A Quick Look at Tesla's Solar-Powered EV Charging Stations

As an EV user myself, I only go to a charging station (240V AC) to extend my range and get rid of 'range anxiety' . When people ask how far I can go in my MiEV I say up to 120 miles (60 mile s one way and 60 miles back after a full recharge in about 5 hours with 240V). They seem surprised. I have yet to pay for any charging station and I see it staying that way for years to come, if not forever. Why? Because the people who charge will always be at a disadvantage (except perhaps for a 'fast charge station') to those who charge for recharging your EV. Walgreens has made a huge step in providing EV charging stations in many of their stores. I spent $50 in one of their stores and they gave me maybe $.50 worth of electricity. They won big time. EV people are a nice captive market for any type of retailer that sells goods and services. After all you have to do something while your car charges and if you need a quick something you can just walk right in Walgreens and buy it. I predict you will start seeing EV charging stations at Walmart, Cosco, Sam's, major restaurant chains etc. coming to a store near you. However, there is nothing like coming home, plugging in your EV and charging it up with free solar energy. Now that is progress! Tesla should provide fee charging for any EV if they are smart. After all the electricity is free is you have a PV array putting in more power then you will ever use at that charging station. Now if only all those stores having EV charging stations had PV arrays on their building!

Just a matter of time before we start seeing the three stage SAE J1772 plugs. EV turnover is not that fast (yet) and as new models get introduced I believe they WILL have the SAE J1772 three way charger plugs. For example, I hope that the 2013 MiEV model has that three way plug and that it will be the standard on ALL EV moving forward! We will see what happens.

"agreed to introduce the "Combined Charging System" in mid-2012". Well not everything and everyone runs on a timely schedule. Even the best and brightest of of get behind now and them.

Let us have ONE standard and not confuse the general public. They are already confused enough!

SAE J1772 currently covers Level 2 AC charging only, < 20kW. Tesla's system is a DC Level 3 charger at ~ 90 kW.

There is an *effort* underway to adapt the SAE J1772 with the addition of very large new pins for DC Level 3, the "CCS". However, this effort has been bogged down for considerable time.

"agreed to introduce the "Combined Charging System" in mid-2012"

Oh they agreed, all the way back in May. It's late 2012, seen one yet? I haven't. No one has. Still waiting...

As I stated earlier, converting from Tesla's system to CCS requires nothing more than a new connector and a firmware change. Every other existing charger will need to do this as well - they don't have CCS either.

Muary

There is a standard in place already. Look up the SAE J1772 on the web. They introduced a new standard plug that will charge 120/240V and DC fast charge ALL IN ONE PLUG about a year ago. I believe it has now been "Seven car makers (Audi, BMW, Daimler, Ford, General Motors, Porsche and Volkswagen) have agreed to introduce the "Combined Charging System" in mid-2012". Now ALL EV makers need to adapt it and all will go much smoother for the EV industry INCLUDING TESLA.

There is NO reason this cannot at this time put that on their cars NOW and all future cars they make.

It is important that the EV industry have standard plugs and I see NO reason why the SAE J1772 cannot be the standard. WHo really cares what a plug looks like as long as one can charge the car from ANY charging station?

> Maury it wasn't the standard I was talking about it was > the exclusivity as they were only going to have the charging > stations for Teslas not any other EV Tesla S owners get free charges, there has been no comment otherwise. As the article noted: 'Though most EVs cannot charge at these stations' ...[because of the mechanical details]... 'it isn't clear whether future non-Tesla vehicles will be allowed to use these charging stations.' ...[which means the company hasn't said]... You can't draw any conclusion from this.

Maury it wasn't the standard I was talking about it was the exclusivity as they were only going to have the charging stations for Teslas not any other EV and last I checked the Roadster and a Ferrari were about the same price. There was a report that came out before the weekend on a Bio-battery that has the potential to put Ford ahead on the EV front as the startup company they are working with has passed the 1Kw per Kg mark and are working on a 3Kw unit. They have also begun testing of wireless passing charging using what they have coined the pillar system in Vancouver which uses a reciever in the vehicle to charge the battery and the transmitters in staggered street lights along a roadway. From the report tests are positive.

It is assumed most EV users will do their primary charging at their home or fleet garage, overnight (or whenever the vehicle is not used). These remote charging stations are for top-up, or extending range. They should be placed where the driver is/can be doing other things (workplace, shopping, rest-stop...) A lot of habits and assumptions associated with the combustion engine need to be dropped when considering life with EVs! :)

> that would be like saying that a shell station would only be
> able to serve Honda's or in comparison Ferarri's

Nope. There is no US standard for Level 3 fast charging now (look it up). Tesla got tired of waiting, so now they're trying to create the standard themselves. If a different standard were to emerge, they could adapt to it by changing the connector and uploading some new firmware.

