https://www.halfords.com/camping/electrical-and-power/halfords-leisure-battery-hlb681-957217.html
This is the battery above.
In the the past I have purchased newMax for example and I didn't need to bench charge it for more than 6 years. Why is it so I need to keep Bench charging this one ??
This particular one when I try and then charge it my smart charger doesn't charge it enough.
There is a green light indicator on the battery when I take it to Halfords they fully charged it with theirs and the green light comes on.
Basically I need a new bank charger to continue to use this battery or try another battery.
The Other van has a battery with the bull symbol and I have not bench charged it for a year and a half.
So two things one my smart charger obviously doesn't want to charge it correctly the Halfords one so which one should I buy ? And two why is it the other battery even in the other van works totally fine not needing a bench
The first thing is that this battery you have linked to is a class C battery. It has a poor NCC rating.
https://www.thencc.org.uk/downloads/Leisure_Battery_Register_Website_November_2019.pdfsee Yuasa Halfords battery specs. 85 discharge cycles to 50%! That's poor. I see they also give a "start-up" rating of 750 amps. What's that? Its not a starter battery.
The other battery sounds like a Banner Battery. If its a starter battery then it will probably accept a faster recharge that the Halfords leisure battery will.
Leisure batteries don't charge quickly so running it off a SCR isn't usually the answer as we don't do enough mileage and vehicle alternator are poor battery chargers.
The only way you can test to see if any battery is fully charged is to let it settle for 4 hours before taking a volt reading across the terminals. 12.8v or higher is a fully charged battery.
If your leisure battery is flat then its going to take a long time to recharge a 115amp battery. A 10 amp charger will take much more than 11.5 hours as the charge rate the battery will accept diminishes as the battery gets a fuller charge. Expect 24 hours at least.
The battery chargers we used in the workshop were large heavy duty brutes that would just force a charge into a flat battery without any thought of battery care. A starter battery will tolerate this occasionally. Your leisure battery won't.
Another thing is that some battery chargers will show a green fully charged light when connected up but without 230v power. The led will only change to orange or red when the battery charger is switch on.
The magic eye in the battery is an indicator of battery charge, water level and discharge. Its basically a crude battery hydrometer which tests electrolyte level density and the battery acid specific gravity which translates into battery charge and state. Its also only an indicator of 1 cell of 6 so doesn't tell you much anyway.
The only way to accurately test the current state of charge is to test the battery voltage across the terminals after it has rested for 4 hours.