Considering buying a 2nd MYP. Add separate second charger or split existing?

[SeaNile]

Love my wife's 23 MYP so much I'm thinking of getting one of my own when my ICE lease is up in 3 months. We had a electrician run wire and install a 60amp breaker and with the Tesla wall charger we get 48a charging, theoretically at least. My question is do I add a second wall charger via the Power Sharing system or do I opt to have a second completely separate wire and breaker installed?

Could easily run another wire next to the original and the conduit has plenty of room for the last 25' so into the garage and to the outside wall of the garage.

Adding the Power Sharing unit seems really simple but would it cut the charging amps in half, etc?

 

[Sophias_dad]

Power sharing would only cut the amps in half when they are both plugged in and actively charging. That's the whole point of smart sharing. I'm not absolutely sure of the algorithm used.

You need to ask how often you both really need to charge your cars at the maximum rate at the same time. If its often, then maybe a second feeder is warranted. IMHO, its unlikely to be warranted.

That said, the install manual says you need a separate circuit/breaker anyway to make it a valid install. It isn't really necessary, but the electrician may well balk at installing it as a second device on that first circuit.

And even if you install a second 60 amp breaker/line(for 48 amps charging), you or the electrician REALLY need to look at your panel and service(main breaker) to see if they will support 3+ hours of an extra 100 amp load(48+48). I'd wager many houses can't.

BTW, if you decide to go the second wire/breaker route, consider putting a ~100 amp subpanel in the garage and still setup power sharing. Assuming the wires coming from the main panel to your first HPWC are already in conduit, pulling slightly larger wires shouldn't be THAT hard(although 3 or maybe even 2 AWG is doubtless a MAJOR pain to bend)

 

[jjrandorin]

Love my wife's 23 MYP so much I'm thinking of getting one of my own when my ICE lease is up in 3 months. We had a electrician run wire and install a 60amp breaker and with the Tesla wall charger we get 48a charging, theoretically at least. My question is do I add a second wall charger via the Power Sharing system or do I opt to have a second completely separate wire and breaker installed?

Could easily run another wire next to the original and the conduit has plenty of room for the last 25' so into the garage and to the outside wall of the garage.

Adding the Power Sharing unit seems really simple but would it cut the charging amps in half, etc?

It only cuts the charging amps in half if both cars are charging at the same time. You can use scheduled charging to avoid that if you wish, or do like I do with my power shared wall connectors.

I have one car set to 3am to start charging, and one set to 4am. If only one of them is charging, it charges at 48amps. If both are charging, they both charge at 24 amps till one finishes, then when one finishes, automatically speeds back up to 48amps.

I have gen 2 wall connectors, but I think gen 3 work the same in that regard (but you would want verification from gen 3 wall connector owners, if thats what you have, which if you bought it new any time in the past 2 ish years, you probably do.

 

[jcanoe]

The automatic load balancing feature would be useful if there is not sufficient capacity for a second 60 amp circuit. The additional Wall Connector would require its own circuit breaker to meet code so unless you have a sub panel located near the garage the wiring for the second Wall Connector would have to be run back to the main service panel. When you have a sub panel and you choose to use the automatic load balancing then both Wall Connectors could be in use at the same time provided the total charging amperage did not exceed 80% of the circuit feeding the sub panel. 80% of 60 amps would support 48 amps for charging both vehicles, the charging amperage can be split 50/50 so 24 amps and 24 amps when both Tesla vehicles are charging or you can set one Wall Connector to always charge at a minimum of 32 amps and this would limit the second Wall Connector to 16 amps when both vehicles are charging. When only one vehicle is charging then the vehicle would charge at 48 amps, the maximum for the 60 amp circuit. It depends on how many miles per day you and your wife will be driving on average to determine how to split the available charging amps with both Tesla vehicle charging.

Depending on the location/layout of the garage and the existing Wall Connector you could charge on alternate days and share the Wall Connector at least until you decide what to do as far as a second Wall Connector.

 

[Sophias_dad]

Keep in mind that to justify two chargers at 48 amps means you are both driving your cars a ludicrous distance daily. Lets suppose you downright empty the electron tank(80kwh) every day. That's going to take around seven hours to fully recharge. Even if you only charge while sleeping(~8 hours), that means unless you are driving a combined >310 miles daily between your two Tesla's, you should have no problem at all power sharing. If you have slightly staggered schedules, or you just have ~12 hours at home, there's even less need for another full circuit.

