The cheap battery maintainers at 500ma will work as they always have. So will the old type from years back but a modern smart charger might just make the battery last longer and shuts down when charged avoiding it being on a constant charge.
I use my old 4 amp chargers if my car battery goes flat and connect two of them so it starts in 20 minutes. Only had one car get a flat battery and it was the Nissan and the battery died at 20 Months. You really need a back up with auto cars to avoid that cold start that might happen one day when the battery snuffs it