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Do electric cars lose charge when parked?

Yes, electric cars lose about 5% of energy each month. This is because all-electric cars today are using lithium-ion batteries. Lithium-ion batters are small and high dens energy storage units. But while remaining idle, the lithium ions are slowly discharging themselves.

5% over a whole month is the best technology we have today. NiMH batteries or nickel-metal hydride batteries are probably the best competitors to lithium-ion batteries, but these can lose up to 20% energy a month. So right now 5% is as good as it gets.

But if you think about it, it’s actually more than enough. If you need to travel away for let’s say 3 months, just leave your car with 50% or so. This will be more than enough, also enough for it to keep the 12-volt lead-acid battery charged.

Is it safe to park an electric vehicle over a longer period of time?

Yes, it is actually even safer than parking a gasoline car. A gasoline car with a combustion engine has thousands of parts where an EV is much simpler.

With all these parts you have to deal with rust damage and leakages from oils and such. Even the gasoline itself evaporates at a pretty fast rate compared to energy stored in a battery.

With the fuel cap open a full tank of gasoline can evaporate in a couple of days, this is because of its incredibly high energy density.

The best you can do, if you are going to park your electric car over a longer period of time, is to leave it charged between 30% and 80%, make sure the air pressure in the tires is sufficient, clean it very thoroughly and keep it someplace dry.

Also, make sure that the place you are storing your EV is not getting incredibly hot. Batteries don’t like it when it’s hot. For example, if a Tesla reaches above a certain temperature, it’ll kick in the cooler which will preserve the life of the batteries.

But this will also decrease the charge of the batteries significantly and could potentially leave the car with no charge at all for when you get back. Also, lithium-ion batteries don’t do well with going to 0% or 100%, so keep that in mind.

If you expose the batteries to high temperatures without the cooler kicking in, you also risk permanently damaging the cells and decreasing the max capacity.

The temperatures need to get high though, at least 40 degrees Celcius before there are any risks. If you park your car in the garage or at least in the shadow, you shouldn’t have any problems, just keep it in mind.

Author: Morten Pradsgaard

Morten has been working with technology, IoT, and electronics for over a decade. His passion for technology is reflected in this blog to give you relevant and correct information.