Ever since EVs were introduced on the road the lifetime of 12v EV batteries in EVs seem to be a lot shorter than in a regular ICE car. This has a couple of reasons and there are a few of things you can do about it. Every 12v battery will eventually die, but there are ways to prolong the life of your 12v battery.
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What is the reason 12v EV batteries die?
The number one cause of a lead acid battery failure is not keeping it charged to a proper voltage. This causes a buildup inside the battery called sulfation. After a while the buildup gets to a point that it will damage cells in the battery. Some cells will be damaged to an extend they stop working. At this point the voltage will drop and it’ll start to cause problems.
In EVs 12v batteries seem to last a lot less long than the ones in ICE vehicles. This has for a part to do with how they are used in the vehicle. In an ICE vehicle the starter motor draws quite a lot of energy from the battery and this large draw of electricity does slow down the sulfation on the metal plates inside the battery. Since an electric car does not have a starter motor and just has to run the 12v electronics there is never really a big draw from the battery and this is causing the sulfation to get worse quicker.
A healthy battery should be reading anywhere between 12.6 to 12.8 volt in resting state and hold this for a decent time. When your battery is reading below 12.2 volt fairly quick after a drive you can almost certainly expect it to fail in the near future.
What kind of problems can my failing 12v EV battery cause?
In most EVs you will start to see little clues your 12v is on its way out. Since almost all electrical components are 12v in your EV you will start to see certain things giving errors. In some cars the automatic boot opener will stop working and in some cases opening the car with the key fob will be problematic. Another sign is that the car starts to display all sorts of random error messages on the display that will disappear after driving the car. But in most cases these errors will come back pretty soon.
Easy way to keep an eye on your battery voltage
At this point it’s advised to check the battery to see if it needs replacing. Some apps that come with your EV will tell you the voltage of the battery, but there are a lot that do not. In both cases it could be interesting to invest in a Bluetooth Battery Monitoring System. It’s a fairly cheap solution, 29 quid on Amazon, but it allows you to keep a good eye on the condition of your 12v battery without having to pop the bonnet every time. Get this great device here.
Keep it topped up is a good way to preserve your battery
It is also advised to use a ‘smart’ charger that doesn’t just top up the 12v battery but also will run a conditioning cycle after that to balance the cells and overcome sulfation issues. If you use this kind of charger on your 12v EV battery once per month overnight, whether it seems to need it or not, and leave it plugged in when it’s fully charged it will allow the conditioning phase to take place and avoid sulfation issues.
Most EVs have AGM batteries nowadays, so make sure the smart charger has an AGM charging program on it. This is important because of the design of the battery that is different from a normal lead acid battery. We have been using the CTEK MXS 5.0 Battery Charger and are very impressed by it. It’ll set you back about 75 pounds, but it’s well worth it from our point of view. We believe it will extend the life of your 12v EV battery a lot longer. Get this great piece of kit here.
Frequently Asked Questions
What occurs if the 12V battery in an EV dies?
When the 12V battery in an EV fails, the vehicle may not start, and essential systems like headlights, infotainment, and climate control may be impacted. It’s crucial to address a dead 12V battery promptly to ensure the smooth operation of the EV.
Reasons behind the failure of 12V batteries in EVs?
The failure of 12V batteries in EVs can be attributed to factors such as age, excessive discharge, lack of maintenance, extreme temperatures, and infrequent use. These factors can reduce the battery’s efficiency and lifespan.
Expected lifespan of a 12V battery in an EV?
The lifespan of a 12V battery in an EV typically ranges between 3 to 5 years. However, this can vary based on usage patterns, maintenance, and environmental conditions. Regular checks can help maximize battery life.
