Preconditioning when on a utility off peak charging program

[y7eah]

Our utility recently changed to a flat rate charging program between 9pm-5am, with increased on peak rates for other hours. We previously used preconditioning for winter driving for 7am (located in WI) however that energy usage now falls into on peak rates (.40 kWh). We got a surprise on our first bill with this new program due to preconditioning.

I can plug in using the Ford charger to a normal 20amp wall outlet and pay out normal rate of .11kWh for preconditioning. Only problem is the next time I use the 55amp charger the car cycles it constantly. It seems like the two charges at the same GPS location confuses the software.

Anyone else in a similar situation? Do you still use preconditioning despite the higher cost? I’m also curious if there might be a battery longevity reason to fork out the extra money…

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[SnBGC]

Using two different EVSEs shouldn't be a problem. Your car charges at 55A?

 

[y7eah]

Using two different EVSEs shouldn't be a problem. Your car charges at 55A?

I’ll try using both again, could have just been a coincidence.

Just double checked, my EVSE is actually 60amp which maxes out what the car can pull when L2 charging.

 

[Mach-Lee]

Only problem is the next time I use the 55amp charger the car cycles it constantly. It seems like the two charges at the same GPS location confuses the software.

Anyone else in a similar situation? Do you still use preconditioning despite the higher cost? I’m also curious if there might be a battery longevity reason to fork out the extra money…

The max the Mach-E can take is 48 amps. If your other charger is on regular metering then I would use that. Shouldn't cycle, not sure what that's about.

One thing you could also do is set a departure time/scheduled start at 4:30 AM, that will warm/cool the battery on the cheap power. Then do just a remote start at 7AM, the battery should be fairly warm still so it will take less expensive power than if it sat all night. Overall it's a little more wasteful but might be cheaper. Another strategy is to delay your charge window as long as possible so charging finishes close to 5 AM, that way the battery will not have as long of time to cool off.

If you have the option, try to shift your "cheap" window to 11PM-7AM. They didn't give you a very good option there IMO. I like to see 10 hour windows that end no earlier than 7 AM for off-peak programs.

 

[SnBGC]

I’ll try using both again, could have just been a coincidence.

Just double checked, my EVSE is actually 60amp which maxes out what the car can pull when L2 charging.

According to the manual. If you set a departure time while plugged into L1 then the car might use some power from the HVB to supplement shore power for pre-conditioning. That should keep your energy use low during the warm up period.

Alternatively, since you are able to set two departure times per day....you can set one at 4:30 am and other at 7:00. That way it will warm the battery and car on the off peak rate and spend less energy to do it again later in the morning.

 

[RickMachE]

Preconditioning at 110v is not very effective.

 

[SnBGC]

Preconditioning at 110v is not very effective.

Agreed. But it could save the OP some demand charges if applicable. Lots of different rate plans out there. Some better than others.

 

[AKgrampy]

So do you have two separate meters? Also am I assuming correctly that your car is outside and not in a garage?

 

[y7eah]

So do you have two separate meters? Also am I assuming correctly that your car is outside and not in a garage?

One meter, but the charger they provide has a cell modem in it that feeds usage and charge data back to them. It's a Clipper Creek EVSE that ZEF Energy modifies to add cellular smart capability (https://www.zefenergy.com/store/115kw-zefnet-singlehead-wallmount-y29hk).

I believe they just deduct whatever the charger gives them for usage from the overall meter usage and bill that based upon reported time from the EVSE. It's a smaller local energy CO-OP so I've given them feedback on it as it's not even possible to see which day you used peak rates when charging. Apparently they have someone who does all the billing manually by pulling the usage.

We park in the garage so probably not a huge deal but it does get very cold here (-35F at times).

 

[RickMachE]

Keep in mind that there are two different options for prepping your car.

1) Preconditioning, i.e. setting a departure time - this warms the battery, then the cabin, designed to work off house current. Helps with range in winter by getting the battery warmer. May not matter if you don't drive far enough to need more range.

