Reprogram the Low Cost Charging/Departure Time/Preconditioning software

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chokahoss

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Jul 26, 2015
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BMW needs to rethink the low cost charging/departure time/preconditioning program. The way it's programmed now, low cost charging is tied to a departure time. The only reason to have a stored departure time is if you are using the preconditioning function. These are two separate functions and should be two separate commands, or programming parameters. Let me explain. First of all, I don't need to precondition my car all the time. I do that only in the winter, so for most of the year preconditioning is turned OFF; but in order to use the low cost charging function I have three departure times programmed: 1. M-F 06:50; 2. Sat. 07:20; 3. Sun. 08:30. My low cost charging window through my power company is 23:00-07:00. My M-F departure time of 06:50 happens to coincide with that charging window. My other two departure times are later in the morning and fall outside the low cost charging window. The program looks at your departure time, not the beginning of the low cost charging window, and delays the charging process in order to have the vehicle charged at departure time. This has led to instances where the vehicle has either not been fully charged or it is charging outside of the low cost window. There has also been occasions where I've needed to use the vehicle earlier than programmed, and the car is not charged because it is waiting for the programmed departure time. Low Cost Charging should be separate from Departure Time/Preconditioning. At 23:00, when the charging window opens, the vehicle should immediately start charging then shut down after full charge; then if you are in precondition mode, wake back up to precondition the car. I have seen my car lie dormant from 23:00 until 04:00, 05:00, 06:00 or more, I guess depending on the discharged state of the battery. That's crazy! Common sense would be start your charge as soon as you can within the window to assure a full battery. There is no benefit to delaying the charging process. Some disadvantages are: not being able to use the vehicle earlier than the programmed departure time; possible power outage later in the charging window, thus car doesn't get charged; as mentioned above conflict with departure times outside of charging window. Most wrist watches have multiple alarm clocks in them, it shouldn't be too hard for BMW to have two separate charging/preconditioning clocks programmed into this machine. In closing to sum this up for the BMW engineers, if they even monitor this blog,TIE LOW COST CHARGING TO THE BEGINNING OF THE LOW COST WINDOW, NOT THE DEPARTURE TIME.
 
More flexibility is useful as long as it doesn't complicate things such that people can't understand or use it.

One thing to consider, though, is that the act of charging the batteries warms them, and for maximum range, the batteries must be warmed when cold, so instead of charging the car at the beginning of your window, if it starts later on, it may not need to use the on-board heater (it's a 1Kw electric device) to provide the heat...it can get the same effect by just performing the charging process...IOW, it can save in overall power consumption off of the mains. While the optional preconditioning of the cabin typically only starts ITOF 30-minutes prior, the battery warming process can start as much as 3-hours prior to your set departure time. I don't have access to tiered rates, so haven't really fussed with its use or when it is available, so might be missing something, but I do use the departure time and select the cabin preconditioning as well fairly often. I will say that on a fully charged car, I've seen my EVSE report a 20A load (it's a 30A unit) when working on warming the batteries and the cabin.
 
jadnashuanh, how did you get an ammeter on your EVSE? Is it built in? I'd like to have that ability, so I could run some calculations.
As far as charging, for us that do have off-peak price differences, it is a big issue. What's the sense of creating a function if it's not going to abide by it. In your example of warming your batteries, I could be wrong, but I don't think my vehicle warms the batteries if I'm not in precondition mode. Maybe you living in NH are in precondition most of the time and the high amp draw is mostly from the cabin heater. I know that device, when I turn it ON, automatically knocks 10 miles off my range. In my example of a charge window between 23:00-07:00, there is no reason the car shouldn't start charging at 23:00 and say complete charging by 03:00; then if need be, start a battery warming process at 06:00. Battery charging is one thing. Battery warming/preconditioning is another. Keep'em separate.
 
The whole purpose of setting a departure time is to maximize range. To do that, at least when it's less than warm out, it needs to warm the batteries up. Some people drive their car without using much of any cabin HVAC, so preconditioning it may or may not be worth the additional power use, but if you do want it warm or cool before you leave, yes, it's important to try to do it while still attached to the EVSE. Warming the batteries is done with a 1Kw electrical heating element inside of the battery compartment. Depending on how cold it is outside, it could be running for as much as 3-hours, or only for a few minutes, or not at all, if you're using the off-peak window and it made the batteries warm enough. Note, too, that if it's really cold outside, and the batteries are also cold, they can be made to hold a bit more if they're warmer, which again, maximizes your range.

My EVSE is hard-wired. On ebay, I purchased a panel mount meter, and installed it in an electrical box to the input to my EVSE. I ended up putting a box extender on it to give me a little more room so it wasn't all crushed inside. Hardest part, cutting a hole the right size to then snap in the meter assembly (used a metal cover, would have been easier if it were a plastic one). Total cost, only about $20. You could get a current reading if you own a clamp-on ammeter, but would then need to open some things up to get access to an individual power lead. I've had it for about a year. The one I have gives a readout of the input voltage, the instantaneous current, and power in wattage. It will also display an accumulated Kw readout that you can zero at any time. I generally do not zero it, so it has an accumulated use indication, essentially since I installed it. It's in the garage, and I usually have the cord passing through the wall and charge outside, so I don't actually look at it all that often.
 
chokahoss said:
BMW needs to rethink the low cost charging/departure time/preconditioning program. The way it's programmed now, low cost charging is tied to a departure time. The only reason to have a stored departure time is if you are using the preconditioning function. These are two separate functions and should be two separate commands, or programming parameters. Let me explain. First of all, I don't need to precondition my car all the time. I do that only in the winter, so for most of the year preconditioning is turned OFF; but in order to use the low cost charging function I have three departure times programmed: 1. M-F 06:50; 2. Sat. 07:20; 3. Sun. 08:30. My low cost charging window through my power company is 23:00-07:00. My M-F departure time of 06:50 happens to coincide with that charging window. My other two departure times are later in the morning and fall outside the low cost charging window. The program looks at your departure time, not the beginning of the low cost charging window, and delays the charging process in order to have the vehicle charged at departure time. This has led to instances where the vehicle has either not been fully charged or it is charging outside of the low cost window. There has also been occasions where I've needed to use the vehicle earlier than programmed, and the car is not charged because it is waiting for the programmed departure time. Low Cost Charging should be separate from Departure Time/Preconditioning. At 23:00, when the charging window opens, the vehicle should immediately start charging then shut down after full charge; then if you are in precondition mode, wake back up to precondition the car. I have seen my car lie dormant from 23:00 until 04:00, 05:00, 06:00 or more, I guess depending on the discharged state of the battery. That's crazy! Common sense would be start your charge as soon as you can within the window to assure a full battery. There is no benefit to delaying the charging process. Some disadvantages are: not being able to use the vehicle earlier than the programmed departure time; possible power outage later in the charging window, thus car doesn't get charged; as mentioned above conflict with departure times outside of charging window. Most wrist watches have multiple alarm clocks in them, it shouldn't be too hard for BMW to have two separate charging/preconditioning clocks programmed into this machine. In closing to sum this up for the BMW engineers, if they even monitor this blog,TIE LOW COST CHARGING TO THE BEGINNING OF THE LOW COST WINDOW, NOT THE DEPARTURE TIME.
Click to expand...

Holy words !!!!!

By the way, even the low cost charging window should be a little beit smarter and not being fixed for all the days of the week. In Italy for example low cost window is 7pm - 8 am mon to fri and 0-24 for saturdays and sundays (same also for any bank holiday)
 

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