How much does granny charging damage the battery life of an EV?

  • Creator
    Topic
  • #164664 Reply
    Redkite999
    Participant

    I’m getting my first electric car (Kia Soul Ev)

    thanks to all the great advice on this forum, I’m thing I will still pick up the car but I will be without the home charger for about 3/4 months.

    it takes approx 29 hours to fully charge. (Which I can cope with)

    so how much damage would this do to the battery and more importantly the range?? I don’t want a car with problems for the rest of the 3 years.

    thanks all in advance

Viewing 11 replies - 1 through 11 (of 11 total)
  • Author
    Replies
  • #164665 Reply
    Rhodgie

    It won’t damage it and it won’t take 29 hours unless you drive it down to 0% and want to wait for it to get back to 100% which isn’t realistic…. instead plug it in to charge when you get home or when you know you’ll need the range to go somewhere 👍

    Try not to charge it if it’s already showing 90% or higher if you want to protect the battery

    #164701 Reply
    Intranicity
    Participant

    It won’t damage it and it won’t take 29 hours unless you drive it down to 0% and want to wait for it to get back to 100% which isn’t realistic…. instead plug it in to charge when you get home or when you know you’ll need the range to go somewhere 👍 Try not to charge it if it’s already showing 90% or higher if you want to protect the battery

    BUT, try and charge up to 100% once a month or so, but don’t leave it at 100% for too long

    Previous Motability Cars
    2006 - 2009 Skoda Superb VR6 2.0tdi
    2009 - 2012 Citroen C5 2.0tdi VTR Nav
    2012 - 2015 Nissan Qashqai 1.5dci tekna
    2015 - 2018 Ford Kuga 2.0tdi Titanium X
    2018 - 2021 BMW 220d X drive 2 Series Active Luxury
    2021- Hyundai Kona Electric Premium SE

    #164707 Reply
    Rene
    Participant

    Generally speaking, charging slowly rather than quick is better for battery health.

    That said, i wouldn’t suggest charging while the battery is above, lets argue, 50%. Nor under 20%. Batteries degrade by charging/discharging fast, by being fully charged and by being very low.

    If you can (and i understand that at 29 hours for a full charge that might not be possible all the time), i’d plug it in at 30%. If possible, you actually want to avoid charging to 100% as well. There’s no reason to do it (other than if you need maximum range of course). That’s a relic from times where batteries suffered from memory effect (reduced capacity if you didn’t charge them fully) – this isn’t the case with EV batteries.

    This is was Kia says (matches what all other manufacturers say, just the first google result).

    https://www.kia.com/dm/discover-kia/ask/how-to-extend-ev-battery-life.html

    1. Minimize exposure to extremely high temperatures when parked

    Exposure to the extreme heat while parking unplugged is when the frequent danger occurs. An automated temperature control system installed in your electric car will needlessly drain your batteries to keep the temperatures down for optimal efficiency. While this performance should only work when your electric vehicle is on the road using its battery, park your electric car in the shade or plug-in so that its thermal management system functions only using grid power, and make sure a stable range of temperatures during operation either.

     

    2. Minimize the batteries at 100% state of charge

    Electric cars already have installed with a battery management system that avoids them being charged and discharged at the extreme state of charge. Keeping the state of battery charge, from 0 percent to 100 percent , also improves the performance of the battery life of your vehicle. Even though a full charge will give you the maximum operating time, it is never a good idea for the overall lifespan of your battery.

     

    3. Avoid using fast charging

    If your batteries are soon-to-be die out, using a fast-charging is a great convenience. However, it presses so much current into the batteries in a short period which strains your EV battery and wanes them faster. While it is hard to notice its degradation, eight years of standard charging will give you 10% more battery life compared to 8 years of using fast charging.

     

    4. Control the optimal battery state of charge during long storage

    EVs that are parked or stored with an empty or full battery also degrades the battery. If you do not use your electric car often or having a long trip plan, get a timed charger, and plug it in. Leaving your vehicle at 100 percent while parked at a certain place for a long period, the battery will struggle with preserving its state of charge while you are away. One strategy is to set the charger to keep the charge just above the low mark, not filling it up to the maximum capacity, at an average charge level between 25 percent and 75 percent.

