10A GPO charging with plug-in timer

[dafrizz]

Hi,

I've recently bought a 2016 Leaf and it looks like the head unit lost all charging timer functionality when it was converted to english.

I will generally be charging it with a standard 10A GPO and was wondering if anyone is using a simple plug-in timer to control the charge (e.g. www.bunnings.com.au/arlec-white-grid-connect-smart-plug-in-socket-with-energy-meter_p0273367).

I would think that as long as the timer is capable of switching the required load (2.1 kW for my charger) this should be ok.

[coulomb]

I don't like this approach, as the timer has to interrupt the charge at full load. The front end of the on-board charger is a boost converter, meaning that it has a large inductor in series with the mains, and cutting power to this will cause a large inductive voltage spike. This spike will eventually destroy the timer's contacts, but much worse, it can also damage components in the on-board charger. There are components designed to absorb these spikes, but every time that they do this, they suffer some loss, and eventually the protection will be gone, and catastrophic failure is imminent.

If the car stops the charge, then the current ramps to zero before the timer disconnects. If yours is a J1772 model, with the push-button to disconnect, this sends a signal to the on-board charger to ramp the current to zero. So it's safe to stop the charge and disconnect that way. If yours is a type 2 model, there should be some way to unlock the connector, which will also safely ramp the current to zero.

[dafrizz]

Thanks for the comprehensive response.

The charger is a type 1, with a simple button/handle lever to unlock and then pull out the plug from the car. Not sure if that's what you were referring to?

Taking into account what you said I should always disconnect the car first, not simply turn the charger off at the GPO?

[coulomb]

Nov 30, 2022 9:56:06 GMT 11 dafrizz said:

The charger is a type 1, with a simple button/handle lever to unlock and then pull out the plug from the car. Not sure if that's what you were referring to?

That's good. It's safe to stop the charge with that button/handle lever.

Taking into account what you said I should always disconnect the car first, not simply turn the charger off at the GPO?

Yes, always stop the charge by using the lever to remove the plug, or wait for the car to stop the charge, and turn off the power at the GPO last.

[3db]

Hi Coulomb,

Could the same be said for using a J1772 to Type 2 adapter? Because the adapter doesn't have the lever, you have 2 options:
1) turn off the power at the GPO
2) pull the J1772 end out of the car while it is still charging (unless the timer has stopped it).

So is option 2 as bad as option 1?

For context, I have an after-market Type 2 EVSE with 15A Australian plug end and have been using the Type 2 to J1772 adapter for charging at home while my solar is exporting. I've been trying to work out the best way to disconnect as my charge timer has also been disabled like dafrizz.

[coulomb]

Sept 18, 2023 20:21:03 GMT 11 3db said:

Could the same be said for using a J1772 to Type 2 adapter? Because the adapter doesn't have the lever, 

? I would have thought that the J1772 plug end, that goes into the car, would still have the lever. And the car would still respect that lever. I'd have to go check, but I'm pretty sure that mine is like that.

you have 2 options:
1) turn off the power at the GPO
2) pull the J1772 end out of the car while it is still charging (unless the timer has stopped it).

So is option 2 as bad as option 1?

Option 2 is less bad than option 1, because the pilot pin disconnects before the power pins. It's only a few milliseconds, but that may be enough to reduce the arcing, especially if you withdraw the J1772 plug slowly.