Is level 1 charging a viable long-term option?

[Wanderer]

I have been a happy owner of a 2016 Model 90D S for the last seven years. After 110,000 miles the car is still doing great and I have had very few issues with it. I had a 240V NEMA 14-50 socket installed in my garage as soon as I got the car and have been charging my car with the mobile charger that came with the car every night. This has been working very well for me - it is always “fully“ charged when I take it out.

I am now moving to a new home and had expected to just install another level 2 charger there, this time a hardwired one. However, I was shocked how much it will cost me to do so. Due to the layout of the house and garage combined with city ordinances for electric installations, it will cost me close to $10,000 to install a level 2 charger in the garage. The costs are due to the need to dig a 95ft trench combined with the installation of two additional sub-panels, one at the house (as there is no space in the existing one) and one in the garage (due to local city ordinances). The trenching alone will cost me $3,000.

Considering this very high cost, I am considering whether I can get by with just doing level 1 charging with the mobile charger. I also have a supercharger very close to my home and another one on my way to work. I commute about 70 miles a day, but typically only three days a week, usually Monday, Tuesdays and Thursdays. How much I drive during the weekend really varies from week to week but it would be typically not more than 100 miles. I typically charge to about 90% to avoid hurting the battery giving me a theoretical 214 miles of driving distance, although from experience I know the actual distance varies significantly dependent on temperature and driving conditions. My understanding is that level 1 charging should add about 2-4 miles per hour. This seems really slow, but my thinking is that if I am fully charged by Monday mornings and plug in whenever I am at home, I should be able to get sufficient charge to get by during a typical workweek and most weekends and I can always use the supercharger to top up when I need more.

I have been reading some threads on the forum and did read that level 1 charging is less efficient, but it is not clear to me if it is is meaningfully less efficient to justify investing $10K in a level 2 charger.

I am a bit uncomfortable going from doing what I have been doing for 7 years, charging my car every night and having a full charge every morning, to moving to trickle charging and “hoping it will be sufficient” but am also reluctant to spend that kind of money on something that I may not need. Is anyone else in a similar situation and does it work for you? Is is bad for the battery to charge continuously on a level 1 charger whenever I am home? Are there any other alternatives or other considerations?

Thank you for any insights!

 

[Cosmacelf]

It can work. Can you see if you’ve got any receptacles nearby that are connected to a 20A breaker, or, even better, actually have a nema 5-20 receptacle (the left blade has a horizontal notch)? If so, then charging at 16A is much better.

 

[ewoodrick]

Here's the charging chart (look at the Tesla store, NEMA adapter bundle to find it)

As you can see, the Model S is showing 4 mph. My Model 3 and Model Y show 4, but reliably get 5.

I charge both of my cars off of 120V 15A alternating which one is charging. And it really does quite well.
Being further north, you will have more issues, but keeping the car in the garage definitely helps, especially if doesn't get really cold in it.

The great thing about it is as you inferred, you have a Supercharger near by. You can always "try" using the 120V plug and see how often you have to stop, it any, at the Supercharger. But the most important thing is that you don't have to spend the money now, only if you decide that you can't live with the option.

I'm in the same boat, panel is on the other end of the house, 75 ft of ditching, two+ sidewalk to bore under. I've got space on the main panel, so at least I'm good there. But it's still a lot of $$

 

[Wanderer]

It can work. Can you see if you’ve got any receptacles nearby that are connected to a 20A breaker, or, even better, actually have a nema 5-20 receptacle (the left blade has a horizontal notch)? If so, then charging at 16A is much better.

Thanks, I will check. I am not an electrician, but would it not be pretty straightforward to upgrade a breaker? If I find a 5-20 receptacle, do I need to do anything to get that increased amperage or will my mobile charger just take care of that?

 

[MorrisonHiker]

Thanks, I will check. I am not an electrician, but would it not be pretty straightforward to upgrade a breaker? If I find a 5-20 receptacle, do I need to do anything to get that increased amperage or will my mobile charger just take care of that?

You'd also need the 5-20 adapter for the Tesla mobile connector.

 

[ewoodrick]

Thanks, I will check. I am not an electrician, but would it not be pretty straightforward to upgrade a breaker? If I find a 5-20 receptacle, do I need to do anything to get that increased amperage or will my mobile charger just take care of that?

Absolutely not.

You have to make sure that the entire circuit can support the additional current and commonly, they can't

 

[beatle]

Thanks, I will check. I am not an electrician, but would it not be pretty straightforward to upgrade a breaker? If I find a 5-20 receptacle, do I need to do anything to get that increased amperage or will my mobile charger just take care of that?

