Reported Range after full charge

[johnf[]]

The tires are fairly new Hercules Ironman iMove. They are supposed to be low rolling resistance tires.

The pressures were 46psi, and 3 at 38psi. They are all at 42psi right now.

I'll drive to work for a few days to get an average Wh/mi reading. What range should I expect?

Thanks,
-j

 

[campfamily]

"]

I'll drive to work for a few days to get an average Wh/mi reading. What range should I expect?

Thanks,
-j

I average 245 wh/mi, driving 55 miles per day, about 75% hwy, 25% city street. Highway driving in the morning is 65-80mph, afternoon, a bit slower. I run the HVAC system most of the time. I live in SoCal, so mild temperatures. I do see spikes in energy useage, as high as 275 wh/mi, when it's chilly (40 deg or so) in the morning. I also use the pre-heat function to heat the cabin and batteries morning while the car is plugged in most mornings.

 

[johnf[]]

Great input. I'm gathering information to go back to the dealership with. My 25mi commute is about 50% back roads at 45-55mi/hr. Then in town with in-town not-to-heavy commute traffic. I'm rolling from stop gently and trying to maximize braking electron recovery; typically 90-98%.

No heater or AC. Just some low drawing radio.

This morning with a full charge at the beginning, I got to work I had a range of about 38mi left. I hooked it up to the ChargePoint station and it took 8.1kWh. So that's burning 321.4 Wh/mi average.

You see spikes to 275 Wh/mi. Hmm, I'll continue to monitor.

Thanks,
-j

 

[WattsUp]

"]This morning with a full charge at the beginning, I got to work I had a range of about 38mi left. I hooked it up to the ChargePoint station and it took 8.1kWh. So that's burning 321.4 Wh/mi average.

The meaning of your figure of 321 Wh/mi depends entirely on where you got that 8.1 kWh number.

Did you get the 8.1 kWh number from the car, or the charger?

Remember that the charging process is, on average, only about 80% efficient, so 8.1 kWh delivered according to the charger is really only about 6.4 kWh stored in the battery. Or, 8.1 kWh stored in the battery according to the car is really about 10.1 kWh delivered by the charger. That's why I'm asking where you got the 8.1 kWh number. It can really skew your results if you mix up the two cases.

That all said... the car always reports Wh/mi based on the energy consumed from the battery, and so this means that dividing the energy delivered by the charger by miles driven will NOT match what the car says (the result of the calculation will always be inflated about 20%). Mind you, that calculation does give the actual "wall to wheels" Wh/mi rate of consumption, since it takes into account ALL the electricity required to make your car "go" (including the 20% wasted by the charging process, and which still also pay for, btw), but the car only tells us the "battery to wheels" rate of consumption.

Which is my point... most of the time here in these forums we talk about the Wh/mi figures displayed by the car. Therefore, it usually makes more sense to compare Wh/mi figures computed by dividing battery energy divided by miles, not the energy delivered by the charger. So, be sure of your computation before getting too concerned that your results don't seem "normal".

 

[campfamily]

Yes, as Wattsup states, my 245 wh/mi average is what the car is displaying, not what the charging station says. I record my miles and energy useage on a weekly basis (every Monday morning) and enter it into a spreadsheet. I use one of my trip odos to do this, resetting each week.

Keith

 

[johnf[]]

Gotcha. I used the 8.1kWh reported by the charging station. Rookie mistake. So [(8.1k)*0.8]/25.2 = 257Wh/mi. This seems ok. But the range I'm getting is in the high 50s to low 60s. On my first commute, I got the pull over safely message after 56mi.

I zeroed out trip meter this morning after a full charge. After my 2.52mi commute, the reported trip usage was 285Wh/mi. That one seems high. I'll keep a log this week of usage.

Thanks for the experienced input.

-j

 

[oilerlord]

Nope, nothing wrong with your battery; you're just putting too much stock in the Guess-O-Meter.

It will NEVER EVER show an accurate miles to empty value....let me repeat that: it will never ever show an accurate miles to empty value.

You'd be better off using the enhanced trip meter and record the Wh used for your trips. You'll most likely find that for the same trips your Wh used will be within a few % of each other for common routes.

this^^^

I haven't bought an EV yet, but after spending time in various EV forums, the Guess-O-Meter probably causes as much grief for customer service techs trying to explain it as it does for end users trying to understand how it works. At the end of the day, energy consumed given the distance traveled is all that matters. You know that your battery holds 23kWh of electricity. If you've driven ~25 miles and used ~7.5kWh of electricity you are on track roughly getting the EPA range for the car (76 miles). As others have mentioned, you mileage may vary due to temperature, speed, elevation, wind, using HVAC, tire pressure, etc.

