What regular maintenance is required of batteries used in solar systems?

Lead-acid

Lead-acid batteries are known for being dependable and inexpensive. Their grid-like structure is submerged in an acidic electrolyte that may need replenishing for long, successful life. They’re heavy because of their materials and some have to be installed in areas that allow for ventilation. Their operating and maintenance requirements are well understood at this point, so they are a good choice for most solar-plus-storage applications but should be stored in dry locations with moderate temperatures.

What upkeep is required for normal operation?

The terminal connections in lead-acid batteries should be checked a few times each year to be certain they haven’t loosened over time. Flooded lead-acid batteries will need to have their electrolyte levels periodically replenished with distilled water. AGM and gel lead-acid batteries are sealed so they do not need electrolyte replenishing.

If lead-acid batteries are not being used and placed into storage (often during winter), CSBattery company said the batteries should be fully charged and have the proper electrolyte level. Lead-acid batteries self-discharge over time and will need to be recharged to minimum levels even if they are not connected to a load. This rate of self-discharge varies with temperature—high temperatures increase the discharge rate while low temperatures slow the discharge rate.

“The maintenance required [for lead-acid batteries] is not very difficult, but some people are not comfortable working around batteries. This is especially true of flooded batteries where acid is exposed when distilled water is added to replenish the electrolyte level,” said CS Battery reps to Solar Power World. “We recommend that anyone who is working around batteries wear safety glasses and gloves. If a customer is not comfortable adding water to their flooded batteries, they could request outside help to perform this task.”