 

[Tronguy]

Um. A lot depends upon how often you and the SO charge cars. The SO and I have a M3 and a MY and a Wall Connector plotched in the vertical bit of wall between the two garage doors. When she needs a charge, she plugs her car in. When I need a charge, I plug my car in. In two years of dual Tesla ownership, we've never had a situation arise where both cars needed a charge at the same time.

Admittedly, we do have a Gen 2 Wall Connector. We could probably find a second on Ebay or something, then get them to power share using the built-in hardware.. But, why bother?

 

[SeaNile]

Shared Power thingy it is then! We plug her car in overnight regardless of miles driven and have it set to "Off-peak Hours" and to 80%. Precondition for departure at 730am.

Next challenge will be does the cord reach MYP #2. It'll be close but I am sure doable.

I've got 4 more payments on my ICE lease and I'm already 3k miles over. Figure I'll be 6k over or about a $1500 penalty. Trying my best to rationalize just buying a 23 MYP which is in inventory but there are zero discounts. The recent price reduction across the Y platform represents any discount according to the SA.

Could always buy preowned but the prices are ever so close to buying new. Don't qualify for the $7500 rebate/reduction. Unless my MIL purchased the Y and gifted it to her daughter.....

 

[father_of_6]

I can't imagine anyone ever needing 48amps for each vehicle... unless you're both taxi drivers.

If it were me, I'd slap a subpanel where that first wall connector is, move it over a bit, then add a second with power sharing.

Also, I'd probably purchase the second vehicle as a *new* buyer and use the referral link from your first account. Then not only will you get $500 off your purchase, but you'll get 10,000 credits which is enough for a free second wall connector.

Have you driven the Model 3 yet? It's cheaper and has better handling, acceleration, and rearview mirror visibility. Since you already have a Y at home, might be worth checking out the Model 3.

 

[jcanoe]

Shared Power thingy it is then! We plug her car in overnight regardless of miles driven and have it set to "Off-peak Hours" and to 80%. Precondition for departure at 730am.

Next challenge will be does the cord reach MYP #2. It'll be close but I am sure doable.

I've got 4 more payments on my ICE lease and I'm already 3k miles over. Figure I'll be 6k over or about a $1500 penalty. Trying my best to rationalize just buying a 23 MYP which is in inventory but there are zero discounts. The recent price reduction across the Y platform represents any discount according to the SA.

Could always buy preowned but the prices are ever so close to buying new. Don't qualify for the $7500 rebate/reduction. Unless my MIL purchased the Y and gifted it to her daughter.....

Are you sure you can't qualify for the full $7500 federal tax credit? You might qualify for part of the $7500 credit. Also, you can convert a portion of your assets from a conventional IRA into a Roth IRA. The Roth conversion generates income that would enable you to qualify for the full $7500 credit. Assuming a 24% tax bracket $30k in taxable income would generate $7500 in federal tax. Consult with your tax advisor.

 

[canbonbon]

Not sure why you need to charge both cars everyday/night? Why can't you charge each on alternate days? We have the wall connector installed in the middle of the garage. That allows us to charge all three cars because the 26 ft cord reaches all three bays. This was recommended by the Tesla service person. Been very happy with it and we only have 2 Teslas. Sometime we have the 3rd when my sister visits. But there has never been any need to charge all three simultaneously. I read your last post and I understand you want to plug in just for preconditioning, etc. but maybe you really don't need to plug in. I guess even if you want to charge only in certain hours due to lower rates, I still feel that you could alternate because 48Amp provides 45miles/hr of charge (mine does that). Thats like 270 miles in just 6 hours of charging. Unless you both are driving over 200 miles per day for commute, your math is just not adding up. So I am not sure why you'd need to plug in *both* the cars daily.

 

[father_of_6]

So I am not sure why you'd need to plug in *both* the cars daily.

One reason might be to keep your state of charge low. We keep ours at 50%, and most days don't go under 40%. While we could still alternate between 2 vehicles, being able to plug them both in is just more convenient.

It's not really about the miles, it's just the convenience of not needing to alternate, and not needing to go out to the garage at night to switch the cable from one car to the other.

