Theyre just magnets, but Ive got to wonder if they are meant to stay energized for long periods of time.
I normally wrap chains through the wheel spokes and put a lock on the chain.
Take a wheel off.
This is what I do! I use the largest Abus security chain that fits through my spoke and chain it through the axle and to signs, trees, posts, etc. Put the highest security shielded padlock on it. Don't buy anything at Lowes or HD. Masterlock and regular chain are poor security. Or just take a tire off....