I already posted a thread here about the 6A/2A chargers being inaccurate, especially the 20-30 dollar cheapos that can be bought at any automotive store. The one which I had overcharged the battery in the 6A mode and undercharged in the 2A mode. These so called “taper chargers” should taper the amp flow once a battery comes close to the 14.40V(ideal) voltage when it is considered to be charged.
Check your charger to make sure that you are not overcharging the battery otherwise you may do more damage than good. The 5 stage Yuasa mentioned above is awesome, I’ve had it for over 10 years back from the days when I was a complete punk and did not know anything about battery maintenance. The technology is impressive, excellent to use when bringing up a dead battery (such as leaving the lights on) because it supplies a constant current of 1.5A until about 13.00V when it switches to a gentler absorb mode hence Sooge’s experience about the voltage cycling until it reaches the ideal 14.40V stage when it shuts off and goes into float mode.
Mine shuts off at 14.32V which is just about fine and the float mode retracts back to roughly 13.10V-13.60V. There is lots of discussion as to what the actual float voltage should be and whether it should be temperature compensated, but most “solid” charger manufacturers do choose a slightly different voltage. The purpose of the float mode is to make sure that the battery’s natural drain is compensated for, yet the 13.10V is not high enough to cause any internal damage to the battery if left on indefinitely.
If you are going the route of keeping a topped off battery due to short driving trips, invest into one of these “smart chargers” as they will take care of everything for you, ensuring that each morning you will be able to start for work.
