Grumpycat
Veteran Member
My understanding of a trickle charger is a low amp charger with minimal circuitry that only keeps voltage high enough to maintain the low amp flow. They were basically what was available for cheap, back in the good ole days. They were supposed to be used intermittently, so they didn't damage your battery.
Traditionally a trickle charger is little more than a small transformer and single diode half-wave rectifier sourcing little more than 100 mA. The theory is this trickle overcomes self-discharge yet will not boil out the battery electrolyte. This is usually safe for simple low tech automobile size wet lead acid batteries for a month or so. No attention paid to voltage or anything, is as dumb and stupid as anything electronic can be.
A modern maintainer will cycle the battery sometimes with more current, sometimes less. In "lithium" mode the maintainer will shut down, monitoring until certain conditions are met, then cycles on.