How long to charge 12V Aux battery using Traction battery ONLY?

[edanto]

I ran into “EV System Error” after drawing too much power from the Aux battery (heater when parked). It was at 9V.

Some helpful threads on this forum helped me realise I’d be able to get started again by using a 12V battery booster and now the car is operational again and I’ve gotten to my destination. I’m overnight here but there is no charger, no granny charger or no battery charger. And I no longer have convenient access to battery booster but it’s available if I’m stuck.

Since powering on, about an hour has passed and I’ve left the car powered on, hoping the AUX battery is getting a charge from the Traction battery (traction is probably at about 60% full).

Do you know how long it might take for Aux battery to get back to a healthy voltage when car is parked and powered on?

 

[edanto]

Update, the answer is less than 2.5 hours because I just checked by powering down and then seeing if AUX was charged enough to do a normal start - success!

(Not sure if this next bit had any bearing on things but the first 30 mins of journey after boost start had “charge” mode enabled.

 

[AndyInOz]

Mine charges the 12V battery for one hour per day, which seems to be sufficient to 'maintain' the battery.

So 2.5 hours seems reasonable to bring it back up from a much lower charge.

Please note that taking a 12V battery to a low voltage like that damages the battery, so it is likely that you'll need to replace that battery in the near future.

 

[edanto]

I saw a mention of that daily 1400 Aux charging but wasn’t sure if that happened for all models and if the car needs to be connected to a charger.

My plan B was to wait until after 3pm today and hope the Aux was recharged.

Seems like a really poor design to allow the Aux battery run so low with out ANY warring. Hope they’ve changed it on later models

 

[AlexBorro]

I saw a mention of that daily 1400 Aux charging but wasn’t sure if that happened for all models and if the car needs to be connected to a charger.

The automatic Aux charging only takes place if the wifi is enabled - the wifi module drains the Aux battery, so the car adopts this strategy.
If you disable the WiFi, your Aux Battery might get depleted after a long period without use, even with full traction battery - Ask me how I know it!

 

[edanto]

Facepalm! What a grim design.

I did enable the car WiFi a long time ago but found it so inconvenient to use I never bothered. I guess that’s helped my Aux battery stay charged.

Do you happen to know for sure if that (2pm Traction —> Aux charge) happens even when car is NOT CHARGING?

My plan B after the Aux battery drained was to just wait until 3pm the next day but didn’t know if that was reliable.

 

[AndyInOz]

For my vehicle, I can confirm that the car does the 12V top up, every day, and it does not need to be on charge (or even plugged in) to do so.

While this charging is occurring, the car emits quiet beeps, approximately one beep every two seconds.

 

[hughwi]

For my vehicle, I can confirm that the car does the 12V top up, every day, and it does not need to be on charge (or even plugged in) to do so.

While this charging is occurring, the car emits quiet beeps, approximately one beep every two seconds.

So THATS what that beeping noise is..... yet another Outlander beeping mystery solved

 

[AndyInOz]

So THATS what that beeping noise is..... yet another Outlander beeping mystery solved

Yeah, I was calling mine 'Beepy' for a while.

 

[edanto]

That’s VERY handy to know. Could be a useful Plan C if Aux battery goes flat again.

 

[phevGoBzzzzzz]

Does the new 2023+ phev also do the daily top up?