High Voltage Battery Heating - NOT Possible cause of 12v battery drain

[MaveRichard]

Hello Hybrid Owners,

I have been monitoring the temperature of the high voltage battery (HVB) for a little over a month as temperatures drop here in Michigan. I have observed that after sitting overnight in 45* temps the battery temp is within a degree of ambient temps. At the same time, the battery coolant is consistently 15-20* higher.

It appears that 100* is the ideal temperature for this HVB.

With this being said, there are a few data points that I don't know at this point.

1. Where is each temperature sensor is located?
2. Where (or how) heating/cooling happens is the battery coolant system? We know that it can use the A/C
3. How much or little the battery coolant is circulated through the system? From Ford brochure there is 4.7 quarts of battery coolant.

My (limited) understanding of lithium-ion batteries includes the knowledge that the problem with cold temps involves the ability to accept a charge at lower temperatures. Because these trucks need to be "ready" to drive and accept a charge at a moments notice (key on) it is my thought/theory that it may be actively heating the HVB coolant to maintain minimum temps and this is done using power from the 12v battery.

To be clear - I have not had 12v drain issues, nor have I had any deep sleep notifications at this point. I got my truck in January of this year so this will be my first full winter. This data will become more clear with time and as temperatures drop.

To those that have 12v drain issues - are you seeing this as a temperature dependent/related problem?

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[Automate]

It appears that 100* is the ideal temperature for this HVB.

I have to question the calibration of that temperature reading. Have you connected FORScan and does it show the same values?

Both Lithium ion and LiFePO4 batteries perform best at around 75*. Trying to maintain the battery at 100* would seem to waste energy and go against standard best practices for batteries.

 

[MaveRichard]

I have to question the calibration of that temperature reading. Have you connected FORScan and does it show the same values?

Both Lithium ion and LiFePO4 batteries perform best at around 75*. Trying to maintain the battery at 100* would seem to waste energy and go against standard best practices for batteries.

I guess I should be cautious with the use of the word "Ideal". It does not rush to heat it to this temperature.

This seems to be the steady state temperature after extended drives (25+ miles) AKA the truck does not actively cool the battery below this temperature.

I do not have access to FORScan but would be curious to see this as well. I would assume that it is reading the same PIDs, but you know how assuming goes... Just starting a discussion here.

Thanks for your thoughtful comment!

 

[Automate]

What is the full name/description that ScanGauge calls it? I will try and find the equivalent value in FORScan.

 

[MaveRichard]

@Automate I believe this is what you are looking for.

This was a picture I took at startup yesterday in 46* degree ambient temps. I have waited to post this, but this differential is what I am seeing regularly at cold start.

Thank you

 

[Automate]

Here is what FORScan shows for my 23 Hybrid after driving and then parking in my garage about 11 hours ago which is currently at 72*.

 

[GPSMan]

I have to question the calibration of that temperature reading. Have you connected FORScan and does it show the same values?

Both Lithium ion and LiFePO4 batteries perform best at around 75*. Trying to maintain the battery at 100* would seem to waste energy and go against standard best practices for batteries.

Mine is showing the same or remarkably similar. I see no battery cooling activated until 106°F and above.

I was about to start a thread just like this. @MaveRichard beat me to it.

I see a software LIMITED charge/discharge current at below 75°F. Seems below 75°F is considered "sub optimal".

 

[GPSMan]

Here is what FORScan shows for my 23 Hybrid after driving and then parking in my garage about 11 hours ago which is currently at 72*.

Can you see that while driving?

(don't do anything hazardous)

If not, take a look just AFTER a 30-60 minute drive in stop n go if possible. And post results, like above.

During my 30-45 min stop n go commute, my battery goes from 65°F which matches ambient, to 100°F with no cooling in this half-hour 12 mile rush hour commute.

The stop n go gives great MPG but works the battery hard.

 

[Automate]

Can you see that while driving?

(don't do anything hazardous)

If not, take a look just AFTER a 30-60 minute drive in stop n go if possible. And post results, like above.

During my 30-45 min stop n go commute, my battery goes from 65°F which matches ambient, to 100°F with no cooling in this half-hour 12 mile rush hour commute.

The stop n go gives great MPG but works the battery hard.

I work from home and try not to go out in rush hour traffic but next time I do, I will take a look.

 

[GPSMan]

Just now, went to lunch.

START: 69°

HV Battery Closely Matches: 68°F
But look at battery coolant??? 88°F

Short drive to lunch spot: 11 min

Look at HV battery, now 90°F

 

[GPSMan]

Just now, return from lunch:

Start condition:

End condition:

Same route, same miles:

 

[GPSMan]

Drive home after dusk. A bit cooler outside:

Start:

End:

 

[MaveRichard]

Thanks @GPSMan for the additional data points. What you are seeing echoes what I see on shorter trips with temps in the 60-80* range. Battery temp moves towards 100* and battery coolant stays within 20* of battery temp.

43* this morning, but I forgot to look at battery temps at startup.

I am very curious to see how it reacts to sub freezing temps and if I will continue to see battery coolant temps stay in the 60-70* range at cold startup.

 

[Bill K]

Wait, wait! How do you call up that screen?

 

[MaveRichard]

Wait, wait! How do you call up that screen?

This is a ScanGauge III - it monitors various parameters via the OBDII port on the truck. It is not factory installed.

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