asthorman
Posts: 5
Joined: Fri May 31, 2019 12:36 pm

Re: Limiting total charge % - hidden feature?

Thu Jun 27, 2019 11:20 am

jadnashuanh wrote:
Wed Jun 26, 2019 8:15 pm
You do realize that even when physically connected, the car does disconnect the acv input once it thinks it's fully charged? It's not like most cell phones or computer batteries. IOW, the batteries are not always sitting with a charging voltage applied to them.
I get that, but research strongly suggests that keeping EV batteries at 100% state of charge will impact long term battery capacity/range. I am hoping to preserve my range as long as possible and if all I have to do it adjust a setting on the vehicle or the charger, it seems like a worthwhile extra step. Luckily my round trip daily commute is only about 52 miles, so leaving home with 80-90% charge isn't an issues, even with the AC cranking!!

Topic change:

Nashua, NH? I went to, and graduated from UNH a long time ago and have been spending time in the Lakes Region (Moultonborough) since I was a kid in the 80's and my grandparents retired there from Long Island, NY. It was only last summer that house was sold!
Andrew in Phoenix, AZ
2017 BEV

gt1
Posts: 367
Joined: Sat Nov 07, 2015 7:31 pm
Location: Baltimore

Re: Limiting total charge % - hidden feature?

Thu Jun 27, 2019 3:15 pm

vreihen wrote:
Thu Jun 27, 2019 4:11 am
Show me a recent cell phone or computer that doesn't also have an intelligent charge-management circuit in it. All of mine sit on the chargers 24/7 when not in use, and the batteries are still fine after several years.....
Your phone maybe at 85% capacity after 3 years and don't even notice it.

I have a 94AH model, I charge when the battery is below 50% and set EVSE timer to 2- 2.5 hours. This way I end up with 85-90% charge.

jadnashuanh
Posts: 5196
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Limiting total charge % - hidden feature?

Thu Jun 27, 2019 4:47 pm

There are timers, even if your EVSE doesn't have logic built-in, that could turn the EVSE on/off. You'd want to probably turn it back on if you wanted to precondition and set a departure time, otherwise, you might suck a bunch of battery capacity out. It would take some calculations to keep things where you want, not worth it in my opinion, but hey, it's your car...

I've lived in various places around the world...NH has some nice perks: interesting terrain, real seaons, no income tax or sales taxes on general merchandise.
Jim DeBruycker
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)

Fisher99
Posts: 402
Joined: Sun May 12, 2019 6:24 pm

Re: Limiting total charge % - hidden feature?

Thu Jun 27, 2019 7:07 pm

So which is actually worse for the longevity of the battery?

A. Charging every night but only to 80% of capacity.

B. Charging to 100% but only every couple of days?

Is reducing the number of charging cycles important? More important than reducing the charging percentage? I often hear of batteries being rated in "Number of charge cycles" so it would seem to be important to limit them? I can get by with charging less frequently if I charge the battery to 100% when I do charge.
2014 BMW i3 with Range Extender Engine, Capparis White/Frozen Black, 20" wheels,, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, TurboCord EVSE

alohart
Posts: 2401
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Limiting total charge % - hidden feature?

Fri Jun 28, 2019 3:16 am

Fisher99 wrote:
Thu Jun 27, 2019 7:07 pm
So which is actually worse for the longevity of the battery?

A. Charging every night but only to 80% of capacity.

B. Charging to 100% but only every couple of days?
Li-ion battery cell electrochemistry degrades more slowly at lower charge levels, so "A" should statistically be preferable.
Fisher99 wrote:
Thu Jun 27, 2019 7:07 pm
Is reducing the number of charging cycles important? More important than reducing the charging percentage? I often hear of batteries being rated in "Number of charge cycles" so it would seem to be important to limit them? I can get by with charging less frequently if I charge the battery to 100% when I do charge.
A full charge cycle is from 0% to 100% charge levels, so charging from 60% to 80% would be only 20% of a full charge cycle. So charging 5 times from 60% to 80% should be similar to charging once from 0% to 100%.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

n1o2c3a4c5h6e7t
Posts: 23
Joined: Wed May 01, 2019 12:35 pm

Re: Limiting total charge % - hidden feature?

Fri Jun 28, 2019 5:45 am

Would a WiFi controlled EVSE be able to stop charging at 80%? Is it possible to make a dumb EVSE "smart" with aftermarket technology? For example, with a WiFi controlled outlet, etc.

Fisher99
Posts: 402
Joined: Sun May 12, 2019 6:24 pm

Re: Limiting total charge % - hidden feature?

Fri Jun 28, 2019 9:59 am

Good info alohart. Thanks!
2014 BMW i3 with Range Extender Engine, Capparis White/Frozen Black, 20" wheels,, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, TurboCord EVSE

jadnashuanh
Posts: 5196
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Limiting total charge % - hidden feature?

Fri Jun 28, 2019 12:04 pm

n1o2c3a4c5h6e7t wrote:
Fri Jun 28, 2019 5:45 am
Would a WiFi controlled EVSE be able to stop charging at 80%? Is it possible to make a dumb EVSE "smart" with aftermarket technology? For example, with a WiFi controlled outlet, etc.
If you use a smart outlet designed for the load of the EVSE, yes, you could set a timer. Now, most, but not all EVSE devices will reset properly when connected to a vehicle upon a power cycle. On some, you might find it will only connect properly if it is first turned on, then the plug is inserted into the car. Try yours first by either unplugging it, or turning it off with the circuit breaker while connected to the car.

But, there's no smart plug that I'm aware of that would interact with the car to identify when it was at 80%...you'd have to guess. That timing would change partly by the battery temperature and the value when it was plugged in.

As noted, charging 10x from 70-80% is the same as charging once from 0-100% in cycles and wear on the batteries.

Nissan, who doesn't have a great reputation for battery management (most don't have liquid cooling, so in hot climates, they can have issues) still finds that their batteries are holding up quite well long-term. BMW's choice on batteries, with their liquid cooling, IMHO, should be even better. IOW, I don't really worry about it. Leaving with 100% in the morning, and having it plugged in so I can precondition them and the cabin is worth it to me.
Jim DeBruycker
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)

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