Slightly OT: New PC925 battery not getting to full charge Options

[Literati914]

Couple days ago I picked up two new Odyssey PC925 batteries from a marketplace seller who was supposedly selling them for his dad. The story was that his dad bought them for a couple of electric bike builds and they were too heavy. Dad chose something else after only opening and trying one of them (one was unboxed and one had never been opened when I purchased). So they sat for 4-5 months, his dad said 'get whatever you can for them'. The seller had them at $200 a piece, before dropping them to $100 each - which is what I bought them for.

The one that was already opened was only showing like 7V so I put it on a little charger I already had (not necessarily the recommended type, that I'll need to purchase I guess). I kept a watch on it so it did not over charge.. but I finally took it off the charger when it reached 12.25V or so (took a long time tbh). I installed it in a 2.5L Volvo wagon (will be going in 914s eventually), it showed 14.3-4v, so I did a 20+ mile loop on the freeway to finish topping it off. I did not check it as soon as I returned but about and hour after the drive, it's still only showing like 12.15V. Is this just a bad battery or need more (proper) charging?

[Superhawk996]

AGM batteries want to charge at higher voltage - 14.7v even up to 15v isn’t unheard of. The Volvo isn’t delivering enough voltage - guessing it is designed to handle Lead acid conventional battery.

Put on a charger that is AGM capable. Should be 12.7v at 90% state of charge. 12.1 is more like 60%.