Battery Condition in Electric Vehicles
Discussion
Motors will outlast the rest of the car, except for Tesla where some should have been replaced under warranty on older Model S and X.
Battery health depends on the car. Some have a display that shows it, but usually the most reliable method is to attach an OBD-II dongle and use an app designed for that vehicle. What cars were you considering?
Battery health depends on the car. Some have a display that shows it, but usually the most reliable method is to attach an OBD-II dongle and use an app designed for that vehicle. What cars were you considering?
I'll cover the motor first:
1) don't worry about the motor!
There are just two moving parts in the motor (2 rotor bearings). As long as the motor is silent in terms of noise and vibration it's fine and will do many thousands of miles
2) The battery
depending on the exact model, the dash display and a hand held scan tool can tell you EXACTLY the State of Health (SoH) of the traction battery. For example, on a nissan leaf the bars on the dash give you an indication of the SoH and cheap scan tools like "leafspy" can tell you exactly the state of every single cell in the battery!
1) don't worry about the motor!
There are just two moving parts in the motor (2 rotor bearings). As long as the motor is silent in terms of noise and vibration it's fine and will do many thousands of miles
2) The battery
depending on the exact model, the dash display and a hand held scan tool can tell you EXACTLY the State of Health (SoH) of the traction battery. For example, on a nissan leaf the bars on the dash give you an indication of the SoH and cheap scan tools like "leafspy" can tell you exactly the state of every single cell in the battery!
aestetix1 said:
Motors will outlast the rest of the car, except for Tesla where some should have been replaced under warranty on older Model S and X.
Battery health depends on the car. Some have a display that shows it, but usually the most reliable method is to attach an OBD-II dongle and use an app designed for that vehicle. What cars were you considering?
I'm not considering anything at the moment. Way too expensive for my tastes. It was more of an idle musing about how the second hand routine would change nowadaysBattery health depends on the car. Some have a display that shows it, but usually the most reliable method is to attach an OBD-II dongle and use an app designed for that vehicle. What cars were you considering?
cobra kid said:
I'm not considering anything at the moment. Way too expensive for my tastes. It was more of an idle musing about how the second hand routine would change nowadays
When you buy a used fossil car you will probably want to get it checked out. The AA offer that service, and those combustion engines are complex devices with many things that can go wrong and many consumable parts that need regular maintenance.When you buy a used EV there are far fewer parts in the drivetrain, and far fewer consumables. You can check the battery with a simple app and £10 dongle in most cases. It should get a lot easier and a lot less risky to buy a used car.
Max_Torque said:
depending on the exact model, the dash display and a hand held scan tool can tell you EXACTLY the State of Health (SoH) of the traction battery. For example, on a nissan leaf the bars on the dash give you an indication of the SoH and cheap scan tools like "leafspy" can tell you exactly the state of every single cell in the battery!
BMW has a little trick to do the same thing - just do a Google search for 'BMW i3 battery health' and it will direct you to a bunch of videos that cover the steps to get it. Pretty sure you can substitute pretty much any OEM and model and get something suitable too. Might be hidden, but usually accessible. Not normally an issue and just like any car purchase, check it out and get the relevant data.Lester H said:
O.P. has nailed it. If you can overcome the first two obstacles of silly price and poor range, there remains the question of battery life direct injection carbonization.
There you go, corrected it for modern Audi, VW and pretty much anything else that uses crappy direct injectors.RAC check etc for EV's already includes a battery health report - although as said, it's normally relatively easy to do yourself. Or in most cases if you're buying from a used car dealer, ask them to do it. If they refuse or act like it's difficult... obviously don't buy.
Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
Max_Torque said:
For example, on a nissan leaf the bars on the dash give you an indication of the SoH and cheap scan tools like "leafspy" can tell you exactly the state of every single cell in the battery!
Leafspy can be fooled, its been proven by buyers who thought they got a great deal on a car with 12 bars of battery only to find after the first charge it was only a 10 bar battery!Fooling, reseting, hacking what ever you want to call it will be the new 'clocking' of used EV sales.
gangzoom said:
Leafspy can be fooled, its been proven by buyers who thought they got a great deal on a car with 12 bars of battery only to find after the first charge it was only a 10 bar battery!
Fooling, reseting, hacking what ever you want to call it will be the new 'clocking' of used EV sales.
Surely it's as easy as just checking the battery % versus the available range? Most EV's don't provide a specific readout for battery health anyway? Fooling, reseting, hacking what ever you want to call it will be the new 'clocking' of used EV sales.
