Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Is slow charging with 110 v outlet bad for your battery?

Kirby64

Member
Jun 28, 2018
485
493
Austin, TX
Focusing only on the charge rate in relation to cell impact, missing the picture in regards to BMS balancing performance. A lower charge rate would allow BMS balancing time to adjust to differences in module pack differences at finer level. Exactly what the limits of the BMS balancing circuit is, I'm not sure, but generally with the lower the charge rate, the easier it is for a pack to be balanced.

My understanding is that the pack doesn't do much balancing unless you charge it above ~95% anyways.

Either way, if it can do balancing below that, what's to stop you from balancing the pack after it 'finishes' charging? I'm not sure why it needs to be actively consuming current from the wall to balance a battery.
 

follow.johnny

Member
May 19, 2018
816
932
Riverside, California
I also only charge using a 120v outlet since I took delivery of the car (3 months ownership). My commute to work Mon-Fri is 24 miles round trip and can get back the miles I lost with a overnight charge.

No issues with always having it plugged it as other members noted Teslas batteries perform better when they are always being charge between 30-90% SOC. As for cost of using the 120v outlet, our bill hasn't changed much minus the additional cost of running the AC during the hot summers in Socal.

I do plan on getting a 14-50 outlet once our garage is cleaned out near the side of our breaker. We have a 50 amp breaker available for the outlet as well.
 

DurandalAI

Member
Dec 20, 2016
962
2,912
US
While you can save on initial cost by charging off of 120/110v outlets, I would recommend at least putting in a 20a 220/240v circuit.
Reasons:
1. Your 120/110v outlet likely shares a circuit with other outlets. You may inadvertently trip the circuit if you plug a high amperage device into the other outlet on the same circuit.
2. Risk of fire.120/110v circuits are typically wired in series, going from out outlet to the next. It's likely that your outside outlet is one of the last or the last box on the circuit. This means every outlet box it hops from has a connection that's heating up due to the connection resistance. Running a dedicated circuit will reduce this risk. There are a number of stories of Nissan Leaf and other BEV owners who've had house fires due to their 120/110v charging.

If you decide to continue L1 charging on a 120/110v outlet, I highly recommend ensuring that the outlet you use is "tight" meaning it's difficult to plug/unplug into, not loose. If loose, swap it out. Also, verify the wires connecting to the outlet are nice and tight. Turn off the circuit, test, pull it out, make sure everything is nice and snug. If you're uncomfortable with this, please have someone knowledgeable or who is an electrician test this out.
 

rideincircles

Member
Aug 9, 2016
159
92
Fort Worth, Texas
Can a 14-50 line be run through the wiring conduit for a normal 120v line? I will have an electrician come to check mine out soon, but it has to route through the attic to reach my carport. I was hoping they could reuse what I have available already. The other issue is that my 120v outlet is not properly grounded. Can that just be fixed by running a new grounding wire back to the box? I checked all the 3 plug outlets in my house and only one of them looks to be properly grounded. Most of the outlets are 2 prongs in my house.
 

Big Dog

Active Member
Mar 7, 2016
1,644
1,639
Irvine, CA
But I still have not installed my NEMA 14-50 outlet yet. One electrician told me that my circuit breaker cannot support it.

my panel would not support another circuit either, so the electrician added a sub-panel in the garage, which was much cheaper than upgrading the whole panel. Total cost+Romex to run the line to the other side of the garage was about $1300.
 

Kirby64

Member
Jun 28, 2018
485
493
Austin, TX
Can a 14-50 line be run through the wiring conduit for a normal 120v line? I will have an electrician come to check mine out soon, but it has to route through the attic to reach my carport. I was hoping they could reuse what I have available already. The other issue is that my 120v outlet is not properly grounded. Can that just be fixed by running a new grounding wire back to the box? I checked all the 3 plug outlets in my house and only one of them looks to be properly grounded. Most of the outlets are 2 prongs in my house.

Assuming your conduit is sized for 120V lines, not likely. 14-50 requires huge wire in comparison.

What you CAN run though, is a 6-20 or 6-15 outlet instead. That will get you at least 11 or 15MPH charging speeds. Those require the same gauge wire as 120V 20A or 120V 15A circuits. Also, yes, to meet code and have the UMC work you'll need a ground as well.
 

rideincircles

Member
Aug 9, 2016
159
92
Fort Worth, Texas
Noted. Thanks, will keep that in mind when I have the electrician come out. My house has a 100 amp box with 2 open breaker spots so I hope it can be figured out without costing a fortune. Running a new line through the conduit that already exists sounds like the cheapest option instead of adding a new line of conduit going through my walls and attic. My house has 4 window units and 4 fridges for beer brewing, so keeping the amperage down may be the best option.
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,483
4,565
Kaneohe, HI
rideincircles, 4 window units, 4 refrigerators and most outlets are two prong? I guess by two prong you mean they don't have the grounding lug port on the outlet? If I was an electrician at your house ( of course I am not), I would not dare do any of what you have suggested.
Nothing personal, but if your house has two prong outlets it must be old. (Mine was built in 1973 and is every outlet is grounded).

