Off-Grid solar electricity systems need to be maintained, and you should plan for replacement of components over time. After all, you will own your own power plant! Just like utility companies need to maintain plants, poles, wires, and transformers, you will need to do the same for your system.
Solar Panels
Solar panels themselves are extraordinarily self-sufficient. They have no moving parts and quietly and consistently put out power for years – actually decades – without much thought. Occasional cleaning may be necessary depending on your location, but for the most part they will be an afterthought in your maintenance plan. They are very durable, and it takes a lot to break a panel, and replacement is surprisingly cheap. Rodents chewing through wires and soiling from birds and dust are infrequent but typical concerns. Checking attachment hardware to make sure nothing has loosened is good practice. Solar panels lose productivity over time. Expect to replace them after 25 years, the typical warranted life.
Batteries
Most off-grid homes now use flooded lead-acid batteries. These are similar to what is found in a car or boat, but much larger and with features that allow them to be deeply discharged. The abuse off-grid batteries endure would make typical automotive batteries melt down in seconds. This is typically the most expensive and the most maintenance intensive part of an off-grid solar energy system. Battery water should be checked at least monthly and water added as needed. Maintaining adequate charge and not allowing batteries to sit in a discharged state are critical usage requirements to avoid premature failure and loss of capacity. Periodic cleaning of battery terminals and frequent visual inspection is important, along with occasional disconnection and testing to avoid bad cells from spoiling a whole battery bank. Expect to replace your batteries every 7-15 years depending on use (or abuse) and at shorter intervals if seriously neglected.
Inverters
Inverters are pretty reliable, and come with 5-10 year warranties. Since many systems have multiple inverters, redundancy can eliminate down-time. Inverters generate a lot of heat and most have fans to cool them. Inverters are known to fail from time to time, and require replacement. Usually this is an easy swap in a well-designed system. There is no maintenance, per se, except to keep dust, bugs, and other pests from getting into the system components. Expect to replace inverters every 10-15 years, but some have been known to last much longer.
Generators
In an off-grid solar energy system, a generator will run for short period of heavy power use and for a few to several hours to recharge severely depleted batteries. Engine-driven generators need typical engine maintenance like oil changes and air/fuel filters. They require maintenance based on how often they are used. If your solar energy system is generating most of the power for your home, the generator may only run on rare occasion and to “exercise” it weekly. However, if you generator needs to make up for system deficiencies or overuse, generator maintenance can quickly become a huge inconvenience and expense, not to mention the fuel usage, and deliver in many cases. Generator replacement and rebuilding is also based on the hours used, with cheap units capable of hundreds of hours and more suitable units providing thousands of hours of use with proper maintenance. Expect to get what you pay for, and buy a unit intended for the rigors of off-grid living.
Balance of System
The remaining components of an off-grid solar energy system are as reliable as a typical on-grid home energy wiring/distribution system, and do not require any special maintenance.