    #164712 Reply
    Wigwam
    Participant

    By comparison, there’s a certain simple pleasure just squirting petrol into the tank. Sometimes fast, sometimes slow, while gazing around the garage forecourt without a care until the nozzle clicks off…

    #164713 Reply
    Rene
    Participant

    Smells better too.

    #164715 Reply
    Intranicity
    Participant

    Ignoring what manufacturers say (They are incredibly risk averse) and much of what they say is to cover themselves and give get out clauses, and the fact that we have these cars for 3 years on a lease and the battery warranties are usually around 8 years!

    The preserved wisdom from people who actually drive EV’s is that once a month it is good form to charge to 100% as the Battery Management Systems does lots of work in the final 10% from 90-100% charge, managing and balancing out the cells, that final 10% often takes longer than it takes to go from 20-80%.

    You also need to be aware that all batteries have buffers, so when the car shows 0% or 100% state of charge, the battery is actually nearer 5% and 95%, theses buffer zones are unusable to the car, but are there to protect from fully discharging and killing a battery.

    AC (Slow) charging is believed to be healthier for batteries, but there are plenty of people (me included) who do that vast majority of charging via DC fast chargers, and are seeing no degradation of batteries (Taxis with well over 120k miles all on DC and battery still healthy). Currently I’m getting around 340 miles on a 100% charge.

    The biggest thing personally to understand is how you car behaves to charging, and the benefits of different types of charging.  I don’t think many new EV owners (Or dealerships) understand how the cars work.  Take the Kona for instance, it has a 64kW (Usable) battery, and will charge at 11kw on AC and 77kW on DC, sounds great… But it will only charge at 77kW for a very short time and only at a specific battery state and temperature, if it’s not in the sweet spot, it will be much slower.  The same goes for chargers, you are lucky to get much more that 44kW from a 50kW charger.

    I do most of my charging on Ionity 350kW chargers and these are the average speeds I get:

    unto 25% – 53kW
    25%-53% – 77kW
    54%-57% – 71kW
    58%-73% – 58kW
    74%-77% – 36kW
    78%-90% – 24kW

    On a long journey, I will only charge the car to 73%, after that it’s quicker to continue the drive to your destination (or next charging stop) than it is to stay on the charger. Once a month I will DC charge to 90% and then go to a free AC charger and top up to 100% to manage the BMS system. I never pay for AC charging, as there are plenty of free ones at supermarkets,

    Back to the original post, the only real issue against regular charging on a granny charger is making sure that the electrics up to the socket are good, you will still be drawing 2.1kW for extended periods, and how long the granny charger will last (Unknown) but they are designed for occasional use, but I’m sure they will last for longer than the 3 year lease.

    Previous Motability Cars
    2006 - 2009 Skoda Superb VR6 2.0tdi
    2009 - 2012 Citroen C5 2.0tdi VTR Nav
    2012 - 2015 Nissan Qashqai 1.5dci tekna
    2015 - 2018 Ford Kuga 2.0tdi Titanium X
    2018 - 2021 BMW 220d X drive 2 Series Active Luxury
    2021- Hyundai Kona Electric Premium SE

    #164716 Reply
    Intranicity
    Participant

    By comparison, there’s a certain simple pleasure just squirting petrol into the tank. Sometimes fast, sometimes slow, while gazing around the garage forecourt without a care until the nozzle clicks off…

    Until you realise you put the wrong fuel in…  Sadly it still happens and leads to a very bad day…

    Previous Motability Cars
    2006 - 2009 Skoda Superb VR6 2.0tdi
    2009 - 2012 Citroen C5 2.0tdi VTR Nav
    2012 - 2015 Nissan Qashqai 1.5dci tekna
    2015 - 2018 Ford Kuga 2.0tdi Titanium X
    2018 - 2021 BMW 220d X drive 2 Series Active Luxury
    2021- Hyundai Kona Electric Premium SE

    #164717 Reply
    Wigwam
    Participant

    Good post Intranicity.  Not sure I agree with your comment about granny chargers being designed for occasional use though.  The Volvo one is massively overbuilt both mechanically and electrically, and I imagine other car maker supplied ones are too.