If its that old, there's no conduit. In old houses, wiring was threaded through holes in studs and stapled to studs. There's no "straw-like" route to pull wire back to the breaker box. Kirby64 is spot on about the size of the wire. You likely run at least three of those window units and all 4 fridges at night. Sounds like 15 amp circuits, little less than 12 amp draw (let's say 10) x 3 = 30 and 4 refrigerators use what 6? 8? amps x 4 24-36 amps. That's at least 40 amps of your 100 amp service you are using. You are thinking of installing a 14-50 that will draw 40 amps and you will likely charge at night. That's the full 80 amps that you are permitted by code to pull from your 100 amp service.

See the problem from just the info you have share with us? Please anyone, jump in and correct me where I am wrong with the info we have been provided or that I took a swag at. Ride... keep us in the loop. Interested to know the outcome.
 
  • Informative
Reactions: voip-ninja

Kirby64

Member
Jun 28, 2018
485
493
Austin, TX
Noted. Thanks, will keep that in mind when I have the electrician come out. My house has a 100 amp box with 2 open breaker spots so I hope it can be figured out without costing a fortune. Running a new line through the conduit that already exists sounds like the cheapest option instead of adding a new line of conduit going through my walls and attic. My house has 4 window units and 4 fridges for beer brewing, so keeping the amperage down may be the best option.

Yeah, with 100 amp service I'd strongly recommend sticking to a 6-15 or 6-20 outlet. Honestly, you could be running pretty close to your main service load already if all the ACs and fridges are on.

Worst case, running 12ga for a 6-20 outlet is pretty easy and cost of copper should be relatively cheap compared to 6-50 wire.
Here's a comparison price (based on Home Depot pricing):
12gauge 3 wire: ~$0.50/foot
6 gauge 4 wire (needed for 14-50): ~$2/foot
 

rideincircles

Member
Aug 9, 2016
159
92
Fort Worth, Texas
Only 2 of the fridges are usually running at my house, the main fridge and my chest cooler freezer for kegs which is temperature controlled and runs occasionally. One other fridge is a vertical freezer for ferment temperature control and is off most of the time lately the other one does not work very well and stays at 65 degrees or so but the freezer part works. I do need to upgrade my a/c eventually, but held off since my gas furnace still works for now. I think the window units are 10k living room, 8k front entrance, 6k bedroom and 5k bedroom. But yeah, my house is 60+ years old and my grandpa did some of the work back in the day.

The most electricity my house has used over the summer in Texas is 1780 kw in August. I was thinking the 14-50 could be overkill. My friend was gonna charge his Tesla off 110v a few months ago, but the charger would not allow it since it was not properly grounded.

I am pretty sure the outside outlet is through conduit entirely, and was a later addition, but is not properly grounded. The house ground wire is connected to the outside water line, but I am not sure if that works correctly for a ground. That could be the issue after having some work done when they replaced the bathtub with a shower a while back and did work on the outside faucet line.

I guess I will find out soon enough, but keeping costs minimal is the goal since I want to rebuild in 10 years or so since the foundation issues my house has are another issue that is beyond easy repairs. I am just trying to keep it functional until it is time to rebuild.
 

Kirby64

Member
Jun 28, 2018
485
493
Austin, TX
Only 2 of the fridges are usually running at my house, the main fridge and my chest cooler freezer for kegs which is temperature controlled and runs occasionally. One other fridge is a vertical freezer for ferment temperature control and is off most of the time lately the other one does not work very well and stays at 65 degrees or so but the freezer part works. I do need to upgrade my a/c eventually, but held off since my gas furnace still works for now. I think the window units are 10k living room, 8k front entrance, 6k bedroom and 5k bedroom. But yeah, my house is 60+ years old and my grandpa did some of the work back in the day.

The most electricity my house has used over the summer in Texas is 1780 kw in August. I was thinking the 14-50 could be overkill. My friend was gonna charge his Tesla off 110v a few months ago, but the charger would not allow it since it was not properly grounded.

I am pretty sure the outside outlet is through conduit entirely, and was a later addition, but is not properly grounded. The house ground wire is connected to the outside water line, but I am not sure if that works correctly for a ground. That could be the issue after having some work done when they replaced the bathtub with a shower a while back and did work on the outside faucet line.

