superfast chargers heat the battery too much, reducing life.

measuring delta means the charger puts a load on the battery to test
it's output voltage. it does this every few seconds. then it goes back
to charging and repeats this until the battery is holding it's highest
voltage. then it stops charging and just trickle charges when voltage
drops a tiny bit


most chargers out there are not smart. they have timers, and cannot sense
delta. these are OK chargers but they can heat the battery longer than needed,
which cuts the life down.

seek a real delta sensing and trickle charger, not a fast charger, for bestest
long life of whatever battery brand you buy. pay a lot more for the charger
is the best investment IMHO