When is charging best for my battery?

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Vach

Well-known member
Joined
May 10, 2013
Messages
130
Location
Ventura County, CA
I currently only commute 8 miles to work; that's round trip. Takes me less than ten minutes.

Even using 110, assuming I don't go anywhere else during the day (I work graveyard), I can usually fully charge the car before I leave again.

Due to my use of power being so low, I was curious if an expert here could tell me what is better for preserving long term battery life. Should I charge the car to maximum every day, or skip a day sometimes maintaining a charge level slightly below maximum?

If it is a factor, the car charges in a garage and does not charge when I park at work (at night).
 
The closer you can keep the battery at 50% SOC and cold, the better. Anything different than that will more quickly degrade the battery.

So, if you want ideal, try an keep it at about 10 or the 16 fuel bar segments as much as possible. For your short commute, NEVER charge to 100% "extended" (you don't even need to worry about a top cell balance).

I would charge to "normal" 80% and not recharge until you get below 10 fuel bar segments illuminated.

FOR HOT WEATHER ONLY:
Keep the car out of the sun when it's hot out. Don't charge the car after it's been sitting in the sun all day; instead charge immediately after you drive while the battery is still cooled from the Temperature Management System (TMS). Don't drive the car without preconditioning the cabin before driving on a hot day. Don't charge unless the cabin was preconditioned OR you just got done driving.

In other words, don't work the battery pack at all (drive or charge) unless you can cool it first. HEAT KILLS THESE BATTERIES.

We do not have the same programming as the Model S / Roadster "active" TMS. When the car is off, so is the TMS on the Rav4 EV. The good news is that you can use the recommendations above to extend battery life. That's a difficult option on the Nissan LEAF with absolutely no TMS of any kind.

This is also why the Tesla recommends leaving the car plugged in for long dormant periods. The active TMS takes power to keep the pack cool. There aren't any recommendations from Toyota (that I've found) on long term storage of your $36,000 battery pack that has no capacity warranty. I recommend leaving the Rav4 battery at 50% charge (10 of 16 fuel bars), all the timers off, and NOT plugged in. Also, put the 12 volt battery on a battery tender (about $20-$40). Do your best to keep the car cool, even if that means moving it "up in the mountains" or putting an air conditioner in the garage.
 
Hmmm. I wonder if it might make sense to leave the car on to keep the TMS going if you need to leave it somewhere hot for a few days.
 
Perfect, thanks. I was mostly pleased to see a reference to those "fuel bars." My car has had "89" miles for 6 miles worth of round trips. Haha.

Curious; how long will the car leave itself on before turning itself off, if plugged in?
 
fooljoe said:
Hmmm. I wonder if it might make sense to leave the car on to keep the TMS going if you need to leave it somewhere hot for a few days.

That would kill the battery, and then the TMS would quit.

Now you have a depleted, hot battery. Bad plan. Before you ask, no, the car can't charge and be in READY. I'm certain that the TMS doesn't operate in ACC or ON.
 
Vach said:
Curious; how long will the car leave itself on before turning itself off, if plugged in?

In my case, it killed the 12 volt battery first, since the charger plugged in inhibits the DC/DC from maintaining the 12 volt.

So, it will stay on until the 12 volt dies in a few hours. And, of course, it won't charge the traction battery at all while plugged in with READY.
 
Of course the battery would die eventually, but I'm sure you could get a couple days out of it. Just gotta figure what the average draw would be.
 
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