Don’t you just hate it when you step into your car, try to power it on, and disappointment strikes. Your Nissan Leaf won’t start. The car decides to quit on you especially when you are in a hurry. If this has happened to you, then you are at the right place as we will discuss what causes this and how you can fix the problem.

But before going any further, it is important to know how your car works. The Nissan Leaf is a Battery Electric Vehicle (BEV) which is completely powered by batteries. So, if the car won’t start, then the problem is most likely related to the word “Battery”.

Let’s dig deeper to find out how the starter mechanism works for this car.

Starter systems in Gasoline vs Electric cars  

Starter mechanism in gasoline cars

First, some background information. In a traditional engine (Internal Combustion Engine), the engine needs to be rotated externally for the first few rotations. Only then can it perform the basic function of sucking in air to combust with the fuel. This process then repeats itself to give power to the wheels.

This initial rotation is provided by a starter motor powered by a battery. Thus, most starter motor problems in gasoline engines can be traced back to this battery. Of course, since there are several parts in traditional engines that need to work in harmony to power the wheels, there might be other problems too.

Now, this information must have you wondering that electric vehicles (EVs) are fundamentally simpler than conventional gasoline or diesel vehicle. Then why would the same problem occur?

Well, if you have popped open the hood of your leaf, you will notice that there is a 12V lead-acid battery inside it. Quite shocking, isn’t it? Why does your car need this old relic of a battery when there is a supercharged lithium-ion battery sitting under your seat?

Starter mechanism in electric cars

As you may have seen in the news all over the world that there is a tendency for electric cars to explode. And when these cars explode, they tend to make it big due to the power density of lithium-ion batteries.

Thus, this “traction battery” (lithium-ion battery) is disconnected from the main car systems by the 12V battery unless the car is in motion as a safety precaution. This keeps you safe and the first responders in the case of an emergency.

Moreover, other than the motors powering the wheels, most of the other vehicle systems are powered by a 12V system. Thus, this power is supplied by the lead-acid battery sitting under the hood of your Nissan Leaf when the car isn’t running.

When the car is running, a DC-DC converter significantly reduces the voltage down of the traction battery to 12V. This enables it to power the other electronic systems like the lights, windshield wipers, and infotainment system.

Thus, the function of the 12V battery can be classified as the following –

• Run the electronics of the car when the traction battery is not connected to the main systems
• Isolate or connect the main (traction) battery to the motors when required.

When you ask the car to start up, the 12V battery connects the traction battery to the motors so you can drive off into the sunset. Therefore, even in an electric vehicle, most of the starter problems can be traced back to this same 12V battery.

Time to see the various problems that trouble the battery and stop you from starting your car. We’ll also check out a couple of problems that aren’t related to this 12V battery.

Corrosion

Corrosion plagues anything and everything metallic in nature. In this case, the thing to be concerned about is the leads of the battery that can get corroded. There can be multiple reasons for this. Mostly the cause is due to the leakage of moisture through the hood or from under the car.

This problem is especially exaggerated in the winter when the salt used to thaw out the ice end up on the leads due to splashes speeding the corrosion up. Corrosion increases the resistance of the battery terminals and thus changes the efficiency of the battery’s functions.

You would be able to identify if this has happened by spotting either green or brownish coloured deposits near the battery terminals.

To solve this problem, all you need to do is remove the corrosion built up around the battery leads. Before attempting to do so, remember to disconnect the battery completely from the car. Once disconnected, you can use a steel brush to scrub away any corroded surfaces. To help you through the process, a mixture of baking soda and water can also be used.

Fused Cable Leads

Another possible reason why your Nissan leaf won’t start is that the cables attached to your battery terminals have fused. Some battery cables come with fuses to protect the rest of the car’s systems from a surge in current. While this surge isn’t common, it is generally seen when you try to jump-start the car.

Thus, if this seems like something you have done to your car in the recent past, then you may need to change your battery cables for the battery to start delivering power to different parts of the car again.

Depleted Battery

A problem as old as time. Sometimes, you just forget to switch off the lights after stepping out of the car. When the car isn’t running, the traction battery is disconnected from the car. Thus, all the systems that would otherwise be powered by this, is powered by the auxiliary 12V battery which can easily get drained overnight.

