Charging the battery in AZ Heat/middle of the day?

[vickh]

I have free 12A charging close to work and was wondering if it's good to plug in as often as possible vs use to 10% then charge at home at night .

Also it will be 110+ this week. How good is battery cooling while charging vs skipping the charge when it's that hot..

 

[Tam]

I have free 12A charging close to work and was wondering if it's good to plug in as often as possible vs use to 10% then charge at home at night .

Also it will be 110+ this week. How good is battery cooling while charging vs skipping the charge when it's that hot..

The manual says plug in as often as possible so I would do that if I were you for the 12A at work.

Your battery has its own thermoregulation system so it will use its own HVAC as needed whether you plug it in or not.

There's no advantage in skipping plugging it in. As a matter of fact, if you plug it in and if it needs HVAC, it would draw from the power outlet as opposed to from your battery (more wear and tear to the battery) when there's no power outlet because you skip plugging it in.

The advantage of frequent plugging in is you don't have to let your battery discharge more than needed.

That means it's better to discharge your battery 5% when it arrives to the work charger and charge it from 85 to 90% than skipping the work charger and let your battery discharge to a total of 5+5=10% for your home charger and charge it from 80 to 90%.

 

[vickh]

Good points. Another factor is I have to turn off cabin overheat since the charging drops to 0 miles if I turn it on. (Interior is now @ 125!)

I might start leaving the windows a little open and buy the roof covers (I wanted to make this quick since I do the charge over my lunch hour to save time in the AM!)

 

[Sophias_dad]

I was gonna point out the problem of cooling using up your available charging. I wonder if at 110f the battery cooling will use a notable amount of your charging as well.

 

[ewoodrick]

The manual says plug in as often as possible so I would do that if I were you for the 12A at work.

Your battery has its own thermoregulation system so it will use its own HVAC as needed whether you plug it in or not.

There's no advantage in skipping plugging it in. As a matter of fact, if you plug it in and if it needs HVAC, it would draw from the power outlet as opposed to from your battery (more wear and tear to the battery) when there's no power outlet because you skip plugging it in.

The advantage of frequent plugging in is you don't have to let your battery discharge more than needed.

That means it's better to discharge your battery 5% when it arrives to the work charger and charge it from 85 to 90% than skipping the work charger and let your battery discharge to a total of 5+5=10% for your home charger and charge it from 80 to 90%.

I'd ask where the manual says "plug in as often as possible". I believe that's an interpretation of another statement.

And your analogy of 5% + 5% really problematic. I suspect that you are a proponent of carrying around a generator just so you don't ever user the battery.
If keeping the battery at exactly the same level is important, why would Tesla just not trickle the battery to match the idle current draw? They seem have to decided a number around 3% is a good hysteresis point for charge. Does that damage the battery?

I had one of the dreaded 2015 Leaf batteries and only charged when needed. When charged, It went to 100%. And over the 4 years that I had it, it had 97% state of life when I got rid of it. So it couldn't be too bad to charge only as needed.

 

[ewoodrick]

I have free 12A charging close to work and was wondering if it's good to plug in as often as possible vs use to 10% then charge at home at night .

Also it will be 110+ this week. How good is battery cooling while charging vs skipping the charge when it's that hot..

Plug in as needed, 110+ isn't a big deal. While some of the early batteries from other manufacturers had some chemistry issues with warmer clients, those have pretty much been resolved.

Charge as you desire, when you desire, life will be good. Tesla has designed the battery to take care of itself.

 

[Tam]

...I have to turn off cabin overheat since the charging drops to 0 miles if I turn it on. (Interior is now @ 125!)...

That's the more reason that I would plug in even if it's 120V outlet that can hardly add any charge to your battery.

I would not shut off the cabin heat protection. I would still turn it on to protect your interior and electronics from the heat.

If you plug in your 120V outlet, the HVAC would monopolize the shore power source and hardly gives any charge to your battery.

That's the point. Zero miles to your battery is good because if you don't plug it in, the HVAC would use your battery instead.

 

[animorph]

If the 12A charging at work is any hassle at all and is not critical for your trip home then I wouldn't bother. Sounds like it might be nice to keep the car cool without using your battery.

We use a scheduled charge due to cheap off-peak electricity rates. That means we're only charging once per day, no matter what. We leave it plugged in unless we know we'll be driving it again soon that day. We're always plugged in before the scheduled charge time every day.

 

[ucmndd]

I’ll go against the grain here and say i wouldn’t bother. Carrying around the UMC and plugging in every day for close to zero range is goofy. Plug in at home and don’t overthink it.

No problem with charging when it’s very hot, but the cooling system will likely use almost as much energy as you gain (or more) charging at 12A/120v (~1kw).

 

[vickh]

I’ll go against the grain here and say i wouldn’t bother. Carrying around the UMC and plugging in every day for close to zero range is goofy. Plug in at home and don’t overthink it.