While I'd find power sharing totally acceptable, I'd also find it very convenient if they each at least have their own charging cable.

 

[SeaNile]

Are you sure you can't qualify for the full $7500 federal tax credit? You might qualify for part of the $7500 credit. Also, you can convert a portion of your assets from a conventional IRA into a Roth IRA. The Roth conversion generates income that would enable you to qualify for the full $7500 credit. Assuming a 24% tax bracket $30k in taxable income would generate $7500 in federal tax. Consult with your tax advisor.

Isn't the federal tax credit based on income? It's not the assets that are the killer it's the W2 and can't hide a thing.

 

[jcanoe]

Isn't the federal tax credit based on income? It's not the assets that are the killer it's the W2 and can't hide a thing.

If you have a conventional IRA account when you move some of the assets (could be cash, could be stocks, bonds, mutual funds etc.) out of a conventional IRA it is normally because you are age 59 and a half or older and can take money out of an IRA without penalty. (You will have to pay a tax on any capital gains from what is taken out. The distributions from an IRA account are taxed as ordinary income.)

The IRS allows you to convert some or all of your assets in a conventional IRA into what is known as a Roth IRA. Like a conventional IRA assets in a Roth IRA grow tax free. Unlike a conventional IRA you don't pay any additional income tax on assets you later withdraw from a Roth IRA.

You can convert a portion or all of your conventional IRA assets into a Roth IRA, even if you are not age 59-1/2 or older, without penalty. This generates taxable income (federal and also State income tax based on the value of what was converted into the Roth IRA.) The (up to $7500) EV federal tax credit can be applied to any federal income taxes owed.

The assets you convert into the Roth IRA will continue to grow tax free in the Roth IRA and are not subject to additional income tax when you later withdraw these assets from the Roth IRA. Depending on that value of the assets you convert from a conventional IRA into a Roth IRA you may not owe any federal income tax after applying the $7500 EV tax credit (you would only receive the tax credit for up to the amount of federal income tax you owe in the current tax year, not to exceed $7500. State income taxes on any IRA withdrawal or Roth IRA conversion would still apply.

 

[canbonbon]

One reason might be to keep your state of charge low. We keep ours at 50%, and most days don't go under 40%. While we could still alternate between 2 vehicles, being able to plug them both in is just more convenient.

It's not really about the miles, it's just the convenience of not needing to alternate, and not needing to go out to the garage at night to switch the cable from one car to the other.

While I'd find power sharing totally acceptable, I'd also find it very convenient if they each at least have their own charging cable.

Why so low? There are numerous threads here and on youtube that show there is no difference in battery longevity whether you do 50% or 90%. The only thing I have heard is to avoid 100% charge on routine basis. You could do 100% once in a while to force rebalancing or when you are on a road trip, otherwise one should stick with 90% or below. Heck even Tesla says do 90% charge (from the manual see below).

Note
Tesla recommends limiting the Battery's full charge level to below 90% for Daily use and charging to 100% only if needed for a long Trip.

Anyway this is a difficult topic and everyone seems to have their own opinion. I think we are paying way too much attention to battery charging %ages and its not worth it. There is no way your batter will degrade 50% in 10 years regardless of what charge you keep it. Since cell dying is a function of time, most of us will arrive at same or similar battery %ages in 10-15 years (regardless of charging %ages) when we might be potentially ready for the next car. Resale value would be barely impacted by battery because there are so many other factors influencing the resale value. My car has already gone down in value by 10K in 7 months of ownership because I did not qualify for tax rebate plus the price of the car went down as well. So my trade in value is 10K less than what I paid in just 6-7 months of ownership. In next 10 yrs there is bound to be new battery Tech which will give lot more efficiency and/or miles. Long story short, I have stopped worrying too much about SOC. Good luck in whatever you decide to do.

 

[father_of_6]

There are numerous threads here and on youtube that show there is no difference in battery longevity whether you do 50% or 90%.

They're incorrect.

What Percent is Your Tesla Charged to While at Home?

let’s be realistic…tesla announced a new model 3…and with the same battery and motors it’s gets a nice bump in range just from aerodynamics…they probably modeled it with fluid dynamics with serious computing power… the same for computer controlled battery charging… how realistic it to google...

teslamotorsclub.com

 

[jcanoe]

Why so low? There are numerous threads here and on youtube that show there is no difference in battery longevity whether you do 50% or 90%. The only thing I have heard is to avoid 100% charge on routine basis. You could do 100% once in a while to force rebalancing or when you are on a road trip, otherwise one should stick with 90% or below. Heck even Tesla says do 90% charge (from the manual see below).

