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My car has a 285V nominal/315V peak battery pack of app. 90kWh. To get that thing charged from 20% back up to 90%+ in a reasonable time (say 6-8 hours) requires 8-10 kW charging capacity.

I was planning to use two PFC-5000 chargers at 4.5 kWh each. That works at the house because I have the necessary 40 Amps available, but how to work this when charging at a commercial stop?

What I can find says that the common commercial station (here in Texas) is 7.2 kW, but that there are also 3 and 5 kW stations out there. All with a J-1772 connector. A 7.2 kW station is 30 Amps.

If I plug in both PFC's "un-checked" on a 7.2 station, that would try to draw 40A from a 30A service so I guess the station's safety would pop? Would the voltage just drop (making things worse)?

If I only use one PFC, I could still over-use a 3 kW station and/or I would under-utilize a regular station and have to hang around for an add'l 6 hours.

Either way, this is not really working??

How do I make the car figure out the capacity of the charging station, and how do I adjust the Elcon's to only charge at rate X? If I could tell a 3kW from a 7.2 kW station I could at least only fire up 1 Elcon and not pop fuses?

I did check with Elcon on this.

At first they suggested an AVC2 interface-box (with is a handshake module to tell the charger there is a valid connection), which is nice but doesn't exactly answer the question. When I double-checked, their engineer told me
We do not have information on any other charging station interfaces. You will have to research it yourself. [end quote]

so, here I am...
 

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Check out Orion BMS, can at least use J1772 control to drive Elcons from public EVSEs

I've also seen mention of Chademo charging via Wakespeed / APS voltage regulators
 

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Part of what happens with J1772 is the charging station communicating with your car. The charger tells the car it's max current, then your BMS needs to take it from there and command the chargers to not exceed the available current.
 

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How do I make the car figure out the capacity of the charging station, and how do I adjust the Elcon's to only charge at rate X? If I could tell a 3kW from a 7.2 kW station I could at least only fire up 1 Elcon and not pop fuses?

At first they suggested an AVC2 interface-box (with is a handshake module to tell the charger there is a valid connection), which is nice but doesn't exactly answer the question. When I double-checked, their engineer told me
We do not have information on any other charging station interfaces. You will have to research it yourself. [end quote]

so, here I am...
All commercial EVSE standards have controls and handshaking. Your first step is to acquire the standards and read them. SAE J1772 and CCS, CHademo and whatever other chargers are in your area.
 

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Part of what happens with J1772 is the charging station communicating with your car. The charger tells the car it's max current, then your BMS needs to take it from there and command the chargers to not exceed the available current.
Yes, and that is exactly the point.

Can the Elcons do that communication, or do I need to do it for them? What does the communication even look like / how do I figure out max charge current? Does an ACV2 somehow help in this (didn't see it in the manual but maybe I missed it?)? If I need to translate and I can figure out the protocol, then can I even set max charge current on the Elcon's?

I figured this is pretty much charger-tech-101 and would be totally done & "understood" between Elcon and J1772 (seeing as this is pretty much what Elcon does for a living) but I guess not ?....
 

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I don't know anything about Elcon chargers, so I can't be much direct help.

The J1772 hand shake and charge limits are set with "pilot" and "prox" lines. If your Elcon wiring diagram includes pilot and prox wires I would think your set as is. I was under the impression this was often handled by the BMS or a dedicated module.
 

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The Elcon CAN protocols for inbound control are well documented, but

obviously that has nothing to do with signaling the EVSE.

The Elcons are designed to work from standard outlets not EVSEs.

There are dozens of ways to do the intermediation, but either DIY or via pricey BMS as listed above.

The specs standards are easily available at a price.

Keep in mind DIY EVs could easily be banned from many networks, so best to fly under the radar

rather than acting entitled about it.
 

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Here is what you do. Set both chargers to draw the max possible you want. For the J1772 communication, lookup the AVC2 board. Wire both chargers in parallel. The J1772 plug will only flow as much current as the EVSE allows.

I used this method to convert a Smith Electric truck to J1772, it has almost an 12kw charger, and I ran it on a 3kw EVSE no problem.
 

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Here is what you do. Set both chargers to draw the max possible you want. For the J1772 communication, lookup the AVC2 board. Wire both chargers in parallel. The J1772 plug will only flow as much current as the EVSE allows.

I used this method to convert a Smith Electric truck to J1772, it has almost an 12kw charger, and I ran it on a 3kw EVSE no problem.

Yes this should work. The Elcon chargers turn on and draw whatever current the are set for.... either via CAN message or according to the output listed on the label in the case of chargers that use the enable feature and not CAN.
 

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More than likely it would pop their breaker.


The EVSE send out a PWM signal to tell you the max current it can supply.


Control Pilot (Current limit): The charging station can use the wave signal to describe the maximum current that is available via the charging station with the help of pulse width modulation: a 16% PWM is a 10 A maximum, a 25% PWM is a 16 A maximum, a 50% PWM is a 32 A maximum and a 90% PWM flags a fast charge option.
 

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The J1772 plug will only flow as much current as the EVSE allows.

I used this method to convert a Smith Electric truck to J1772, it has almost an 12kw charger, and I ran it on a 3kw EVSE no problem.
That doesn't make sense to me.

Yes this should work. The Elcon chargers turn on and draw whatever current the are set for.... either via CAN message or according to the output listed on the label in the case of chargers that use the enable feature and not CAN.
That's why this shouldn't work: the Elcon will draw the current for which it is set, regardless of whether or not that is within the EVSE capacity.

What happens when the Elcon is set to deliver a higher current than the EVSE can supply?
More than likely it would pop their breaker.
Well, that, or the EVSE would just shut off, assuming that it monitors the current.

Here's the reason why expecting the EVSE to limit current shouldn't work:
The EVSE send out a PWM signal to tell you the max current it can supply.
The EVSE just tells the charger what current is allowable, and turns the power switch on when the communication requirement has been satisfied; the charger is responsible for regulating that current. The EVSE (for AC charging) is just a smart on-off switch, not a regulator.
 

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That doesn't make sense to me.


That's why this shouldn't work: the Elcon will draw the current for which it is set, regardless of whether or not that is within the EVSE capacity.



Well, that, or the EVSE would just shut off, assuming that it monitors the current.

Here's the reason why expecting the EVSE to limit current shouldn't work:

The EVSE just tells the charger what current is allowable, and turns the power switch on when the communication requirement has been satisfied; the charger is responsible for regulating that current. The EVSE (for AC charging) is just a smart on-off switch, not a regulator.


The EVSE limits the current from the wall. That's why it works. The Smith truck doesn't have any externally signalling. You give it power, it tries to draw 11kw, and the EVSE only passes as much as it can, and that's it.
 
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