Model S Dual Chargers, what do I need to do?

[Fragger]

Hi Friends,

It seems like my Model S comes with dual Chargers. In my garage, I seem to have the following outlet and the breaker to it looks like this in the attached pictures, 3 feet apart.

Question is, as I arrange an electrician to give me a home charging solution (was thinking a SEMA 14-50 outlet with 40 amps)... Do I need to consider anything else knowing my car comes with dual chargers?

I don't have Free Supercharging, and my work is like a ~30 miles round trip...

Any advice, considerations for me?

 

[Seth2020]

NEMA 14-50 on a 40A line (at 240V) will charge about 25 mi/hr. If you wish to use that as your main overnight charging, it should do the trick.

The Tesla Wall Connector can accommodate up to a 60A input line (again at 220V) delivering 48A to your car, resulting in 44 mi/hr

 

[Fragger]

NEMA 14-50 on a 40A line (at 240V) will charge about 25 mi/hr. If you wish to use that as your main overnight charging, it should do the trick.

The Tesla Wall Connector can accommodate up to a 60A input line (again at 220V) delivering 48A to your car, resulting in 44 mi/hr

Thanks Seth. But none of this is an exclusive benefit set up for the dual charging cars right? What would I need to consider if I was going to take advantage of that feature in the car? Thank you.

 

[Sandman1847]

You need a hpwc and a 100amp breaker that will deliver 80amps to the car. 80 amps at 240V is 19.2 kWh. Should be good for around 50 miles an hour. Or if you have a Usable battery of 70kwh it will take about 3.6 hours to charge from zero.

 

[BlueRocket]

I could be wrong but I thought I remember reading on this forum that Tesla capped the home charging speed such that the dual charger could no longer use current above 50 amps?? I may be thinking of limitations on the newer wall chargers.

 

[Sandman1847]

Gen 1 and gen 2 hpwc will deliver 80amps. Gen 3 will will deliver 48amps.

 

[Missile Toad]

I've got a Gen 2 WC, which is internally set to limit to 80A. However, it is on a sub-breaker box that supplies current to 12 or so circuits. The master breaker box has a 100A breaker... Long story short, the sub-breaker shares current to a wide array of home appliances and lighting. Consequently, if I charge above 71A, there is a high risk of that 100A breaker tripping.

The secret, is to set, on your car's console (Charging screen), an Amp limit below what your observations of breaker tripping behavior.

Incidentally, I swap use of the WC with my wife's X, which is capable of 72A charging. Here car also has a manually set amp-limit.

 

[murphyS90D]

My early 2016 car with dual chargers charges at 80 amps in my garage when I choose to set it that high.

 

[bob_p]

Our 2012 S P85 had dual chargers, connected to an HPWC that charged at 80A - and once Tesla deployed superchargers, we never needed to charge faster than 40A.

Our 2017 S 100D has the standard 48A and has hardware to support 72A (by purchasing a software upgrade), and we haven't found any need to charger faster than 48A.

Our 2018 X 100D can support 72A and is connected to an HPWC limited to 48A, and we haven't found any need to charger faster than that.

The reason why Tesla's latest home charging hardware is supporting lower amperage is because for home charging (primarily overnight) usually won't benefit from faster charging speeds, and Tesla can reduce the cost of the equipment by capping the charging at lower amps.

 

[Sandman1847]

Ideally you would have at least 200 amp service to your house and you would run a 100amp breaker off the main panel and wire your hpwc to that.

Of course you want to run do a load test. It sounds fancy but it’s just a calculation. You can do some reading and figure out if your breaker box and electrical services can support a 100 amp breaker.

 

[Kandiru]

If you want long battery life charge at 40A (30A really nominal power). I too have dual chargers for total of 80A on my car for that unusual higher power J1772 outlet which I have yet to discover on my Appalachian travels.

If you are a physician or mortician or similar with unpredictable schedules, the 80A HPWC makes more sense.

That said beware of the Tesla you buy off a condo/HOA or rental yuppie who exclusively supercharges the car for lack of better. Count on significant range loss in time.

 

[Nosken]

I've got a Gen 2 WC, which is internally set to limit to 80A. However, it is on a sub-breaker box that supplies current to 12 or so circuits. The master breaker box has a 100A breaker... Long story short, the sub-breaker shares current to a wide array of home appliances and lighting. Consequently, if I charge above 71A, there is a high risk of that 100A breaker tripping.

The secret, is to set, on your car's console (Charging screen), an Amp limit below what your observations of breaker tripping behavior.

Incidentally, I swap use of the WC with my wife's X, which is capable of 72A charging. Here car also has a manually set amp-limit.

