Model S/X dual connectors for dual chargers?

[CroDriver]

I think a symmetrical charge port on the opposite side of the car as an option would be brilliant. This would make combining sources possible without going around safety protocols.

Something like this...?

You can do it, but it is not so easy to do as it seems - it requires a lot of additional hardware and some software which increases cost, complexity and weight.

 

[Kipernicus]

When there is no sign, I think the general protocol is that whoever gets there first gets the station until they come back and unplug--which really stinks if you are the newcomer and you have no way of knowing how long your wait will be, or if the car sitting there really needs the charge or not.

This is the sort of thing that my wife (and possibly kids) would not tolerate and would earn me a big "told you so". While the infrastructure should continue to improve, at the same time there will be more and more EVs on the road using them up.

I think it would be brilliant to have dual connectors to take advantage of unused charging stations, but given CroDriver's post I'm not holding my breath that Tesla will implement it.

 

[RDoc]

Something like this...?
You can do it, but it is not so easy to do as it seems - it requires a lot of additional hardware and some software which increases cost, complexity and weight.

If the car already has two chargers I don't see where any great increase in cost or complexity would come from. Almost all the cost would be in the power electronics for the charger which is in the price of the dual chargers. The connector and wiring aren't particularly expensive items, although the hidden connector under the light might add a bit. There must already be software to coordinate the two chargers, so that doesn't seem particularly difficult. Again, with the second charger in place, where would any weight more than a kg or two come from?

 

[TEG]

Tom & Cathy Saxton found out that the SOC displayed by CHAdeMO stations is way off. Read here:
Quick Chargers: Ignore The Charge Percent! - Tom Saxton's Blog
So even in advanced DC QC stations that have a complicated protocol, lots of control electronics, and a display, they get it wrong.
And what about sharing a NEMA 14-50?

Some discussions have theorized that the CHAdeMO charger simply displays the SOC that the car tells it, and that the car (e.g., LEAF) intentionally "lies" about the SOC to control the charging. For instance, the LEAF internally may say that the car is 80% full, but then tell the charger that the car is purportedly 90% full so that the algorithms in the charger start to slow down the current. We still don't have all the answers, but it seems (via CHAdeMO protocol) the car and charger do some sort of "song and dance" where the car plays games with the SOC reports to influence the charging in an effort to reduce battery heating. We also have cases where someone starts a CHAdeMO session at very low SOC and it shuts off after 30 minutes even though the user requested to charge all the way to 100%. We are a bit off topic for this topic, but I wanted to point out that those seemingly erroneous SOC reports seem limited to what CHAdeMO stations are showing. Charging from J1772 (or even Tesla plug), I think the car itself could offer a much more accurate representation of "fullness" and remaining time before the charging session is complete (and when the cable could be offered to someone else.)

 

[CroDriver]

If the car already has two chargers I don't see where any great increase in cost or complexity would come from. Almost all the cost would be in the power electronics for the charger which is in the price of the dual chargers. The connector and wiring aren't particularly expensive items, although the hidden connector under the light might add a bit. There must already be software to coordinate the two chargers, so that doesn't seem particularly difficult. Again, with the second charger in place, where would any weight more than a kg or two come from?

That is true if only one charger is always connected to one port.

If you want to make it possible that both chargers share the current from one port (as the Model S is doing now [I believe] when using a high-current source), and that each charger can run on its own port when both are plugged-in, you will need additional hardware.

 

[TEG]

Yeah, that is what I was envisioning... It would need to be able to run like in "series" or "parallel" (well more appropriately "joined" or "separate" inputs), depending if you found (for instance) one 70A plug, or 2 30A plugs. I imagine it would need some sort of relay/"contactor" mechanism to reroute the input current depending on which configuration was desired at the time.

Now sure how you did it with Concept-One, but I gather you could route the power based on which port flaps were open. If only one port is open then the AC would go to both chargers in parallel. If both port flaps were open then you could separate the AC wiring and have each port go to a separate charger.

Not sure if there would be any special consideration for both chargers to "coordinate" on charging in unison. Would it be OK for one to operate at 16A while the other operates at 30A for instance?
I gather the current Model S arrangement operates both chargers in parallel using the same parameters. Currently, input voltage would be basically identical. You could just divide ampacity in half. If you did "split chargers" would it cause a problem if the voltage of one plug was different from the other? (Say you got 240V on one side, and 208V on the other?) Hopefully the charger modules would be flexible enough to deal with different inputs all on their own, and be able to both charge together to the same pack in parallel (output) without issue.

Note, my mention of specific volts and amps is somewhat North-America centric, but I gather those used to European power standards can still relate to the concepts.

 

[RDoc]

That is true if only one charger is always connected to one port.

If you want to make it possible that both chargers share the current from one port (as the Model S is doing now [I believe] when using a high-current source), and that each charger can run on its own port when both are plugged-in, you will need additional hardware.

Certainly, but it would just be two relays wouldn't it? There already are disconnect relays with the chargers, so I'd think all that would be needed would be two more to allow cross connecting the plug ports.

 

[jkirkebo]

Certainly, but it would just be two relays wouldn't it? There already are disconnect relays with the chargers, so I'd think all that would be needed would be two more to allow cross connecting the plug ports.

One relay could be enough. Charger 1 could always be connected to the driver side port while Charger 2 could switch between passenger side port and driver side port by a relay (not a on/off relay, but A/B-type).

Passenger side port would then be limited to 40A. Not a big deal I think.

 

[arg]

All of this assumes that the chargers are isolating (eg. by containing a transformer).

They might be, but I wouldn't count on it. The alternative - that one side of the battery is 'hot' to the mains during charging - would mean that exactly the same problems would apply here as with the other suggestions for paralleling up multiple outlets to feed the existing single charge port.