"low cost charging" option grayed out...?

[808Pants]

Is there something missing from my i3 that prevents me from the setting to "low cost charging?" Our rate is lowest between 9AM and 5PM, and I've set the rest of the associated settings to correspond to that, but the "low cost charging" option (vs "charge immediately") is grayed out so apparently I can't select it for some reason. Here's a pic: https://photos.app.goo.gl/iGPdDU9mRXjKJXLb9

 

[eNate]

I believe you have to first set a departure time for LCC to be enabled.

 

[808Pants]

I should have started with "what's a departure time, and why would it have anything to do with the setup for low-cost charging?"

<5 minutes of googling and eating breakfast>

er, no, I should have just googled up your old post at https://www.mybmwi3.com/forum/viewtopic.php?t=17276 . I will look for a way to disable the preconditioning setting...

thanks, Nate.

 

[eNate]

Yeah, it's a myoptic take on low cost charging. I would love to hear BMW's rationale.

 

[808Pants]

Nate, I spent a lot longer than I'd like to have, NOT finding a way to disable the preconditioning setting while out yesterday, then googling some more just now, which would have saved me the trouble of even looking. From the above, seems like I'm stuck with setting a departure time. At least it's not likely (here in Honolulu) to consume any power for battery-warming (which kicks in below 50F, per a post of Alohart's).

The other potential energy-leak: I don't understand whether it's possible to prevent wasting power preconditioning the cabin when I'm not actually going to leave at any given time related to the low-cost charging period (of 9-5PM). A vid I was just watching says the cabin-temp target is determined by however it was last left before being locked. So if I set departure to any particular time between 9-5, the car's going to be warming up from daytime temp increases (cover is on, and it's in sunlight) to well past whatever my last temp setting was: the AC would try to cool it down during charging between 9-5, while it's sitting, right?

I wonder whether "departure time" 'times out' if the car doesn't move during that preset time?
Does preconditioning only happen when the EVSE is plugged in?

Seems like I'm going to have to either give up on this or verify clumsily and experimentally. I've got an ammeter hanging on the AC feed to the EVSE, which I was using to monitor charging current, so I guess if I saw it going over 15A during a charging session, or reading any flow OUTSIDE of the 9-5 period, I'd know there was a problem

But...this starts to seem like way too much of a time-suck now that I'm writing this.

 

[alohart]

The i3's low-cost charging implementation has been buggy over the years. It might work fine in some integration levels (system software versions) and poorly in others. Because of this, I've never tried it.

It seems that you might be on HECo's Residential Time-of-Use rate schedule as I am in which the lowest cost occurs between 9 am and 5 pm when the solar power produced can actually exceed what HECo can use on some days. Because I am retired, our i3 is usually parked in its apartment parking garage space between 9 am and 5 pm, so it's easy for me to charge during that period. I just plug in our EVSE, notice the estimated time when charging would finish, and set an alarm on my Apple Watch that reminds me when I need to unplug our EVSE. I don't usually charge to full, so I know that if I stop charging ~1 hour before the estimated completion time, the charge level will be around an indicated 90%.

 

[808Pants]

Thanks, Art.

Yes, in theory, as of a few months ago, I am on time – of – use, with HECO. That would probably take several more posts in some other forum, so I won’t go into that for now.

I had not yet stumbled across the estimated charge-completion hours that I think you were describing… Have not looked for it either, but it sure makes sense that there would be such a feature. Is it easy to find?

On your TOU bill, the paper one: does it do anything to distinguish between kilowatt hours billed at each of the three different rates?

I’ve been drafting a complaint to the PUC because I think HECO has been knowingly or unknowingly overcharging people who are on the TOU program, most of whom are diligently trying to minimize their bills. I have only found any indication of each months breakdown by digging deep into the HECO website (in your tracking portal.). The short version is that they apparently are charging mid- or peak – use rates during the supposedly lowest-cost 9 to 5 period.… But it’s very difficult to see how that sausage is made.

 

[alohart]

I had not yet stumbled across the estimated charge-completion hours that I think you were describing… Have not looked for it either, but it sure makes sense that there would be such a feature. Is it easy to find?

A few seconds after beginning a charging session, the estimated completion time is automatically displayed on the instrument panel.

