of that car is so slow that it may not be available for some time to come (and it appears to me that Ford's "heart" really isn't in producing BEVs, just hybrids). The LEAF is here, now, and is a kick to drive.

· Arun (not verified) · 1 year ago

Very useful information. One key point missed is mileage: isn't the battery expected to last a certain number of charge cycles (a count each for deep discharge, optimal voltage range discharge, ...)? In this case, wouldn't the "miles/kwh" figure is important to (essentially bang for buck out of the number of charge cycles).

Here's my usage profile on my 1 year old 2012 Leaf:
- Mileage: 10500 miles
- Average: 4.4 miles/kwh
- Weekday profile:
- 2 charges/day to 80%, charge state between 10 bars and 7 bars except a few days so far
- Weekend profile:
- 1 charge/day to 100% - deep discharge (down to 3 - 4 bars) perhaps 20 - 25 times so far
- Always drive < 60 miles/hr on highways with about 70% of my driving on local roads (<45 miles/hr).

I already feel that I'm seeing some capacity loss (I don't trust the "charge bars to indicate this) - I generally see between 8 - 9 miles/bar (translates to the average of 4.4 miles/kwh). However, lately, I'm seeing this down to 6 - 7 miles/bar. I haven't changed my driving habits at all.

The loss of capacity seems to coincide with the 1-year service (the only time I've taken the car into the dealership). Does anyone know what they do (if anything at all) as part of their "battery health check"?

· · 38 weeks ago

Where did you hear that regular fast charging degrades the battery by 1% per yr - Was there a study done or what has established that statement?

· · 20 weeks ago

Bad advice.

It specifically states in the Spark EV manual that whenever you can, keep the car charged and plugged in. This conditions the battery and allows the battery management system to maintain temperatures properly for the next drive.

Also, as far as fast charging goes...such as L2 or DC, is there proof it degrades?

New to EVs? Start here

  1. What Is An Electric Car?
    Before we get going, let's establish basic definitions.
  2. A Quick Guide to Plug-in Hybrids
    Some plug-in cars have back-up engines to extend driving range.
  3. Electric Cars Pros and Cons
    EVs are a great solution for most people. But not everybody.
  4. Eight Rules of Electric Vehicle Charging Etiquette
    Thou shalt charge only when necessary. And other rules to live by.
  5. Seven Things To Know About Buying a Plug-In Car
    A few simple tips before you visit the dealership.
  6. Eight Factors Determining Total Cost of Ownership of an Electric Car
    EVs get bad rap as expensive. Until you look at TCO.
  7. Federal and Local Incentives for Plug-in Hybrids and Electric Cars
    Take advantage of credits and rebates to reduce EV costs.
  8. Guide to Buying First Home EV Charger
    You'll want a home charger. Here's how to buy the right one.
  9. Electric Car Utility Rate Plans: Top Five Rules
    With the right utility plan, electric fuel can be dirt cheap.
  10. The Ultimate Guide to Electric Car Charging Networks
    If you plan to charge in public, you'll want to sign up for charging network membership (or two).