Dudes:

Ford never wants the battery to fall less than 30%. There IS a relay that opens when the battery hits 30%.

That explains why it flat lines at 30%.

However, 6 years ago I found my battery was losing 4% PER WEEK of being parked.
That was years ago and it's probably worse but not enough for me to notice after parking a week now.

I think you have a paracitic load somewhere that you shouldn't have. Not normal.

I'll bet if you pull the switch on the back battery cover you will lose 1-2% per night.
It is totally worth trying and speaks volumes of data. You should have done that day one.

 

Regarding paracitic loads:

The 330v battery runs everything and recharges the 12v battery any time the vehicle is on or in ACC mode.

With key off or out, everyting SHOULD run from the 12v battery alone. Perhaps your problem is something is preventing your car from going to sleep?

 

Thanks gpsman. Good information.

So if something is pulling amps from the battery when it shouldn't be then that should show up on ScanGauge assuming the car's computer is active and reporting on the OBD port and that we have an XGauge code for HVB amps. I'd check, but the problem only rarely happens to me.

I wonder...does the OP have a bad 12v battery. Maybe the paracitic load is the 12v charging current that can't quite ever get the 12v battery to full? I just recently changed out my 12v battery as part of routine maintenance at 90,000 miles and 5 years of life. I'll post back if it happens again with the new 12v battery.

 

Pretty sure my 12v is good, it's not that old (will have to look up date when I get home) May 2016 it was replaced
What's confusing is how Soc will stay flat for about 24hrs, say I park at 53.2%, it's still at 53.2% the next day. But I don't know the magic time, but a little over that (once it was less then 24hrs) it dropped to 30.0 %.
I have not had time to mess with the HV disconnect switch yet.
But if there was a draw would it not show up in shorter times as well? Like 10% in 12hrs?

 

How are you guys reading your pack SOC?
Are either of you guys using a Scan Gauge brand device?

I had one continuously velcroed to my dash for years. Then my FEH started acting up. The ScanGauge failed somehow and was "talking" gibborish over the CAN network confusing the car. The moment I disconnected it, my FEH went back to normal and has been normal ever since. That was 2 years ago.

Second- The ScanGauge or other scanner can be the paracitic load. I came back from a long business trip once and found my ScanGauge "on" and the backlight glowing. Heaven knows how long that was going on for.

Third- The scan gauge "wakes up" whenever it detects a rapid voltage change. This was designed as a "feature" based on when you open the car door, it detects the drop in 12v voltage from the dome lights going on and readies itself for "your convienience". This could be inconvienent and contributing to the problem if your 12v battery is dropping for other reasons. The 12v battery is always suspect in cases like this.

 

I have the SG, and I used a elm327 BT at times as well thinking the SG might be the issue; but the car still behaves like the batter is low (ie the 30%) So I assumed then the SG was OK.

Could it be the problem & drain? maybe; but then again why flat, no drop for 24ish hours, then 24-36hrs it will drop from 53% to 30% (presumably more if there is a fail safe relay doing it's job & stopping the drain at 30%)

Unfortunately it's rare & unpredictable if/when it will sit for 36hrs w/o being driving, so doing the HV disconnect is hard to 'schedule'

I could unplug the SG for a while; but the wife has taken the FEH back from me, and she won't help trouble shoot, she just gets in & drives, she won't bother to tell me it was 'sluggish' this morning, or I had no re-gen brakes.

I don't suspect the 12V, as it's not that old; but on the other hand one of my other cars just replaced a 12V that' only 18mo old due to 'bad cell' (but I suspect the Alt is over-charging the battery, 14.5V all the time, even after several min idling [I heard it should drop to a maint charge of like 13ishV])
Nothing else new has been added, plugged in.
I did replace the AC system; but this problem was around prior to that as well.
Could be the weak AC, let the batts get to warm & they're pre-maturely failing, not holding charge as well.???

Just put a meter on, 12.56v (parked about an hour) 13.55 running

 

I only recently got the SG and I keep it in my Fusion Energi. My wife drives the Escape Hybrid and I've never plugged it in on her vehicle. Just today I told her to let me know if it goes into recovery mode when started now that we have the 12v battery replaced. The way we know the SoC is low is with the NAV screen. It only shows 1 bar when it's in recovery mode.

I agree with gpsman. It seems more likely that something is pulling amps from the HVB. Under what conditions would the vehicle's computer not go into sleep mode? Is it possible the computer is staying active overnight?

 

I've had a Scangauge for many years, first on my 06 FEH and now on my 09. I've also had one installed on longer trips on my wife's 09 Subaru Forester. I've never seen it "wake up" when opening the car door, only when moving the ignition to "On".

 

I've now been hit with a similar problem.

I garaged the FEH yesterday at SoC = 40%. 24 hours later I found the SoC at 6%. FEH started okay and charged up to 53%, goes into EV as normal. But when stopped in EV mode (ICE off), it is losing SoC at a rate of 2%/minute.

Regen braking seems to be disabled or very weak.

The 12v battery is a relatively new Optima and reads 12.0v key off and 13.9v key on. I do have a Scangauge connected as always.

So I forced a recharge to 53.0%, noted the time, and will leave it garaged for a few hours to see what happens.

The only event I can associate with this problem is that yesterday before parking in the garage I was running in EV mode and the ICE started (SoC=40%) at exactly the moment I was turning the key off. So it's like I turned the key off during the startup. Probably not related but was a coincidence.

Should also add that for the 10 days preceding this problem the FEH had sat idle, and lost only about 2% SoC.

 

I officially give up on my issue. This past weekend it sat 3+ days w/o being touched (and I forgot to pull the 'plug') and it was still at ~53%.
Wife has taken it back from me, so I don't get to observe it often; but for now just going to try to ignore it until something dies completely!