Hybrid Battery odd gauge function

[ptjones]

I had a funny thing happen on my trip with the Hybrid Battery Gauge after I had twice stopped for gas and once stopping to stay over night in Motel.  I had EVed prior to stopping so EV battery was low, but when I started the car, the gauge showed almost full. This also happened once or twice before trip to Arizona. The Gauge goes down fairly quickly so I guess the Battery is not full, but is a surprise to see it jump up like that. Anyone see this happen?

 

Paul

[Adair]

Not that much of a jump, but I've driven to work, stopped the car with the battery *VERY* low and came back out at lunch with nearly half a charge.

 

Jus blamed my aliens.

[drdiesel1]

The battery will gain some charge back after sitting and cooling off, but it's only a surface charge. That's why it drops off so quick.

[fotomoto]

I guess it depends on what Paul is calling "low" and "almost full".   I've seen about 1/2 rise up to almost full after sitting but without pics folks won't know my reference points either.  Taking a page from either my former Prius or Volt, I wish the Cmax had individual pips for battery level.  

 

I have a scan gauge and finally added a custom X gauge for the HV battery state-of-charge (SOC).  Although I don't understand the scale yet, the SOC is in numerical form which is much easier to read.  Please excuse blurry pic:

 

 

 

[wab]

I guess it depends on what Paul is calling "low" and "almost full".   I've seen about 1/2 rise up to almost full after sitting but without pics folks won't know my reference points either.  Taking a page from either my former Prius or Volt, I wish the Cmax had individual pips for battery level.  

 

I have a scan gauge and finally added a custom X gauge for the HV battery state-of-charge (SOC).  Although I don't understand the scale yet, the SOC is in numerical form which is much easier to read.  Please excuse blurry pic:

 

 

Off topic

I've printed this picture and tomorrow I'm going to duplicate it, anybody think I'll get 50+mpg?

 

Back on topic.

Where did you get the PID code for the xguage SOC?

 

The cmax is truly a hybrid, 1/2 Europe 1/2 N. America, maybe you need a hybrid pid???

 

wab

[fotomoto]

Back on topic.

Where did you get the PID code for the xguage SOC?

 

The cmax is truly a hybrid, 1/2 Europe 1/2 N. America, maybe you need a hybrid pid???

 

A thread had a link to them on the Energi forum.  Note:  PID's are originally from the fusion energi so some may or may not work.  I've only loaded the SOC gauge so far.

 

http://fordcmaxenergiforum.com/topic/1293-scangauge-x-gauges-programming-c-max-ffh/

[wab]

Thanks...added to bookmarks.

 

Your trouble is probably in the "MTH" pid

 

Hv  Battery State-of-Charge: units %

TXD:07E4224801
RXF: 046245480601
RXD: 3010
Mth : 000100050000
NAM: SoC

 

How much bigger is the Energi battery than our hybrid? Looking at your display it looks about 40+/-%???

Ask them where they got the mth#. It's probably just 1 or two digits that need to be changed.

 

 

[ptjones]

This is something that has started in the last three weeks I think. It hasn't happened since I got back from my trip two days ago. I did get my oil changed yesterday, but that's all. I will comment if it happens again.

 

Paul

[HPRifleman]

Off topic

I've printed this picture and tomorrow I'm going to duplicate it, anybody think I'll get 50+mpg?

 

You will if you keep the state of charge high. I have done this on the interstate but it takes a lot of vigilance.

[wab]

Off topic

I've printed this picture and tomorrow I'm going to duplicate it, anybody think I'll get 50+mpg?

 

Back on topic.

Where did you get the PID code for the xguage SOC?

 

The cmax is truly a hybrid, 1/2 Europe 1/2 N. America, maybe you need a hybrid pid???

 

wab

 

 

You will if you keep the state of charge high. I have done this on the interstate but it takes a lot of vigilance.

 

I didn't notice his battery until I tried to duplicate, took the picture THEN :drop:

[drdiesel1]

The Energi battery is 7.6 kWH's and the Hybrid is 1.4 kWh's.

[hybridbear]

I guess it depends on what Paul is calling "low" and "almost full".   I've seen about 1/2 rise up to almost full after sitting but without pics folks won't know my reference points either.  Taking a page from either my former Prius or Volt, I wish the Cmax had individual pips for battery level.  

 

I have a scan gauge and finally added a custom X gauge for the HV battery state-of-charge (SOC).  Although I don't understand the scale yet, the SOC is in numerical form which is much easier to read.  Please excuse blurry pic:

With my ScanGauge I have gathered lots of data about the battery SOC. See this post at the FFH Forum and subsequent ones I've made in that thread.

 

In that thread I also explain what ptjones observed. As the car sits and the HVB temp changes the SOC also changes. Click the link for more explanation.

 

In this post I talk about the relationship between the battery icon on the dash and the useable SOC. The battery icon on the dash does not follow a linear scale.

Edited November 10, 2013 by hybridbear

[ptjones]

It has been 5 days and I haven't seen this happen again. I'm wondering If this has something to do with FWY driving and then EVing to a stop with low HB, near bottom of gauge. Sitting time varied from 20min. to 8hrs.

 

Paul

[ptjones]

I have seen this happen at least 4 times in the last month, couple  of times on my trip to SF. Curious, I haven't seen any ill effects though yet. :) 

 

Paul

[Tdefny]

It happened to me last week. I had a great morning commute for this time of year and got to work with 53%, but found 47% when it was time to leave and about 12 degrees colder. I barely made it home without the ICE.

