Confusion when battery full

[WoodlandsCamper]

I am confused by various statements as to when the leisure battery is fully charged.

An article in the CC Magazine says a battery is fully charged when the 'rested' battery is at 12.7 to 12.8v.

My standalone intelligent battery charger has settings at 14.7v for normal batteries, and 14.4v for Gel batteries so as not to 'cook' them.

I have heard that in-van chargers are only 13.8v as they can be charging for a long period, but at this voltage the battery will only be charged to about 80% capacity.

As the charge state of the battery is defined by voltage (see below) then surely any charger that has an output of at least 1v more than a fully charged battery will do the job, but the bigger the difference the quicker the charge?

12.7v 100% charge state
12.5v 75%
12.4v 50%
12.2v 25%
12v or under - discharged.

 

[Damian]

You are right in as much as a larger charging capacity will charge a battery quicker, but within certain limits.
Too high a charge and you stand the chance of buckling the plates, boiling the acid/water solution or causing an explosion.

An intelligent charger will give a 14.7 or 14.8 v charge for a short time, which desulphates the plates and provides the initial boost, then will reduce its charge as the battery charges and end up giving a holding charge, trickle charge to keep the battery fully charged.