Vehicle battery on way out?

Hi, My vehicle battery is I assume the original, coming up to 6 years old. It always reads at 12.4 volts since we bought the van in December, and although it starts first time, it does turn with a bit of sluggishness. I recently bought a trickle charger to charge it whilst sitting on the drive, and despite the lovely sunny weather we have had for the past 3 weeks, the voltage hovers between 12.4 and 12.6 volts.
Is the battery getting a bit tired, and if so is it time to invest in another? It'sfitted to a Fiat 160 Multijet.
Thanks in anticipation

Cheers

Ken

i got three delivered next day delivery from rochdale,i got the adress from KEN {ksh}.very good price.

12.4v is only about 75% charged, personally id take it off or disconnect it from the vehicle, give it a good charging and test again, if it drops back to 12.4v then I'd change it.
Also put the meter on when vehicle running to make sure it's charging ok from the altenatoraltenator

Thanks for your replies. I have checked the charging when engine going, and the alternator is putting out 14.4 volts, and even after a longish run, the battery voltage seems to drop back down fairly quickly, which makes me think that it may be beneficial to renew now than to wait until it gives up the ghost completely. A new battery would cost me £120 from local battery dealer.

Cheers

Google Alpha batteries from Rochdale, they are good to deal with and do free next day delivery

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Fits Fiat Ducato.