Low HVB hard start

[adlo101]

I have a 2013 SE. 65k miles. Sometimes when I start the car in the morning, my state of charge is very low and the car starts immediately and very rough at times. I can leave the car with the SOC meter reading halfway and the next morning it will be at the bottom. It only seems to happen when climate control is left on when the car is parked for the night. Do I have a bad HVB?

 

Also, I'm pretty sure my 12 volt battery is slowly dying. I get a low battery warning in the center if I have anything on when the car is off, even just for a few minutes. Could low 12 v battery somehow cause my HVB issue? Is this a common thing if the climate control is on immediately when starting the car?

 

Any help is greatly appreciated. Thanks

[plus 3 golfer]

Has your 12V battery ever been replaced?  The message in the center is normal   But with a new battery AND the 12 V battery age reset to zero days when the new battery was installed, the message will take 10 minutes to display if you leave the car on. Dealer failed to reset mine when my battery failed at 30 months. Otherwise, as the battery ages, the time until the message is displayed decreases. So If your battery is original and no age reset, the message will come on quickly. Get your battery tested. 

 

The SOC will decline with colder temps and increase with warmer temps all other things being the same.  So, when you shut down after running, the HVB will be hot (above the in car temp) especially if using EV+ and when you startup in the morning, should be at the ambient surounding temp. Your HVB is likely OK.

 

I assume you mean the gas engine is very rough at times and you have no check engine light.  That sounds more like a  fuel / ignition issue. Do you use Top Tier gas?  Try a double dose of techron or other fuel injection cleaner and see if the problem goes away.

 

 

 

[homestead]

My car does the low HVB in the morning thing sometimes, randomly ( maybe 1 out of 20 starts).  I have no idea what is causing it.  

I have a guess that something is the car is still drawing power after being shutdown and the HVB is draining to charge the 12V battery.

My 12v battery is relatively new so I don't think that is a problem.  It never draws the HVB down completely.

Would be interesting to have a chart recorder on the 12v battery to see if it is being charged after shutdown.

[icanhazc-max]

FWIW, I make an effort to turn OFF the headlights (never relying on the auto on/off function), audio system (started this habitually after the hard learned and known issue with battery drain necessitating a fuse pull when the system become unresponsive), climate and any/all interior lights & accessories. I've a 2013 SEL with original battery that seems to be holding up thus far, though, like others have said, a replacement is due simply due to age -- notwithstanding the forthcoming colder months.

[jestevens]

If you have a 2013 I would suspect 12V battery nearing end of service life..  I replaced mine when keyless entry stopped working and I had to use the safety key 4 times in a row during 4F mornings last year.  Ford Service didn't want to replace the battery because it tested good but I asked them to do it anyway and after the first 24 hours everything started working fine again..  At the time I did mine they had a slight discount on battery cost, it was still pretty pricey, $200 with labor I think but it's worth it - this car has soo many computers and electronics that all need good voltage.

[cr08]

Also going through the whole rigmarole of 'shutting things off' before you exit the vehicle is a bit redundant and useless. These aren't old vehicles with dumb electronics and relays that can occasionally 'stick'. Everything's operated and communicated electronically. Right off the bat, 'turning off' the radio is just muting/pausing the media playback and nothing else. All the various modules are still running and will continue to turn off/on as needed depending on the car's operation. 

 

The most common battery drain concerns have been the automatic tailgate with a known fix and the obvious radio being unresponsive. The latter is an unfortunate bug but simple enough that you start seeing it becoming wholly unresponsive, pull the fuses for it and be done with it for a while.

 

As also mentioned by jestevens, 5 years is a pretty good run for a 12V battery and it may just be up for replacement.

 

To jump back to the HVB drain concern by homestead, please re-read Plus 3 Golfer's post right above yours. This is in most cases normal. It is just the battery settling as its own temperature drops. Driving and a regular charge/discharge of the HVB will heat it up and as a result will naturally raise its voltage. After it settles back to ambient temps that voltage will drop. Gauging charge level on ANY battery is nothing fancy, it is just reading the voltage and knowing the normal operating range of that battery style and saying 'Here at xx.xx volts is at xx% per this graph'.

