Lv2 DC charge stations instead of AC?

[NissanLeafCamper]

I was wondering if it is only possible to DC charge the leaf batteries @ CHAdeMO speeds, or if one could charge at other DC speeds? I'm just wondering why there could not be say lv2 DC charge stations? I understand AC is more readily available, but would you be able to charge LV2 speeds @ DC? Are there any limits? :?:

 

[cwerdna]

http://www.teslamotorsclub.com/showthread.php/42176-CHAdeMO-Make-Model-Review-%C2%97-Using-with-a-Tesla/page16?p=961564&viewfull=1#post961564
http://www.teslamotorsclub.com/showthread.php/42176-CHAdeMO-Make-Model-Review-%C2%97-Using-with-a-Tesla/page16?p=971287&viewfull=1#post971287

 

[arnis]

There is no such thing like DC speed. Either you feed AC to vehicles onboard charger or you feed
DC to vehicle using offboard charger (lvl3 charging station). DC speed can be anything up to 50kW.
Charger with ChaDeMo plug and protocol costs A LOT. It won't make sense at speeds below 20kW.
Leaf onboard charger supports up to 7,2kW speed.

 

[cwerdna]

There is no such thing like DC speed. Either you feed AC to vehicles onboard charger or you feed
DC to vehicle using offboard charger (lvl3 charging station). DC speed can be anything up to 50kW.
Charger with ChaDeMo plug and protocol costs A LOT. It won't make sense at speeds below 20kW.
Leaf onboard charger supports up to 7,2kW speed.

Agree w/basically most of the above. Leaf's OBC only supports up to 6.6 kW from the wall.

Our power grid is AC, not DC. When charging at L1 or L2, the car's on-board charger's responsible for the AC to DC conversion and converting the voltage to the appropriate levels.

If you had a low wattage CHAdeMO charger, well, the above is being done by the external unit and it seems redundant and fairly dumb (if you ask me) to install an expensive unit w/a very expensive connector to do what the car's OBC does at the same power levels. And, not all Leafs have CHAdeMO inlet. And, of the installed base of most EVs and PHEVs, excluding Teslas, most of them cannot be DC charged anyway. (I can't think of a single PHEV sold in the US that can be DC charged. Most models of EVs sold in the US also can't be DC charged) They have no connector. So, it seems pointless. Better to install J1772 L2 stations that can be used by all.

 

[NissanLeafCamper]

Wow 10kW CHAdeMO chargers I would have never thought of that and also the 6kW chargers are Leaf-to-home units with CHAdeMO, installed both for electric car charging and for emergencies. That is pretty cool!

Sad to hear the EQ is expensive to install I was thinking 'Solar Panels' but the amount of panels you'd need for a CHAdeMO unit would be huge. Plus you'd need some storage for the energy so it doesn't go to waste and the charge could hopefully work at night (If it had a large enough field covered in panels for a large supply.)

 

[cwerdna]

^^^
Re: costs, some links at http://www.mychevysparkev.com/forum/viewtopic.php?f=7&t=3753 might be insightful.

 

[miscrms]

I've thought a bit about this as I'm interested in the possibility of charging a Leaf from a Prius for remote charging.

It _may_ be possible to charge L1/L2 from a DC source but it won't be any faster than charging from AC. You will still be limited by the current capacity of the wiring to the charger, and the power output limit of the on board charger (3 or 6 kW depending on your Leaf). And your DC source will have to be stable, in the window of what the charger expects to see after rectification, and capable of delivering the current the on board charger expects to be able to pull.

There are ways you could get direct DC in and bypass the onboard charger limit, but you will need an external charger not just an EVSE like device. That will either require a CHAdeMO setup (Leaf w/QC and a compatible charger and controller) or hacking your Leaf to add a direct DC input (and a charger, controller, and probably some CAN spoofing). Either is expensive, but feasible. Using CHAdeMO will be more expensive but take less hacking, direct DC will be a bit cheaper but take much more hacking.

If you want to charge from solar by far the most straightforward thing to do is use a grid-tie inverter to put power into the grid, and then charge from the grid using AC either at the same time or some other time. Even if you have an off grid system, it will still be much simpler to use an AC inverter even though there are some efficiency penalties. In theory you could use solar to charge direct from DC, but you would still need a high power charge controller as in either of the above approaches. There is no way to directly feed the DC from a solar array into the battery safely. You need a charger to supply the right voltage / current to the battery under a wide variety of solar output voltage/current conditions, and to load the solar array appropriately for decent efficiency. A poorly designed dc:dc system could easily be less efficient than a dc:ac:dc system with proper max power point tracking.

Rob

 

[fooljoe]

I'm not aware of any lower limit on CHAdeMO (or other DCQC) charging speed. CHAdeMO chargers slow down to L2-like speeds as your battery gets topped off, so why shouldn't they be able to charge at those low rates all the time? There's a CHAdeMO charger set up near Joshua Tree that's fed by a large solar array and I believe the power it charges at fluctuates along with the solar production. And its max rate is 20 kW, which is within the L2 range.

While the points explaining why public CHAdeMO stations at L2 speeds don't in general make much sense are valid, having a "personal size" CHAdeMO charger could make sense for some, if the connector and other required components weren't so friggin expensive. For example, if you only have the 3.8 kW charger but spend a lot of time charging at RV parks, it'd be great to be able so suck down the full 10 kW available.

Also if you have a failed internal charger you might want to invest in something like this instead of an expensive charger replacement, and get more for your money, as you could crank up the charge to perhaps 20 kW if your home's power supply is capable. I don't know if our on board chargers "wear out" from lots of use, but if someone thought that was a concern he could use a solution like this to bypass the onboard charger and "preserve" it. In theory at least it should be much easier to service a charger located outside of the car than one on-board.

 

[XeonPony]

Out here all the L2 chargers tend to be 70 amp, so for me a small 15Kw dc fast charger would be a perfect go between to charge at full rate, go from 4h in winter to a meer 2h! is a huge bonuse for quick turn arounds in the shitty,,, oops some call them cities.