To check if this is the case, you can simply connect a multimeter across the battery terminals and check if the voltage is measuring above 12V or not. Anything below 11V and there is a high chance that your Nissan Leaf won’t start. Remember, in this case, your auxiliary systems will still function.

There are a few solutions to this –

• The first one is to charge the battery externally. This can be done with a variety of adaptors that fit into your home outlet. Depending on the outlet, the time taken to charge the battery may differ.
• The second solution is to jump-start the vehicle. But remember what you just learned in the problem above.
• Finally, you can just go ahead and change the entire battery if the above steps don’t work.

Internal Short Circuits

Another less common that occurs in a lead-acid battery is the occurrence of internal short circuits. This may be caused due to one of two reasons.

Firstly, the separator between different cells melts due to overheating of the battery. The second possibility is that due to overcharging and discharging sulphite crystals were formed internally.

Unfortunately, if this happens, there is no cure for the battery. The solution is to replace the battery with a new one.

Internal short-circuiting leads to faster discharge rates than normal. So, if you suspect something, get the battery changed immediately. We say this as continuously using such systems may damage the charging system in the long run.

Old Battery

Finally, the worst-case scenario you could have encountered is if the life of your battery has just worn away. Every type of battery has a number of cycles (charging and discharging) that it can go through before it starts to lose a significant level of charge. At the end of this life, the battery can barely provide any voltage to the car even if it is charged fully.

This problem is further exasperated if you make the battery undergo multiple deep discharge cycles. In this type of cycle, you tend to drain the battery to close to 0% of the charge and then recharge it back to 100% or even overcharge the battery multiple times. This reduces the life of the battery even more.

At this point, the only thing to be done is to replace the entire battery.

Inverter/Converter Unit Overheating

Most electric vehicles have an inverter or converter to convert the utility AC power to DC for charging the battery. DC from the battery also needs to be converted into AC power for the motors.

These systems tend to overheat. Thus, they have cooling systems to keep them within operating temperatures. However, due to irregular maintenance, these cooling systems may be impeded owing to dust or debris.

While it is rare, the malfunction of this system leads to less power being delivered to wheels and thus starting problems. Simple cleaning and maintenance should fix this problem.

Charging Latch Problem

One common problem noticed by some of the Nissan Leaf owners is that weather often messes with the charging port door. During icy winters, the charging port doesn’t close fully. This makes the car believe that you are still in charging mode even if you aren’t actually charging the car.

Since you aren’t allowed to drive with a cable tethered to your car, the Nissan Leaf won’t start. A simple solution to this is to use a hairdryer to defrost any ice stopping the latch from closing.

Key Fob Battery Down

The key fob is used to verify the identity of the driver to access the systems. It communicates with the car’s internal systems and allows the car to be turned on. This is done with the help of radio signals.

Thus, if the key fob’s battery is running low or dead, it won’t be able to send the signal to allow the car to start. Thus, you might need to charge or replace your key fob’s battery to allow you to start the car again.

You would usually get a warning on your dashboard warning you of your key fob’s low battery level. Remember not to ignore this and charge your key fob in time so you don’t face this problem in the future.

Reboot Required

The oldest trick in the book – “Did you turn it off and turn it on again?”. Electric vehicles sometimes need to be rebooted like every other electronic device on the planet. While the cause of the problem is unknown, the system reset can fix any software issues that you were previously dealing with.

You could try a soft reset where you just wait for 15 minutes before trying to restart your car. If this doesn’t work, unplug the 12V battery (remove the cables on its terminals) for 10-15 minutes. Then reconnect and try to start your car. Many Nissan Leaf owners have suggested that this works for them when everything else seems fine with the car.

Final thoughts

The 12V battery in the Leaf is notoriously problematic. Most of the start-up problems can be associated with this single part of the car. That’s why, if you have tried everything and your Nissan Leaf still won’t start your best bet is to try replacing the entire battery.

Otherwise, make sure you take care of it. Remember not to overcharge it or drain it to the absolute limit multiple times. If you fancy charging your car overnight, consider buying a charging management system. It would protect your battery by charging your car slower than usual without overcharging it.

If you still face starting problems after trying all these fixes, it is probably best to take your car to the dealer and let them figure it out. There might be a factory defect in the car that cannot be fixed on your end. We hope the article helped and you get moving again in your Nissan Leaf in no time!