Thoughts about next-gen EVs, Charging

[pbui19]

there is a CHAdeMo to Tesla adaptor, expensive though $450:

http://shop.teslamotors.com/collections/model-s-charging-adapters/products/chademo-adapter

 

[PV1]

That, but the other way around, so an i-MiEV can plug into a Supercharger.

And no, a Supercharger will not blow up an i-MiEV battery like people seem to think. Like CHAdeMO, the car dictates voltage and amperage parameters. Basically, the car tells the charger max voltage and what current to push at each moment.

 

[wmcbrine]

And no, a Supercharger will not blow up an i-MiEV battery like people seem to think.

Elon himself seemed to be spreading a bit of FUD on this:

"The intent of the Supercharger network is not to create a walled garden. Any other manufacturer that's interested in using them, we'd be happy to accommodate. It's just that they need to be able to accept the power level of the Superchargers, which is currently 135kW and rising, so any car needs to meet the Supercharger standard. And they'd also need to agree with the business model, which is we don't charge people on a per-charge basis. They'd need to contribute to the capital costs proportional to their fleet's usage of the network." -- http://www.engadget.com/2014/06/09/tesla-to-share-supercharger-patents/

Of course the "business model" thing is the real issue.

 

[PV1]

So, if it's not pay per kWh or per charge, how do they plan on access being affordable? Is it a one time fee (like the enable option on the Model S) or setup more like a membership (yearly dues to be a part of the network)?

I'm not sure why he phrased it like that. Maybe he wants the cars to be able to pull 100 kW? The LEAF can momentarily take more than the 50 kW CHAdeMO puts out until the battery voltage hits the limit and switches to constant voltage charging. Both the LEAF and i-MiEV will fully charge in about an hour on DCQC.

 

[wmcbrine]

So, if it's not pay per kWh or per charge, how do they plan on access being affordable?

He said that he wants the manufacturers to pay. How and whether they pass that cost on to their customers would be up to them, presumably.

Personally, I'd like to see Tesla bypass the manufacturers. The one-time fee was, what, $2000? And they sell a CHAdeMO-to-Tesla adapter for $450. So, sell a Tesla-to-CHAdeMO adapter for $2450, complete with access rights to Superchargers. But, I'm not sure how many people would go for that. Those prices are easier to swallow when you're already paying $70000+ for the car.

 

[pbui19]

So can JoePublic with the appropriate adaptor use the Tesla supercharging station now ?

just because the station can supply 135kw, the charger doesn't need to pull that rate.

 

[PV1]

Before, it was thought that the charger authenticated the car by checking the VIN against a database, but after some investigation, owners found that the car told the station whether or not it was allowed to charge.

So, with the appropriate signalling and a custom adapter, Supercharging another car may be possible, but it depends on if the SC does any online verification.

just because the station can supply 135kw, the charger doesn't need to pull that rate.

Exactly. Just like if you start a CHAdeMO charge on an i-MiEV when near full charge. The QC can push 50 kW, but that doesn't mean it will in all circumstances. Likewise, an SC to CHAdeMO adapter would start the Supercharger at 50 kW and ramp down as full charge is approached, basically acting as a protocol translator (it talks to the car over CHAdeMO protocol, and translates and uses SC protocol to talk to the Supercharger).

 

[PV1]

Does anyone have experience using the SAE Combo plug? How does it compare to CHAdeMO?

Also, what are your opinions of the Chargepoint network and their units?

 

[PV1]

My post on TMC about plugs:

True. It's the SC access that people want, not so much the HPWC.

Ultimately, the standard charging network needs standardized and built out. I've been thinking a lot about this lately, and I would say that standardizing on ChargePoint's equipment would be a great start. There are currently at least 5 charging networks. The ones I know of are:

1. NRG EVGo
2. Semaconnect
3. Greenlots
4. ChargePoint
5. Aerovironment

Of the ones that I've researched, ChargePoint has the most equipment on the ground. Their equipment also has the best appearance, with the level 2 stations having automatic cord management, meaning the cords never touch the ground and stay clean, and their Express 200 has some awesome lighting (picture attached. There is another picture on PlugShare showing this unit at night, and they do a good job of lighting up the area around the unit). They also support reservations and recently released their Waiting List feature, which will allow drivers to queue their spot receive a notification when a port opens up (when someone using the station returns and unplugs their car and leaves). Also, being networked units, station availability is shown real-time in the app and on the website. One doesn't have to gamble on station availability like with non-networked stations.

