Charging from 80% to 100% -- What's the issue?

[GaslessInSeattle]

agreed, +1

I've got over 15,000 miles (58 miles per day avg.) and I've charged to 100% all the time. The dealer said my battery was in perfect condition at the 15k checkup the other day...

There is nothing wrong with charging to 100% and driving away, I do that a lot. By the time you get 10 or 15 miles down the road it will be down a couple of bars anyhow.

The only thing I would avoid is charging the car to 100% and then going on vacation for a month, now that would not be a good thing to do.

KJD

[gbarry42]

My understanding is that another reason to go for 80% (if it suits your needs), is that the last 20% of charge is less efficient. Does anyone have a ballpark estimate to quantify that effect?

I looked through my notes, and charging from 8 to 10 bars (as well as calculating two bars by doing arithmetic on longer charge runs) comes out to 30 - 45 minutes to charge 2 bars. When I do the same thing to go from 10 to 12 bars, it takes about 90 minutes.

[jfreire]

The power drops as you approach 100%.

I've been monitoring the charging times and the charging power, and from observation I've watched the power drop from the maximum power of 3.7Kw (~240V 16A) to below 3Kw as it nears the end.

It's quite obvious that the charging is done carefully when you're nearing 100%. Maybe it's that cell balancing thing I'm always hearing about...

My understanding is that another reason to go for 80% (if it suits your needs), is that the last 20% of charge is less efficient. Does anyone have a ballpark estimate to quantify that effect?

I looked through my notes, and charging from 8 to 10 bars (as well as calculating two bars by doing arithmetic on longer charge runs) comes out to 30 - 45 minutes to charge 2 bars. When I do the same thing to go from 10 to 12 bars, it takes about 90 minutes.

[TangoKilo]

I've got over 15,000 miles (58 miles per day avg.) and I've charged to 100% all the time. The dealer said my battery was in perfect condition at the 15k checkup the other day...

Do you have it timed so charging finishes shortly before you leave?

Although wasn't the question specifically about charging to 80%, and then later topping off to 100%? Although come to think of it, you can't charge to 100 without first charging to 80? Unless there is some concern about "pausing" the process at 80. I have done this a few times when I first thought I'd only need 80 then later decided I needed more range before I ever left and topped off to 100.

I don't use the timers. I plug in whenever, wherever...

[ebill3]

The power drops as you approach 100%.

I've been monitoring the charging times and the charging power, and from observation I've watched the power drop from the maximum power of 3.7Kw (~240V 16A) to below 3Kw as it nears the end.

It's quite obvious that the charging is done carefully when you're nearing 100%. Maybe it's that cell balancing thing I'm always hearing

That is the way Li cells are charged.

The charge starts at constant current (16 Amps for L2) and stays at that current until cell voltage reaches 4.1 volts.

Then the voltage is held constant and current decreases to some design percentage of 16 Amps. Maybe 10% (1.6 Amps)? I don't know, but I believe 10% is rather common.

Bill

[TomT]

The main reason I charge to 80 percent is that I have about a 1,000 foot descent from my house and I much prefer having regen available for that descent. The difference in range between 80 and 100 percent is small for me because of that...

[Ingineer]

I have yet to see the Leaf ever "fully" charge according to it's SOC number, now I haven't looked every time, just occasionally. My last charge where I checked was from about 45% SOC and it completed on it's own at 94.591% SOC. The stored capacity was reading 22.240kWh.

I always charge to 100% as well and have zero loss of capacity after almost 200 charge cycles.

-Phil

[mkjayakumar]

Phil, where do you read the SOC % value and the stored capacity ? Does the car provide that data in the Nav windows, or do you get that using your own device which you had designed and installed in your car ?

thanks
Jay

[mkjayakumar]

Reading through the posts in this topic, do I conclude there is no clear consensus that charging full to 100% all the time does some harm or no harm from the perspective of long term health and capacity of the battery ?

I am planning to only charge through L1 at my home for the foreseeable future. Would that make any difference ? I am planning to not plug in until it comes down less than 50%, and then charge fully to 100%. That might mean charging every day or skipping a day or two depending on how much I end up driving that day.

thanks
Jay

[LEAFfan]

I have yet to see the Leaf ever "fully" charge according to it's SOC number, now I haven't looked every time, just occasionally. My last charge where I checked was from about 45% SOC and it completed on it's own at 94.591% SOC. The stored capacity was reading 22.240kWh.
I always charge to 100% as well and have zero loss of capacity after almost 200 charge cycles.
-Phil

On L2, I did hit 100%SOC one time. I have no idea how it happened, but it was a big surprise because all the other times it's always between 94-95%SOC. With QCing, the highest I've gotten is 93.5%SOC and that's after the additional 30 minutes beyond the 20-30mins. to 80%.