Mini-QC Rapid-Charger (RC) Project for LEAF QC Port

[MPaulHolmes]

Quite amazing work - that seems so straight-forward, but definitely is not.

Do you believe it is possible to DC/QC an EV using a typical home based PV systems (say 5 to 10 KW) with minimal/no "battery backup". I realize its not actually "QC", but would seem to be much more efficient than using the Level II charge system - and for me with a 2012 Leaf, almost 3 times the charge rate (at 10Kw).

Could the DC/DC converter be designed for "opportunity charging" so that the EV's charge rate simply varies with the solar energy available? If MPPT function is added, it would become the first truly high voltage (battery) solar MPPT battery charger- at least from what I can find.

Yes you sure could! Here's a video of me doing that with +/-200v solar in, 93v battery out.
https://www.youtube.com/watch?v=dxp8kX_golA

I have since configured my panels are configured for 400v in (at max power).

[boelle]

i know this is an old one, but what happend?

not sure if i will get a leaf but will sure go for something with chademo,


located in europe

[Marktm]

There is substantial activity in the V2X realm going on globally. Check Setec Power for a CHAdeMO/V2H unit. Princeton Power offered a V2G CHAdeMO based energy converter in 10kW and 30kW sizes, but I understand they are out of business (tough market!). Nuvve is offering an AC based charge controller that is bi-directional, however no current EV manufacturer offers the bi-directional, J-1772 protocol, on-board charger yet - that I know of anyway.

IMO, it is only a matter of a year or so and we will see some very early (expensive?) CHAdeMO level 1 (~10kW) V2H/V2G commercial, plug and play units. Hopefully, some will have solar MPPT based inputs also.

[arnolde]

Has there been any new progress yet? I have a 7.7kWp solar generator and 2 EV's with Chademo sockets, I'd love to experiment with DC charging. Since I already have 400-800V DC readily available, I "only" need to solve these 2 tasks:
a) CAN messaging
b) how exactly does the EVSE need to regulate the voltage/current going to the EV?

The only downside to this approach is that I won't get any money for the self-usage of electricity, since it wouldnt go through the "pv generated" meter. The upside is that it's much more efficient than converting to 230VAC and then back to DC.

I don't understand yet what exactly makes "the DC charger circuit" sooo expensive (several 1000 EUR), can anyone explain? Seems to me any owner of a 400V 3-phase supply can simply rectify that to get 400VDC and then use that to charge the 350VDC EV battery simply by limiting current&voltage, which at 30A can't be THAT complicated? Isn't it the same as any voltage/current regulating lab power supply does, just with a larger power stage? And microprocessor controlled?

[Marktm]

Has there been any new progress yet? I have a 7.7kWp solar generator and 2 EV's with Chademo sockets, I'd love to experiment with DC charging. Since I already have 400-800V DC readily available, I "only" need to solve these 2 tasks:
a) CAN messaging
b) how exactly does the EVSE need to regulate the voltage/current going to the EV?

The only downside to this approach is that I won't get any money for the self-usage of electricity, since it wouldnt go through the "pv generated" meter. The upside is that it's much more efficient than converting to 230VAC and then back to DC.

I don't understand yet what exactly makes "the DC charger circuit" sooo expensive (several 1000 EUR), can anyone explain? Seems to me any owner of a 400V 3-phase supply can simply rectify that to get 400VDC and then use that to charge the 350VDC EV battery simply by limiting current&voltage, which at 30A can't be THAT complicated? Isn't it the same as any voltage/current regulating lab power supply does, just with a larger power stage? And microprocessor controlled?

Being a US home owner, 240 VAC is the only practical grid voltage available. Both SolarEdge (StorEdge) and Pika Energy have commercial solutions for hybrid energy converters that are grid tied, of course have MPPT PV inputs, and work seamlessly with high voltage Li battery systems (wall type). These battery systems can of course provide backup energy in grid failure scenarios.

I've tried working with Pika as they have communications systems for other OEM battery systems. However, they are not willing to take on the CHAdeMO protocols as they believe it is too limited in use AND they don't have the bandwidth to support.

IMO, there will be at least two offerings that have (likely expensive) solutions similar to what we want this year - we will see.

In my situation, any PV energy used to charge my Leaf will back out full value of a kWh of grid supply - the best I can do as I only get the energy cost (about half) if I have excess energy to return to the grid.

[goldbrick]

The upside is that it's much more efficient than converting to 230VAC and then back to DC.

I don't understand yet what exactly makes "the DC charger circuit" sooo expensive (several 1000 EUR), can anyone explain? Seems to me any owner of a 400V 3-phase supply can simply rectify that to get 400VDC and then use that to charge the 350VDC EV battery simply by limiting current&voltage, which at 30A can't be THAT complicated? Isn't it the same as any voltage/current regulating lab power supply does, just with a larger power stage? And microprocessor controlled?

They are probably so expensive due to the small number of units that could be sold vs the large one-time engineering cost to make a high voltage device that won't kill someone. There is a lot of testing and certification that costs $$$ required and those costs have to be covered by a small number of units sold.

Also, with inverter efficiencies in the 90+% range these days, the gains aren't that huge. It's technically possible and would be a cool 'science project' for some EE but getting a company to bring a consumer product to market is a different story.

[Marktm]

A recent development that is hopefully just the beginning of home bi-directional DC port based power converters that do not use the onboard charger.

https://electrek.co/2020/01/06/wallbox- ... issan/amp/

With hopefully some robust control logic, this could be "AC coupled - sort of" with a conventional grid-tied solar system.

[powersurge]

A recent development that is hopefully just the beginning of home bi-directional DC port based power converters that do not use the onboard charger.

https://electrek.co/2020/01/06/wallbox- ... issan/amp/

With hopefully some robust control logic, this could be "AC coupled - sort of" with a conventional grid-tied solar system.

Let's see... Bidirectional charging could put electricity BACK into your house. What would be the utility of this?

a) Run your house electricity from the Leaf's battery in an emergency.

b) You can go to local charging stations every day, and charge up your Leaf to get as much free electricity as possible for your house.

c) Price is $4,000... Maybe.

I can't see the cost/ benefit of either of these choices.

The only regular use of this is to power a cabin off the grid with your car..... And then you would not have any electricity left to drive out of there... My rating? Bust. Very limited use product which will never sell.

[Oilpan4]

One way use of the leaf battery degrades it enough as it is.
I say use that money to get a good backup generator that can run for several days before needing a refuel.

[powersurge]

One way use of the leaf battery degrades it enough as it is.
I say use that money to get a good backup generator that can run for several days before needing a refuel.

+1