How to get the BEST out of you alternative energy.
Solar panels themselves do not need any maintenance, in fact they depreciate very slowly and are well worth their weight in gold. However, the environment in which they are placed does. Solar panels are only as good as the sunlight they receive, dust and mud build up on the panels over time, this needs to be cleaned off of the panels to ensure that the panels receive all the sunlight they can get.
Maintenance free PB (Lead acid) and Li-ion (lithium ion) batteries do not need any maintenance at all. Flooded lead acid batteries like Trojan batteries do require the occasional top-up in order to keep them working properly. Make sure you know what batteries you have and what, if any maintenance they require. Keeping batteries filled and happy will save you having to replace them prematurely.
Regular testing of your house, factory or farm's main earth leakage is highly suggested, not only for safety purposes but to make sure there are no parasitic loads. Parasitic loads include, failing electrical motors, frayed wiring, rusted light fittings and even illegal connections to your power supply.