Knowing how many kWh's used also gives you an indication of how much the trip cost. If your electricity rate is 10 cents per kWh, that above 25 mile trip using 7.5kWh would have costed $0.75 - or if you are able charge the car for free or with solar - put $0.75 in your jeans.

 

[johnf[]]

I'v been documenting my inbound trip from home to work.

Miles 24.8

Mon 294Wh/mi
Tues 289Wh/mi
Wed 294Wh/mi
Thu 274Wh/mi

This morning the Battery mile indicator said I had 41 mi to go.

23,000 x .90 = 20,700 Using 90% of full battery capacity
274 x 24.8 = 6,795 Wh consumed during commute
20,700 - 6,795 = 13,905Wh I should have left
13,905Wh/274Wh/mi = 50.7mi Remaining range based on average consumption

So I'm about 10 miles off in range. No A/C, no heater, headlights on most of the way.

The car has an EPA range of 76 miles and a fuel economy rating 310Wh/mi based on a report I have.

I'll do this again tomorrow and get back to the Ford dealership with my numbers.

Let me know if I'm not looking at this correctly.

Thanks,

-j

 

[WattsUp]

"]23,000 x .90 = 20,700 Using 90% of full battery capacity
..
Let me know if I'm not looking at this correctly.

A little incorrectly.... your 90% assumption, and usable energy computation, is too high.

To clarify, the car reserves "buffers" of nearly 10% of the total capacity at the bottom and top of the battery (to prevent under- or over-charging), for a total of a bit under 20% reserved exclusively for battery protection. This leaves something a bit over 80% of the battery available for use, not 90%.

Thus, the usable energy is more like 19,000 Wh, not 20,700 Wh.

 

[johnf[]]

Ok,

23000 x .80 = 18,400 Wh

18,400 - 6,795 = 11,605 Wh remaining

11,605/274 = 42mi

So the reported 41mi remaining range is in line with calculated.

It appears like this car is starting to behave now.

Thanks,

-j

 

[WattsUp]

"]So the reported 41mi remaining range is in line with calculated.

It appears like this car is starting to behave now.

Seems so.

I think the car actually has somewhere above 80% available, but none of us know what internal software parameters are for sure (only Ford does). But, as you can see, assuming 80%-ish makes for reasonable calculations and seems to align with the behavior we see from the car.

 

[v_traveller]

"]The tires are fairly new Hercules Ironman iMove. They are supposed to be low rolling resistance tires.

As one might imagine, not all LRR tires are created equal.

Out of curiosity, I looked up these tires and compared them to the OEM Michelins, here are differences:

- iMove has a 420 treadwear rating, Michelin has 480. Hercules may have a stickier compound, which increases rolling resistance.
- iMove is 25.3lb, Michelin is 22.2lb, so iMove is heavier.
- iMove has a 10/32in tread depth, Michelin has 9.5/32in. Deeper tread typically increases rolling resistance.

Hercules also seems to position their iMove as a performance tire, so although they claim LRR, "fuel" efficiency may not be one of its strengths. Kinda explains why they are heavier.

Long story short - I'm guessing that the tires are a contributor to experiencing a lower range than expected. Since they are new, you may experience an increase range as the tires wear in.

Is it worth swapping for OEM? If you're okay with the range, performance, and ride comfort, I'd say definitely keep them. The OEM Michelins are almost twice the cost of the iMove.

EDIT: forgot to cite references:
http://www.herculestire.com/tire-gallery/passenger-and-light-truck/uhp/
http://www.michelin.ca/tire-selector/category/passenger-car-minivan/energy-saver-a-s/tire-details#techspecs

 

[johnf[]]

It's good to get into the details.

When driving on a freeway with rain grooves, the car was definitely influenced by them; it wiggled quite a bit.

I have to think much differently when driving the FFE, than when driving the BMW 540 it replaced.

So many factors come into play when driving one of these I didn't think of when there is a gas station on every corner.

Thanks,
-j

 

[johnf[]]

I wanted to post the fix for my issue.

I dropped off my car at the Ford dealership service department. They hooked it up to a level 3 charger for 2 full days.

