DC solar directly to EV (no AC!)

[summit]

I had to give my impression about their highly optimism 200 miles of range based on my experiment with my Vanabolt (almost 100 000 km done since conversion), but I finally find this image.
And if you need 200 miles of range, drive the low roof van at 35 mph

pop-up certain will improve range. There are few in the pipelinee: VW e-bus, Nissan e-NV etc..

I can drive 200 miles on a single charge with my Vanabolt, but the reality is it can be challenging to drive 100 miles some days of the years.

can the Vanabolt accept DCFC now ? it's amazing how far you've gone with just level 2. With more and more Tesla supercharging station opening up with the MagicDock to accommodate CCS DCFC, 200-mile per day sehould b quite doable. I think my longest single day in an S was about 700-mile

 

[eXodus]

pop-up certain will improve range.

While frontal area is important -

Velocity is even more important - since it's square. That's why in Europe Semi Trucks are only allowed to drive 80 km/H - 55 MPH

Because between 80km/h (55mph) and 120 km/h (75mph) the air resistance doubles.

Further most of the Air resistance from a big vehicle is coming from the square-form at the rear:

The height is less important then the rear. Most RVs and Vans have a bad rear end to aero.
But there is slowly movement in the Market:
For instance the Rivian Amazon Delivery Van has an Amazon Drag coefficient of 0.3

What I Found When I Crawled Under Rivian's Amazon Delivery Van - The Autopian

Your next overnight delivery might arrive in a Rivian-built Amazon EDV 700 delivery van. We crawled underneath to find out how it ticks.

www.theautopian.com

They take Aero serious. The rear and underside are optimized. Much better then any contemporary Van.

I can drive 200 miles on a single charge with my Vanabolt, but the reality is it can be challenging to drive 100 miles some days of the years.

Something to try to increase the range.

 

[yabert]

can the Vanabolt accept DCFC now ?

Yes, work since 2 years now.
I can now enjoy the Bolt fast charge (slowest of the industry) and wait hours at the fast charge station ?
My wife have the record of the longest fast charge session: 1h50mins to do 5%-80% few weeks ago during a really cold night

It's simple, every other EV charge faster than the Bolt.
Thankfully, most of time it's not a pain as we simply stop few minutes to add a bit more range to reach destination or during a trip we schedule a lunch during the charge.

Anyway, back to the subject of this thread. With the new increase of solar available after this winter, I'm starting to expect to charge my EV from solar.
As I have the PV installed since less than a year, it's just amazing to me to notice how poor is the production in December and have now the house battery fully charge at 11 in the morning during a sunny day.

 

[BenQ]

Here ya go, California company is going for it!

 

[summit]

is 30% a realistic gain ?

 

[BenQ]

is 30% a realistic gain ?

??‍

 

[meetyg]

is 30% a realistic gain ?

I think so, if you compare to charging an EV with solar and AC charging.
Think of the losses you get: From the PV DC to AC via inverter, then from AC to DC of the EV battery pack, via the on-board charger (OBC).
DC to AC inverters can be around 90% efficient, but most are only around 85%. Then the OBC also has losses, converting that AC to DC (again, around 85% efficient, depending on the charging rate).
DC-DC converters can be up to 95-98% efficient, depending if you do stepping down (more efficient) or stepping up of the voltage.

However, as mentioned in the video, you would need a massive solar array (probably a string with high voltage, above 450v DC) in order to charge with solar only.
So for the average household with solar, I think it's not so practical, or maybe it is, but you would be charging fairly slow (3 to 7kw).
I think this would be more practical for a commercial solar install, like on warehouses, malls etc...

 

[eXodus]

I think so, if you compare to charging an EV with solar and AC charging.
Think of the losses you get: From the PV DC to AC via inverter, then from AC to DC of the EV battery pack, via the on-board charger (OBC).
DC to AC inverters can be around 90% efficient, but most are only around 85%. Then the OBC also has losses, converting that AC to DC (again, around 85% efficient, depending on the charging rate).
DC-DC converters can be up to 95-98% efficient, depending if you do stepping down (more efficient) or stepping up of the voltage.

However, as mentioned in the video, you would need a massive solar array (probably a string with high voltage, above 450v DC) in order to charge with solar only.
So for the average household with solar, I think it's not so practical, or maybe it is, but you would be charging fairly slow (3 to 7kw).
I think this would be more practical for a commercial solar install, like on warehouses, malls etc...

efficiency and usability are interrelated. Depending how you formulate the efficiency goal.

If your efficiency metric is - how many KW you get from the PV array into the EV battery - then DC-DC is best. So this makes only sense for a PV array which is mounted on the EV.

But as soon as you add another metric - like the cost of the charging system and ease of use - DC- AC - AC -DC is pretty darn close.
For instance when you got a PV array on your house - don't bother going DC-DC yet. Just get a Inverter, it's not worth the trouble retrofitting the car- for the 10% efficiency gained - it will take you a lifetime or more to have any benefits.

