Check the capacity of your system – is my battery holding charge?  Maintaining the battery at float charge creates a potentially artificial environment whereby it may appear your battery is fully charged but when the battery drifts below the float voltage and forces the charger to go back into absorption or trickle charge mode at a constant voltage.  There is no way to know if your battery is holding capacity. Remember voltage is only an indicator of your battery’s potential to supply energy. If your battery is already aged, then this will potentially damage it further. When the charger is removed if the voltage on the battery decreases faster than expected it is likely your battery is on the way out.  Better to know this well before you are about to leave on the next trip.

Check system is safe – a visual check to observe corrosion, cable integrity, browning of terminals (increased resistance due to poor connections), battery has not vented and has maintained its structural integrity. If in doubt, check with a suitably qualified auto electrician.

Allowing the battery to be placed under load down to 75-80% of its capacity lets you see the charger or power management systems operating effectively.  If something has malfunctioned, the battery may have been accidentally allowed to enter into a discharged condition, leading to battery sulphation and a shorter life span. 

Temperature also has a big effect on appropriate charging and the capacity of your battery.  Most power management systems and chargers do not allow for temperature compensation.  Some may at the actual charger however don’t measure the temperature of the actual battery.  Batteries heat up during charging and if compensation for this is not allowed for over-charging can occur. Higher temperature increases the aging of a battery. At higher temperatures, it is well proven that the life of a battery is greatly reduced.  Charging and discharging your battery does not help prevent this but something to be aware of as your battery ages.

In summary Jeff, your charger may well be capable of maintaining your battery setup at float charge for an extended period and therefore the advice may not be relevant to your circumstances, however, there is no extended harm to your battery in letting allowing it to drop back in charge level to 75-80% of its capacity to check on the aforementioned and maximize the battery life.

Safe travels,

12V Guru