This was part of a rebalancing of the batteries. Recommended by the engineers at the mothership.

I no longer get the erratic behavior and the car seems like it will make the 70+ miles on a full charge now.

Before, just turning on the fan at the lowest setting with the AC off would cause the range to drop 10 miles or so.

This no longer happens.

Early on I mentioned, using lead acid battery language, it seemed like it had a dead cell. I was almost correct.

After driving it for a few days, the car is behaving much better now.

-j

 

[jeffand]

Equalizing the cells in the battery happens at the end of the charging cycle. Variations cell temperature during the charging process could result in variations in invidual charge. Keeping battery on the charger for an extended period will allow the cells to be all at the same temp. Since cell capacity is affected by temperature. This should allow for more accurate equalization to take place, if all the cells are at the same temperature.

 

[electrons]

The Guess-O-Meter is a tad strange at times. This morning it said 98 miles, unexplainable since it usually would read 75 miles at that time.
And, after rolling down a mountain, it can read 138 miles or so. Just crazy.
I'm not sure why the software on board can't just place a reasonable cap, a limit, on the range displayed, like 85 max. Anything higher is just fraud.

"]I wanted to post the fix for my issue.
I dropped off my car at the Ford dealership service department. They hooked it up to a level 3 charger for 2 full days.

Level 2, at a 6.6 kW energy flow rate, is the most a Focus Electric can take.

"]This was part of a rebalancing of the batteries. Recommended by the engineers at the mothership.

Nice to know for future reference. I'm wondering if they just let the Focus's own on-board software computer run that show, with no outside intervention, and leaving it plugged in for a long time may allow errant battery cells to "catch up". Weird science, this battery stuff.
Does anybody know if the Ford techs (and us) can read individual battery cell voltages via the OBDII port? Of course I'd expect the on-board monitoring computers to notify the driver at some point if there was a lazy cell someplace (threshold voltage difference maybe).

"]I no longer get the erratic behavior and the car seems like it will make the 70+ miles on a full charge now.

Wow, the fact there was not a dashboard warning light (Check Engine, aka MIL) telling you something was wrong is just not right.

Now, for the rest of us, lesson learned: If our range is down, then try to convince the Ford dealership to "re-balance" our battery cells. Of course, we, at home, shoud first try just leaving it plugged in for 2 or 3 days straight to see if that alone fixes it.

 

[electrons]

"]The tires are fairly new Hercules Ironman iMove. They are supposed to be low rolling resistance tires.

As one might imagine, not all LRR tires are created equal.
Out of curiosity, I looked up these tires and compared them to the OEM Michelins, here are differences:

All this talk about tires, a big subject all by itself, I have a couple of observations:
My favorite LRR tire is the Bridgestone Ecopia in our 225/50-17 size. Really any name brand LRR should be fine, and choices abound (Michelins are great, Goodyear, etc.). I even think any of the $80 TireRack.com tires in our size would be OK for non-ice/snow climates, but I'd only get a cheap tire from S. Korea, not China, out of all the low-cost tire choices.

That said, your Hercules (Cooper really) tires should be OK.

I'd not go over 40 psi on the tires. 42 is too much. The tire placard on the car's door says 38 psi, not to exceed that too much.

 

[johnf[]]

I read through the Corrective Actions taken as recommended by Ford. "Fully charge the HVTB using a 240V charger. After the battery has been fully charged, leave the charger connected to the vehicle for 2 full days. Disconnect the charger and perform the SOC balancing procedure using IDS. This will re-balance the cells and correct any voltage/cell variations."

What ever the IDS SOC balancing procedure did, worked.

Cheers,
-j

 

[electrons]

"]I read through the Corrective Actions taken as recommended by Ford. "Fully charge the HVTB using a 240V charger. After the battery has been fully charged, leave the charger connected to the vehicle for 2 full days. Disconnect the charger and perform the SOC balancing procedure using IDS. This will re-balance the cells and correct any voltage/cell variations."

What ever the IDS SOC balancing procedure did, worked.

The IDS (Integrated Diagnostic System) is a laptop computer hooked up to the car, commanding stuff to happen.

Thing is, I'm surprised the car doesn't just do all that "balancing" on its own, without having to get a dealer to do it. Granted, the 2-day soak on a Level 2 240v outlet is more than I could do, since I only charge at home with an easy 120v.

 

[johnf[]]

Is IDS out on the net somewhere where it can be downloaded?

-j