2022 S90 T8 Recharge charging

redbrock · Apr 4th, 2023, 17:34

Hi
Hoping someone can answer this question regarding my 2022 S90 t8 Recharge.
Does it charge the 12v Battery when being driven on EV batteries.
Does charging the EV batteries also charge the 12v battery via a step down transformer or similar.
I ask this as I use the car these days mainly using the EV Battery with occasional journeys using the ICE.
This has resulted in a totally Flat 12v battery on two occasions necessitating assistance from Volvo assist.
Its something new to me as this has never happened until purchase of the S90.
Incidentally Volvo have advised the battery is fine and the system charging normally. Unfortunately I could not get a firm answer to the two questions listed above.
Having a definitive answer to the above will help in determining if I should use the ICE more often than I do.
Thanks

Philip Fisher · Apr 4th, 2023, 18:15

My understanding is yes. I believe, through 7 years of experience and messing about with the car that the 12v battery is charged from the 400v battery.

The 12v battery is there to only run the car systems. The car also does not have a 12v alternator. It has a 400v starter generator. So logically the only way the 12v battery can be charged is from the 400v system.

Finally disconnect the 12v negative connection and the systems still work. The only logical conclusion I could come to was that the 400v battery was providing the continuous earthing through the vehicle body and so the 12v system continues to work.

Over 151k miles and 7 years I have never had a flat 12v battery and have never had the need to worry about.

Plenty of other people with AAOS cars have reported flat 12v batteries.

Apr 4th, 2023, 17:34	#1
redbrock New Member Last Online: Nov 17th, 2023 22:18 Join Date: Dec 2019 Location: Bangor View Photos By: redbrock	2022 S90 T8 Recharge charging Hi Hoping someone can answer this question regarding my 2022 S90 t8 Recharge. Does it charge the 12v Battery when being driven on EV batteries. Does charging the EV batteries also charge the 12v battery via a step down transformer or similar. I ask this as I use the car these days mainly using the EV Battery with occasional journeys using the ICE. This has resulted in a totally Flat 12v battery on two occasions necessitating assistance from Volvo assist. Its something new to me as this has never happened until purchase of the S90. Incidentally Volvo have advised the battery is fine and the system charging normally. Unfortunately I could not get a firm answer to the two questions listed above. Having a definitive answer to the above will help in determining if I should use the ICE more often than I do. Thanks

Apr 4th, 2023, 18:15	#2
Philip Fisher Premier Member Last Online: Today 16:30 Join Date: Dec 2002 Location: Sheffield	My understanding is yes. I believe, through 7 years of experience and messing about with the car that the 12v battery is charged from the 400v battery. The 12v battery is there to only run the car systems. The car also does not have a 12v alternator. It has a 400v starter generator. So logically the only way the 12v battery can be charged is from the 400v system. Finally disconnect the 12v negative connection and the systems still work. The only logical conclusion I could come to was that the 400v battery was providing the continuous earthing through the vehicle body and so the 12v system continues to work. Over 151k miles and 7 years I have never had a flat 12v battery and have never had the need to worry about. Plenty of other people with AAOS cars have reported flat 12v batteries. __________________ Currently:- MY16 XC90 T8 Momentum, Magic Blue 174k miles. MY17 V60 T4 Power Blue. Previously:- 1997 V70 T5 exPolice; 2005 V50 2.0D; 2013 XC70 D5 Last edited by Philip Fisher; Apr 4th, 2023 at 18:17.

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