Model S

Every New Tesla Owner’s Dilemma: Dual Chargers vs High Power Wall Connector (HPWC)

An analysis of the HPWC and Dual Charger options for charging the Tesla Model S.

When you purchase a car, you typically buy what’s on the lot and it’s either fully loaded or stripped down with the bare necessities. Custom orders are few and far between. With Tesla you almost always end up configuring the vehicle to your exact specifications. While they do have inventory cars for immediate sale, they’re often used vehicles with a previous life as a service loaner or test drive vehicle.

There are really 3 kinds of buyers for the Model S when it comes to options:

  1. Those who opt for every available option and price is not a factor.
  2. Those that go for the bare minimum options and stretch their budgets in order to get into the car. These are the owners with the stripped down Model S 60 kWh’s (or even 40’s!) with no Tech package etc.
  3. Those that are in between and select only those options that they really need in order to save money.

If you’re in category 3 then read on.

Tesla High Power Wall Connector (HPWC)

Two points that need to be considered when ordering a Tesla Model S is whether or not the High Power Wall Connector (HPWC) is really for you; a $1,200 option that provides two times the charging rate of the standard option.

The second point to consider is whether you want the on-board dual chargers,

another $1,500 option which allows twice the conversion capacity as the single charger when the power is available.

Originally the HPWC and Dual Chargers were a single option around $3,000 and later on Tesla split the options out. Why they did that is interesting and indicates that there maybe a reason for having dual chargers without the HPWC.

Also see: Should You Leave Your Tesla Universal Mobile Connector (UMC) Plugged In?

I drive a lot: 35K miles per year. Other than a relative who’s a full time truck driver, I drive more than anyone I know. I plan on driving my Tesla just as much. On a daily basis I range from 90 miles to 175 miles in a given day just based on my usual pattern of family shuttling and commuting.

Do you really need the Tesla High Power Wall Connector (HPWC)?

Tesla has a good charging speed calculator on their site. If you take a conservative 200 miles per day and charge on the “standard recommended” home adapter through a NEMA 14-50 outlet, you can replenish the battery capacity in 6 hours 48 minutes. This measure of time is somewhat misleading as Tesla tends to provide “best” numbers and, unlike an ICE car, charging from an empty battery state is faster than charging from 20% left. Assuming you don’t arrive home with 0 miles left, the time to charge could be a bit longer. Most people I know, once home from work, are there for a minimum of 8 hours thereby giving them a significant amount of time to charge up. While Tesla recommends the HPWC for anyone regularly driving over 100 miles a day, I think the guidance is incorrect and the HPWC is not needed for the most part.

That being said, there are possible edge cases where it could be needed:

  • On-call type people that can come and go from the charge location with few hours each time and long times away from the charger. Doctors and other professions like that should carefully consider their patterns.
  • People that can take advantage of time-of-use metering (discounted off-peak electricity rates) from their electricity provider. Here in Massachusetts you have to consume at least 2,500 kWh per month over a 12 month period to qualify and generally this doesn’t work for homeowners even with high energy consumption. My utilization can run as high as 2,296 kWh/month but this still wouldn’t qualify.
  • The HPWC is one way to get a second charging cable. It’s not the most efficient way since a second mobile connector is just over half the price, so you’re better off buying that second mobile connector and leaving it connected in the garage.
  • It’s for a business or public use environment. Here people need to come and go as fast as possible. Whether that’s your business or you decided to share your power via PlugShare or the like, then you’ll want to provide the fastest charge possible to get people moving on.

So you don’t need the HPWC. Also don’t forget that the HPWC requires a lot more power and will likely cost more to install than a standard NEMA 14-50. A NEMA 14-50 home installation can run between $1,000-$1,500 but this varies greatly depending on the distance that power lines needs to be pulled and the underlying power supply/infrastructure of your home set up.  I was fortunate enough to have mine installed at $675 since, apparently, my infrastructure didn’t require too much of an upgrade.

Tesla Dual Chargers

Tesla-Dual-Charger

If you don’t purchase the HPWC option do you really need dual chargers? Personally, unless you never plan on taking an extended road trip or don’t care about future proofing you car, the on board dual chargers could provide some tremdous value.  It’s this very same reason why I modified my order at the last minute and added the dual charger option.

At home using a NEMA 14-50 or on the road using only the Tesla Superchargers network (ie, epic 12,000 mile Tesla road trip) you wouldn’t need dual chargers. The dual chargers provides no benefit in each of those scenarios.

However, by having the dual chargers, you’d be able to take advantage of several fast charge options out there while future-proofing your vehicle as public charging technology advances.

  • Publicly available HPWC’s out there like those at a Tesla Store or Tesla Service Center or those shared by homeowners and businesses which will grow over time. To take advantage of max charge rates on these you need dual chargers. Not all HPWCs provide more than 40A though.
  • Public EV Plugs (J1772) can go up to 70A. The number of these that are over 40A is very limited today but that is rapidly changing. To take advantage of max charge rates on these you need dual chargers.
  • CHAdeMO outlets  offer higher speed charging for those that can take advantage of them. Tesla has been promising an adapter for a while but has yet to deliver.

While dual chargers are an extra cost on top of an already expensive car, at roughly 1% of the cost of the car and potentially saving hours of frustrating wait time, I think the decision to get dual chargers is a no-brainer and provides some future proofing for the car. HPWC likely always an unnecessary expense.

Thoughts/comments? Would love to hear from you.

 

 

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