Differenct charging impact to battery SOH

713 Views 18 Replies 12 Participants Last post by mghamms, 9 d ago

Immelstorn

Discussion Starter · 11 d ago

Hey guys,

I'm new here and maybe these questions were asked before, but I couldn't find the whole answer to my questions.

Maybe you can help me?
1. Theoretically, if I will always charge my car from 220v socket. It 2.3kW, so will take pretty long, I know, but is it good/bad for battery if I will change it every day for 10-15%?
2. Again, theoretically, if I will ALWAYS change on fast charger - what will happen over time?
3. If the answer for the previous question "your batter will lose 10% of your capacity in a year" - is it a warranty case?
4. What are the warranty cases regarding the battery? I mean where can I see something like "if your battery lost more than n% of capacity over years - we will replace battery"?

Thanks for answers in advance!

1 - 19 of 19 Posts

1bad440gtx

· #2 · 11 d ago

There are many nice articles and studies on the internet on this topic. Here is one set of interesting data: EV Battery Health: What 6,000 EV Batteries Tell Us | Geotab

The general consensus is AC charging is only slight better for your car over DC fast charging. There are so many other factors that affect degradation as well that are common to both. The real advantage is the cost savings of AC over DC. For your AC charging option you don't mention your phase or available current (Amps)? Must be small if you can only get 2.3kW, you might want to run a cost benefit analysis for getting a new electrical service that can max out the car's onboard charger over paying for fast charging (I assume this is not free for you).

I'll leave the warranty questions to others.

bogiesan

· #3 · 11 d ago

Welcome to the group, congratulations on your new Volvo. There are a few threads here on the forum about our various charging habits. You should be able to find those threads easily. Someone may link to one or more them. There are opinions about long-term battery performance. The problem around here, and on other Volvo groups, is that you are going to receive well-meaning but conflicting and mutually exclusive suggestions. My opinion is that insufficient data exists to make claims -- and I could be wrong or misled by the research I have performed myself.
1. Charge your battery so you have the capacity and range you need fopr each day's driving. If you are worried about the long-term effects, I suggest you set a lower state of charge, say 80%, until you find the research that satisfies your curiosity.
2. By "fast charger" do you mean a DC unit? Opinions vary but high speed DC charging appears to diminish battery performance over long periods of time, especially if DC charging is one's only source of energy. How much capacity would one lose and over several years? No one knows; there are too many variables and not enough data.
3 & 4. You must ask Volvo that question for answers you can depend on. Get it in writing. Your Recharge's warranty has an entire section dedicated to explaining the propulsion battery's warranty protection and exclusions.

See less See more

Reactions: 1

SeattleCat

· #4 · 11 d ago

Lots of good advice above.

Unless something has snuck in while I was not looking do we even have a SoH value to look at?

I heard that volvo service can get a SoH. Has anyone been given one after a service?

Margo is now 2 years old and heading into service in July. I wounded if I get a SoH then.

That said I fast charger her to 90 on public chargers and over the last 2 years I have not seen the noticeable degradation I see on apple phones over the same period.

Reactions: 1

f1geek

· #5 · 11 d ago

No SOH value. Theoretically, my 2022 pack has ~75 kWh usable energy. Perform a driving test to verify. AC charging is far better for cell health than DCFC. Even pulling 11 kW is C rate of 11/78=0.14, well below 0.5. 150 kW DCFC is a C rate of about 2, much more impactful to cell health. 80 - 20 SOC rule will give max pack health using AC charging.

Reactions: 1

SeattleCat

· #6 · 11 d ago

f1geek said:
No SOH value. Theoretically, my 2022 pack has ~75 kWh usable energy. Perform a driving test to verify. AC charging is far better for cell health than DCFC. Even pulling 11 kW is C rate of 11/78=0.14, well below 0.5. 150 kW DCFC is a C rate of about 2, much more impactful to cell health. 80 - 20 SOC rule will give max pack health using AC charging.

80-20 health might give max pick health.
Volvo has backed the 90-20.

I agree with the driving test but that is alas open to a lot of variables. Hard to compare apples to apples especially over years.

