Short Commute - Trickle Charging OK?

[maglianera]

A little background:

I recently got my M3 Dual Motor Performance for commuting and errand purposes.

I have about a 12 mile commute (each way) 5 days per week = 120mi/week or 480mi/month or 5760 mi/year. I typically don't drive my M3 on the weekends. That being said, my commute is up and over a pretty sizable toll road/pass and that 12 mile (each way) really consumes around 17-20 miles of juice when it's all said and done... not to mention that I drive would could be considered as 'spiritedly' @ 80-85mph on the toll road.

I'm in the process of selling my home, so I haven't bothered with installing a NEMA/L2 charger in my garage simply because I think it will be a waste of money. I have been charging (when needed) but typically won't get through that full charge in a weeks time. I have been 'topping off' with my normal 110v, trickle charging a few days during the week, OR I'll leave it plugged in from Friday afternoon all the way through Sunday afternoon to obtain a full charge for the following week. Right now, I'm getting 5 miles of charge / hour with my 110v outlet.

My question is - am I degrading the battery by solely using my 110v outlet? Is 'topping off' the battery not a good thing? The reason I ask is that I have my charge rate set to 100% and I keep getting a message about how this is not good for the battery. If I am to continue with my trickle charging for the time being, would anybody have a recommendation as to what would be the best method? Should top off at night, or simply wait until the end of the week and do a full 48 hour trickle-charge @ the 5 mile/hour rate to preserve my pack?

Any insight would be helpful. Thanks!

 

[TexasEV]

Set the charge level to 90% and keep it plugged in when you can. Only use 100% for trips. Oh, and RTFM. It answers these and other questions.

 

[HelloJohnny]

I also have a short commute 10 miles (each way) and have been surviving on a 120v outlet. I set my daily charging to 90% for work and 100% for trips that are over 250+ miles. I have over 11,000 miles on my LR RWD Model 3 with no battery degradation (charged to 100% last Friday and have 312 miles) - Still pending the 5% range increase update

As the manual says - Always be plugged in even when the car is not in use.

 

[Dre78]

https://www.tesla.com/content/dam/tesla/Ownership/Own/Model 3 Owners Manual.pdf

Specifically the section "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.

 

[duanra]

I am wondering something about this section. Is that important to keep it plugged because it won't let the battery deplete to a dangerously low level ?
Or the main thing is to keep the battery at a good level by going to SC or level 2 charget once in a while.
Of course, having the car plugged is the easier way, however for the people who live in apt it might not be possible.

 

[Knightshade]

I am wondering something about this section. Is that important to keep it plugged because it won't let the battery deplete to a dangerously low level ?
Or the main thing is to keep the battery at a good level by going to SC or level 2 charget once in a while.
Of course, having the car plugged is the easier way, however for the people who live in apt it might not be possible.

Keeping it plugged in also means if it needs power for anything while plugged it uses wall power instead of battery power.

(thus you can preheat or precool your car in the mornings without losing any range before you leave)

Basically there's no good reason NOT to have it plugged in whenever it's easy to have it plugged in- just keep the max charge at 90 or lower and it'll be fine.

 

[duanra]

Keeping it plugged in also means if it needs power for anything while plugged it uses wall power instead of battery power.

(thus you can preheat or precool your car in the mornings without losing any range before you leave)

Basically there's no good reason NOT to have it plugged in whenever it's easy to have it plugged in- just keep the max charge at 90 or lower and it'll be fine.

So what I understand, it is just a precautionnary measure (a good one). But it could be replace by making sure you keep a good level of charge by manually taking care of it.

 

[Tam]

...it is just a precautionnary measure...

Also, it's better to avoid deeper discharge as much as possible.

That means if you set at 80%, it's better to recharge from 79 to 80% than from 70 to 80, from 50 to 80 or 0 to 80%...

 

[duanra]

Makes sense. I can also imagine that Tesla wants to avoid a bunch of phone calls from people who let the battery goes to 0 and use the warranty.