2) Remote starting - doesn't do anything for the battery, just warms the cabin (or cools it). Can run off house current or off the battery, will of course use some battery with the latter.

#1 and #2 result in the same for the cabin comfort.

Also note that if your vehicle is plugged in, it will start charging (i.e. pulling wall power) at non-programmed times if it determines that the battery needs to to stay warm, or colder, regardless of how you set the car. In other words, car is at your set 90% charger. At 4AM it decides to pull current for 15 minutes. The only way to prevent that is via an intelligent wall charger. Mine is set to only provide current during my off-peak hours of 7PM - 11AM Mon-Fri, and all day on weekends. So, if at 11:30AM on a Tuesday it's 10 degrees in my garage and the car wants to warm the battery, it's going to have to do so off the battery power, I'm not providing any wall current.

 

[AKgrampy]

One meter, but the charger they provide has a cell modem in it that feeds usage and charge data back to them. It's a Clipper Creek EVSE that ZEF Energy modifies to add cellular smart capability (https://www.zefenergy.com/store/115kw-zefnet-singlehead-wallmount-y29hk).

I believe they just deduct whatever the charger gives them for usage from the overall meter usage and bill that based upon reported time from the EVSE. It's a smaller local energy CO-OP so I've given them feedback on it as it's not even possible to see which day you used peak rates when charging. Apparently they have someone who does all the billing manually by pulling the usage.

We park in the garage so probably not a huge deal but it does get very cold here (-35F at times).

I live in Alaska but only have my car for the last month so no winter experience yet. My suggestion would be to skip preconditioning if your car is in a heated garage. Mine is set at around 55 deg F and I think battery conditioning will not provide much benefit. I would suggest you set your EVSE to not charge outside the off peak time. If you want your cabin warm and range is not an issue I would start the car in advance. This would consume some of your battery but it would be 11 cent power versus 40 cent. Finally provide feedback to utility to stretch window to 7:30 AM as most workers on a schedule should depart by then. Obviously that would depend on what the power grid looks like demand wise at that time of day.

 

[Murse-In-Airy]

My question for you to start with would be, why are you preconditioning? One can’t really help you with the cost benefit analysis if we don’t know the benefit (your goal).

From my experience, preconditioning is nice for longer trips where I’m trying to maximize my miles/kwh. When I’m trying to squeeze every last mile out of my battery. So a warmed battery gets me the best efficiency.
But 99% of the time, I’m not driving over 40 miles, and preconditioning doesn’t matter one iota. On those days a 5 minute remote start warms up the cabin and preheats my seat so I can drive away in comfort. This cost relatively little electricity, way less than it would have cost to remote start my ICE vehicles in the winter. So I’m willing to buy a kwh or two to warm up my seat. But unless I’m trying to drive 200 miles, I’m not willing to buy many more kwh to prewarm my battery.

 

[AKgrampy]

My question for you to start with would be, why are you preconditioning? One can’t really help you with the cost benefit analysis if we don’t know the benefit (your goal).

From my experience, preconditioning is nice for longer trips where I’m trying to maximize my miles/kwh. When I’m trying to squeeze every last mile out of my battery. So a warmed battery gets me the best efficiency.
But 99% of the time, I’m not driving over 40 miles, and preconditioning doesn’t matter one iota. On those days a 5 minute remote start warms up the cabin and preheats my seat so I can drive away in comfort. This cost relatively little electricity, way less than it would have cost to remote start my ICE vehicles in the winter. So I’m willing to buy a kwh or two to warm up my seat. But unless I’m trying to drive 200 miles, I’m not willing to buy many more kwh to prewarm my battery.

Exactly, and just use car’s battery to warm it up if the cost of power is significantly greater at the time you start it. For myself there is no price differential on electric rates (always high!) so it does not matter.

 

[y7eah]

All good points here, I think we will skip preconditioning next winter unless going on a roadtrip where range matters.

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