EV OwnershipDiscussionCommunity Starter

2025 Porsche Macan — eV has plenty of main battery but shows a 12V warning

ShopRoadieCommunity StarterSep 1, 20262025 Porsche Macan Electric 4STexas

Traction battery is charged, but a low-voltage warning appeared after the car sat overnight. I know the small battery can still immobilize an EV. What information would you capture before service?

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2023 Porsche Macan

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15 replies

RoadTripWrench299Community StarterCommunity StarterSep 1, 2026permalink

Low-voltage gremlins will strand you even with a full pack. Try a second charger before blaming the 2025 Porsche Macan — site sharing and pack temp change the curve a lot. I'd do that before spending real money. Run the total, not the monthly, before you commit. Might be overthinking it, but I'd rather overthink than overspend.

OldSchoolCommuter155Community StarterCommunity StarterSep 2, 2026permalink

Don't clear the alert just to make the screen pretty. Leave the alerts on the 2025 Porsche Macan so service can see what you saw. I'd do that before spending real money. This is from a 2025 Porsche Macan in Texas. If it doesn't change the out-the-door or the repair estimate, it's noise. I'd sleep better after that step, even if it finds nothing. Happens in gear, not in park, for what that's worth.

NewCarNomadCommunity StarterCommunity StarterSep 2, 2026permalink

I'd treat 12V warnings as a no-ignore. On the 2025 Porsche Macan, I'd get the 12V/DC-DC side checked even if the traction pack looks fine. I'd do that before spending real money. On “ev has plenty of main battery but,” that was the fork that mattered for me. Write the result down so the next test isn't a repeat of the last one. This is the filter I use when the thread starts repeating itself. That's my plan before I call anyone.

RoadMom737Community StarterCommunity StarterSep 2, 2026permalink

Asking because it changes the advice: Try a second charger before blaming the 2025 Porsche Macan — site sharing and pack temp change the curve a lot. Then you'll know the next fork. Was this after sitting overnight? I've seen both outcomes, which is why I'd test instead of assume. If the story changes I'll post the new data.

HighwayRoadieCommunity StarterCommunity StarterSep 3, 2026permalink

That's a good start, but I wouldn't stop there. Match starting SOC and battery temp if you're comparing 2025 Porsche Macan charge sessions. I'd do that before spending real money. I'd want a dollar figure or a measured spec, not 'should be fine.' Heat soak after errands is the other window.

SunBeltPilot913Community StarterCommunity StarterSep 3, 2026permalink

That's a good start, but I wouldn't stop there. Match starting SOC and battery temp if you're comparing 2025 Porsche Macan charge sessions. I'd do that before spending real money. Learned this the expensive way on a previous car. That's coming from doing this as an owner, not a shop. Next check is the cheap one I can do in a driveway.

OldSchoolCommuter155Community StarterCommunity StarterSep 2, 2026permalink

Charge curves lie if you don't match starting SOC and temp. Match starting SOC and battery temp if you're comparing 2025 Porsche Macan charge sessions. Then you'll know the next fork. Run the total, not the monthly, before you commit. I'll poke at it this weekend.

RoadDailyCommunity StarterCommunity StarterSep 2, 2026permalink

Don't clear the alert just to make the screen pretty. Leave the alerts on the 2025 Porsche Macan so service can see what you saw. That's where I'd start. Keep sale price, fees, and rate as three different conversations. I'd rather be boring and correct. Checking again after work.

RotorHunterCommunity StarterCommunity StarterSep 2, 2026permalink

Don't clear the alert just to make the screen pretty. Leave the alerts on the 2025 Porsche Macan so service can see what you saw. I'd do that before spending real money. This is from a 2025 Porsche Macan in Texas. That's the sequence I'd use. Cold start is when I can actually reproduce it.

CamberCamper245Community StarterCommunity StarterSep 2, 2026permalink

Charge curves lie if you don't match starting SOC and temp. Match starting SOC and battery temp if you're comparing 2025 Porsche Macan charge sessions. That's where I'd start. Run the total, not the monthly, before you commit. Doing the boring step first on purpose.

CleanBuyer879Community StarterCommunity StarterSep 2, 2026permalink

Low-voltage gremlins will strand you even with a full pack. Try a second charger before blaming the 2025 Porsche Macan — site sharing and pack temp change the curve a lot. That's where I'd start. This is from a 2025 Porsche Macan in Texas. Keep sale price, fees, and rate as three different conversations. Parking it somewhere I can hear it better next time.

ShopRoadieCommunity StarterCommunity StarterSep 2, 2026permalink

Cleared nothing. I want service to see the alert on the 2025 Porsche Macan first. Heat soak after errands is the other window.

ShopRoadieCommunity StarterCommunity StarterSep 3, 2026permalink

OP update: scanned the 2025 Porsche Macan again and still only have the one pending code, no new lights. Checking again after work.

ShopRoadieCommunity StarterCommunity StarterSep 3, 2026permalink

OP update: scanned the 2025 Porsche Macan again and still only have the one pending code, no new lights. Trying not to diagnose from the couch.

ShopRoadieCommunity StarterCommunity StarterSep 3, 2026permalink

Checked the easy stuff on the 2025 Porsche Macan and found one clue worth chasing before I book a shop. If that fails I'll eat the diagnostic fee.

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