Change in battery %

[richguy82]

Yesterday, I had a long day at Regatta where we brought the coolers and such and parked right next to our team tent. We arrived with 63% battery. I shut the truck off and it sat there from 7:15am until about 4:30pm. Temps ranged from mid 50s to 78, but the truck was in direct sun all day. The tailgate was left open and I periodically would go into the cab or open the frunk to get something. When I started the truck to leave I was at 59%. I did not use PPO at all. I am confused by this 4% drop as this seems like a lot even if there was some low power draw. Has anyone else experienced this?

Sponsored

 

[Henry Ford]

Gremlins of some sort. 4% equals about 5 kWh. There's no way you used 5 kWh in none hours without moving or having something plugged in. My best guess is you witnessed the extremes of the error rate in the battery percentage calculation. If the error rate is +/- 2% and the "actual" battery level was 61% then 59% and 63% would both be correct.

I have no clue what the calculation error is and there is no "actual" battery level. What is displayed is a calculation based on pack voltage, temperature, and probably other things I'm not aware of. I'm sure there is someone more knowledgeable than me who can weigh in.

 

[PJnc284]

What is the saying about trust and the bms.

 

[richguy82]

Also of note, this was the also the first time I saw the message in my app that said that the vehicle was in battery saver mode. I assumed this had something to do with a combination of open and closing the frunk a dozen or so times, and the almost total lack of cell phone reception where we were.

 

[richguy82]

What is the saying about trust and the bms.

It’s weird. This is the first time I have experienced something like this in 1 year of ownership. My truck is my daily driver. I vacationed earlier this year for 8 days without the truck and the battery reading was exactly as I had left it when I returned.

 

[RickLightning]

I suspect you were draining the 12v battery by being too close with your PaaK and/or fob, plus the dozen openings, and that the 12v was recharged by the large battery and that used up some.

 

[The Weatherman]

I was going to say exactly what @RickLightning just voiced. Especially, if you have your approach(welcome) lights toggled on.

 

[richguy82]

I was going to say exactly what @RickLightning just voiced. Especially, if you have your approach(welcome) lights toggled on.

I was close enough for sure. I specifically turned my welcome lights off as soon as I arrived. Maybe that modem was working overtime to try to find a signal .

 

[Kansan]

Also of note, this was the also the first time I saw the message in my app that said that the vehicle was in battery saver mode. I assumed this had something to do with a combination of open and closing the frunk a dozen or so times, and the almost total lack of cell phone reception where we were.

Every time you wake the truck the modules draw significant power from the 12v for a half hour.

 

[FloridaMan655321]

I always keep my key away from the truck, or leave it in as it doesn't seem to wake the exterior lights on approach.
Another thing to point out is you may have been at just 63.0% and drained to 59.9%, and with the percentage of being a little off, would make sense it could drop this much

 

[Henry Ford]

I suspect you were draining the 12v battery by being too close with your PaaK and/or fob, plus the dozen openings, and that the 12v was recharged by the large battery and that used up some.

5kWh over nine hours is the equivalent of five incandescent bulbs running the whole time. Do you think waking up the truck draws 500 watts continuously? That seems extremely high to me but I genuinely don't know.

 

[electricpig]

FWIW,I think it's your 12V battery on edge of failure. From proximity and repeated openings of the frunk repeatedly hitting a "weak" battery. This could reduce a weak 12V to the point that the BMS could end up drawing power from the HVB repeatedly trying to level the 12V up, but having difficulty doing so due LVB being on the edge of failure. Just my internet opinion.

 

[ZSC100]

As others have said here, the 12 volt system draw is significant. For multiple hour module firmware updates the 12 volt system needs over 60 amps continuous. Also the SoC displayed really doesn't mean anything and can vary five% easily just from temperature change. Haven't you driven your truck 20 plus miles before on 100% SoC? If you get car scanner you can look at the actual SoC and tell exactly how many kWh are in the battery to the 100th decimal precision.

 

[Zprime29]

My truck has a weird quirk in that SOC % range. I often see while in the mid to low 60's a rapid drain after sitting all day at work and turn the truck on. No warnings, it just drops 3-4% then it goes back to acting like normal. I attribute it to the BMS having trouble determining the SOC in that voltage range.

 

[ZSC100]

My truck has a weird quirk in that SOC % range. I often see while in the mid to low 60's a rapid drain after sitting all day at work and turn the truck on. No warnings, it just drops 3-4% then it goes back to acting like normal. I attribute it to the BMS having trouble determining the SOC in that voltage range.

SoC is mainly known by Coulomb counting and will not adjust inside 0-100% displayed. The problem is everyone just sees "SoC displayed" on their Instrument Panel which is a funny number massaged by Ford with the influence of temperature and other things. To see the real SoC you need CarScanner.

Sponsored