with south poles

where it has to be able to withstand extra wind and weather when the containers are moved around in a heavy-handed way with many blows and bumps

The amount of strength you can extract from a magnet depends on the magnet’s neodymium density

For example:

This MagSwitch gives you up to 60 kg

Power magnet, Skive 12x2 mm. Auto-translated (EN) with south polesNeodymium magnets Permanent magnets Diameter: 1. 2 cm Height: 0. 2 cm Strength: approx. 1. 6 kg. You no longer have to worry about your papers falling off the fridge. Due to the size of this power magnet, it's not strong enough for glass boards. SPECIFICATIONS: Strength: approx. 1,600 gr. Material: NdFeB Magnetisation: N45 Gauss: 13200 13700 (1. 32 1. 37 T) MGOe: 43 45 Max. temperaturee: 80C Surface: nickel plated (Ni Cu Ni)