Ability to limit charging current

[michael]

There should be an option to limit the charging current when using an L2 EVSE.

This is important when using a portable L2 EVSE. Normally, the EVSE advertises the maximum possible charging current using the pilot tone, and the car honors that value, limiting the charging current. The problem comes when using a portable unit, such as the Clipper Creek LCS-25. Since the EVSE doesn't know the capacity of the circuit it's plugged into, it always advertises 20 A. If it's plugged into a 220 V 15 A circuit, the breaker blows. While some EVSE's provide a way to change the current capability they advertise, others do not.

How about a way to dial in a limit?

 

[WattsUp]

The LCS-25 is a 20-amp device. You're not supposed to plug it into a 15-amp circuit.

 

[michael]

Exactly, that's the point.

It's a 20 Amp device ONLY because the software is programmed to advertise (via the pilot tone) 20 Amps. Then the car draws 20 Amps. If plugged into a 15 Amp circuit, the breakers would blow.

The LCS-20 is exactly the same hardware, it just has different software which advertises 15 Amps. So the buyer has the predicament: buy the faster-charging LCS-25 but be restricted to 20 A and higher outlets; or buy the slower charging LCS-20 which can operate in all 220 outlets 15 A or higher.

My suggestion would allow the purchaser to buy an LCS-25 (or use any large-size plug-in EVSE) but dial down the current draw by asking the car to limit itself to 15 A.

You could literally take an EVSE intended for 30 A service, install a cord and plug, and use it on RV, Dryer, L6-30, L6-20, 6-15 or any other 220 outlet (with suitable plug converters, of course) and still not exceed the capacity of the outlet.

 

[jmueller065]

Or get a different EVSE; one that can be adjusted--such as the Power Xpress:
http://www.pluginnow.com/power-xpress

(granted it isn't supposed to be adjusted frequently but there is a dial on the circuit board to set the current.)

Or get an Open EVSE and modify the software so you can select the current via a menu...

https://code.google.com/p/open-evse/wiki/OpenEVSE_boards

If you are really adventurous you could modify the software and hardware on the open EVSE to automatically detect 120V vs 240V (but not the current available on 240V).

It doesn't necessarily have to be in the car...hack away...!

 

[WindPowered]

You could literally take an EVSE intended for 30 A service, install a cord and plug, and use it on RV, Dryer, L6-30, L6-20, 6-15 or any other 220 outlet (with suitable plug converters, of course) and still not exceed the capacity of the outlet.

You have just described what OpenEVSE already does. I built one of these units and can adjust the pilot signal to whatever my outlet is rated for. With a few pigtail adapters I can take any outlet 110V or 220V from 6A to 30A and charge my car.

This is exactly what the J1772 spec is designed for. It's the EVSE's job to advertise maximum current available to the EV, not the EV's job to regulate its draw.

Take a look at the project and see for yourself.


WP

 

[WindPowered]

Or get an Open EVSE and modify the software so you can select the current via a menu...

https://code.google.com/p/open-evse/wiki/OpenEVSE_boards

If you are really adventurous you could modify the software and hardware on the open EVSE to automatically detect 120V vs 240V (but not the current available on 240V).

FYI, Both of these are standard features on the OpenEVSE Plus v2 board. It will automatically detect 120/240V, and you can use any button (i.e. momentary switch) to toggle through the menu and select the amperage you want advertise.

No customization needed!


WP

 

[Crown123]

If it If it If it If it :ugeek: :ugeek:

 

[Astrand1]

Well the tesla model s charging can be adjusted from the car. You have a screen where you can dial in down to the amp how much current to draw. So there is no reason something similar could not be put into our cars via software.

 

[davideos]

Yes, it could be put into the car via software, but only if the charger supports it. I don't know the variability of the Tesla settings, but if it is more than the standard options negotiated when you plug the charger in, it would likely be different hardware in the FFE.