better charging rate adjustment options

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psquare

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Oct 15, 2014
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i3 120
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.
 
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.
 
gt1 said:
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).
 
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.
 
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)
 
psquare said:
gt1 said:
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.
 
I would like to see some options in configuring level2 charging. either adjustable amperage or at least three choices like level1 charging.
 
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.
 
jadnashuanh said:
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.

This winter, I utilized 120v EVSE to charge my battery overnight during the polar vortex. When it was sub zero temps outside I was able to keep the battery charging by doing a trickle charge. That's the main reason I would like the vehicle or EVSE configurable. The TESLA will allow you to configure from 2amps on up. The Juice Box will allow you to configure via app, it's output from 6amps to 32amps.


If the BMW would add a 8amp or 10amp level2 setting, that would do it for me.
 
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