When does Plugging in charge the 12V?

[MrLoganRoss]

Hi.
I was out of town for a few days and my 12V charge dropped. I plugged in about 3 hours ago (Ford Level 1), and in the pics you can see the effect on 12V charge.

Not sure it matters to anyone but thought I would post it.

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[TheVirtualTim]

Yes … but … why did you doubt that it charged the 12v when you plug in the car?

 

[MrLoganRoss]

Because the 12V FAQ Thread states that the 12V is only charged when the car is on.

I have not driven the car and it remains off. It has been sitting unused for the past 5 days.

 

[Sikkun]

FAQ and many other times this forum states the 12V only charges while plugged in AND charging. Or while the car is turned on.

Which may have been true at some point, but I also see mine charging anytime it is plugged in, car does not have to be charging.

 

[Mach-Lee]

Because the 12V FAQ Thread states that the 12V is only charged when the car is on.

I have not driven the car and it remains off. It has been sitting unused for the past 5 days.

It says the 12V is only charged while the car is on, or when the high voltage battery is charging.

If you plugged in and the big battery charged, then the 12V would also be charged. If you plugged in and were already at charge target %, then no 12V charging will occur.

 

[Sikkun]

It says the 12V is only charged while the car is on, or when the high voltage battery is charging.

If you plugged in and the big battery charged, then the 12V would also be charged. If you plugged in and were already at charge target %, then no 12V charging will occur.

My OBD and Multimeter read a 13.4v when plugged in while HVB is already at charge target and SOC% goes up overnight, while HVB is already at charge target.

 

[MrLoganRoss]

Got it. Makes sense.

 

[Mach-Lee]

My OBD and Multimeter read a 13.4v when plugged in while HBV is already at charge target and SOC% goes up overnight, while HBV is at charge target.

Something else is going on then. The car does not stay awake to charge the battery unless you have an OTA scheduled or it's performing a recharge event because it hit a low threshold. Are you sure it's not charging? No pulsing blue lights on the charge port? If your target is 90% but it's at 89.5% it might charge for a little while (display will show 90% the whole time due to rounding). It also might run for thermal management after plugging if the battery is hot or cold.

 

[Sikkun]

Something else is going on then. The car does not stay awake to charge the battery unless you have an OTA scheduled or it's performing a recharge event because it hit a low threshold. Are you sure it's not charging? No pulsing blue lights on the charge port? If your target is 90% but it's at 89.5% it might charge for a little while (display will show 90% the whole time due to rounding). It also might run for thermal management after plugging if the battery is hot or cold.

Charge limit set to 90%, it’s been done charging for hours now. The blue light is still pulsing though. Unless PAAK is just keeping it alive all the time? Has been like this for the last two weeks though. If I unplug voltage drops, I plug back in it goes up. SOC% in the 12v is normally 100% by the morning.

 

[Mach-Lee]

Charge limit set to 90%, it’s been done charging for hours now. The blue light is still pulsing though. Unless PAAK is just keeping it alive all the time? Has been like this for the last two weeks though. If I unplug voltage drops, I plug back in it goes up. SOC% in the 12v is normally 100% by the morning.

If the blue light keeps pulsing after you've reached charge target, then you have a software bug. It needs an update. See this: TSB 24-2094 - High Voltage Battery Continues To Charge After Target Met

 

[Space_Pony]

What does it do with a level 2 charger?

 

[MrLoganRoss]

I won’t have my level 2 until this week ?

 

[Sikkun]

If the blue light keeps pulsing after you've reached charge target, then you have a software bug. It needs an update. See this: TSB 24-2094 - High Voltage Battery Continues To Charge After Target Met

Guessing that isn’t likely to fix itself with an OTA? Still a little annoyed they didn’t run any updates when it had been sitting on the lot almost a year.

 

[dj_stang]

If you plugged in and were already at charge target %, then no 12V charging will occur.

Still boggles the mind how dumb this decision is.

I’ve literally had the 12V die not allowing me to open any doors, start the vehicle, or get in, while plugged in all night. Also degrades the 12V having it fall below the 20% or so threshold to maybe hopefully trigger emergency charging (which doesn’t work as in my case). At best it prevents updates from taking place exacerbating the embarrassing rollout problems.

 

[Snakebitten]

During an L2 charging session, I have logs for the LV AGM battery voltage being measured at the battery itself with a Bluetooth meter permanently mounted.
(Rather than the OBD port being kept alive with the scanner app)

This is from a few minutes ago and the Mach-E is currently being charged L2 at 240V/32A

A few days ago when I installed the meter, I immediately started an L2 charging session with a target of 80% SOC.
Below is the LV voltage log for that session and the rest of the day.

At the beginning of the L2 charging session, the DC/DC converter provides a short period of ~15 minutes of 14.2-14.5V. And then it drops to a very stable 13.5V for the remainder of the charging session.

You can clearly see that when the L2 Target SOC is reached, and the EVSE goes to zero amps, (separate app) the low voltage battery no longer receives the 13.5V charging current either.


Note below that the L2 charging session that I am running as I type this has an identical low voltage curve as the first one logged above.

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