Guide to Lasting Longer – And Who Wouldn’t Want THAT!
10/31/2023 / John Beck
Oh, great… ONE MORE THING to think about when you buy an EV: How to charge the battery all the way – and then keep it from wearing out.
In a convention Internal Combustion Engine (ICE), the gas tank is one fixed size. It never changes. You fill it; you empty it; the gas tank stays the same size and capacity.
But in an EV, the battery is a lot more complicated to fully replenish, and the effects of charging and re-charging can be cumulative over time.
If you already own an EV, you’ve probably noticed that the range you’ll get with a “full charge” can vary pretty substantially.
Here's how to stay ahead of the game and max out every charge and hold out as long as you can.
Stay in the zone
Vocab check!! That gauge in your EV that shows the percentage of charge in your battery is called the “State of Charge (SOC) Meter”, and in a brilliant feat of numbering, it goes from 0% to 100%. But here’s something you might not know: The lithium-ion batteries in EVs can never truly be charged to 100% or drained to 0%, no matter what the SOC meter says. All EV batteries have a “buffer”, a little extra space above 100% and below 0% which can never be used. Why? For the health of the battery and for safety reasons (which, no, don’t include bailing you out if the meter shows 0 and you’re still miles from home )
Let’s leave that buffer aside for a sec. To keep your EV battery charging effectively – and in its best long-term health – the experts recommend keeping your SOC Meter in the zone between 20% and 80% charge. It’s easy if you follow our 3-part plan:
Charge the battery to 80% (Most EVs allow you to set a max charging limit)
Drive your EV until it hits 20%
Recharge back to 80%
Repeat as necessary.
But hold on: Can you ever charge above 80%? Of course! If you’re taking a longer trip, charging all the way to 100% makes sense because you won’t need to stop as much. Charging to 100% occasionally won’t have a major effect on your battery life, but you should aim for staying in that 20-80% zone when commuting, around town, or in your “regular” life.
Not everyone has a choice with this one. If you live in Vegas and it’s July, extreme temperatures are a fact of life. Even so… heat is one of the main enemies to an EV’s battery health. Relentless heat puts stress on your battery and causes it to deteriorate faster. If you live and drive in an area where the temperature regularly tops 80°F (27°C), here are a few tips:
Park out of the direct sun wherever possible, in the shade or in a garage (although garages can be just as bad or worse than outside)
Plug in your EV, so the battery’s cooling system can get power
Avoid charging above 80% (as we saw above)
Try not to use a DC fast charger (DCFC) to charge your EV (more on this below)
Stay cool, but not too cool
Yep, with an EV sometimes you’re damned if you do and damned if you don’t.
Because just like heat takes a toll on EV batteries, cold weather does the same in a different way. Extreme cold slows down the chemical reaction inside your battery, limiting the amount of charge you can get into the battery and reducing your range. You can run the heater (which your passengers will also appreciate) but that uses up battery power, as does heating the battery to maintain a proper operating temperature. Your range may actually be cut in half (50% reduction) in wintry conditions.
So what can you do? Well, many of the tips are the same for heat OR cold:
Keep your EV in a garage, where the temperature is bound to be warmer
Stay plugged in, which will keep the battery warm
The good news here is that while cold weather operation does cause issues, the cold itself won’t hurt your battery. Of course, if you’re only getting half the range, you’ll probably need to recharge twice as much – and that will drain your battery over time. (Ugh.)
Resist the sexy seduction of those DC Fast Chargers
DC fast chargers (DCFCs) love to tempt you with a “quickie”, a quick charge and then you’re on your way. But like your mama always told you… speed can kill. Speedy charging leads to battery degradation and can kill your battery over time. Those high currents from a fast charger produce insane amounts of heat. And if you’ve been paying attention, we already talked about how heat is the enemy. One estimate puts the loss of capacity at 10% after eight years – and that’s on top of any other losses from aging, charging to 100% too much, and operating in extreme heat!
Of course, just like the guideline about staying between 20-80% charge, rules are meant to be broken. Sometimes, the tradeoff for a DCFC is worth it, such as when you are on a long trip or if a DCFC is the only game in town. Just try to make DCFCs a “sometimes” situation, not your daily dose. A standard Level 2 charger is much better for the long-term health of your battery and should be your go-to choice. Keep the home fires burning – stay loyal to your home charger.
Stay at a steady pace:
Everyone loves the thrill of powerful acceleration, and EVs offer some of the best off-the-line thrust out there. But (buzzkill alert) all that fun does come at a cost. If you’re blowing through battery life too quickly – as a result of repeated full-blast acceleration from a standing start or prolonged high-speed highway cruising – you’ll degrade your battery. Fast discharging is as bad as fast charging.
Nothing lasts forever – love, money, EV batteries – but if you follow these tips, you maximize your chances of prolonging the last one as long as possible.