[icanhazc-max]

"The most common battery drain concerns have been the automatic tailgate with a known fix..."

 

Not to threadjack, but do tell...

[cr08]

Not to threadjack, but do tell...

Essentially the latch wasn't aligned properly on some vehicles so it never registered as closed so much like any other vehicle when a door is left ajar it could cause a decent battery drain when off. Not too bad a fix if memory serves. Just need a mechanic who knows the TSB and just realign the hatch/latch system.

[homestead]

To jump back to the HVB drain concern by homestead, please re-read Plus 3 Golfer's post right above yours. This is in most cases normal. It is just the battery settling as its own temperature drops. Driving and a regular charge/discharge of the HVB will heat it up and as a result will naturally raise its voltage. After it settles back to ambient temps that voltage will drop. Gauging charge level on ANY battery is nothing fancy, it is just reading the voltage and knowing the normal operating range of that battery style and saying 'Here at xx.xx volts is at xx% per this graph'.

If this was normal drop I would expect it happening more often than 1 in 20 starts.  How often is this happening to others?

[plus 3 golfer]

I see changes all the time in SOC from overnight shutdown to morning startup.  I've attached a thumbnail of a graph by NREL based on curve fit of actual testing of a Li Ion battery. Note how much the Ah capacity changes with temperature of the battery.  I've also attached the actual SOC (as determined by the C-Max algorithms) of the HVB compared to the displayed SOC (battery symbol on dash display).  I believe one could easily see a 10C (18F) drop in HVB temperature overnight.  Assume the drop corresponds to a 4% drop in maximum capacity.

 

Assume when you shut down the car in the evening, your battery symbol was at 50% which corresponds to an actual SOC = 45%.  In the morningy assuming you lost 4% of maximum SOC, your actual SOC would be offset 4% or at  41% on the X axis of the graph.  That 41% will be displayed on the battery symbol as about 38% capacity left in the battery.  So based on the battery symbol, it appears that the HVB has lost about 12% when it only lost 4%.  

 

Now, assume a 20 C drop in HVB temperature and your display showed about 40% SOC when shutdown in the evening.  Going through the same as above the display will likely show less than 20% of the battery symbol filled in the morning.  It looks like you've lost over 20% SOC when you only lost about 8 of actual SOC.  

 

Having said the above, it doesn't take much EV operation to heat the HVB up and SOC to rise due to temperature effect.  :)

 

Bottom line is that you can't tell much simply watching the Battery Symbol.  My suggestion -- get ForScan and record relevant HVB data at shutdown and startup and analyze what is going on. You should be able to see how HVB temperature affects SOC and look for any anomolies.  Also, HVB discharge current affects SOC.  The higher the discharge current, the lower the SOC.  What is discharge current when you arrive at home (likely very low) and what is discharge current when started and first driven (likely higher than when arriving home).  

 

Edited November 9, 2018 by Plus 3 Golfer

[jestevens]

Just like the Toyota I believe this car has a set of relays that are commanded to close by 12V modules when you start the car up, by default when the car is off the relays are open and the HV wiring is not energized as a safety measure.  I believe HV is only used for the traction motors, AC compressor (and the heater if you happen to have an Energi). I would concur with battery fluctuations due to temperature.  Also, EV+ will allow the car to run down the SoC even more than usual if you drive to the same place many times.

 

I guess it's possible that a particular HVB could be starting to go bad but I have yet to hear of it on any of these forums, without hard data can't tell.

Edited November 9, 2018 by jestevens

[plus 3 golfer]

Exactly. 

 

Several modules remain active after shutdown for a period of time to monitor HVB disconnect.  I believe there would be many DTCs and likely the car would not start if there were issues with the HVB disconnecting / connecting to vehicle.  Also, the HVB is made up of 76 cells in series (individual cell voltages are additive).  I can't think of a scenario where 1 in X times, the voltage of several cells or group of cells voltage would fall sufficiently to drop the SOC estimate and then work "normally" the other times. There are monitors of cell voltages, PIDs of performance, and DTCs if out of range. 

