[Andreas]

I am new with EV and have a new Ioniq electric from 2020. I asked the dealer in my hometown I sweden if I should charge 100% and they said yes. I do not know if they acctually have the knowledge. What do you say? Charge between 20 and 80? Is it better to charge small amount of kw everyday or is ot better to charge once nearly full? What is best for the batteries?

Tanks for I nice forum
/Andreas

 

[Superhero]

Stay as close to 50% as you comfortably can. After all it's an expensive car so you must find a way to maximize the bang for the buck too.

I could charge to 100% every other day or charge everyday to 75% and drive down to like 30%. The latter is to prefer of course. But in some cases the first use case better suites my comfort that day, then I choose that. But that's very rare, still I would not hesitate. If knowing I will go for a trip on the weekend I might choose to charge to 100% at Friday leaving work with a full charge.

Use the car full out but do your best to keep it close to 50% and all is as good as you can make it. Think of it like oil changes. You follow the service books 30000km and all is fine, no need to make more changes than needed. Some might opt for 15000km and yes, you could argue 15000km is better than 30000km but it would make zero sense to jump to 5000km intervalls. Same here.... Keep it as good as you can without letting it become some sort of ghost haunting you. Still 0% is not zero and 100% is not hundred after all.

 

[Harpers Tate]

I think there is a lot of "fear" out there about charging percentages and for myself, I'm not at all convinced that it's justified. I had a series 1 Ioniq EV for two years / 18k miles and always charged it to (as) full (as it would go given the time I had and the type of charger) with a broad mix of rapid (94%) and 7kW (100%) charging. During this time there was zero indication of any battery deterioration. I am now doing the same thing with my 2nd generation EV. At 7k miles, it's too early to make any meaningful comment. But if you do some searching, you will probably find some stats about battery longevity esp. in Tesla cars (which have always enjoyed a dedicated network of (very) rapid chargers, from which you will see that even after several years and many tens of thousands of miles the capacity is barely affected.

I contacted another Ioniq owner who has had his series 1 longer than I kept mine and he provided this picture of his dash taken recently

In his case, he mostly uses a slow charger overnight and always to 100%.

Almost 29k miles and 151 miles range when full, which will be as good as it ever was.

 

[Superhero]

I think there is a lot of "fear" out there about charging percentages and for myself, I'm not at all convinced that it's justified. I had a series 1 Ioniq EV for two years / 18k miles and always charged it to (as) full (as it would go given the time I had and the type of charger) with a broad mix of rapid (94%) and 7kW (100%) charging. During this time there was zero indication of any battery deterioration. I am now doing the same thing with my 2nd generation EV. At 7k miles, it's too early to make any meaningful comment. But if you do some searching, you will probably find some stats about battery longevity esp. in Tesla cars (which have always enjoyed a dedicated network of (very) rapid chargers, from which you will see that even after several years and many tens of thousands of miles the capacity is barely affected.

I contacted another Ioniq owner who has had his series 1 longer than I kept mine and he provided this picture of his dash taken recently
View attachment 32752

In his case, he mostly uses a slow charger overnight and always to 100%.

Almost 29k miles and 151 miles range when full, which will be as good as it ever was.

It's not easy to say for sure about degradation. The Ioniq from what I know has no proper gauge of degradation. There is a health percentage but that seems to stay at 100% for very long while the pack uses up the buffer reserved for that purpose(?!) Also the displayed range really says nothing about battery health.

I agree it's probably not an issue, still by fact it's better to stay as close as you can to 50%. How much better we do not know. But if you have home charging it's so easy just to keep it around 50% rather than going to 100%. Also temperatures affect the batterys life where Arizona cars degrades way faster than out nordic cars.

Teslas are it's own history with everything changing back and forth all the time. Fast charging nerfed, capacity nerfed, charging upped again, new packs here and there etc etc, so no real good data there I'm afraid. You could probably find examples of very low degradation, also the other extreme.

 

[Harpers Tate]

Also the displayed range really says nothing about battery health

I'd agree with what you say about "using the buffer", and what remains of that is clearly unknown, but the GOM range DOES indicate to a degree the health at least as far as the stated/rated capacity. Around 5 miles/kWh is (in my experience) typical average for sensible driving in an Ioniq in the UK and you will see from the dash that his recent history is showing at 5.2. Simple arithmetic 5.2 mpkWh * 28kWh rated = ~145 miles. So with a GOM range of 151, it's evident that he still has pretty much his full 28kWh usable. If the buffer is ~10% then he has fairly evidently not lost that 10% yet after ~29k miles of mostly 100% charging.

 

[HandyAndy]

I've just bought a 2019 38 kWh Premium EV. Tha manual recommends charging to 100% once or more per month. Reason for doing this is to balance the (many) cells making up the HV battery. What you do NOT want to do to a Li-ion cell is over-charge it. So as the charging approaches 100%, there are a variety of techniques used to balance them, but it amounts to getting them to all sit at the same final voltage after the charge. I've noticed my charging to 100% gets very slow at the end, it's down to about 2kW around 98-99% - and I suspect this is a side-effect of the BMS (Battery Management System) doing the careful balancing & fine-tuning needed to keep them in tip-top shape.

The first time I charged to 100% was for a long trip the next morning. I actually charged to 80% on a Rapid, then early the next morning got up early, went to the Rapid planning to charge to 100% in (I thought) 45 minutes, go home, pack for an hour, and go. It actually took 1hr 40 mins to do that last 20% charge! Luckily I had plenty of time, and no-one else turned up wanting the Rapid!

It's reckoned to be a good idea to keep the battery between 20% & 80% charged for the longest life; Amperas have been doing this for years, they only let you use 65% of the true capacity, and hardly any of those 2012-vintage batteries have failed or had any degradation that the owners can see. One of them has done over 400,000 miles, still on original battery, so 200,000 of those are purely electric, the rest petrol-though-exercising-the-HV-battery mode. GM ended up with shelf-loads of replacement batteries they'd expected to have to supply under warranty, and had to flog them off cheap as there weren't needed!

Li-ion batteries don't like sitting at 0% SOC, or 100% SOC, for long periods of time. The EV mfrs leave some space (buffer) at the top & bottom end of the HV batteries, but it's not huge like the Amperas is, maybe 3% at each end, something like that. Otoh the newer chemistries used now should be making the batteries even more reliable than Ampera ones are, so maybe it's safe to leave Ioniqs at 100% SOC overnight. Trouble is, we won't know for a few more years yet if this is the case, so I for one prefer to sit in 20-80% range normally, and only go outside that region for as little time as possible. I wouldn't leave my EV at 100% for days. A few hours I don't mind. Now we're in lockdown, I did my last 100% fillup at home to balance the cells, then ran the heater with the windows open for a couple of hours to drop it to 80%. And that's where it's been the last 2 weeks.