[hybridbear]

When the HVB cools the SOC increases slightly.

[ptjones]

When the HVB cools the SOC increases slightly.

What I'm talking about is a big change like 1/3 to 3/4 full. :)

 

Paul

[hybridbear]

What I'm talking about is a big change like 1/3 to 3/4 full. :)

 

Paul

The dash icon isn't linear. A jump in useable SOC from 35 to 55% would appear on the icon to jump from 1/3 full to 3/4 full. The dash gauge appears half full at about 40% useable SOC and 3/4 full by 55-60% useable SOC. At 60% useable SOC the ICE will stop charging the battery. ICE HIGH happened at 60% useable SOC. At 40% useable SOC the car begins to reduce the amount of charge going into the HVB.

 

It's not unusual in my observation to see a 20% useable SOC jump when the battery cools from 70+ degrees to under 40 degrees

Edited March 2, 2014 by hybridbear

[ptjones]

I guess I need to set my ScanGauge to read SOC. This has happened a number of times when my car has been in the garage over night. :)

 

Paul

[plus 3 golfer]

Measuring SOC is a challenge for the engineers.  We don't know the algorithm used.  The following is what I have gleaned from my research.  If someone finds something to the contrary, please post.

 

IMO, the reason the SOC increases after the car is shut down is not related to temperature change but discharge rate change.  There is actually more available capacity in the battery at higher temperatures than lower temperatures as indicated in the discharge curves in the figure below for lithium ion battery. So, as the battery cools one would see less capacity not more.   One should not confuse battery degradation or capacity loss due to high operating temperatures (charging / discharging) over time (like the Leaf with no active battery cooling) with SOC.

 

Under a higher discharge rate, cell voltage and battery capacity will be lower than under a very low discharge rate.  There have been studies and many papers written on this subject.  Simplistic algorithms might rely heavily on cell voltage in determining SOC.  More complex algorithms will accumulate discharge / charge current over time along with the voltage in estimating SOC. IMO, after the car has been off for a length of time (discharge rate is virtually zero), voltage and capacity will likely increase. So, depending on the algorithm SOC will likely show a higher SOC after the car is off for a period of time than when operating the car at higher discharge rates.  

 

Also, it's possible that using EV+ might yield a lower SOC displayed as there might be a longer / higher discharge rate for the last 1/4 mile or so.  In any event, I see no reason for concern.  It certainly appears that Ford is very conservative in using the battery capacity.  My SOC usually ranges from about 42% to 54% in normal driving.

 

Edited March 3, 2014 by Plus 3 Golfer

[ptjones]

I think what you say makes sense.  Do you know what the actual Voltage of HVB is, I have seen a few different numbers? :)

 

Thanks

Paul

 

I just checked my manual and it said approx. 300Volts and going by your graph it would very from 150Volts to 300Volts.

Edited March 2, 2014 by ptjones

[plus 3 golfer]

IIRC, the hydrid has 76 cells in series. The curve is not for a C-Max cell but only to demonstrate the shape and discharge capacity vs temp. But, say 4.15 V per cell would be about 315 V max. I doubt the PCM would allow the voltage to get anywhere near 150 V on the low end. If the battery were cold, the operation of using the battery would likely be severely restricted until the battery warmed up. Once the battery is warm, one still wants the operation to stay fairly far away from the knee of the curve.

 

For example, at 25 C and above you might want to operate down to 35% SOC (65% discharge on curve) which looks like about 3,75 V per cell or about 285 V. So, 300 V looks like a good average voltage for the hybrid battery.

[chrisl]

I've noticed this as well- first I noticed that when I got home it would be almost full charge (maybe one row of pixels short), then I'd get in the car the next day and it would be full.  I attributed this to temperature - it can get pretty cold overnight here, even if it's warm during the day.

 

Lately, I've been starting the car to leave work and seeing it around 2/3 charge, despite an extended EV+ range as I get into work (as I notied in another thread, I have an EV+ location about a mile before work because I stop for coffee regularly).  I had been thinking that I just wasn't watching the battery level, but now I'll watch more closely to see if it's a real effect.

[kostby]

How about the opposite function?

 

Anyone ever parked with the HVB indicator showing about 'half full', and then, the next day, it shows absolutely no charge?

 

Had this happen yesterday, for the second time. Thinking back, the first was on the first test-drive of the car in March, when the HVB was blank, but at the time I didn't know how the displays worked, so it didn't seem abnormal.

 

This was after driving about 2 miles from home near another frequent destination, thus the EV+ indicator.

 

 

Car unlocked and started normally, so the 12V Battery functions seem OK. Noticed no charge in the HVB.

 

Drove a mile or so with ICE on, because the car had been parked for several days. HVB still showed nothing. Turned the car completely off and back on at a 4-way stop, just to see if there was a change. No change. HVB still showed nothing.

Drove about 10 miles in the interstate. The car went in and out of EV,  showing the symbols above and below the HVB charging and discharging, but the HVB remained blank.

 

Parked the car.

Returned an hour later, and the HVB indicator now showed about 95% full.

 

Ideas?

Edited June 4, 2014 by kostby

[Adrian_L]

I'd like to get one of those scan gauges.  Is there a good one out there that is a bit bigger and perhaps has full-sweep gauges?