Building Mobile DC Fast Charger, 125KW using LFP cells. Assistance Needed.

[sunfunkits.com]

Hi,

We would like to know if there are currently any Mobile DC faster Chargers, something that can charge at 125KW or faster rate using DC supply such with LFP cells.
If anyone knows or has Tesla Protocol information, please PM me.

The same for CS1 protocol and infrastructure.

I have access to many 3.2V, 300AH cells can and can setup a 480v DC supply using 150 Cells or 400V supply using 125 cells.

The idea would be to have a mobile DC fast Charger that can bring cars to 200 miles of range in less than 1 hour. The current Level 2 charger is not very good for road side rescue use.

 

[RTPEV]

To answer your first question, yes, there are mobile DC fastchargers: Electric Vehicle Mobile Charging | SparkCharge

Their use case, particularly for road rescue use, is not 200 miles of range, but rather 15, using 20kW of charge power from a 3.5kWh pack. That is likely plenty of added range for someone that had to probably go to great lengths to get themselves into a position where they are that far from a charger or even an outlet of some kind. Not that it won't (very) occasionally happen that someone underestimates their range, but they are likely not going to wind up a full 200 miles away from a charger...more than likely they are only going to miss by a few miles.

The Sparkcharge Roadie solution is also modular, so if the 15 miles is not enough, you can stack several modules together to get 30 or 45 miles. It's also portable with a 73 lb battery. Your proposed solution using 150 what I am guessing are LFP golf cart batteries at 10 lbs each, would be a monster 1500 pound affair! Keep in mind that you don't literally need to string together 150 cells in series, you can/should use a DC/DC boost converter to provide the requested voltage (or current) to the vehicle.

 

[Rocky_H]

The biggest problem I see is that you think you can have something "mobile" that is going to have the capacity to put 200 miles into an electric car, regardless of the speed. It WILL be over 1,000 pounds.

 

[sunfunkits.com]

I'm looking for something like charging only that can take in a DC supply. We need something like 100-200 miles of range, weight is not an issue. The setup would be able to provide up to 60 KW of charging if needed.

The spark will not work it comes with its own DC supply, we just need the charging portion not the supply portion.

 

[RTPEV]

I'm looking for something like charging only that can take in a DC supply. We need something like 100-200 miles of range, weight is not an issue. The setup would be able to provide up to 60 KW of charging if needed.

The spark will not work it comes with its own DC supply, we just need the charging portion not the supply portion.

If by "DC supply" you mean the DC/DC converter (aka "the charger"), then perhaps you don't understand how DC fast charging works. You always need that component as the car will command a specific current and/or specific voltage that the charger needs to comply with and you need a DC/DC converter to do that.

On the other hand, maybe you are talking about something else. I don't understand what you are talking about when you say the "charging portion" and the "supply portion".

 

[sunfunkits.com]

I have many of these they are 3.2-3.3 volts, 305AH capacity, 125 in series will make 400v so 400x305 = 122 KW of power.

140 of them will be 450 volts.

What type of apparatus would be needed to take a 450V supply and send it to the car so that it can communicate with the car and initiate DC faster Charging. Like a DC to DC charger with CCS or Tesla compatible protocol.

We can draw up to 2C from the batteries so they can provide (400x305) x 2c = 244KW of DC power. The entire battery bank would weigh less than 1300 lbs.

This will eliminate the DC to AC and then back to DC conversion that happens with a level 2 charger.

The battery bank would be recharged via solar panels using a 20 KW array that can recharge the back in about a day.

 

[RTPEV]

What type of apparatus would be needed to take a 450V supply and send it to the car so that it can communicate with the car and initiate DC faster Charging. Like a DC to DC charger with CCS or Tesla compatible protocol.

You will essentially need half the "guts" of a Tesla Supercharger. You won't need the AC/DC converter, but you will need the DC/DC converter. But you will also need components to charge the batteries as well.

 

[Rocky_H]

What type of apparatus would be needed to take a 450V supply and send it to the car so that it can communicate with the car and initiate DC faster Charging. Like a DC to DC charger with CCS or Tesla compatible protocol.
[...]
This will eliminate the DC to AC and then back to DC conversion that happens with a level 2 charger.

There have been a lot of threads of people asking about this, trying to do straight DC to DC charging without the conversions. But these protocols rely on very particular communication between the station and the car for any kind of DC charging. So this stuff just isn't available. It's going to have to be a packaged AC to DC charging device that outputs CCS or CHAdeMO. And yes, there are several of these types of things out there, but they're not very high power. You can get some that do about 20 or 30 kW, but they are a few thousand dollars. There's something like this:

60kW DC Fast Charger - SETEC POWER

SETEC POWER Portable 60kW DC Fast Charger offers the perfect balance of size and power, ideal for personal and small fleet use.

www.setec-power.com

That one does 50 kW, but the input for that is 380V 3 phase AC. So you would need a transformer to create that. Or there are other ones that can take a standard split phase 240V 100A AC circuit.

 

[miimura]

What type of apparatus would be needed to take a 450V supply and send it to the car so that it can communicate with the car and initiate DC faster Charging. Like a DC to DC charger with CCS or Tesla compatible protocol.

Fundamentally, you need two things:
1. You need to speak the correct protocol with the car - CCS or Tesla.
2. You need to modulate the current between your battery pack and the car. This will probably be a bank of MOSFETs in the correct arrangement to PWM the current with the correct voltage and amperage to follow the command from the car.

You also need to consider the variation of pack voltages across vehicles. Tesla vehicle packs are anywhere from 84S to 110S. A Plaid Model S/X may not fully charge if you don't have a DC-DC boost converter because the max charging pack voltage is about 460VDC.

 

[sunfunkits.com]

From what I understand CCS is open standard and Tesla has opened patents for this charger?

We can set output to 500v if needed (155 cells).

I can setup the output circuit, I just need CCS protocol documentation, or better yet tesla documentation. I have tried contacting tesla and they told me to go away basically, I have not found a way to contact anyone regarding CCS.

In Europe they are using CCS2 protocol.

 

[miimura]

This looks like a good place to start:

J2847/2_201504: Communication Between Plug-In Vehicles and Off-Board DC Chargers - SAE International

This SAE Recommended Practice SAE J2847-2 establishes requirements and specifications for communication between Plug-in Electric Vehicle (PEV) and the DC Off-board charger. Where relevant, this document notes, but does not formally specify, interactions between the vehicle and vehicle operator. This

www.sae.org

 

[avs007]

One thing that's interesting to point out about using a portable DC charger on the Tesla... Bjorn has a video when he was visiting Nokian. They had a portable DC charger, which was limited to providing 16kw, because of the limitations of where their remote location was... Anyways, the Tesla draws more power for conditioning the batteries when DC charging, then when AC charging... Because of this, he found that when they plugged in the portable DC charger, it said it was providing the car 14kw, but the battery conditioning was consuming 7kw, only leaving 7kw to actually charge the battery, which is actually slower than what you can do with a wall connector... Of course, once the batteries warmed up, then the full 14kw was able to flow into the battery...

He was saying the Tesla was programmed to heat the batteries on DC fast charging, thinking it is going to "fast charge", but in this case, the charger is only 14kw, so it doesn't really need to heat the battery, but the car is going to heat the battery thinking you can send it 200kw, etc...

 

[sunfunkits.com]

Thanks for the replies, we are doing some hardware designing right now. The small portable chargers may have there place, but I'm wanting to do something Big, like 250KW - 1 MWH battery capacity, charge the whole parking lot type of power.

Or FULL speed Full Tank charge, e.g. like on a drag strip.