Of course, this will all likely be based on J1772/CCS, as these are the "official standard" connectors. This keeps Tesla's network open for their cars, and it lines up with their goal to have a full, non-Tesla specific network built out, though it won't be built by the automakers outside of the dealers. This will still totally rely on 3rd parties, because you know mainstream buyers aren't going to park at a dealer and walk to their destination. Some early adopters don't even like doing this, and some of us have been chased off by dealers (including myself, but luckily the quick charger was faster than the salesman).

Building out a CCS network will end up supporting more cars down the road than CHAdeMO. Currently, only the LEAF, i-MiEV, and Soul EV natively support CHAdeMO. However, the i3, eGolf, Spark EV, Bolt, and the future Focus Electric all have CCS. Even though the LEAF is the most popular non-Tesla EV, I am starting to see a lot of i3s on the road. And yes, even though I drive a CHAdeMO car, it'll also screw me out of a lot of charging possibilities.

Post also includes the following pictures:

https://www.dropbox.com/s/0jk9zbwtqmbbee7/Chargepoint%20DCQC.jpg?dl=0
https://www.dropbox.com/s/6iekxnh88tyqzgm/82052.jpg?dl=0

 

[jray3]

[
Elon himself seemed to be spreading a bit of FUD on this:
"...It's just that they need to be able to accept the power level of the Superchargers, which is currently 135kW and rising, so any car needs to meet the Supercharger standard. ." -- http://www.engadget.com/2014/06/09/tesla-to-share-supercharger-patents/.

I take this to be a defensive move against Supercharging Squatters. If the Supercharger won't engage low-power packs, and furthermore, shuts down when a car is no longer accepting super current levels, that preserves supercharging capacity, pushing L2 charging rates back onto L2 equipment. Nissan's allowing a LEAF to stay on CHAdeMO to 100% has caused a lot of conflict between EV drivers. Since the iMiEV shuts down CHAdeMO at 80% and won't go below 5 amps even on a 'double-pump', that ensures against squatting on a CHAdeMO station for just a finishing charge. Manufacturers need to enforce usage standards to make the system more useable for all of their customers, rather than allowing a selfish/ignorant few to muck it up.

 

[tigger19687]

Now see I GET what Elon is saying. Why should he ALTER the SC's for others? What you are asking is like saying that all the Chedemo's should ALSO charge at L2. BTW, He offered to give other manufacturers the stuff on the SC and everything else, they said no. Mainly because they don't WANT EV's ! But that is another story.

I also wish that the 'i' would charge to 100% fast. That saves me from stopping all the time on a long trip. Would I do that if I was not going on a long long trip? Hell no, there would be no need. Not to mention I would be sitting there doing nothing and waiting.....

There wouldn't be such an issue with users filling up 100% if there were MORE CHARGERS. THAT is the real issue here, if there were more chargers there wouldn't be 1/2 the issues.
Also consider that there are people that are just in it for themselves. The ones that will just NOT EVER have any EV Etiquette... like the new C-max driver at my work that thinks someone else should UNPLUG because she is not there! :roll:

 

[JoeS]

...I also wish that the 'i' would charge to 100% fast. That saves me from stopping all the time on a long trip....

By the time the i-MiEV is charged to 80% using CHAdeMO, the charge rate is waaay down anyway as the pack is already at 360v and the absorption current is dramatically reduced and thus the remaining time to 100% would be little-better than L2. What I do when I want 100% charge when CHAdeMO is 'done' is to simply move over and finish charging using L2 for about 45 minutes.

Back on topic, as now a Tesla owner spoiled rotten on long trips by the incredible (really incredible!) SuperCharger rate into my 85kWh pack and the already-busy SuperCharger stations, I would not be happy to see an i-MiEV sitting there and taking the same amount of time (as a Tesla) to charge it's 16kWh battery because it cannot charge faster - you simply cannot stuff high amounts of current into the battery pack for more than a few initial minutes because when the pack voltage gets to 360vdc the charger goes into current limiting. Recall, when charging the initial current is constrained by dc charger capacity (constant-current mode), but as soon as the battery gets to 360v then it cuts back the current while holding 360vdc constant (absorption mode).

 

[PV1]

Even a "double pump" on CHAdeMO will charge the top 20% faster than level 2. I've seen some conflicting observations on how CHAdeMO works. There are some quick chargers in Maryland that reportedly charge straight to 100% without stopping at 80%, but I still haven't figured out if it is the car or the charger that triggers the stop at 80%. I started a QC once at 75% and the i-MiEV went straight to 100%.

