Couple of thoughts:
Are you looking to maintain or recharge? A 200W solar panel seems excessive as a storage "maintainer" solution.
Anything not bolted down (or secured up on the roof) has MORE incentive to grow legs and walk away. Are you okay with that at your storage lot?
They have plug and play (built in solar controller) battery "maintainer" units that are relatively cheap and can do what you're asking. Just as an example, Battery Tender has 5, 10, and 15 watt panel kits available. This is the 15 watt kit:
https://www.amazon.com/Battery-Tende.../dp/B004Q820TQ