TheDeuce said:
RAC check etc for EV's already includes a battery health report - although as said, it's normally relatively easy to do yourself. Or in most cases if you're buying from a used car dealer, ask them to do it. If they refuse or act like it's difficult... obviously don't buy.
Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
This is the stuff I'm interested in, in general. It should almost be a case of "find and buy" then.Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
cobra kid said:
TheDeuce said:
RAC check etc for EV's already includes a battery health report - although as said, it's normally relatively easy to do yourself. Or in most cases if you're buying from a used car dealer, ask them to do it. If they refuse or act like it's difficult... obviously don't buy.
Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
This is the stuff I'm interested in, in general. It should almost be a case of "find and buy" then.Although if you didn't worry about it or bother checking you would be very unlikely to get a significantly worn battery unless the car has done spaceship miles. The onboard software manages and cycles each group of cells to make sure they're looked after as well as possible. Way better than, for example, the same sort of cell in your mobile phone which is entirely down to how you charge cycle it.
Early signs are that the battery packs in ten year old EV's are absolutely fine for many more years of use with surprisingly little range degradation. There are some horror stories if you Google it, but those are mostly due to known faults or bad battery management routines in the software.
Without specific diagnostic kit and hardware for each make you don’t stand a chance. An OBDC reader is unlikely to tell you much about the main battery which is the traditional way of checking the health as seen by the cars computers. Tesla needs a specialist adapter and some third party software, leafspy has already been mentioned above and it’s reliability questioned. You get the idea.
Battery health is also more than retained capacity, the BMS can adjust charge rate profiles, plenty of teslas had their profiles butchered to protect the battery.
Heres Johnny said:
Battery health is also more than retained capacity, the BMS can adjust charge rate profiles, plenty of teslas had their profiles butchered to protect the battery.
Probably far less of a concern to most that capacity though I'd suggest, and a lot more difficult to confirm. Even if you could take the car to a local rapid charger as part of the test drive the variability in charge speeds caused by a multitude of different factors are going to make it a real challenge. SWoll said:
Heres Johnny said:
Battery health is also more than retained capacity, the BMS can adjust charge rate profiles, plenty of teslas had their profiles butchered to protect the battery.
Probably far less of a concern to most that capacity though I'd suggest, and a lot more difficult to confirm. Even if you could take the car to a local rapid charger as part of the test drive the variability in charge speeds caused by a multitude of different factors are going to make it a real challenge. I’ve a torch with a rechargeable battery, I’m sure many have. It worked fine for years, measure it’s voltage and it’s still great, but as it aged it’s performance has dropped off a cliff.
A lot of people don't realise, or are in denial about, the indicated 'range' is not rigidly tied to battery capacity.
EVs don't ted to use 100% capacity when they are new, they attempt to optimise the use of the battery to get a good life out of it.
The nett result is that everything appears to be lasting very well until some years down the line, then battery wear and range decline will be more rapid.
A lot of EVangelists are making claims about battery longevity somewhat beyond the data from cell manufacturers.
The truth is probably a) variable and b) somewhere in the middle.
EVs don't ted to use 100% capacity when they are new, they attempt to optimise the use of the battery to get a good life out of it.
The nett result is that everything appears to be lasting very well until some years down the line, then battery wear and range decline will be more rapid.
A lot of EVangelists are making claims about battery longevity somewhat beyond the data from cell manufacturers.
The truth is probably a) variable and b) somewhere in the middle.
Kind of, certainly don’t listen to people who feel their contribution to forums is measured by their post count.
Another factor not mention is the BMS system themselves can drift. There are guides on how to calibrate them on certain models but even if you asked the car for a health report it might not have a totally accurate reading. It’s not uncommon for a 5% recovery of reported degradation through a combination of cell balancing and BMS calibration techniques.
The real question is does it matter? Most cars have something like an 8 year warranty and the vast bulk of used cars are likely to be under 4 years old. In 4 years time I imagine there will a thriving cottage industry repairing batteries if it starts being an issue.
Another factor not mention is the BMS system themselves can drift. There are guides on how to calibrate them on certain models but even if you asked the car for a health report it might not have a totally accurate reading. It’s not uncommon for a 5% recovery of reported degradation through a combination of cell balancing and BMS calibration techniques.
The real question is does it matter? Most cars have something like an 8 year warranty and the vast bulk of used cars are likely to be under 4 years old. In 4 years time I imagine there will a thriving cottage industry repairing batteries if it starts being an issue.
Gassing Station | EV and Alternative Fuels | Top of Page | What's New | My Stuff