I am going with the “I am happy with it” method and just not worrying about it

but was curious if a SoH had snuck in

DcinBC

· #7 · 11 d ago

The owners manual used to say that frequent 240 volt charging will cause no appreciable damage to the battery. All Li-ion batteries degrade over time, albeit more slowly than we might think - I charge my car weekly in the summer, and semi-weekly when it’s cold, so a half life of 1500 charges translates to about 20 plus years for me. I’ll be too old to drive by then.
Perhaps a better way to put it is that wall charging is like attaching a home trickle charger to the battery. Very little risk of damaging the plates or overheating, particularly if you don’t overcharge the battery. The charging software does protect it, but forcing a lot of current into a too cold or too hot cell is eventually going to have an effect. Bjørn Nyland did a piece on a 10 year old Leaf with 40% degradation. Even with passive cooling, it turned out to be a single cell, which was replaceable. I suppose the question will be if the manufacturers make replacement cells available for battery rebuilds, so that we aren’t stuck with a huge bill for a new pack, in the same way that companies specialize in engine and transmission reconstruction.
Volvo does have an eight year warranty for the battery, so I have to think they have the ability to measure its performance and fix it. Not sure I’d want a vehicle with the battery integrated into the body of the car for that reason. Once the battery is shot, the car is done!

See less See more

Reactions: 1

Immelstorn

Discussion Starter · #8 · 11 d ago

Wow, that's one useful forum I found! Thank you for all the tips and opinions, folks!

For your AC charging option you don't mention your phase or available current (Amps)? Must be small if you can only get 2.3kW

I think it is 1 phase 10A, just regular home socket. I have solar panels and every day in this time of the year I have ~15kW of excess energy that is just flowing back to the network. From June network operator will pay me almost nothing for the energy, so I would like to maximize consume and want to charge my car from the free sun energy as much as possible.

By "fast charger" do you mean a DC unit?

Yes. I'm still new to the terminology

I heard that volvo service can get a SoH. Has anyone been given one after a service?

Since I'm getting 1 year old car with 16k kilometers, I asked the dealer to provide the SoH, will post it here for stats after I get the car

80 - 20 SOC rule will give max pack health using AC charging.

This is a little bit sad, looks like I will have to try to use only 60% of my battery, so ~200km of range. Not like I need more everyday, but just sounds sad.

Does Volvo put any buffer of +10% for battery? Do the let us really charge to 100% and discharge to 0%?

Reactions: 1

Venomer

· #9 · 10 d ago

Volvo advises against charging to 100%, if you don't need the range for your trip. They also advise against draining the battery completely. But you can safely charge to 100% every now and then if you are planning a long trip. Just don't leave the car standing at 100% for longer periods of time.

I usually charge to 90% and am comfortable to drive it below 10% if I know I can charge at the destination. This is sufficient for most day to day trips.

Reactions: 1

LDIR_16384

· #10 · 10 d ago

Venomer said:
...and am comfortable to drive it below 10% if I know I can charge at the destination.

Has this ever triggered turtle mode? My commute is motorway/dual carriageway almost door to door so not something I want to experience on those journeys.

SeattleCat

· #11 · 10 d ago

LDIR_16384 said:
Has this ever triggered turtle mode? My commute is motorway/dual carriageway almost door to door so not something I want to experience on those journeys.

If I remember right turtle life triggers before 10%. On some journeys you will have to charge to 100 and end up sub 10%. These at least in good areas are rare.

I thought the advice for 10O% charging was to only do it when needed (which normally goes with a fixed max velocity of 50 mph for that leg) but to also charge to 100 and go. To not leave it at 100 at all. Not sure how significant say an over night of 100 is compared to 5 minutes …

The devil is in the details alas the details are behind a service/technology wall.

Reactions: 1

VolvoElectric

· #12 · 10 d ago

LDIR_16384 said:
Has this ever triggered turtle mode? My commute is motorway/dual carriageway almost door to door so not something I want to experience on those journeys.

Yes it can go into reduced power mode below 10% depending on recent efficiency. Mine has done it at 9% before, think that was the highest I can remember with red SOC %. Normally goes orange around 7% then will go red.

Reactions: 1

Charcoal interior

· #13 · 10 d ago

SeattleCat said:
I thought the advice for 10O% charging was to only do it when needed (which normally goes with a fixed max velocity of 50 mph for that leg) but to also charge to 100 and go. To not leave it at 100 at all. Not sure how significant say an over night of 100 is compared to 5 minutes …

I don't understand why being at 100% would be damaging. I think that manufacturers want to guard against edge cases where you've charged your car to 100% and live at the top of the mountain and there's no storage headroom for the regenerated power as you start driving.
I understand there are practicalities such as taking a long time to reach the 100% so giving the general public guidance about not fully charging to 100% in order to avoid "disappointment". Like many things in life there's some nuance that gets lost because the rules have to be general and simple for the public at large.