I guess I will find out soon enough, but keeping costs minimal is the goal since I want to rebuild in 10 years or so since the foundation issues my house has are another issue that is beyond easy repairs. I am just trying to keep it functional until it is time to rebuild.

If the outside outlet is entirely through conduit, then swapping it out for a 6-20 with proper ground should be pretty straightforward. If you have two free breaker spots, then you have room.

I'd start with that. At 15mph of added range, that's plenty for almost any driving situation.
 

Akikiki

A'-Lo-HA ! y'all
Nov 26, 2012
6,483
4,565
Kaneohe, HI
I think you mentioned part of the wire run will be through the attic? They will not use conduit there. So if your outside outlet runs through the attic, its not through conduit. That means a bit more labor for someone to crawl up there and run the new wire. I think you have several upgrades that need to occur particularly the new grounding for the house and new wire for an outlet be it new wire for the 110 or 6-20 like Kirby says. I know FW is hot this time of year, but your winter cools off enough that you are likely to see a range loss from cold weather. I believe its going to be hard for your 110 to keep up especially if it sits outside. Good luck to ya'll. :)
 

voip-ninja

Give me some sugar baby
Mar 15, 2012
4,124
4,698
Colorado
Only 2 of the fridges are usually running at my house, the main fridge and my chest cooler freezer for kegs which is temperature controlled and runs occasionally. One other fridge is a vertical freezer for ferment temperature control and is off most of the time lately the other one does not work very well and stays at 65 degrees or so but the freezer part works. I do need to upgrade my a/c eventually, but held off since my gas furnace still works for now. I think the window units are 10k living room, 8k front entrance, 6k bedroom and 5k bedroom. But yeah, my house is 60+ years old and my grandpa did some of the work back in the day.

The most electricity my house has used over the summer in Texas is 1780 kw in August. I was thinking the 14-50 could be overkill. My friend was gonna charge his Tesla off 110v a few months ago, but the charger would not allow it since it was not properly grounded.

I am pretty sure the outside outlet is through conduit entirely, and was a later addition, but is not properly grounded. The house ground wire is connected to the outside water line, but I am not sure if that works correctly for a ground. That could be the issue after having some work done when they replaced the bathtub with a shower a while back and did work on the outside faucet line.

I guess I will find out soon enough, but keeping costs minimal is the goal since I want to rebuild in 10 years or so since the foundation issues my house has are another issue that is beyond easy repairs. I am just trying to keep it functional until it is time to rebuild.

You need to download the NEC load calculation and run a load calc before you do anything.

Here’s a form based on the NEC

http://www.douglas.co.us/documents/single-family-dwelling-service-entrance-standard-calculations.pdf

1780 KWh is an enormous amount of electricity to use on 100 amp service.

Remember that your car will be charging continuously, for hours, on a 30 amp breaker it would be pulling 24 amps or 25% of your max load. Also keep in mind that some appliances like electric ovens, air conditioners, etc also have high loads and their startup load can be a lot (my 22 amp air conditioner is on a 50 amp breaker for a reason).

Rather than spitballing what you think your peak load is run the calculation and find out.

It’s not worth messing around with this stuff, if you have an older home, and it sounds like you might, there is a lot of risk of running near your peak load for extended periods of time.
 
  • Informative
Reactions: Akikiki

Kirby64

Member
Jun 28, 2018
485
493
Austin, TX
You need to download the NEC load calculation and run a load calc before you do anything.

Here’s a form based on the NEC

http://www.douglas.co.us/documents/single-family-dwelling-service-entrance-standard-calculations.pdf

1780 KWh is an enormous amount of electricity to use on 100 amp service.

Remember that your car will be charging continuously, for hours, on a 30 amp breaker it would be pulling 24 amps or 25% of your max load. Also keep in mind that some appliances like electric ovens, air conditioners, etc also have high loads and their startup load can be a lot (my 22 amp air conditioner is on a 50 amp breaker for a reason).

Rather than spitballing what you think your peak load is run the calculation and find out.

It’s not worth messing around with this stuff, if you have an older home, and it sounds like you might, there is a lot of risk of running near your peak load for extended periods of time.

My record is 2400kWh on a 100 amp service. :) And this was before the Tesla... that's what a 70s house with crap insulation and 20 days straight of over 100 degree weather get you... It's not too crazy. And that's without an electric water heater or oven.
 

voip-ninja

Give me some sugar baby
Mar 15, 2012
4,124
4,698
Colorado
My record is 2400kWh on a 100 amp service. :) And this was before the Tesla... that's what a 70s house with crap insulation and 20 days straight of over 100 degree weather get you... It's not too crazy. And that's without an electric water heater or oven.