 

[rustythorn]

victron is working on V2G and high DC voltage storage solution so maybe that might work?

for those saying it makes more sense to use your house mounted solar panels all day to charge your household batteries vs charging the EV directly if it is parked at home, now you can do both. instead of using a 48 VDC storage use 480 VDC storage. 48 kwh pack at 48 volts is 1000 ah and at 480 is 100 ah. that way you only need one system to charge either the EV or the house batteries.

 

[rustythorn]

How are you going to fit that on a Van? 30 sq meters is over 300 sq feet

its been done for a while now

 

[Ampster]

that way you only need one system to charge either the EV or the house batteries.

I can charge my house batteries and when they are done charge my EV with excess solar with my existing system. Others may prefer a different system. Different flavors for different people, which is why Baskin Robins has 31 flavors.

 

[rustythorn]

I can charge my house batteries and when they are done charge my EV with excess solar with my existing system. Others may prefer a different system. Different flavors for different people, which is why Baskin Robins has 31 flavors.

that is true but once an easy and reasonable solution exists you can do the same thing but skip the DC -> AC -> DC step, hence relevance for this thread. thus, if victron makes a V2G charging system and a high VDC storage solution AND they talk to each other then we will have an easy and reasonable solution, unfortunately for me even if that gets made it is unlikely to help me. i'm guessing such a victron product would be 10 kVA+ but i only need 5-6 kVA for my camper van

 

[Ampster]

but once an easy and reasonable solution exists you can do the same thing but skip the DC -> AC -> DC step

The only step I take is to plug in my EVs. So far no one has talked about the economic benefit of skipping the DC to AC to DC step. That is what is relevant to me. EV ownership is moving out of the early adopter phase in some places and I do not see the mainstream car owner caring about that step either. It is an interesting intellectual exercise.

 

[zanydroid]

There may be an economic advantage if you have a V2X system which will already require at least a unidirectional HVDC bridge from the car to the HVDC bus in the solar setup. Make that a bidirectional design and you can do DC DC charging for a minimal extra component cost.

If you don’t have V2X then all this talk is more like having an elegant system to flex on others with. Engineering performance art and porn. For an on grid system especially

 

[yabert]

Oooooook! There is some news. Let put the CCS communication on the side for a moment and focus to DC solar to DC 360V battery.

I did a test with a Meanwell HLG 320-12 power supply. Those one can take 90-305V ac, BUT also 127-431Vdc at input.
So I connect my unit directly to my 4 panels array (around 160-190Vdc) and it work!!!
Now you can ask yourself why it's so nice to have 12Vdc out of 4 panels... it's not nice, nobody care ?
But meanwell also sell High Voltage unit (UHP, HEP, PHP, CSP) who can take input at similar range of 127-431Vdc and output 380-400Vdc ?

Now if you ask yourself why I'm so excited about all this, it's because a compact UHP unit able to output 1900W at 400Vdc only cost 270$ ?
Big deal if this can be the missing link for DC solar directly to EV.

My personal experiment with Meanwell unit was to use an RSP-500 as DC-DC converter for one of my EV for a decade now (180Vdc to 12Vdc), use RSP-1000 and 2000 unit and SE-350 unit as 48V battery charger and use my HLG 320 unit as DC-DC converter (360Vdc to 12Vdc).
All this to say that I like those unit and they work great.

 

[zanydroid]

Sweet.

Are you going to derate it for feeding in DC through the rectifier stage? Or maybe bypass that? Doubling the DC voltage to halve the current may help too. (Just going by what I've heard & speculated on) When I was looking at meanwell datasheets the past few days the derating charts do not cover these kinds of off-the-books use cases.

Do you think you can series or parallel stack these to get more power than 1.9kW? They have some power supplies that support parallel stacking if you daisy chain communications through them, I assume they do things like balancing voltage and current to ensure an even split. I think chargers typically can be parallel stacked as long as the charge parameters are synchronized, esp since CC mode already has a control loop that should help ensure balance.

 

[rustythorn]

1.9 kW is the max solar you can reasonably get out of a car or even a van before you need to have some kind of fold out/tilting system for additional solar

 

[zanydroid]

I’m asking for the general case of trying to achieve DC DC charging of an EV in the general case. As I said above about 5 posts ago I don’t find charging a car with solar panels that are installed on it super practical except as a thought experiment etc

 

[Ampster]

I’m asking for the general case of trying to achieve DC DC charging of an EV in the general case.

I also think it is important to distinguish between a custom EV like the one from @yabert where the battery cables are accessible and OEM EVs where they are typically not as accessible and there may be warranty concerns about accessing them.
If I still had an EV conversion, I would have no issue trying a DC charging system because I would have installed the BMS and the batteries and integrating them would be easier.

 

[zanydroid]

I don’t think CCS communications have been sorted out for DIY in easily reusable form, and I presume anyone embarking on this kind of project would know that means you have to go down the route of physically modding the car if it is CCS.