 

[deenko]

Just be aware that charging at 110 is the least efficient way to charge, but also the "best: way for battery life. Also the lower you set your max charge %, the more cycles you can get out of the battery. So if you can make it your whole week on an 80% charge, then your battery will last that much longer, but the reality is that at 90%, most people will be looking for a new car before the battery deteriorates past a usable range.

 

[Dan123]

Any insight would be helpful. Thanks!

Trickle charging will not degrade your battery (although it is likely that it is less efficient and you are going to spend a little more in electricity). But charging to 100% will degrade your battery over time.

I would set the charge limit to between 80% and 90%. Probably 90% since you need to have a reserve.

As for how often to charge, it doesn't really matter. Whatever is convenient for you. 2 times per week, overnight, seems sufficient for your needs.

 

[Troz]

Similar situation here, 30-45 rated miles used daily and trickle charge back to 90% every night. 80% would probably be slightly better for the battery but not enough to worry much about.

The one piece of advice I have is to try to use a 20 amp (NEMA 5-20) 120v outlet with the corresponding UMC adapter. For my SR+ it adds 6.8-7.0 miles of charge per hour which doesn't sound like a lot but is definitely better than 5 in time and cost. It's still not as efficient as any 240v solution but for me it's close enough to push off the upgrade until we get a second electric car.

 

[BrianG1970]

Thanks for all the useful information. I was hesitant to move forward with the 3 based on limited charging capabilities. My commute is short and I live 5 minutes from a supercharger. I take delivery Nov 5 and absolutely cant wait.

 

[joebruin77]

I have charged at home using a standard outlet, a Wall Connector, and a 14-50 Nema outlet, so I am speaking from personal experience of using different charging methods. While it sounds like you can get by using the standard outlet, there are two reasons I would consider at least having a 14-50 outlet installed.

First, I am concerned about the effects of multi-day charging on a standard outlet. Of course, it depends on your specific house and the design and age of your electrical system, but charging for several days over the long haul would make me a bit nervous. I would be concerned not about the car but about the house and the electrical system. At the very least, I would have a licensed electrician come out and inspect your outlet to make sure it can handle this type of use. Make sure it has a GFCI installed and also that the outlet and wires can handle that type of chronic use. And as long as the electrician is there, he or she could also give you an estimate to have a 14-50 nema outlet installed. It may not be as expensive as you might be assuming.

Second, given the winds, wildfires, and power outages (both planned and unplanned) that have recently occurred throughout our state, I like having the security of knowing I can charge at the rate of 30+ miles an hour. That way, if the power does go out, when it comes back on I can quickly top off the battery. If you are planning on using a public charger if the power goes out, you would have to find a public charger that is still working and not effected by the same outage. Plus lots of other EV drivers are going to be seeking out the same.

 

[ngogas]

A plug in Tesla is a happy Tesla. Set it, plug it and forget it.

 

[TW14 9LF]

I see you are in Orange County, CA. Having your property set up to charge an EV might be a selling point for your home, particularly here. Lots of EV owners here.

Keith

 

[SSedan]

This idea that 120volt is trickle charging and different from 240volt charging is a bit laughable.
Compared to what the pack can take from a supercharger. 14-50 outlet is trickle charging.
As others have said low power connections like 120volt 15-20amp outlets are less efficient due to overhead percentage, but that has nothing to do with battery health.

 

[Amyshubby]

I guess everyone's situation is different. I drive about 75 miles round-trip and can charge for free two hours a day at work which adds about 50 miles. I supercharge for free on Sunday (right near my house) and my SOC drops about 25 miles a day. If the battery level drops below 50% then I plug in my level 2 charger at home and charge back up to 90%. I'm charging at work 2 hours a day and at home once a week. Since my SOC is almost always between 50 and 90 percent I don't think I'm doing any damage to the health of the battery.