    #164719 Reply
    Rene
    Participant

    The preserved wisdom from people who actually drive EV’s is that once a month it is good form to charge to 100% as the Battery Management Systems does lots of work in the final 10% from 90-100% charge, managing and balancing out the cells, that final 10% often takes longer than it takes to go from 20-80%.

    Yes. That’s, as you mentioned, because EV chargers “balance charge” rather than just charge. Where you’re wrong is the “good to charge to 100% once per month” – there’s literally zero upside to it. It doesn’t do any good. I’ve worked with batteries for almost a decade now, i’m very certain of that. All this “preserved wisdom” is, is the equivalent of “boot her once per drive to clean the catalytic converter”.

    It’s not how it works.

    You also need to be aware that all batteries have buffers, so when the car shows 0% or 100% state of charge, the battery is actually nearer 5% and 95%, theses buffer zones are unusable to the car, but are there to protect from fully discharging and killing a battery.

    That’s partially correct. While true that you have buffer zones (plus overcharge and over-discharge protection, obviously), the voltage remains the same. It’s 3.7V nominal, or 4.2V on full charge – even if it’s only at 95% capacity. And that’s where the problem is.

     

    AC (Slow) charging is believed to be healthier for batteries, but there are plenty of people (me included) who do that vast majority of charging via DC fast chargers, and are seeing no degradation of batteries (Taxis with well over 120k miles all on DC and battery still healthy). Currently I’m getting around 340 miles on a 100% charge.

    No, it’s a fact. As in, physical fact. The more you strain the battery, the more it degrades. What’s happening is that, under load (particularly, when hot), the electrolyte in the batteries split (it’s called electrolytic decomposition, and well known. It’s also visible to the naked eye, but because packs are usually not visible in an electric car, that indicator falls away. What’s happening is, that under load and high voltage, the “stuff” in the batteries decomposes, into lithium and oxygen (amongst other stuff, but those two are the important ones) – which leads to two things. A: the batteries visibly grow in size (they “puff” due to the internally released gas), and B: the internal diodes of the battery corrode (that’s the battery degradation, plus of course the loss of carrier-electrolyte).

    The biggest thing personally to understand is how you car behaves to charging, and the benefits of different types of charging.  I don’t think many new EV owners (Or dealerships) understand how the cars work.  Take the Kona for instance, it has a 64kW (Usable) battery, and will charge at 11kw on AC and 77kW on DC, sounds great… But it will only charge at 77kW for a very short time and only at a specific battery state and temperature, if it’s not in the sweet spot, it will be much slower.  The same goes for chargers, you are lucky to get much more that 44kW from a 50kW charger.

    I actually do agree that dealerships don’t seem to understand how EVs work, but it’s hard to blame them. I’ve worked with various variations of lithium packs in the last decade (Li-Ion, Li-Po, LiFe-Po4), and it’s not like your average AA battery – nothing with them is.

    The very fact is, to prolong the life of a battery (any lithium battery), you only charge it to slightly above their nominal voltage (3.7V), and discharge it slightly below. That’s where these batteries are “storage charged” as well (i don’t think EVs have that option, though imho they very much should – but that’s how they’re charged by the factory – to roughly 40% capacity and 3.7V, because that’s where the least degradation happens). Everything above 3.7V is various levels of bad for the battery, getting worse the higher you go. That’s why “charging to 100% (regardless of whether it actually is 100%, or 95%) isn’t good for the battery and should only be done if you need the range.

    One should also mention that while i agree that dealerships/salesmen are clueless, those battery warnings don’t come from the car manufacturer, but the battery manufacturer, just relayed.

    Lastly: batteries have come a long way in the last decade or two, and the degradation is nowhere near what it was even 5 years ago (if i recall the article correctly, it’s almost slashed in half) – but basic physics and chemistry don’t change. The packs are more resistant, but they still degrade. And they will always degrade for the same reasons, until we get to solid state batteries (not another decade, would be my guess) that don’t require an electrolyte. This is all kinda moot though, since we only have the car for three to five years, even if you blast it, at most you’ll lose around 15% in that timeframe. Which, btw, doesn’t show in the indicator. The indicator doesn’t measure the internal resistance of the battery (which increases due to the poles corroding through released oxygen/lithium), which means that the battery indicator can read 100% (or 3xx miles), but the battery discharges itself completely within 100 miles (extreme example).