If you find a 5-20 receptacle, it should already be on a 20a breaker and have the wiring to support it (generally just 12 awg).

You won't want to use anything else on that circuit while you're charging, though. If these are all in the same space (say, in your garage) you should be pretty good to go. Even better, if you have a 5-20 and a 20a breaker, you could upgrade to a 6-20 and get 240v service if you have an extra slot on your panel for the double pole breaker. Again, keep your receptacles consistent throughout the circuit and upgrade any other receptacles to 6-20s along the way.

I don't know if I could survive on a 5-15, but a 6-20 will do a pretty good job at keeping you topped up if you can swing it.

 

[ucmndd]

How many circuits do you have running out to the garage now? If more than one I’d investigate the feasibility of switching one to 240v like @beatle suggests above. A 6-15 or 6-20 would be a big improvement and alleviate pretty much all of your concerns.

 

[ATPMSD]

will cost me close to $10,000

This seems excessive. Backing out the $3,000 for the trench leaves $7,000. I suggest you get additional quotes.

 

[Cosmacelf]

Thanks, I will check. I am not an electrician, but would it not be pretty straightforward to upgrade a breaker? If I find a 5-20 receptacle, do I need to do anything to get that increased amperage or will my mobile charger just take care of that?

You can’t upgrade the breaker without also upgrading the wiring, so not a possibility. But it is fairly common to use 15A receptacles on 20A breakers, so do check the breaker (which is a job in itself since most electrical panels aren’t labeled very well!). If you do have a 20A breaker, then you can upgrade the receptacle to a 20A receptacle and use the Tesla nema 5-20 adapter with the mobile connector to charge.

 

[ATPMSD]

Even in a full breaker box you can usually convert the 120V outlet to 240V. In the example below, if you had two 15-amp breakers side-by-side you can this quad breaker. It provides two 15-amp 120V circuits plus a 20-amp 240v circuit. In this case you connect the existing 15A circuits and the garage outlet to the 240V posts - and you also free up the old 20-amp breaker. There are many other combinations to choose from, as well a tandem breakers.You should be able to find what you need. Just remember that a new 240V outlet needs to be dedicated, that is nothing else can be supplied by that breaker.

BR152015 - Eaton - Quad Circuit Breaker

Eaton Cutler-Hammer BR152015 quad (AKA triplex) circuit breaker.

www.simplybreakers.com

 

[ATPMSD]

One downside of my suggestion is the quad breaker is NOT GFCI. So you will really need to use tandem beakers to make room in the panel, then install a 240v GFCI breaker for the garage outlet.

 

[ewoodrick]

This seems excessive. Backing out the $3,000 for the trench leaves $7,000. I suggest you get additional quotes.

I was thinking that as well, but once I started thinking about the cable and the time needed to install the panels it did start to add up.

 

[ewoodrick]

Even in a full breaker box you can usually convert the 120V outlet to 240V. In the example below, if you had two 15-amp breakers side-by-side you can this quad breaker. It provides two 15-amp 120V circuits plus a 20-amp 240v circuit. In this case you connect the existing 15A circuits and the garage outlet to the 240V posts - and you also free up the old 20-amp breaker. There are many other combinations to choose from, as well a tandem breakers.You should be able to find what you need. Just remember that a new 240V outlet needs to be dedicated, that is nothing else can be supplied by that breaker.

But in many garages, the plugs and the garage door opener are on the same circuit. That means that you can't do it.

 

[fuelsman]

I have been a happy owner of a 2016 Model 90D S for the last seven years. After 110,000 miles the car is still doing great and I have had very few issues with it. I had a 240V NEMA 14-50 socket installed in my garage as soon as I got the car and have been charging my car with the mobile charger that came with the car every night. This has been working very well for me - it is always “fully“ charged when I take it out.

I am now moving to a new home and had expected to just install another level 2 charger there, this time a hardwired one. However, I was shocked how much it will cost me to do so. Due to the layout of the house and garage combined with city ordinances for electric installations, it will cost me close to $10,000 to install a level 2 charger in the garage. The costs are due to the need to dig a 95ft trench combined with the installation of two additional sub-panels, one at the house (as there is no space in the existing one) and one in the garage (due to local city ordinances). The trenching alone will cost me $3,000.