I don't think anyone has mentioned altering Superchargers, but simply pointing out how long the top 20% of charge takes woulddiscourages people from sitting on high power equipment longer than necessary. Yes, there are times when I will sit on a CHAdeMO unit for a full hour to get to 100%, but that is because I use nearly a full charge to get home from that location. I have yet to have someone else pull up wanting a CHAdeMO charge while I'm there. If somebody does one day, I'll move over to level 2 to continue charging and let the next person burst charge to 80%.

But, if the i-MiEV is to charge faster near the top on DCQC, it would need to allow the cell voltages to rise above 4.11 volts. If it would allow the cells to go to 4.2 volts while taking a charge and stop at 99% SoC, the i-MiEV would probably take a full CHAdeMO recharge in 40 minutes instead of an hour.

Every time I think about the current mess (pun intended ) , I get a different feeling. From my everyday usage of my EV, I almost never use public infrastructure, and when I do, the 3.3 kW charge rate works just fine. But, I think of the future and which standards and charging techniques would work best with whatever the grid of the future may be. It seems that more and more folks that are installing solar are wanting batteries. The transmission style that works best with variable renewable energy sources is DC because the grid could be directly coupled to large battery banks with energy sources providing power to the battery banks (picture a typical off-grid PV system, but grid-scale, where the PV charges the batteries, and the loads run from the batteries). With this, I tend to imagine the future of EVs being totally DC power transfer, with the on-board charger being relegated to emergency use only. CHAdeMO has been proven in Japan to be able to send HVDC both to and from the vehicle's battery (Mitsubishi's M-Tech Labo and the MiEV Powerbox). I don't know if either SAE CCS or Tesla's TSL02 protocols support this.

The reason I feel bi-directional DC power flow is important is that I picture future homes having their own "micro-grid", where RE sources charge battery banks and run the house directly most of the time, with the home only falling back to grid power for power assist or to send out excess power. The grid itself would run on DC, and based on what I've heard from some folks in the industry, it seems that 380 VDC is the preferred nominal voltage. Regional grids connect multiple houses with central battery banks (the grid voltage is actually the terminal voltage of these large-scale batteries, which may or may not have some central RE generation equipment), and these regional grids can be connected by an ultra-high voltage backbone, which allows long distance inter-regional power sharing. But, the bi-directional power for EVs comes into play at the home. The homeowner could plug their EV in and use its battery in parallel with the dedicated home battery. In most circumstances, this would keep the EV's pack around 90% charge, and a 20 minute heads up to the system would allow the car to fully charge if necessary (I picture a button on the system's control pad to Prepare for Car Usage). Otherwise, the homeowner could simply just unplug the car when they leave and the system automatically disconnects from the car's battery when the connector is removed (similar behavior to how J1772 shuts down the charger when the button is pressed on the connector). The button to prepare the car would only be necessary if the car needed a full charge or was to be used again in a short period of time after returning with a low charge level. When this button is pressed, the system diverts excess generation to the car and, depending on the SoC of the house pack, uses energy from the house pack to rapidly recharge the car. If there isn't enough energy at the home to charge the car in a short period of time, then the system draws power from the grid to recharge the car. The car becomes part of the home micro-grid instead of a simple energy consumer.

So, how does a fully DC system fit into public charging? The Model S is soon to have a 100 kWh battery (currently offers up to 90 kWh). The max power output covered under the J1772 spec is 19.2 kW, which takes 5 hours to recharge a Model S, but nearly all charging stations only output 30-40 amps, which is 6.2 - 8.3 kW, which would take more than 10 hours to fully recharge (the current Bolt EV configuration takes 9+ hours to fully recharge on AC power). Tesla Superchargers are continuously improving and currently max out at 135 kW. CHAdeMO will handle 60 kW, and CCS is said to support 90 kW. While we do need more charging equipment, that equipment is going to need to have higher power outputs to satisfy the folks who can't think outside the "Gas Station Mindset". Is the AC grid going to be stable enough to handle a few million cars randomly pulling 50-140 kW each on top of the every day demand? Most likely, as there haven't been many if any instances where an EV causes a brownout/blackout, but the grid is in desperate need of an overhaul, much like the rest of the infrastructure in the US. I picture the electricity infrastructure becoming a tiered DC system, with redundancy down to the individual building. Each home and building can function on its own, but all buildings in a region are connected and can act as one, and each region is connected and makes up the entire electrical grid. Under this new structure, should something like a substation fail, it won't darken a region, but the buildings just lose their ability to share power and continue to run independently. Family members could use their EVs as mobile power sources in emergency situations (see here: http://www.nytimes.com/2011/05/08/automobiles/08JAPAN.html?_r=2&emc=eta1). But, this tiered system also applies to public charging locations, with quick chargers being battery-based so a steady current is drawn from the grid and not slammed with 100 kW each time a car is plugged in. With a solar canopy and a wind turbine, even the public chargers can operate independently if the grid goes down.

