Question about auxiliary battery (3rd battery) in Astra L GSe / PHEV

    • Neu

    Hi everyone,

    I've been trying to figure this out and want to make sure I understand the battery setup in the Astra L GSe (PHEV).

    As I understand it, the car has three separate batteries :

    1. High-voltage traction battery (the main hybrid drive battery used for EV driving)

    2. Regular 12 V starter battery (under the hood)

    3. Small auxiliary 12 V battery (ininteriorunder the center console)

    My question is:

    ✅ Is it correct that the Astra L PHEV really has three distinct batteries , including this auxiliary battery?

    ❓ Is this auxiliary battery the same part used in other Stellantis PHEV models (eg, Peugeot 308/3008 PHEV)?

    🔋 And specifically, is the auxiliary battery model Exide EK131 (12 V AGM, ~13 Ah, ~200 CCA) the correct/typical part for this application?

    I've heard from some owners and independent sources that the auxiliary battery is known for early failure and triggers hybrid system warnings when it fails.

    Thanks in advance for clarifying!

    • Neu

    I had this exact question today, but with my EV. Currently in the process of buying a used Astra Ultimate EV. While I know it'll be a bit different from your GSe PHEV, I thought I'd share what I learned.


    So, dealership has had to replace the 12V battery - which they've done, so new 12V battery under the bonnet. They then discovered that the secondary auxillary 12V battery needed replacing. They've sent me a video, it's directly under the center console, and is used as a buffer.


    My Astra EV has a fault with this battery, although from what I can gather, previous Astra L models prior to them adding this battery sometimes had issues with waking up if the big main 12V had died or was low on charge. Overall, it looks like it reduces faults, but doesn't neccessarily eliminate them.


    Your PHEV GSe likely has a similar setup, but it'll be a different 12V battery model to my BEV. Likely the same as the 308 equivalents, though. It's worth noting that replacing the auxillary battery may require dealer-specific software.


    Hope this helps somewhat, even if it's a different model of vehicle.