Considering this very high cost, I am considering whether I can get by with just doing level 1 charging with the mobile charger. I also have a supercharger very close to my home and another one on my way to work. I commute about 70 miles a day, but typically only three days a week, usually Monday, Tuesdays and Thursdays. How much I drive during the weekend really varies from week to week but it would be typically not more than 100 miles. I typically charge to about 90% to avoid hurting the battery giving me a theoretical 214 miles of driving distance, although from experience I know the actual distance varies significantly dependent on temperature and driving conditions. My understanding is that level 1 charging should add about 2-4 miles per hour. This seems really slow, but my thinking is that if I am fully charged by Monday mornings and plug in whenever I am at home, I should be able to get sufficient charge to get by during a typical workweek and most weekends and I can always use the supercharger to top up when I need more.

I have been reading some threads on the forum and did read that level 1 charging is less efficient, but it is not clear to me if it is is meaningfully less efficient to justify investing $10K in a level 2 charger.

I am a bit uncomfortable going from doing what I have been doing for 7 years, charging my car every night and having a full charge every morning, to moving to trickle charging and “hoping it will be sufficient” but am also reluctant to spend that kind of money on something that I may not need. Is anyone else in a similar situation and does it work for you? Is is bad for the battery to charge continuously on a level 1 charger whenever I am home? Are there any other alternatives or other considerations?

Thank you for any insights!

I have regularly charged using a 115-125V 15 Amp outlet. At 115V it’s 3 miles per hour and at 125V it’s 4 miles per hour. However, do not have any other load on the circuit. If the garage door is on the same circuit unplug the car temporarily. If you want plug in a saw, leaf blower, etc. Unplug the car temporarily. In most homes built before the recent electrical code updates the branch circuits are shared between outlets, lights, and apparatus such as garage door operators. To add to this overload of devices allowed on branch circuits the code permitted 14 gauge wiring which has maximum amperage of 15 amps. The new electrical code specifies the outlets, lights, and apparatus must be on their own separate branch circuits. It also encourages the use of 12 gauge wire with 20 Amp service for branch circuits. So if your circuit breaker box has 15 Amp breakers you cannot replace it with a 20 Amp breaker unless you run new wiring. I have seen 15-20 Amp outlets installed on 15 Amp circuits. This a fire hazard due to wire heating. Also note that regardless of wire gauge the length of the circuit from circuit breaker box to outlet will determine ultimate allowable amperage. The longer the circuit the less amperage is allowed. Charging a Tesla (or any EV) is a unique electrical load as it is constant, up to 80% load, and the load is constant for hours.

 

[DP26]

Is there a dryer or stove outlet within 25 ft or so? As a backup, you CAN safely use proper extension cords (such as for an RV) if you really needed a boost. I would not make that your daily plan:

 

[Wanderer]

This seems excessive. Backing out the $3,000 for the trench leaves $7,000. I suggest you get additional quotes.

I appreciate the feedback. Admittedly, I did round up a bit, but the breakdown was about $3,200 for the trenching, $4,950 for the electrician (supposedly three days worth of work) and $750 for a chargepoint charger. Even if I get another electrician to come down by $1,000-$2,000, we are looking at an investment of close to $7,000. I may try to see if another electrician may have another a better approach to this issue that does not require so much work and trenching.

 

[DP26]

I appreciate the feedback. Admittedly, I did round up a bit, but the breakdown was about $3,200 for the trenching, $4,950 for the electrician (supposedly three days worth of work) and $750 for a chargepoint charger. Even if I get another electrician to come down by $1,000-$2,000, we are looking at an investment of close to $7,000. I may try to see if another electrician may have another a better approach to this issue that does not require so much work and trenching.

Look at all outlets within reach. Hot water heater closet or hvac closet may have a usable outlet. What you can do with planning and management could save $. Reach can be gained via the quality extensions if needed.

 

[ItsNotAboutTheMoney]

I appreciate the feedback. Admittedly, I did round up a bit, but the breakdown was about $3,200 for the trenching, $4,950 for the electrician (supposedly three days worth of work) and $750 for a chargepoint charger. Even if I get another electrician to come down by $1,000-$2,000, we are looking at an investment of close to $7,000. I may try to see if another electrician may have another a better approach to this issue that does not require so much work and trenching.

95ft of trenching for $3k? That's $31.58/ft. Are you using a tunnel boring machine?

 

[Wanderer]

Is there a dryer or stove outlet within 25 ft or so? As a backup, you CAN safely use proper extension cords (such as for an RV) if you really needed a boost. I would not make that your daily plan:

Unfortunately not - I checked that. There is really nothing nearby except for four regular outlets in the garage, the lights in the garage and the automatic garage door. I haven’t managed to figure out the breakers yet.