No problem with charging when it’s very hot, but the cooling system will likely use almost as much energy as you gain (or more) charging at 12A/120v (~1kw).

it's 12A/220 so gives me about 10miles/ hr. If HVAC comes on it drops to about 0. I might use cabin overheat w/o AC to see how well that works

 

[vickh]

If the 12A charging at work is any hassle at all and is not critical for your trip home then I wouldn't bother. Sounds like it might be nice to keep the car cool without using your battery.

We use a scheduled charge due to cheap off-peak electricity rates. That means we're only charging once per day, no matter what. We leave it plugged in unless we know we'll be driving it again soon that day. We're always plugged in before the scheduled charge time every day.

How cheap is your off peak? APS plan?

 

[darth_vad3r]

it's 12A/220 so gives me about 10miles/ hr. If HVAC comes on it drops to about 0. I might use cabin overheat w/o AC to see how well that works

It probably only drops to 0 temporarily. After it cools down a bit the AC backs off and you should see some positive mi/hr charge even with AC on. Wait 5 minutes to see.

 

[Tam]

I'd ask where the manual says "plug in as often as possible". I believe that's an interpretation of another statement.

Agreed. I got my understanding or interpretation from the manual which says:

"About the Battery
Model 3 has one of the most sophisticated battery systems in the world. The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it. This is particularly important if you are not planning to drive Model 3 for several weeks. When plugged in, Model 3 wakes up when needed to automatically maintain a charge level that maximizes the lifetime of the Battery. Note: When left idle and unplugged, your vehicle periodically uses energy from the Battery for system tests and recharging the 12V battery when necessary. There is no advantage to waiting until the Battery’s level is low before charging. In fact, the Battery performs best when charged regularly."

"LEAVE YOUR VEHICLE PLUGGED IN when you are not using it" or "not using it" happens quite often as most cars are not running on the road 24/7. They may take an 8 hour break while its owner is at work.

...why would Tesla just not trickle the battery to match the idle current draw? They seem have to decided a number around 3% is a good hysteresis point for charge...

If I turn off the timer for my Model 3, it would charge quite often. It stopped charging when it reached what I have set at 70% but from midnight till the next 14 hours, it would continue to charge from 70% to 70%, 69% to 70% at least 9 more times every 2 hours or less for just a few minutes in duration, from 1 minute to 8 minutes of charge:

...I suspect that you are a proponent of carrying around a generator just so you don't ever user the battery....

I am practical when it comes to Tesla battery charging. I just plug it in and forget about it. If there's no plug, I don't need to worry about it because I'll plug in some other time.

However, when people ask me, then I support giving them the knowledge and let them decide.

 

[Big Earl]

I would plug it in at work and leave cabin overheat protection on. It might not add anything to the battery on the hottest days, but it’ll keep your interior at a reasonable temperature without reducing your range.

 

[vickh]

I would plug it in at work and leave cabin overheat protection on. It might not add anything to the battery on the hottest days, but it’ll keep your interior at a reasonable temperature without reducing your range.

no ac option? (doesn't do much, but saves range)

 

[Big Earl]

no ac option? (doesn't do much, but saves range)

I prefer the AC option. It only runs the AC when the fan by itself is in able to keep the temperature under control.

 

[animorph]

How cheap is your off peak? APS plan?

APS Max Saver, it's $0.055/kWh 8p-3p. We use a load controller to trim peak usage.

 

[Saghost]

With a 30 mile daily drive, I wouldn't bother.

The car will keep the temps under control either way, and the percentage you're using is small enough not to matter.

 

[vickh]

APS Max Saver, it's $0.055/kWh 8p-3p. We use a load controller to trim peak usage.

That's what I have too. aps - saver choice max

They have another ev plan too. I'm not sure if it's worth the switch or still avail. aps - saver choice tech

 

[ewoodrick]

Agreed. I got my understanding or interpretation from the manual which says:

"About the Battery
Model 3 has one of the most sophisticated battery systems in the world. The most important way to preserve the Battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it. This is particularly important if you are not planning to drive Model 3 for several weeks. When plugged in, Model 3 wakes up when needed to automatically maintain a charge level that maximizes the lifetime of the Battery. Note: When left idle and unplugged, your vehicle periodically uses energy from the Battery for system tests and recharging the 12V battery when necessary. There is no advantage to waiting until the Battery’s level is low before charging. In fact, the Battery performs best when charged regularly."

"LEAVE YOUR VEHICLE PLUGGED IN when you are not using it" or "not using it" happens quite often as most cars are not running on the road 24/7. They may take an 8 hour break while its owner is at work.




I am practical when it comes to Tesla battery charging. I just plug it in and forget about it. If there's no plug, I don't need to worry about it because I'll plug in some other time.

However, when people ask me, then I support giving them the knowledge and let them decide.

I'm practical as well, I charge periodically and don't spend time worrying about plugging in all the time.

So, you start to show my side of the equation "They may take an 8 hour break while its owner is at work." What if it was only 4 hours? Is that better? Or 12 hours? Is that worse? 24? 48? What about those who charge only at work? They are off charge for 16 hours, is that detrimental?

The manual is just a little guidance and honestly, as far as I know the ONLY official statement at all about the battery. I can extrapolate a number of interpretations of the statement, the most extreme being "Don't let the battery go to 0%, you idiot"