Battery life / cycling

On the Bolt, the setting “Hilltop Reserve” restricts charging to ~89%. It should be in the manual. As long as you are plugged in it will keep your battery at this state of charge. This is the setting I use every day.

There is not a setting to keep it below 80% I don’t think. The pre-2015 Leaf had an 80% charge setting that came back to bite them in the butt due to US regulations. Nissan had a lower official EPA range than they expected because they were suggesting users only charge to 80%.

 

I am flabbergasted that any production EV doesn't at least give you multiple choices of what level of charge you want to set the car to. Yeah, I've read that Nissan eliminated the pre-set choice of 80% charge because they wanted to "game the system" of the EPA range rating, to make it look like the car had increased range altho nothing was actually improved. However, I thought (or at least hoped) that there was still some way to tell the car "stop charging when the battery pack gets X% full".

So, new Leafs won't let you stop before charging to 100%? Well of course, you can fix that by installing a meter on your home charger which will shut off the charge at a certain point, but that won't solve the problem when, for example, using a DC fast charger!

If the Leaf has no built-in ability to stop charging before reaching 100% charge, then that means most Leaf drivers can't use the advice to balance daily charging/discharging around the 50% SoC (State of Charge), which means that Leaf battery packs are getting worn out faster than they need to.

Apparently Nissan's EV engineering sucks even harder than I thought.

 

Yeah they dropped it pretty early for the exact reason you stated.

In order to do that they outright removed the 80% charge option. As far as I am aware they have not replaced it with another solution in the years since. GM skirts around this by labeling it “hilltop reserve”.

https://insideevs.com/2014-nissan-leaf-mostly-unchanged-as-range-technically-moves-up-to-84-miles/

“On a technical level the range has increased from 75 miles in 2013 to 84 miles, but this is due to the fact Nissan has eliminated the EPA blended range rating (which averages the 80% charge range and the 100% charge range) by deleting the option to charge to 80% on the 2014 LEAF itself… now only the 100% range number applies.“

 

There is a way to do an end run around this shortcoming. I use the charging timer most of the time to take advantage of lower charges at night. I generally find that each hour on my 6.5kw charging dock gives my about 20% charge. So at the end of the day suppose I am at 50% and want to charge to 80% the next day I'll set the timer for 1-1/2 hrs. Next day I'm pretty close to the 80% target. That being said, in the recent spell of bitter cold weather I have been setting the timer for 5 hrs regardless so that I'm at or close to 100% in the morning because of the range loss.

 

Don't overthink this. Just enjoy the car and do what works for you. My parents don't always charger their Model S, but I charge my Volt and PacHy every chance I get.


2011 Chevy Volt;
2018 Chrysler Pacifica Hybrid

 

I'm guessing that timer is external to the car? That is, you're simply using a third party timer to shut off the EVSE (the EV charger)?

If so, then sure, that's a possibility. I don't know that it's an elegant solution, but it is a practical one if you buy and install such a timer, and learn how to use it. But since that is an aftermarket add-on, it's not a standard "thing" that most EV buyers will be able to use. Furthermore, you have already pointed to one problem with using that approach: That the driver needs to be aware of what the temperature will be the next day, and set the timer accordingly.

As the EV revolution advances, I would hope that "smart charging" would include the car's software automatically checking the local weather report, and increasing the charge level as needed to account for loss of range due to cold weather. Well, ideally, I would hope that battery tech will improve to become far less affected by bitterly cold weather... but perhaps that's wishful thinking, so long as PEVs are powered by batteries using chemical reactions to produce energy.

 

Many owners I know never did anything but charge to 100% and the battery was perfect with no capacity loss. The Chevy battery is very well managed on the SPARK EV, Volt and Bolt. The only thing I would advise is not letting it sit for a long time like a week while on vacation. Other than that just drive an be happy you have a great system and battery.

For batteries with no or air cooling they will die fast no matter what you do. I had a 20111 LEAF in AZ and only charged to 80% the first year and still lost over 10% . We have had 14 SOUL EV with air cooling in our HOT Phoenix area and all 14 have failed. Nothing can replace a properly liquid cooled battery pack.

 

Perhaps they are not aware of any capacity loss, but it's impossible to cycle li-ion batteries repeatedly without having some capacity loss.

The good news is that loss of capacity over total distance has been proven to be a lot less than many feared, for any EV with a liquid cooling system for the battery pack. EV bashers used to tell us that we'd have to replace the battery pack multiple times over the lifetime of the car, but we have enough data now to be confident that's simply not true. Unless you're driving a Leaf or maybe a Mitsu i-MiEV, your battery pack should last the life of the car. Of course there will be rare exceptions, but then some gasmobiles have to have their engine replaced, too. Entropy happens.

 

The way to do an end run around this is to use the charging timer which is a built in feature. My 6.5kw charger gives me about 22% per hour. I set the charger to stop at 7am when the rates increase and set the start time according to how much I think I'll need the next day. So if I arrive home with 35% battery and only have local calls the next day I'll set my start time at 5am which brings me pretty close to 80% =/- a bit by 7am. Only charge to 100% when working out of town next day. It's a simple matter to learn what 1 hour on a particular charger will bring you up percentage wise. That's how ya do it.