**If you don't want to read the wall of text above, here are the highlights:

1. EVs evolve to have Bi-directional DC power as the primary connection, for both charging and mobile power source.
2. A tiered, DC grid to allow redundancy down to the building level, so a failure of the grid doesn't darken houses and buildings. Each building is a micro-grid, a bunch of buildings make up a regional grid, and a bunch of regional grids make up the national grid.
3. The EV becomes part of the house power system to allow rapid recharge and providing extra battery capacity for the house (see here for a similar concept done by Mitsubishi: https://www.youtube.com/watch?v=RTNM61W9lVU M-Tech Labo at 2:35).
4. Massive expansion of a DC EV charging network using whichever connector ends up fitting the bill to support rapid charging of a very large number of EVs, with these stations also having their own battery-based RE system for the same benefits as #2.

 

[Phximiev]

That's informative and the video new to me. I did note at roughly 2:12 into the clip that Mitsubishi showed their Ductless Heating and Cooling System, something that I have been looking at and available through Home Depot, see: http://www.mitsubishicomfort.com

Its supposed to be much more efficient than the current central heating and AC system that we have now.

Anyone have any experience with it?

 

[ed5000]

So, how does a fully DC system fit into public charging?

DC would be great. It would just flow right into our batteries without a charger as long as we have the right voltage (i.e. 380vdc). Come to think of it the only thing that runs on AC without any specialized equipment are simple AC motors, resistance heating, and incandescent lamps and even at that, the last two items run on DC as well. Everything else requires power supplies, ac to dc converters, rectifiers, etc.

I'm a believer of solar charging an i-miev through the CHAdeMO port. At least I think it could be done. It would require a string of panels set up in series with an Arduino board to close the i-miev's CHAdeMO contactor and to monitor voltage. Of course we would have to wake up the bms too but, without that you could at least charge to something like 80% and switch to the on board AC charger for a finish charge. It would be beautiful and much more efficient.

 

[PV1]

I've seen Mitsubishi's Mr. Slim ceiling mounted units at the local ice cream parlor, and they work very well (always frigid inside even on the hottest days). Other Mitsubishi systems I've seen also run very quietly.

Here's one that's super-efficient and runs on DC power. I don't know how reputable the brand is, but I like their concept.
http://www.hotspotenergy.com/DC-air-conditioner/

They also have systems to capture waste heat from your AC and either heat a pool or your domestic hot water.

I was hoping that my previous post made sense. I didn't have time after writing it to proof it. It would be really nice if our cars already contain the necessary code to allow a device such as the MiEV Powerbox to be used with the car. Charging from a DC power source would still require circuitry to limit current, but it would be a simple PWM and not have to switch between AC and DC 4 times like our on-board chargers do (incoming AC -> DC -> AC -> DC output).

 

[Phximiev]

Do you suppose the Ductless Mitsu folks talked to the iMiev design folks about the heating and
AC system in the 'Miev before Mitsu brought the car to market?

It would seem to make sense given the power draw of those systems and the need for a super efficient heat pump.

 

[jray3]

Do you suppose the Ductless Mitsu folks talked to the iMiev design folks about the heating and
AC system in the 'Miev before Mitsu brought the car to market?

It would seem to make sense given the power draw of those systems and the need for a super efficient heat pump.

It would've made sense, but instead we got an electric 'boiler' and a cooling-only compressor system. I've seen good results with MR SLIM mini-split air conditioning units for cooling computer server rooms, even in one instance where it was poorly designed (undersized with very long refrigerant lines).

 

[PV1]

Another thing that needs improvement, station reliability. I'm currently sipping on level 2 because a QC is broken. My fault for skipping a quick charger several miles back. :evil: :roll: