Micky 32 don't go too strictly on figures alone, especially from battery tester Mystic Meg type life predictioins. As always with 100% (full) you have to ask 100% of what, in this case it might be 100% of available in battery or 100% charger satifaction perhaps . Like you've put the voltage figures are good but they don't, like my memory, retain as much as they previously did. That's why on a suspect battery you do further checks/tests. Repeatedly starting the car's engine whilst taking voltage readings can be a good real world indicator of the battery condition on the car the battery as fitted with all the usual drains from the car. Yes I would expect my 4-amp charger maintainer to take many hours to get from 80 to 100% when charging it on the car but (without any real checks) to me our battery seems fine and I expect it coulkd last many more years of useful service with us and how we use and maintain things (and I do the very minimum maintence on the car as I can). The Ring charger maintainer I use won't get to full ("FUL") on a battery not capable of it from the way the Ring is set up (and I believe it may accept to charge a battery as low 2v in charge). I'm not a fan of these (expensive) CTEKs though others say they're great and I know people that own them I just don't have the confidence in them as my mate had two of them identical and they gave different stage of lights when tersted on the same battery, perhaps a rare one off case but at the cost and my limited experience that puts me off, they seem more suited to the type of people that like Audis and that certainly ain't me but as always each to their own. If you have an EFB battery you can often check it's 'water' (electrolyte) level in each of the 6 cells to make sure they are at correct levels and also see a bit the condition of the plates which will give you an idea of any damage of furred upiness reducing performance and make a decision about whether to replace that batterry. Check again after fully, or as far as it gets charging. How many hours after the charging had finished, was it directly to the battery terminal posts alone not the post clamps. Up to you, if you believe your tester replace the battery now. Would 530 amps start your car in the coldest bit of winter with whatever electrics and electronics you and your car's computers run at those times, would you still have 530 amps available at that time anyway, how much lower could that figure go and still start your car and the battery still successfully run all the electruics and electronics you and the car's computers want at those times. Doctor Google sez 530 is 75.71% of 700 if that helps. As I can no longer do even the very simple maths I was once capablke of I don't bother too much with all the figures and maths and anyway it's not all as strictgly straighnt forward as some of the simple maths, I prefer prevention and that sdaves what's left of my feeble brain for more importasnt matters than farting about with cars u nnecessarily. I've had decades of attendig to use/abuse/neglected batteries on some of my neighbours' cars and I often had to take the batteries out of the cars, where possiblle check each cell, and start with using my 30+ year old "dumb" (like me) charger with its needle guage and misaligned numbers and within minutes I'd roughly know how longer the chargiung might take and swap over to my 20+ year old "smartish" (I can't remember what they were called then, marketuing terms change over years) and then as it only has one light that no longer seems to change colour (unless turned off-n-on-agen) I mght finish with the Ring "smart" charger just to confirm "FUL" or not. Wow, another long un, could cure insomnia.