[raadsel]

Just like the Toyota I believe this car has a set of relays that are commanded to close by 12V modules when you start the car up, by default when the car is off the relays are open and the HV wiring is not energized as a safety measure.  I believe HV is only used for the traction motors, AC compressor (and the heater if you happen to have an Energi). I would concur with battery fluctuations due to temperature.  Also, EV+ will allow the car to run down the SoC even more than usual if you drive to the same place many times.

 

I guess it's possible that a particular HVB could be starting to go bad but I have yet to hear of it on any of these forums, without hard data can't tell.

 

My understanding is all Hybrids, and even EVs, operate this way; with the HV battery being electronically disconnected. The major reason is safety (and I believe there may be laws requiring this) for the protection of first responders.

Edited November 9, 2018 by raadsel

[ptjones]

I use EV+ which allows the SOC get down to 32%, I watch the SOC with my ScanGaugeII all the time and this is what I see when leaving home in the morning. When I start the MADMAX the SOC shows the SOC from the previous night first and then current SOC, If I stop with 40% SOC or lower the SOC will drop as low as 27% and the ICE struggles to start. If I stop with a SOC of over 41% at night in the morning it will jump up 5-20% depending the stopping SOC, the higher the SOC the more it will go up. I have seen it go from 53% to 80% in the morning. You have to love the ScanGaugeII to show you what's going on.

 

Paul

[ptjones]

This morning I checked my SOC and it went from 52% to 60% SOC.over night. Another interesting thing was I had to get on the gas going to work so the ICE started, I probably went a half a mile with the ICE on yet the MPG gauge was pegged at 60 mpg until the SOC dropped below 50%. Cool :)

 

Paul

[DarenHayes]

Paul a few times ive driven my car on trips (3 1/2 hr drive about 225 miles) during hot summer weather.. 90-95 f... Anyway.. I turn the car off and the battery is half charged.. Upon returning it was fully charge(2 hrs later) . Its happened a few times.. Lol... It charges on its own.. This only happens on SUPER hot days.. It doesn't work in the winter.. Neat though. Curious if it's ever happened to anyone else?

Edited November 12, 2018 by DarenHayes

[jestevens]

Never happened to me but maybe the car was limiting current draw from the battery as a safety measure because of the extremely hot temps?

[ptjones]

My example happens all the time, needs to sit for an half an hour. :headscratch:

 

Paul

[jestevens]

I know the prius had several different idle states and modes of operation depending on the SoC, ICE, engine temp and other variables - someone once did a detailed analysis on priuschat.  I don't know if C-MAX does that too but maybe, if things extremely well going, battery is cool, etc. it runs phenomenally well, extended EV range, etc.  I don't have scangauge so I can't pinpoint exactly when the switch would occur.

[ptjones]

Having some kind of OBDII makes things alot more easier to see what is going on.  Last two mornings the SOC went down, 40% down to 34%, 34% down to 29%.

 

Paul

[bigqueue]

On 11/12/2018 at 3:15 PM, DarenHayes said:

Paul a few times ive driven my car on trips (3 1/2 hr drive about 225 miles) during hot summer weather.. 90-95 f... Anyway.. I turn the car off and the battery is half charged.. Upon returning it was fully charge(2 hrs later) . Its happened a few times.. Lol... It charges on its own.. This only happens on SUPER hot days.. It doesn't work in the winter.. Neat though. Curious if it's ever happened to anyone else?

 

 

BTW: This is a great website with information on Lithium Ion Batteries and how they are affected by all sort of stimulus. (heat, charge/discharge rates, imbalance, SOC, etc....)

 

Here is a particular article on what affects battery life, but there are plenty of other articles that teach all about batteries.

https://batteryuniversity.com/learn/article/batteries_will_eventually_die_but_when_and_how

 

Here is an article on heat:
 

https://batteryuniversity.com/learn/article/how_heat_and_harsh_loading_reduces_battery_life

 

[fbov]

We know Battery University... great site. 

Edited January 29, 2020 by fbov