I replaced the battery on my diesel AstraVan as it was becoming a bit slow cranking on cold mornings. New battery is working great but thought I’d have a go at rejuvenating the old one and keep topped up for emergencies. Added battery water and used my 3 stage charger that I got from Lidl. It charges up then goes into float mode. A friend lent me their 8 stage Ctek charger as it has more functions and also a “Recond” function which says it recovers deeply discharged batteries. With the Lidl charger it says it’s fully charged and goes into float mode, however when connecting the Ctek 8 stage charger it quickly goes through the bulk charge phase into absorption charge but seems to just stop on the absorption mode. It’s been connected since yesterday and still no further than the absorption charge, digi meter showing 14.2v. Is it likely the battery is kaput or does it normally take a long time on absorption?