Note
Tesla recommends limiting the Battery's full charge level to below 90% for Daily use and charging to 100% only if needed for a long Trip.

Anyway this is a difficult topic and everyone seems to have their own opinion. I think we are paying way too much attention to battery charging %ages and its not worth it. There is no way your batter will degrade 50% in 10 years regardless of what charge you keep it. Since cell dying is a function of time, most of us will arrive at same or similar battery %ages in 10-15 years (regardless of charging %ages) when we might be potentially ready for the next car. Resale value would be barely impacted by battery because there are so many other factors influencing the resale value. My car has already gone down in value by 10K in 7 months of ownership because I did not qualify for tax rebate plus the price of the car went down as well. So my trade in value is 10K less than what I paid in just 6-7 months of ownership. In next 10 yrs there is bound to be new battery Tech which will give lot more efficiency and/or miles. Long story short, I have stopped worrying too much about SOC. Good luck in whatever you decide to do.

The latest charging information from Tesla for most Tesla vehicles includes only charging to 80% for daily use. The exception is the Model 3 RWD and the Model Y RWD equipped with the lithium iron phosphate battery (LFP). Tesla vehicles that have LFP batteries should be regularly charged to 100% to ensure proper calibration of the battery management system (BMS). Other than when charged to 100% the BMS cannot precisely measure the state of charge (SOC) of the LFP battery as the LFP battery's operating voltage is very linear across a wide range of the SOC. A weekly charge of LFP equipped Tesla vehicles to 100% SOC will help ensure good BMS calibration with the LFP battery.

 

[Mardak]

I've got 4 more payments on my ICE lease and I'm already 3k miles over. Figure I'll be 6k over or about a $1500 penalty

That sounds like you drive roughly 750-1000 miles/month or 170-230 miles/week, so that could fit in a 20%-80% recharge cycle of a MYP. We usually have wife's car plugged in every night even though she uses at most 20% normally, and one night a week, we switch to charging the other car.

Don't qualify for the $7500 rebate/reduction. Unless my MIL purchased the Y and gifted it to her daughter

Both of them could be on the title, and the IRS only allows one of the owners to claim the full credit anyway.

 

[Silicon Desert]

Are you sure you can't qualify for the full $7500 federal tax credit? You might qualify for part of the $7500 credit. Also, you can convert a portion of your assets from a conventional IRA into a Roth IRA. The Roth conversion generates income that would enable you to qualify for the full $7500 credit. Assuming a 24% tax bracket $30k in taxable income would generate $7500 in federal tax. Consult with your tax advisor.

You make a good point to that person's question. Similarly, our CPA told us some time ago that when we bought another Tesla, we would not get the full $7500 tax credit since our only income now is only social security. So, he suggested we transfer funds from our IRA account to an individual stock account in order to get the full credit as it counts as income. After all, when we take out IRA funds in future years, we have to pay taxes on it anyway so might as well do it earlier as much as we could. Turns out it was good advice.

 

[Mardak]

our CPA told us some time ago that when we bought another Tesla, we would not get the full $7500 tax credit since our only income now is only social security

You can now (as of January 12, 2024) get the full $7500 tax credit when buying a Tesla even if your income was "too low" in previous years.

Electric Vehicle & Energy Incentives / Federal Tax Incentives / Consumer Vehicles / New Vehicles​

​

Customers who take delivery of a qualified new Tesla vehicle and meet all federal requirements are eligible for a tax credit up to $7,500, which can be deducted from the purchase price at time of delivery for eligible cash or loan purchases through Tesla. Customers are limited to two time-of-sale tax credits per year.​

https://www.tesla.com/support/incentives#new-vehicles

Tesla says it's limited to 2 purchases each year, so maybe OP will consider a 3rd Tesla? Although if it's still the same 2 people driving, a single charger could still be sufficient.

 

[SpicyPaneer]

I’m using Enelx l2 chargers with load sharing on the same 60 amp switch. I think they are the only ones to offer load sharing tech on the same switch.