Sometimes updates can cancel in car charge settings.
Are you aware you can set the Output limit on the HPWC?
Gen 1 https://www.tesla.com/sites/default/files/blog_attachments/ms_hpwc_installation_guide.pdf

Gen 2 https://www.tesla.com/sites/default/files/downloads/wall_connector_installation_manual_80A_en_US.pdf

Gen 3 https://www.tesla.com/sites/default...ng/Gen3_WallConnector_Installation_Manual.pdf

 

[Sandman1847]

If you want long battery life charge at 40A (30A really nominal power). I too have dual chargers for total of 80A on my car for that unusual higher power J1772 outlet which I have yet to discover on my Appalachian travels.

If you are a physician or mortician or similar with unpredictable schedules, the 80A HPWC makes more sense.

That said beware of the Tesla you buy off a condo/HOA or rental yuppie who exclusively supercharges the car for lack of better. Count on significant range loss in time.

Is there any evidence that charging at 80amp causes damage? Or rather measurable damage? My hospital has 80 amp chargers so I charge at 80amps. Might change my behavior if there is damage.

 

[dk10438]

Is there any evidence that charging at 80amp causes damage? Or rather measurable damage? My hospital has 80 amp chargers so I charge at 80amps. Might change my behavior if there is damage.

no evidence that 80A charging would damage the battery and some would argue less damage since it spends less time charging v. 40A.

80A is something like 0.2 C for 100kwh battery so perfectly fine. Wish my hospital had 80A charging!

 

[animorph]

I charge at 72A with my 2017 Model X and Gen 2 HPWC on a 100A circuit. We have two Gen 2 HPWC's sharing the 100A circuit. That is a feature of the Gen 2 HPWC. With both cars charging at the same time they each get 40A.

I don't think I've ever needed the 72A charging speed. It might be better on a road trip if you had to use a destination charger, or share one at a destination. Or if you drive a lot and need to charge at home during the day. So while I was happy to have the capability (the X is our road trip car), it hasn't been super useful so far. I wouldn't spend extra money on a charging setup to get over 40A unless you have identified a need for it.

 

[SSedan]

AC charging is slow charging in Tesla's since it is 80amps of 240 or less. This is peanuts compared to supercharging. The suggestion otherwise is baseless and only made by folks who can't grasp context.

I would also argue those who say your daily needs should drive your charging hardware decisions are short sighted. I have a predicable schedule, a 15 mile round trip commute yet have several times been glad I installed a HCWC on a 100amp circuit.
I did so after a family emergency that came up while I was out of town caused me to rush home low on charge to offload the wife and kids and have to hit a supercharger 10minutes out of the way on the way to the hospital to meet my parents.
Since I have had a few cases where the 58miles per hour added came in handy. Going big on the circuit also allows for potential load sharing later as well. I would go as big as your supply allows, unless you are capped out at less than 40amps then I would upgrade service.

Said another way, if the electrician says 50amp breaker max then go with it. If you have room for more, do it, it shouldn't be much more money and you might just be surprised at when you find use for more speed especially since the old dual charger cars have had a lot of range and supercharging speed taken away.

 

[bob_p]

When our house was built, we had a 100A HPWC installed on one side of the garage and a 14-50 outlet installed on the other side, in case we purchased a second Tesla.

When we purchased the second Tesla, we installed the referral HPWC to replace the 14-50 outlet. The electrician reviewed the wiring and determined he could upgrade the breaker for that circuit from 50A to 60A, so we're now able to charge on that HPWC at 48A (the max when on a 60A circuit).

For almost all drivers, it's difficult to justify the expense of upgrading to a dual charger (for vehicles with the original 40A charger) or to a 72A charger (for vehicles with the 48A charger), because with overnight charging 40A or 48A is enough to recharge a vehicle overnight. Plus many owners only use the mobile connector that comes with their vehicles, which is limited to 40A (for the original connector) or 32A (with the newer connectors).

If there are at most a handful of times when the faster charging could be useful, that may not be enough to justify spending over $1K to upgrade the charger. At least that's what we decided with our 2017 S 100D, even though it has the 72A charger onboard, we couldn't justify spending over $1K to increase the charging rate from 48A to 72A.

 

[Shadious]

The best bang for your buck is using a gen1 UMC that charges at 40 amps on a 14-50 outlet. They can be had for about $200 here or on EBay, unless you have an older model S or X that came with them (like my 2014 P85DL).

 

[SSedan]

I advise folks should have a backup charging plan which might be a second UMC which is $300 vs the $500 for a wall connector. So a $200 difference there, BUT now you can skip the $70 premium 14-50 outlet and the savings of 3 wires vs. two offsets some of the cost to upsize wiring. If you are thoughtful the difference is nowhere near $1000.
The wire to run a 100amp circuit is like $2.60 a foot and the wire for a 50amp circuit isn't free...........

 

[nativespinner]

I have had my S for two years and have 45 mile round-trip to work and 40 amp charging has been fine. In those two years I have put 45k miles on the odometer.