parodielin

Last Saturday I cannot unlock my 2021 Audi A8 Plug-in Hybrid. Keyfob is good with good battery. The car is not responding. I have to use the physical key to open the car. Turned out the 12 V battery was dead. Audi roadside assistance came and tow the car to the dealership (they jump started it). Dealer replaced the battery under the warranty.

This puzzled me a lot. I drove the car every day. Granted, they are short distance. I mostly use the EV mode. The gasoline engine barely active. If this is true that the battery will die within the first 3 years if the gasoline engine barely active, this is a car design flaw. This means I need to use battery tender from time to time. When the car is dead, the EV battery is almost fully charged. There is no warning sign on the dashboard. There are multiple "faults" message when dealer diagnose the car but nothing visible to the driver. The previous day, the HUD is not working (now I know this is a sign of dying 12 V battery). This means the Plug-in architecture is really fragile. A single 12 V battery can brick the car.

Thoughts?

Torque450

My 25,000 miles old A8 also needed a new battery after 3 years and its a diesel.

But, I used to own a Volvo V60 plug-in hybrid with 25 miles EV range. I used to charge the 12v battery every month with a CTEk ...

pcc125

The average battery lifespan is 3 to 4 years. If you drive your car mostly in e-mode, I recommend you charge your battery regularly as Torque450 stated. Without the engine running, your 12 v battery will not charge itself if all you do is e-mode.

angrypengu

The industry keeps on saying that semi-PHEV is the way to go and I'm one of the very few people who are loudly on the fence of "go big or go home". E.g. full BEV or ICE. This is one reason why.

pcc125

I like the concept of semi-PHEV and I have a Range Rover PHEV on order. For me, it removes range anxiety, and that is one reason I am not sold on fully electric vehicles with no engine to run when your charge is out. I guess I will experience the semi-phev soon and may regret my choice or love it.

angrypengu

Semi-PHEV is absolutely a great application and though some may argue it's a jack of both trades and a master of none, I would also say it's the perfect product for the "power" buyer. Battery packs in semi PHEVs are not that heavy so it's not really a compromise in that regard, but ask the typical car owner what fuel dilution is or how long ethanol laced fuel will last without a stabilizer or how the 12V battery pack charges....most people don't know or care to know any of those things.

It's not the buyer's fault of course, but I do think semi PHEVs are a great product but geared towards the power user. It certainly makes *more* sense than the P0 mild hybridization in the D5 as an example. hey kids, let's carry a 11AH (or was it 13, I forget) battery pack, add a BSG that self explodes if you look at it funny, and save 1 CO2 per year

pcc125

The range on the semi-PHEV Range Rover is a mere 58 miles so that is sufficient for in town short trips; that is all I personally care about. The comfort of having the combustion engine for long trips removes any range anxiety and the need to plan your trip based on where there are charging stations. I would never use a public charging station when I get my semi phev car, and the only place I would charge it would be at home.

Torque450

That was exactly my approach with my Volvo plug in hybrid diesel AWD. I bought the different cable for charging stations and never used it. I enjoyed the game of maximising range. My best ever mpg was lots and lots of short trips over 400 miles and charging at home to give 158 mpg. Over 3 years it averaged 70mpg.

My job and mileage profile changed, so the Audi A8 diesel gives me 650/700 miles range with a 3 minute 'recharge' time.

pcc125

@Torque450 those are impressive mpg numbers!