> Firstly, as we all know, quick charge will only shorten the battery
> lifetime dynastically, it means increasing the cost of ownership.

Nope. The cells used in these cars are rated for high current. They have to be, so that the car can accelerate rapidly. Current use during acceleration is in the hundreds of Amps, far higher than what this charger is pushing.

> Second, although the charging time from 3hours or 6hours
> down to 30min is a big improvement, simple, it is still too long to wait.

A 30 minute stop every 4 hours? They call it "a quick snack".

If you think charging stations are expensive, you should check out the cost of gas pumps. I've worked in gas station construction - not only are pumps expensive but the infrastructure is extensive with gas, additive and electrical lines, fire precautions, venting of backfills etc. adding cost that would mostly be avoided in an EV charging station.

According to the item in the local paper (which covers the Tesla factory within its distribution range), the Supercharger stations will only charge the battery up to some %age of full charge (70%?), avoiding the reduced battery life effects mentioned in comment #4.

Tom,

Thanks for the correction. I think those DC fast charge stations cost about $5K-10K a pop just for the charging station. With a complete gas station look, I bet you are looking at $50K or more and that is without PV arrays.

YES! Charging stations are popping up all over the Denver area. The 110V stations are usually home owners, but 110V charging stations are basically worthless IMO because you gain only about 4 miles for every hour you charge. 240 is a whole different world.

There are only one 240 V public charging stations in Boulder, CO and many in the Denver area. I only need a few hours of 240V recharge when I go to Boulder and that is generally no problem after I am done shopping there. My range on my MiEV is easily 120 miles or more when I plan a trip where I plug in at a charging station for FREE!

Nothing wrong with charging stations as long as they are STANDARDIZED! That is the key IMO to more acceptance of EV's.

Ed Musk is a great guy, but not that wacky!

It is actually 100 Supercharger stations in the US by 2015. Thanks.

kvdavis- "the pumps at gas stations don't work without electricity and don't have back-up batteries for when the grid goes down" great point.

john-dangelo-175629- I agree about the need for public transit for long distances. Do you think charging stations may be something that we may see more of in suburban areas?

30 minute charging may seem long compared to a gas fill up, but wise owners will schedule breaks for lunch to coincide with charging, or for facilities at malls; it is hard to get in and out of shopping in a half hour, so the charging time is not an issue. Electric cars do require a higher degree of planning, but that does not seem like a big drawback considering the advantages of an EV.

100,000 charging stations by 2015. Possible, but highly unlikely. Maybe 10,000 is more realistic. I think that was misquoted by the poster. I drive an MiEV and thought I made a mistake by not getting a "fast charge option" and glad I did not. It seems to me that one of the greatest things the EV industry has done RIGHT is standardize the cord for EV on 120 and 240V AC. What they have not done yet is standardize the fast charging plugs. I am all for the next step in standardizing the 120/240/ J1772 plug to accommodate a standardized fast charge feature which they have done. Now all the EV companies have to do is ACCEPT IT.

What I think is sad is that Tesla seems to want to go out on their own and create their own fast charge plug (I may be wrong). In the Denver area I know of NO fast charge stations and I do not anticipate any for some time until they standardize what a fast charge plug looks like. My car has two charge ports, one is for fast charge, which is empty and the other for 120/240 V which is used all the time. I am glad to have the 120/24 ability. I use the 120 at the house and 240 when I juice up for free as a range extender with all one plug. TO me that is just a major breakthrough! My next EV I hope will have a standardized J1772 plug for 120/240 and fast charging stations, but we will see.

Some people will drive their EV for long distances, but to me the car of the future will have no need to ever travel really long distance s as in the past. WHy not? Because if we are smart we will have a nation wide system of high speed trains that will get us to places far faster than any EV ever could. Driving cars long distances in general will be a thing of the past and is an overhang from days of cheap gasoline and V8 engines.

Charging stations are truly over rated and may be a white elephant some day.

Cool .. literally. I know of one developer that double dips on commercial solar parking lots - 1)they make power, 2)they charge a premium for covered/shaded parking. For owners of certain production vehicles and vehicles with a retrofit, they have a plug-in to maintain air conditioning. Combining this with EV charging would make it a triple.
Many production vehicles (not EV) have a charging port which is used to support the battery against phantom loads during periods of storage. For a typical passenger car driven 40 miles a day, external charging during the work day could produce ~4% improvement in fuel economy and this will go up when micro-hybrid rolls out.

