Q5-e PHEV charging and 12volt battery
 

When I plugin the 120v charger and charge the Q5-e overnight, does it also charge-up the conventional 12v "vehicle battery" ?

Or said another way ...

If I'm charging the Q5-e in garage, can I also be inside (with car in accessory-mode), and using tech (loading music, testing CarPlay, doing map-updates, editing radio/XM presets, etc.) without fear of "running-down" the conventional 12v vehicle battery (to the point that its considered a "dead battery" and won't have enough amps to start the Q5-e next time)?

Or asked yet another way ...

In a conventional car, the alternator charges the 12v vehicle battery while the engine is running. In the Q5-e, in what all ways does 12v vehicle battery get recharged?

Does the Tech in the Q5-e run from the 12v vehicle battery or the high-voltage hybrid battery?

Based on what I read so far, the 12V battery is being charged when the car is "ready to drive" with either the ICE running or in EV mode.

I believe DirkM is correct. Charging of the 12V battery only happens when the ignition is on, according to the manual. I believe the 12V is charged from the high voltage battery. If you don't run the car enough, the 12V can drain down. Most of the tech run off the 12V system so, it won't operate with a dead 12V battery and you can't start the car. It is recommended that you run the car at least once a month.

I've actually measured the voltage of the 12V battery with the vehicle off and not charging and with the vehicle off and charging. I know for sure that in my 2020 Q5e, the 12V battery is also being charged when the vehicle is being charged.

The vehicle has a DC-DC converter that supplies the 12V battery from the high voltage battery, both for charging the 12V battery and for supplying the electricity that runs the 12V part of the electrical system.

The only purpose of the 12V battery in starting the vehicle is to energize a relay that turns on the high voltage battery. The high voltage battery is always off when the vehicle is off (and not charging) for safety reasons. As such, it takes very little electrical power to "start" the Q5e since there is no standard starter or starting circuit. If the gas engine needs to start, it is "spun up" by the electric motor powered by the high voltage battery.

That's some good info. That is more like I would expect a PHEV to operate in this regard.

So, I can safely/worry-free use the Q5-e in Accessory-Mode as long as:
a. High-Voltage battery has a charge (says 3 miles or better)
b. Or, the 120v is connected and the Q5-e is charging.

Very nice !

And just so yall know what prompted this post. With our new 2014-MDX, I once accidentally ran the battery down/dead setting-up the tech (and auto-ripping CDs) in accessory-mode in garage. Like many vehicles, it just had the one 12v battery. I once read that it was suppose to warn-you or disable the Infotainment if battery got to low, but it never seemed to. Overall, a nice high-tech SUV (but I think over-worked 12v battery like many cars).

The question remains how long the 12V outlets will provide power when ignition is off, or if they are on at all even if the car is charging.

I haven't had a need to use the (round "cigarette-lighter") 12v sockets yet. One of us could probably test it and post about it.
May I ask why you want to know?

Hi,

Today my 2021 Q5e completed 1st full charging from 0-25mi, in a 120V home socket. it took around 25hrs (1mi/hr).
So is it recommended to charge only when battery is fully down or one can charge even when just 50% down? that way it'll get fully charged in 12 hrs. Is there a harm to batteries life with short-term charging?
any views....
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2021 Q5e Premium Plus, District Green

I plug it in whenever I get home, still waiting for my 240V outlet to get installed so it always takes forever to fully charge. No idea if that is good or bad, being still a PHEV noob...

I read multiple sources that level 2 charging is actually more efficient than level 1 charging. The Q5e has a 7.4 kW charger onboard, so take advantage of that. Most PHEVs only have 3.3 kW chargers. In general, deep discharge-charge cycles are harder on lithium ion batteries.