DcinBC

· #14 · 10 d ago

LDIR_16384 said:
Has this ever triggered turtle mode? My commute is motorway/dual carriageway almost door to door so not something I want to experience on those journeys.

I remember watching a Norwegian video where Kris Rifa drove a C40 in sub-freezing temperatures at 110-120kph and hit turtle mode at 12%, which the he was disappointed at. He was also driving at this speed in slush, so the car’s consumption was pretty high. Obviously, slowing down for the road conditions would have made sense, but the difference between 60 and 70mph in a Recharge will make a difference, regardless of the season. I get about 200 miles between charges in Summer, and about 150 in the winter, driving at 60mph (I don’t drive from 100% to 0%, but 250m/400km would be my 100% range). If you need to drive further, you’ll want to allow time for charging anyway, so maybe leaving early to avoid the heaviest traffic (although OPD in stop-start traffic is a breeze) might be a good idea.

DcinBC

· #15 · 10 d ago

Charcoal interior said:
I don't understand why being at 100% would be damaging. I think that manufacturers want to guard against edge cases where you've charged your car to 100% and live at the top of the mountain and there's no storage headroom for the regenerated power as you start driving.
I understand there are practicalities such as taking a long time to reach the 100% so giving the general public guidance about not fully charging to 100% in order to avoid "disappointment". Like many things in life there's some nuance that gets lost because the rules have to be general and simple for the public at large.

The Volvo doesn’t have much of a top buffer, so the battery is very slow to charge to 100% in any case. Not sure I would want to ignore their tested recommendations given the cost of a new battery. With regard to regeneration and the battery is fully charged, the brakes kick in, so no problem.

SeattleCat

· #16 · 10 d ago

Charcoal interior said:
I don't understand why being at 100% would be damaging. I think that manufacturers want to guard against edge cases where you've charged your car to 100% and live at the top of the mountain and there's no storage headroom for the regenerated power as you start driving.
I understand there are practicalities such as taking a long time to reach the 100% so giving the general public guidance about not fully charging to 100% in order to avoid "disappointment". Like many things in life there's some nuance that gets lost because the rules have to be general and simple for the public at large.

It is not about time. Charging to 100% and leaving it is meant to be damaging.

Why? brushes off his physics degree and finds it lacking on why

Don’t know why. It is common knowledge yet common knowledge can be proven to be totally wrong.

I don’t know why also I don’t know why not so for now I am going to go with not charging to 100%

The you waste regenerative power when at 100% is somewhat true but is not the stated reasons. The stated reason is it causes damage.

Perhaps after we work out how bicycles stay up and ice skates work we will move on to batteries.

I would hope though that test data on multiple charge cycles show more degradation if charged to 100 vs say 90 or 80.

See less See more

Reactions: 1

f1geek

· #17 · 10 d ago

80-20 rule for daily / routine charging. Sure, charge to 100% if you need it for a road trip and take pack down to single digits if you need to, also. Stay within 80-20 for the majority of your charging and pack will maintain high SOH for more time than if you completely fill and deplete battery on a regular basis. This has been shown in numerous peer reviewed papers and is the reason why companies like Volvo and Tesla and VW (and others) recommend charging to less than 100% and part of the reason why the car has warnings at very low SOC (warnings are also there at low SOC to ensure you don't get stranded).

Here are the primary things that cause rapid NMC lithium ion battery cell degradation:

Super low SOC for extended periods of time
Very high SOC and very high temperatures for extended periods of time
Very high SOC for extended periods of time

Greg S

· #18 · 9 d ago

Charcoal interior said:
I don't understand why being at 100% would be damaging. I think that manufacturers want to guard against edge cases where you've charged your car to 100% and live at the top of the mountain and there's no storage headroom for the regenerated power as you start driving.
I understand there are practicalities such as taking a long time to reach the 100% so giving the general public guidance about not fully charging to 100% in order to avoid "disappointment". Like many things in life there's some nuance that gets lost because the rules have to be general and simple for the public at large.

Charging and discharging batteries is a chemical and physical reaction. Without getting into the technical details (you can google it and see more about it) undesirable chemical and physical reactions can occur inside the battery that can shorten its life if you charge to 100% regularly and/or let it sit at 100%. Note this is a bit different for lithium iron phosphate batteries (not in the XC40/C40 currently).

mghamms

· #19 · 9 d ago

Now I think that the app should allow us to set the charging limit. So that we don't have to go to the car every time we need 100% charge. That would make it much easier to regulate the charge.

Reactions: 2

1 - 19 of 19 Posts