One thing that may make this charging time thing a discussion of the past is that Ultracapacitors and Supercapacitors are slowly inching there power levels up towards legacy lead acid battery capacity. Though they are still way behind at under 10%, when paired with a battery pack, they reduce the charging time, and increase the useful charge of a battery pack by taking the hard current surges which leaves the battery pack to sustain the speed. Therefore making each charge last longer.

As technology increases the Supercapacitor energy storage density, the need for batteries will go down and charge times will too. The main advantage is that the basic nature of a capacitor is that it can charge instantly. So a large density supercap can reduce the charge time significantly away from standard battery charge times.

Check out this article.
http://www.sciencedaily.com/releases/2012/07/120719103225.htm

Stuart, great clarification on how grid-tied solar works - regardless of what it's powering (in this case, EV charging stations). The solar system will be 'pushing' to the grid when it is generating power (sunny days). The EVs will be pulling from the grid when they are charging. As Stuart says, the sizing of the system is the way to assess its net clean-energy contribution, and at 2.5 Teslas a day, it works out. Tom Jackson, no battery pack necessary (and the CEO of Tesla may also not understand net-metered grid-tied solar). And wkb4447, the pumps at gas stations don't work without electricity and don't have back-up batteries for when the grid goes down, so there's parity there. Finally, mile-cheung, it is assumed most EV users will do their primary charging at their home or fleet garage, overnight (or whenever the vehicle is not used). Quick-charging is not the current intent for all charging - right, no one would wait 30 minutes to fuel their car! Some places of work are considering installing EV chargers, which would make those EVs with 40-mile ranges more reliable for commuters; other good places for quick-charging would be places such as highway rest stops, where a half-hour can be spent at the restaurants. Covered parking lots with solar can be designed to provide maintenance access from below. So - two good but different things here, EVs and solar. It is not immediately apparent even to smart folks like the ones on this board how the two technologies are optimally paired.

Musk must be smoking something. 100,000 charging stations in 3 years? It would take billions of $$$ to build that many and you would have to mobilize an army to build them.

In addition to not let other EVs charge there is not only short sighted, it won't make financial sense. You will need that extra revenue otherwise the entire cost of the stations will be borne by Tesla buyers only?

This guy has made blunders in the past and now I am thinking he is a little disconnected from reality.

The first thing to note is that this is a grid-tied system, with no storage. The PV modules feed on to the grid, and the car charges from the grid. Tesla claim that the solar panels more than offset the energy consumed by charging the cars over the course of a year.

If that is the case then they must have very low usage expectations for these charging stations...

The roof area of the charging station shown appears to provide about 30kW of PV, which in California would give about 100kWh of output per day on average. Each vehicle charge is ~40kWh. Therefore the yield from the PV array would only be sufficient energy to charge 2.5 vehicles per day. This equates to a 1.3% duty cycle for each of the four charging points shown.

Given that Tesla have only sold 255 cars to date, then that is probably a realistic number for now, but it doesn't appear to scale up very well. If they are successful I presume they will install more PV elsewhere to offset the energy consumed in the charging network, so they can continue to claim that the cars run on clean energy.

This article does not address this potential shortcoming of the system.

Two comments on the quick charging station. Firstly, as we all know, quick charge will only shorten the battery lifetime dynastically, it means increasing the cost of ownership. My guess all the deep cycle battery need to be replace within 1 year if we are doing 30min quick charge every day. Second, although the charging time from 3hours or 6hours down to 30min is a big improvement, simple, it is still too long to wait. I recently read some article, Japan is having a station which automatic change the whole battery bank within short time, the business model is renting the battery, personally, I think it is really make sense.

That is the dumbest thing I ever heard! that would be like saying that a shell station would only be able to serve Honda's or in comparison Ferarri's so if you can afford a Ferrari come and charge up. Fortunately the big three are thinking more along the lines of the average person as they will be releasing a 400 mile EV next year in the mid price range and Domo will be adding a charge lane for generalized rapid charge.

Though the stations are connected to the grid, I'd also assume that they must have battery banks (given the nature of "charging stations.")

Elon Musk, the CEO of Tesla, understands the issue you bring up:

"You can put solar panels at point of use... We need to pair that with energy storage in order to have 24 hour a day power. How to lower cost for batteries for grid storage is going to be important as well."

If they're "grid-tied", that means that if the grid goes down, so do the stations, unless Tesla has figured out some way to avoid that problem at least for day-time users. Battery would have to be part of the design to keep this up and running during local grid failure which would make for a much more costly and higher maintenance station.