Jesus buy some solar panels already.
 

rideincircles

Member
Aug 9, 2016
159
92
Fort Worth, Texas
I know the feeling on that. I can barely stand going into my attic during the summer. It is brutal and filled with old dusty insulation from ages ago. Luckily this week will be nice temperature wise. I might have one section where solar panels could be feasible on my roof, but otherwise the trees block out most of the direct sun to my roof. The good thing about my house is that its on 1/3 of an acre less than 10 minutes from downtown and my taxes are only $1500 a year. Next year I plan on getting a lot of upgrades done across the board. For now I will just see what needs to be done on the electrical side. Hopefully we have reached the end of the a/c running all the time, but this is Texas. Things change weekly.

Tonight I will probably go through the attic and clear a path to see what the electrical connections look like. I know there are random wires strewn about. I would consider this house to be grandfathered under electrical codes, and I haven't had an electrician look into it at all. Just keeping it functional is my main goal, the foundation problems are much worse than the electrical problems. That is why rebuilding is the plan over remodeling, but that is still years away. I don't want to invest more than is required to keep it functional.

Thanks for all the info though. I know my house is a can of worms on many issues. I am not sure where I need to start on the load calculations stuff. Where are the instructions on that? I am not sure where to get the numbers it requires. Electricity is not my forte.
 

voip-ninja

Give me some sugar baby
Mar 15, 2012
4,124
4,698
Colorado
I know the feeling on that. I can barely stand going into my attic during the summer. It is brutal and filled with old dusty insulation from ages ago. Luckily this week will be nice temperature wise. I might have one section where solar panels could be feasible on my roof, but otherwise the trees block out most of the direct sun to my roof. The good thing about my house is that its on 1/3 of an acre less than 10 minutes from downtown and my taxes are only $1500 a year. Next year I plan on getting a lot of upgrades done across the board. For now I will just see what needs to be done on the electrical side. Hopefully we have reached the end of the a/c running all the time, but this is Texas. Things change weekly.

Tonight I will probably go through the attic and clear a path to see what the electrical connections look like. I know there are random wires strewn about. I would consider this house to be grandfathered under electrical codes, and I haven't had an electrician look into it at all. Just keeping it functional is my main goal, the foundation problems are much worse than the electrical problems. That is why rebuilding is the plan over remodeling, but that is still years away. I don't want to invest more than is required to keep it functional.

Thanks for all the info though. I know my house is a can of worms on many issues. I am not sure where I need to start on the load calculations stuff. Where are the instructions on that? I am not sure where to get the numbers it requires. Electricity is not my forte.

If you aren't comfortable doing the load calc the electrician can do it but of course charge you for it.

Do a google search on how to do a load calc. It's not that hard to do. Some of it is simply based on square footage of your home, including any semi or unfinished areas that could still have things plugged in (basement space, for example). The rest of it is based around the loads of all of your appliances. You can either google the model # of an appliance to find out the load rating or you can look at the electrical plaque on the appliance. In rare cases you will need to open a panel or something to get this info.... I had to do this to get the motor rating on my AC.

Again, it's not hard and it is absolutely worth your time to do this because it will tell you if you are already overloaded, or if you are on the bubble where you might have to choose a 20 amp vs a 30 amp circuit for charging your EV.

If you're already over-subscribed the safe thing for you to do is pursue having your home service upgraded to 200 amps. Nobody wants to spend $$ on electrical service upgrades but you also don't want to have an older home with older wiring that is running maxxed out on amperage all the time..... that is a recipe for an electrical fire.

A common mistake people make is to assume that if they aren't tripping breakers the load on their home is "safe".
 

fsch

Member
Sep 21, 2015
151
177
Montreal, QC
But I noticed that when I charge to 80% of capacity I am getting only 245 miles today, but I vague remember I was getting 247 miles last week. (Theoretically, I should have 248 miles since 80% of 310 miles=248 miles

Just to answer more precisely to this part of your question, you lost a bit more than 1% in range. If the M3 battery degradation follows the trend of the MS and MX, at the very beginning, you should expect to loose about 1% every 6000 km or 4000 miles, down to about 5% loss after the first 80 000 km or 50 000 miles. But after that, the degradation slows down to 1% every 50 000 km or 30 000 miles. I'm past 200 000 km (120 000 miles) and still have 93% of my original range.
 

rhumbliner

Member
Sep 24, 2015
702
861
Las Vegas
Keep in mind that a load calculation will still be just an estimate. Instead, I was able to just call my electric utility and ask what my max load had been over the last 5 years. After hearing my proposal and reviewing my past usage, the EE recommended I bump my capacity up from 200 amps to 300 amps.

I would remind folks here, that several threads have pointed out that if your 120v receptacle is the only receptacle on a circuit, it’s fairly easy (and safe) to convert it to 240v. This assumes, of course, that a safety ground wire is present.
 

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top