"Trickle charger" is a term sometimes used to cover a "battery maintainer", but there is a difference.
My bikes are on battery maintainers when in the garage. They monitor the battery for level of charge and top up as needed. They also run discharge then recharge cycles, which, it is claimed, are designed to reduce sulfation and generally keep the battery conditioned. A constant trickle charge, if it doesn't switch off at a certain voltage, will cook the battery. If it does switch off, the battery will then start discharging.
I've not had a battery fail on the bikes since I started maintainers on them about 7 years ago. However, I've swapped some of the bikes, but the longest and oldest battery constantly in my ownership under this regime is now 4 years old, so I've not yet fully proved to myself they work.