Preserving Battery Life in an EV

I now have a brand new battery in my 2019 Chevy Bolt EV thanks to Chevrolet. I am wondering the best way to charge my car to make sure the battery will last as long as possible. Is it better to plug in at home every night or only when the battery is getting lower? I can get almost 300 miles on a charge now, and since I mostly drive on shorter errands around town, I can often go 1-2 weeks without charging, but wondering if I am better off charging more regularly to help extend the life on the battery.

Just keep the battery between 40% and 80% and it should give you a long life. Charge it when it gets to 40%. Pull it off charge, if convienient for you, when it gets to about 80%. If it fully charges, don’t worry about it.


Does the owners manual say anything helpful about this question?

Mr. Mustang says just exactly what a simple Google search found .

What did the dealer say when or if you asked then this question ?

It is the same as your cell phone battery. Don’t drain it all the way and don’t charge to 100%. Also, slow charging is better than fast charging, so save the fast charging for when you are on a road trip and don’t have another choice.

Too often someone at the dealer is not a credible source. Owners manual more likely credible.

I was surprised when a Tesla owner asked this question a while back. Turned out the factory didn’t have clear instructions about charging. Amazing that the super expensive battery doesn’t get better directions.

Tesla is still using laptop batteries… those cylindrical cells a bit bigger than an AA battery, lots of them. Treat them like your laptop or cellphone! :laughing:

Tesla is currently using a larger size cell than the traditional laptop cells.
21 x 70mm now, moving to 46 x 80mm vs 18 x 65mm for laptops.

As stated above, today’s lithium-ion cells don’t like being fully charged or drained near empty.
They also don’t like heat, whether it’s from the ambient, rapid charging or rapid discharge.

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This is one advantage of regular hybrids-the battery charging is in the car computer’s hands, not the owner’s.

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Most new EV’s do have programming that will only charge to 80% and do slow charging unless the owner bypasses it.

Whenever possible, I charge my phone via the USB port on my laptop, and I try to avoid charging it higher than 80-82%. This typically takes a couple of hours. I also have a fast charger, but I use that rarely, and only if my time is very tight.

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I figured out that my cell phone charges 10% for every 11 minutes, on the “wall wart” I routinely use.
So I connect the charger to an interval timer and set it to reach 70-80%.
That typically lasts me about 3 days down to 30-40%.
Similar routine with the laptop computer and e-bike.

It’s not just cycling, but time that degrades the battery. The rate that lithium ion degrades over time is highly dependent on temperature. A laptop computer that is kept on all the time and has the battery near the back where it is always warm or hot, and kept at 100% charge, will usually be shot within 10 years. Noticable reduced capacity after 5 years needing replacment is common. Now if the battery is placed in the front where it is kept at room temperature, it’ll usually still be near original capacity after 10 years.

Storing at 30C versus 40C cuts the storage life down by something huge like 3 times.

The state of charge also affects this. At 100% charge the rate it degrades over time is 3 times as much as if it were stored near 0% charge.

If you have to store your car for an extended period of time in the summer, run the battery down to 30% or so and then plug it to change with a wall timer that’s set to let it charge for 15 minutes a day or something. The problem is if you don’t most EVs will drain the battery down to 0 in a few weeks or months. This behavior seems to be intentional because there is no way an EV needs that much power when parked. A traditional car with modern electronics can stay parked for up to 6 months with just one lead acid battery. I wonder if disconnecting the 12V battery from an EV would stop this traction motor battery draining behavior.