On your TOU bill, the paper one: does it do anything to distinguish between kilowatt hours billed at each of the three different rates?

Yes, the total number of kWh for each rate period is itemized.

I’ve been drafting a complaint to the PUC because I think HECO has been knowingly or unknowingly overcharging people who are on the TOU program, most of whom are diligently trying to minimize their bills. I have only found any indication of each months breakdown by digging deep into the HECO website (in your tracking portal.). The short version is that they apparently are charging mid- or peak – use rates during the supposedly lowest-cost 9 to 5 period.… But it’s very difficult to see how that sausage is made.

When I started the TOU program in January, 2018, the first three or so statements included the cost under the previous residential rate as well as under the new TOU rates. If the total cost under the TOU rates exceeded those under the residential rate, I was given the option of returning to the residential rate. That didn't happen. I asked HECo how they computed costs and configured a spreadsheet to continue comparing residential with TOU rates over the months since. My average savings of the TOU cost vs. the residential cost has been over 7% with no month where the residential cost would have been less than the TOU cost. I haven't noticed any change in the savings over 5 years, so I'm still happy with the TOU rate and haven't seen any evidence of overcharging.

However, HECo hasn't installed its new digital electric meter on our electrical service. Another i3 owner in Honolulu has complained that his electricity bill increased by 30% after a digital electric meter was installed. His increase in energy consumption hasn't been explained. He suspects that the meter is inaccurate or something with the billing is incorrect, but he hasn't gotten much help from HECo.

 

[808Pants]

Art,

Thanks for all that background.

Not that I'm Erin Brokovich, but I just sent you a PM. I recall you had some issues retrieving them but maybe it's working now...(or maybe THEY are out to stop me...)

Regarding

However, HECo hasn't installed its new digital electric meter on our electrical service. Another i3 owner in Honolulu has complained that his electricity bill increased by 30% after a digital electric meter was installed. His increase in energy consumption hasn't been explained. He suspects that the meter is inaccurate or something with the billing is incorrect, but he hasn't gotten much help from HECo,

I do wonder if what I PM'd you about is a smoking gun for that guy.

I'm no meter-nerd but I'd have assumed HECO couldn't parse your usage periods without installing a new meter...maybe your existing one was an earlier version but recent enough to do so? After seeing my PM, you might wonder whether you've been getting overcharged (a lot), especially if you're diligent about your i3 charging hours, as it seems you have been (why else would you have signed up for TOU back in 2018, otherwise?)

Hasta - Dave

 

[808Pants]

Yeah, it's a myoptic take on low cost charging. I would love to hear BMW's rationale.

Nate, I've been thinking about this a little more. Do you have knowledge (or an opinion...) as to whether my approach below would make sense?

I get home daily at, say, 4PM (start work at oh-dark-thirty.) That schedule would give me just 1 hour of potential charge-time before the 5PM rate-hike from low- to mid-cost kWh, since low-cost hours are 9-5PM. (EVSE is as basic as they come, so no timing option there.) So if I were to set a fake i3 "departure time" for our cooler hours (well after dark), assuming it's not going to try to warm up batteries in Honolulu temps, it seems like the only potential for wasted energy would be if my cabin heater turns on to try to regulate interior temp before that fake departure time. I'd probably best monitor for that at first. Anyway, I can't come up with a better general scenario than that. Ideas?

My regular commute and excursions leave me at about zero by mid-Thursday, so other than running on Rex, I don't have a low-cost charging option until Saturday 0900 otherwise. An hour's charge (level 2) each night would probably deal with all of that, but I really need to automate the timing.

 

[alohart]

I get home daily at, say, 4PM (start work at oh-dark-thirty.) That schedule would give me just 1 hour of potential charge-time before the 5PM rate-hike from low- to mid-cost kWh, since low-cost hours are 9-5PM. (EVSE is as basic as they come, so no timing option there.) So if I were to set a fake i3 "departure time" for our cooler hours (well after dark), assuming it's not going to try to warm up batteries in Honolulu temps, it seems like the only potential for wasted energy would be if my cabin heater turns on to try to regulate interior temp before that fake departure time. I'd probably best monitor for that at first. Anyway, I can't come up with a better general scenario than that. Ideas?

