psquare
Posts: 495
Joined: Wed Oct 15, 2014 5:57 am
Location: i3 REx, 225xe Hybrid UK
Contact: Website

better charging rate adjustment options

Mon Jul 18, 2016 1:20 am

Trying to use my Solar PV to partially charge the car whenever the British sun makes an appearance, I am finding that adjusting the charging rate in line with PV output is a pain. I seem to remember that the bigger and costlier version of the BMW Wallbox has a PV solar intergration, but not sure if this also automatically adjusts the i3's charging rate.

It would be great if an intelligent enough PV inverter could communicate with the vehicle to adjust charging rate. This could be done via a BMW-provided and regulated API. However it could also be achieved with an IFTTT service, which is more likely and would still allow for all the safeguarding options.

In addition, it would be great to build charging rate change functionality into the iRemote app.

gt1
Posts: 308
Joined: Sat Nov 07, 2015 7:31 pm
Location: Baltimore

Re: better charging rate adjustment options

Mon Jul 18, 2016 11:16 am

You don't need a BMW cooperation for this. Your EVSE is able to communicate the maximum allowable charging current via the pilot signal, and the car should adjust the draw accordingly. OpenEVSE can accept the remote commands to change the current, your solar system just needs to send them.

psquare
Posts: 495
Joined: Wed Oct 15, 2014 5:57 am
Location: i3 REx, 225xe Hybrid UK
Contact: Website

Re: better charging rate adjustment options

Mon Jul 18, 2016 3:49 pm

gt1 wrote:You don't need a BMW cooperation for this. Your EVSE is able to communicate the maximum allowable charging current via the pilot signal, and the car should adjust the draw accordingly. OpenEVSE can accept the remote commands to change the current, your solar system just needs to send them.


The car regulates more than that. Plus, there are programming options like departure time etc which would need to be tied in. It would be preferable to have the vehicle determine the charge rate and not just an EVSE. It would be a the smarter solution. The EVSE being the "dumber" solution (no disrespect).

jadnashuanh
Posts: 4394
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: better charging rate adjustment options

Mon Jul 18, 2016 9:14 pm

Not sure I agree...as long as there is enough time to accomplish what you've told the i3 to do, it should adjust its timing on when it starts things based on what the EVSE says it has in current available. Now, if the solar output was radically changing, you might be disappointed sometimes if you told the car to wait (low-cost charging selected), and then the EVSE couldn't recharge things in the allotted window. What might work better would be to have a buffer to accept excess power, and then feed it back to the car as needed until it was full. But, if you were not time pressed, just adjusting the pilot signal should allow you to never exceed your solar output.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

Schnort
Posts: 238
Joined: Wed Jan 28, 2015 7:16 pm

Re: better charging rate adjustment options

Tue Jul 19, 2016 7:50 am

I would just like to see the charging data in V, A, and W.

For such a nerdy car, it really offends the engineer in me I have to divine charging rate from percentages of "full" (whatever that really is)

gt1
Posts: 308
Joined: Sat Nov 07, 2015 7:31 pm
Location: Baltimore

Re: better charging rate adjustment options

Tue Jul 19, 2016 10:27 am

psquare wrote:
gt1 wrote:You don't need a BMW cooperation for this. Your EVSE is able to communicate the maximum allowable charging current via the pilot signal, and the car should adjust the draw accordingly. OpenEVSE can accept the remote commands to change the current, your solar system just needs to send them.


The car regulates more than that. Plus, there are programming options like departure time etc which would need to be tied in. It would be preferable to have the vehicle determine the charge rate and not just an EVSE. It would be a the smarter solution. The EVSE being the "dumber" solution (no disrespect).

With the solar your priority should be to get all the generated energy directly into the car- regardless of the departure time. The solar system will determine the allowable charging current, and it doesn't really matter if it will be communicated to the car or to the EVSE. I doubt that either software exists. You can write a code to work with OpenEVSE, but not with the car. The experimental IFTTT access provided by BMW is way too crude and restricted.
BTW, how the solar works for you in UK? Few times I visited London completely confirmed the foggy and rainy climate sterotype.

tongsli
Posts: 3
Joined: Mon Apr 30, 2018 12:48 pm

Re: better charging rate adjustment options

Mon Mar 11, 2019 8:25 pm

I would like to see some options in configuring level2 charging. either adjustable amperage or at least three choices like level1 charging.

jadnashuanh
Posts: 4394
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: better charging rate adjustment options

Mon Mar 11, 2019 9:36 pm

At least in the USA, 240vac devices tend to be on dedicated circuits, so restricting the car to less than the EVSE can provide isn't generally very useful. As mentioned earlier, though, if you're dealing with solar inputs, telling the EVSE to adjust its pilot signal could have some benefits. 120vac devices are often on shared circuits, so restricting the car's draw has a much larger benefit.

The way the whole thing was defined is that the EVSE announces how much power it can provide, then the vehicle decides how much, up to that stated maximum, it wants to take. It's quite possible to design an EVSE that has an adjustable output and in fact, there are some out there. One of the smarter ones could be programmed to take a signal from some controller that was monitoring solar output and respond by changing its pilot signal.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

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