charging amperage adjustable by app and by external signal

[Zwerius]

Hello,

I live in a net zero energy house (including charging of the i3). For details, see my website (in Dutch): http://geen-energierekening-meer.weebly.com/

To prevent exchanging too much electricity with the grid, I try to use the charging current of my i3 to control the system.
For the moment it doesn't matter in our country when I use electricity from the grid and when I supply electricity to the grid. I get payed the same rate as I have to pay.
But it seems logical that this will change in the (near?) future.

So I want to use the largest possible part of the electricity produced with my solar panels directly. So without it first supplying it to the grid and taking it back at a later moment.

Charging the i3 could be a big help in this, but it means I have to start and stop charging at the right moments, but that I also like to use the possibilty of adapting the charging current to the energy available at that particular moment.

At the moment I have to do this "manually". So plug in and out at the right moments and going to the car and adjust amperage settings at certain moments.
It can not be too difficult, to make the car's system change these settings based on an external signal once it has been made possible to change the settings through the i-remote app.
In this way, the whole control issue could be automated.

It would be a hughe Plus for BMW (and renewable energy) when this could be incorporated in a next software version.

 

[ironsia]

Me too. I haven't got my PV system yet, because Im looking for a suitable house first, but that is exactly what I want to do, using hybrid PV-T panels, so as to have relatively cool PV, and warm earth around several vertical bores, reducing the electricity needed to pump heat back at higher temperature to heat the house and hot water. Because we're both retired (and have a Rex) we can afford to keep the i3's battery less than full when it's cloudy, ready to store electricity when it's sunny.

The new BMW wallbox pro <https://www.press.bmwgroup.com/global/pressDetail.html?title=fast-convenient-smart-the-bmw-i-wallbox-pro-the-new-home-charging-station-for-electric-and-plug-in&outputChannelId=6&id=T0193947EN&left_menu_item=node__8601>
may help, but it's rather big and expensive. I also wondered if some kind of informal mash-up could behave like an automatic manual control, maybe with a camera watching the export watt-meter and controlling the i3 charging rate visa the phone app or otherwise.

It's also unlikely that I will often have more than 2.4KW spare, so charging might be best the lower powered mode 2 cable from a normal domestic outlet, rated at 13A, 3KW here, but limited by the i3's onboard charger to 10A. This can be reduced to 7.5A or 6A, but I'm not sure if it can be down remotely by iRemote.

 

[jadnashuanh]

The box made by a small company in the USA www.emotorwerks.com has a Wi-Fi interface as an option, and you should be able to program it to do what you want. Changing the pilot signal in the EVSE should do essentially the same thing, and maybe with less granularity than the options in the vehicle. This assumes that the i3 continuously looks at the pilot signal, and doesn't just decide on its option when first plugged in. Talking to the car via the BMW networked link is probably not going to be as fast or reliable. I know I've not been able to talk to my car for the last week or so and am getting annoyed with BMW. NO idea if they'll ship overseas, but you might contact them to discuss your idea.

 

[ironsia]

The box made by a small company in the USA http://www.emotorwerks.com has a Wi-Fi interface as an option, and you should be able to program it to do what you want. .....

Thanks, jadnashhuanh. I've emailed them and got a prompt helpful reply, except on whether they had any European approvals. I've PM'd Zwerius to tell him about the correspondence.

 

[Zwerius]

Thanx Ironsia,

I've received your mail. It looks like an interesting concept. I'll have to study this more in detail.
The doubt I have at this moment is this:
When I adjust charging (from a homeplug) to 100% (=10A/230V in European I3's), it is a setting in the control system of the car.
When I adjust the charge amperage in the external charger electronics to a lower setting (determined by the PV overcapacity in my case), would that not cause a fault in the control system of the car (that's expecting a higher amperage, according to its own settings).

Nice you enjoyed my webpage! Thx.

 

[ironsia]

Zwerius, I think that the car electronics always has a dialogue with the system it will charge from. Like you, I'm using a normal European domestic socket, which in the UK is limited to 13A. Because the domestic socket is not intelligent, the BMW-supplied mode 2 'occasional use cable' has a intelligence box (EVSE) built into the cable, which presumably tells the car that it is connected to a normal socket and that the earth/ground is also present. Presumably it tells the car only 10A is possible. I think that's the pilot signal.
With 7.4KW charging, the intelligence is again provided by an EVSE, just it's usually a box that's mounted on a wall. There's no dialogue between the EVSE and the rest of the domestic electrical system, just some system tests by the EVSE. The expensive new BMW Wallbox Pro appears to have more control over the charge taken by the car, so presumably the car does respond to a varying pilot signal. The worry would be if the car-EVSE dialogue was one-time event at the start. This is from the BMW press release:

"Assisted by its intelligent charging functions and the optional energy meter, the BMW i Wallbox Pro is unique among home charging stations in the extent to which home-generated electricity can be integrated in the charging process – for example electricity from a home solar system. This option is used whenever possible. The intelligently integrated wallbox detects the availability of solar power and immediately uses it for charging. If no home-generated energy is available, power from the grid is used instead.
If the BMW i Wallbox Pro is integrated with a smart home system, the efficient charging functionality can be extended even further to reduce peak loads on the household electrical system and optimise the use of home-generated electricity."

It's still not entirely clear if it would meet your needs or mine.