I don't have any experience with battery pack or cabin preconditioning, but I believe that they are not automatically active when low-cost charging is active. If you don't choose either type of preconditioning, neither would occur while low-cost charging is active.

I also don't have experience with low-cost charging because of so many complaints about it not working as expected. For me, low-cost charging is just too uncertain and too troublesome, so I start and stop charging manually, setting an alarm on my Apple Watch to remind me when to stop charging.

I don't know what the low-cost charging software would do if it tried to start charging before you plug in your EVSE. Would charging start immediately upon plugging in your EVSE or would the low-cost charging session be cancelled for that day because no EVSE was plugged in when charging should have started? I guess the answer to that would be pretty easy to learn by trial and error, or maybe someone who knows will respond.

Low-cost charging doesn't work perfectly with a time-of-use electricity rate because the primary goal of low-cost charging is to fully charge the battery pack even if that means charging outside the low-cost window. Therefore, if you set a departure time of 7 pm and fully charging would take more than 3 hours, charging would try to start earlier than 4 pm. If fully charging would take more than 1 hour and you plug your EVSE at 4 pm, charging would continue past 5 pm. Unless your TOU rate is different from mine, 5 pm - 10 pm is the most expensive rate period, currently 19¢/kWh higher than 9 am - 5 pm, so I have a lot of motivation to avoid charging after 5 pm.

If low-cost charging were set to be active on every weekday, and you don't drive enough to make fully charging take more than 1 hour each day, your battery pack might be full before the electricity rates climb at 5 pm.

A more reliable solution would be to start charging when you arrive home and manually stop charging by 5 pm. If you don't need the full range, charging to full every day isn't necessary and might even result in somewhat faster battery cell degradation over time. I manage charging manually and usually stop at a charge level of ~90% (indicated) or at 5 pm if the battery pack isn't full by then. Living in an apartment with my parking space in our parking garage, I consider walking down and up 2 flights of stairs and ~1,000 ft. of walking round-trip to my parking space to be good exercise. If you really want charging to be automated, you might have to accept paying more for charging than if you managed it manually.

 

[frictioncircle]

Hello 808Pants –

I've been driving i3 BEVs since 2014 and live in a US state with expensive electricity that's now billed by time-of-use.

I didn't care for the behavior of BMW's "Departure Time"-based charge settings and subsequently switched to an EVSE with clock-based charging times and setting the i3 to "Charge Immediately".

My EVSE is set to charge only when rates are lowest.

When I get home and need a charge, I plug in, regardless of the time of day. The i3 displays the "connected" icon in the instrument cluster which confirms the connection, but my EVSE won't deliver any charging until I'm in the lowest-rate time period.

If you're able to upgrade your EVSE then I think you might find it a more pleasant experience over dealing with Departure Time.

 

[808Pants]

Thanks frictioncircle - I just ordered a 30/240V timer-relay to avoid having to replace my EVSE (which I'll install adjacent to my load center & which will interrupt feed to 240V receptacle for the EVSE), but yes, it's time for me to give up on what sure seemed like it was a pre-engineered on-board means to tailor charging hours. ["Good, fast, cheap...pick any two..."]

 

[alohart]

Thanks frictioncircle - I just ordered a 30/240V timer-relay to avoid having to replace my EVSE (which I'll install adjacent to my load center & which will interrupt feed to 240V receptacle for the EVSE), but yes, it's time for me to give up on what sure seemed like it was a pre-engineered on-board means to tailor charging hours. ["Good, fast, cheap...pick any two..."]

Beware that stopping charging by interrupting the EVSE's input power will likely result in a charging fault being set on the car. I have a manual on-off switch on our EVSE's circuit so that it doesn't continuously consume a few watts of power when charging isn't occurring. I once accidentally turned off the switch while charging was active. I don't recall any problems as a result of this fault. It might have been implemented merely to alert an i3 owner that charging didn't complete as expected or was interrupted.

Another potential problem is that some EVSE's won't always automatically restart normally after input power has been interrupted. EVSE's run computer code to implement the charging protocol safely, so suddenly stopping the execution of this code could leave an EVSE in an unexpected state from which it cannot recover automatically. Power-cycling an EVSE while it's not plugged into a charge port usually fixes this problem. This problem likely doesn't affect most EVSE's, but some EV owners have reported such problems.