    #164721 Reply
    struth
    Participant

    Tough leads have ths to say; I’d agree with them personally.

     

    Why do posts on many on-line forums say that only 2.5mmsq flex should be used?

    The 1.5mmsq vs 2.5mmsq flex debate seems to be the most common one with regards to EV leads on on-line forums, and sadly the most uninformed. For lengths of up to 20m, our advice is that the 1.5mmsq flex used in all of our leads is the best option for the following reasons (apologies for getting rather technical!):

    BS 1363-1:1995 A4:2012 the British Standard for 13A plugs, specifically states that flex must not exceed 1.5mmsq with the line ‘having nominal conductor cross-sectional areas not exceeding 1.5 mmsq’. Therefore, other than manufacturer fitted molded plugs, 2.5mmsq flex should not be terminated in a 13A plug.
    The IET Code of Practice for portable appliance testing allows a safe max length for 1.5mmsq flex without an RCD of 15m, and 30m with an RCD. When PAT testing an extension lead you check for the resistance of the earth- a 15m 1.5mmsq lead would be within the 0.2 ohm limit. Voltage drop on the same lead would be calculated according to the wiring regs as 5.17v, again well within the limit.
    The data sheets for 1.5mmsq H07RN-F cable generally state a max current of 15A. If the cable is a sensible length, the manufacturers recommended max current is nowhere near exceeded.
    1.5mmsq H07RN-F rubber cables do not degrade over time if used up to the full 13A, as this is well within their safe load limit.
    In contrast, 2.5mmsq is more expensive, heavier, and more challenging to manage.
    How do I know the electricity supply is safe?

    Irrespective of whether an extension lead is used, it is important that you consider how safe the supply may be before plugging in your charger.

    Domestic electrical installations can deteriorate with use and age. It is therefore important that a periodic inspection is carried out every 10 years for an owner-occupied home and every five years for rented properties or HMOs.
    As sockets age the contacts can loosen, meaning that the contact between the socket and plug pins is not as firm as it should be, which may increase the risk of over heating. We would always recommend charging your EV from a relatively new branded socket, such as one manufactured by MK, Crabtree, Schneider, Hamilton etc.
    Carefully check the socket for signs of damage, such as brown marks around the receptacles or cracks.
    Only use either a single socket, or a double socket which has nothing else connected to it.
    We would always recommend that the supply is checked using a plug in socket tester. Whilst the unit does not provide the same level of testing or assurance provided by a periodic inspection, it does at least provide a simple check of the supply in order to identify basic problems. The unit simply plugs in, and a row of lights illuminate to confirm that the supply is safe to use e.g. there is an earth connection and the live/neutral are the correct way around.
    Is it worth using an RCD?

    Whenever you mix electricity, the great British weather and a metal car, it is absolutely vital to ensure that the entire lead is protected by an RCD. A residual current device (RCD) is a life-saving device which is designed to prevent you from getting a fatal electric shock if you come into contact with a live wire or current. RCDs offer a level of personal protection that ordinary fuses and circuit-breakers cannot provide.

    Due to their size, RCD plug units often prevent a lead from being used in an outside socket, or where there is anything above the socket. All of our leads therefore come with the option of an RCD plug or an RCD unit which is fitted in-line with the cable, to prevent such issues.

     

    a 15m extention with rcd is about 50 quid

     

    13A weatherproof double socket extension lead (RCD option)

    #164722 Reply
    Wigwam
    Participant

    Regarding the condition and quality of power sockets – over the last four years, as rooms have been decorated or re-fitted, I’ve replaced each of the power sockets with new ones, simply because the old ones have been there an unknown time before we moved in. They only cost £2 to £3 for a quality make.  Similarly with light switches which cost about a pound.  It’s an easy DIY job (once the powers off).  No harder than scraping old paint off them.

     

     

Viewing 11 replies - 1 through 11 (of 11 total)
Reply To: How much does granny charging damage the battery life of an EV?
Your information: