Should I Charge My Electric Car Every Night

If you have an electric car that you use every day, you may be wondering if you can charge it on a nightly basis. Perhaps doing so will do harm to the battery it will not charge properly due to overcharging it. I know that you are worried that it will damage the battery if you let it continue to charge once it is full.

Should you charge your electric car battery every night? Yes, you should charge it each night if you had used it doing the day. They are calibrated to slow down the charging process when they are close to being fully charged. No need to worry about overcharging them.

Is it dangerous to the battery to Leave your Electric Car Plugged in Overnight?

Some people feel that they might be damaging their electric car battery by charging it overnight constantly. I can understand this fear because it will be reaching close to full capacity every night which could possibly alter the performance of the battery pack.

However, it is extremely hard to damage a battery pack by simply charging it. The main manufacturers have made sure that it is next to impossible to overcharge the battery. They have programmed their vehicles via a battery management system to slow down the charging once the battery has been charged to a certain level.

Here is a list of manufacturers that have a battery monitoring system:

  • Nissan Leaf
  • Tesla
  • Chevy Bolts

How does this battery system that prevents overcharging of the battery pack work exactly?

  1. Once the battery is close to a charge level of 100 percent, the monitor will reduce greatly the charge rate. This reduced rate is called the trickle charge.
  2. The battery pack will trickle charge at a rate that is equal to the rate of discharge so that the battery is not overcharged.

Does Fast Charging Your Electric Battery at Home Damage it?

Fast charging an electric car battery does save us a lot of time. Nevertheless, will it cause damage to the battery pack because of the stress that is being placed on it? Also, if you do end up damaging your battery pack, will the warranty be voided because of your lack of judgment?

Level 2 charging is, of course, faster, but it is not going to damage your battery pack.  If you were to install a battery pack that was charging at level 3 (highly unlikely because of the cost involved), you might need to be concerned about it.

Here is a chart showing the specs on the different charging station levels:

Car- Nissan Leaf Level 1 Level 2 Level 3
volts 120 240 480
time to charge 20 hours 8 hours 30 minutes

I had written an article on whether or not fast charging is bad for electric cars, click here to view this article. 

Is it Bad to Charge a Tesla Overnight?

If you own or wish to own a Tesla, you should be concerned whether or not you should charge it up each night.  It is not going to harm your battery if you do so unless you allow it to charge to 100 percent each night.  

There is a way to set the maximum charge level to 90 percent, which is what the manual recommends.  What is odd about the Tesla manual is that they do not seem to mention how often you can charge up, so I guess that frequency is not an issue or they would have mentioned it.

The Tesla manuals even mention that you should charge as often as you can so that you never run into a situation where your charge is too low.  I have heard of people charging up even after just driving to a grocery store that required a 2-mile trip.

So in other words, charge it up each evening, but never to 100 percent.  You will realize over time whether or not a lower charge is adequate for you based on your average daily mileage, but the range is high enough that you should be OK with lowering the maximum amount of the charge.

Besides setting a maximum charge level for your Tesla, you should try to set the scheduler on it to charge about 1 hour before you are to use it in the mornings.  This charging before usage will warm up the battery pack.  A warm battery pack will not use battery power to warm itself up and you will then be able to enjoy the full benefit of regenerative braking.

Even if you end up accidentally charging to 100 percent by charging overnight without setting a limit I do not feel that you are going to do harm to the battery pack.

Tesla realizes that some clients will try to charge fully and they have programmed the battery pack to slow down the charging once the level is around 90 percent.  It will charge only a rate that coincides with the rate that the battery pack is depleting its charge level.  In other words, the on-board computer will protect the battery pack from overcharging.

Another reason for charging overnight your Tesla is that they advise you to never allow the battery to be depleted below a level of 10 percent.  This is advisable for the general lithium battery.   

Even Elon Musk stated in twitter that the best range for the charge is between 30-80 percent.  I feel that the best way to maintain this level is to plug it in each night and to set the upper level at around 80-90 percent. 

Charge Level at Home to Maximize the Cycles Possible for your Electric Car Battery

If you are charging your EV at home, you need to be aware of the correct charge level that will allow the highest amount of charge cycles.  Charge cycles are the number of times that you will be able to charge the battery.  

I can remember buying rechargeable batteries that stated that they could be charged a total of 100o times.  It is the same principle with the lithium battery packs that make up most of the battery packs for electric cars.  There is a limit on the number of charges, battery packs will not last forever.

If you are not concerned about your battery pack, you may be the type of person that delays charging the pack and ends up at the zero level before you charge it.  Or perhaps, you leave it plugged in without setting the upper limit to be only 90 percent.

I searched online to find out which levels seem to work best for getting the highest amount of charge cycles for an EV battery pack, see the following chart:

Charge Level in Percentages (upper and lower limits Cycles before the capacity is reduced to 90 percent
100-50 3000
80-30 4500
80-70 12000

It is evident by the above chart that maintaining the charge level at 80-70 percent is the best for the number of cycles.  It is possible to do so, especially if you are charging at home each night and you are setting the upper limit to 80 percent. 

Personally, I would be ok with the 80-30 charge level because it reflects more the average use per day for most drivers.  

Why Charging At Night Could be More Damaging to the Environment

Since many of us purchase electric vehicles to reduce the negative effect on the environment, you need to be aware that charging your battery does indirectly impact in a negative sense, the environment.

When you charge your electric car each and every night, you are using electricity that is produced at power plants. There are power plants that produce electricity using non-carbon sources or low-carbon sources such as nuclear reactors, sun, wind, water.

However, some power plants burn fossil fuels to create electricity. For instance, some power plants are burning coal to produce electric power. The higher the demand for electricity, the higher the probability that there will be a negative impact on the environment.

It is fine that society is trying to weed out gas-powered cars so that we all are driving electric cars, but we take into consideration the production of the electricity.

Most Americans believe that electricity is green energy. The electricity that is produced in California is mostly green. The average electric car will create 100 grams of greenhouse gas pollution per mile if it were to use the electricity that had been produced in California.

The midwest and in the Southern portion of the United States produce some electricity using coal that releases CO2 into the environment when it is burnt. Here is a comparison of the greenhouse gases created by electric cars based on the type of electricity production used:

Levels California Midwest and Southern Part of the States
carbon level of electricity production Low Relatively High – due to the probability of coal-burning
greenhouse gas production per mile by electric car using electricity produced 100 g 300 g

Even outside of the states, for instance, in China, power plants use coal to produce electricity.  If China switches to essentially electric cars, the impact on the environment could be catastrophic.   

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