They could buy just the battery and not the solar if their problem is really the power company turning off the juice. 

Landlords can enter a tenant's property for a variety of reasons, including: Making repairs or replacements Responding to a tenant's request Removing unauthorized window coverings Preventing waste of utilities Changing filters, testing, or replacing smoke detector batteries Inspections Helping with an emergency inside the unit Posting a notice of eviction"Research your state laws because some of your comments indicate a lack of understanding of the landlord/tenant laws where you are operating (like threatening the tenants to keep the security deposit if they don't respond to you, I doubt that is actually a valid reason to keep their deposit, or evicting for late payments, or charging the tenants for your warranty repairs because you missed your 11 month inspection window which was your responsibility, and it looks like your lease says you can charge up to 18% interest for unpaid fees, is that actually legal?).

Batteries wear out, that's just reality, and were talking batteries for a house, yeah, that's $.

Further Evaluation (Professional based)Comment 2: Yard wetComment 23/24/25/26/27: Electrical WorkComment 4/5/6/7/40: Glass repairs/sealedComment 28/29/30: Hvac repairsComment 49: Chimney inspected/cleanedRepair (Handyman based)Comment 3: Vegetation removalComment 12: Leaking hose bibComment 13: Sewer cap replacedComment 19: Door knob replacedComment 22: Replace all batteries in smoke detectorsComment 38: Replace clamp in sinkComment 39: Replace dishwasherComment 41/48: Dry wall prepareComment 44/47: Door repairHave you decided on a property manager yet?

It would be a better investment to buy lithium or platinum, at least they have some uses in the battery and oil industries respectively; Gold has no use anywhere, it is just a shiny metal.

Lightbulbs, batteries in smoke detectors is on them and written in the lease.You can really do whatever you want if it is written in the lease contract but bear in mind they don't own the home and won't care on certain things.

I use Executive Villas and they just charged me $500 to repair some table legs and replace the batteries on a remote.

IF, they are supposed to cut the power when there’s a fire then they have to buy a bunch of Tesla’s mega pack batteries to power the water pumps.

Or plan was to recondition 100% of units.  

They do not just stop paying because there is a door knob loss, or a smoke detector missing a battery.