Battery Maintenance, Or How To Spend About 2 Hours Per Month

We probably spend more time thinking about our batteries than any other component in our solar power system.  They are by far the most maintenance intensive, with the generator coming in second.

Battery maintenance is pretty easy and doesn’t take that much time.  Here’s the basics:

• Fluids. Our batteries are called flooded lead-acid, whcih means they have lead plates inside them that are surrounded by liquid acid.  The liquid needs to be supplemented at times with distilled water.  I would say overall we have to use about 3 gallons of distilled water per year on the battery bank.
• Connections.  The batteries won’t work well without tight, clean connections.  So twice a years, usually in late fall and spring time, I take all the connections apart.  I clean all the terminals and connectors of corrosion, and spread an anti-corrosion goo (that’s the scientific term) on the terminals and connectors.
• Ventilation.  These batteries generate hydrogen gas in the chemical process of storing electricity.  This gas can build up, so the shed they are located in has special ventilation.  I make sure that the vent in the roof is working, and that the vent in the battery storage bin is clean and clear.
• Equalization.  Equalization may be the least known but most effective form of battery maintenance.  While cycling up and down in charge, batteries form hard layer of sulfur on the lead plates.  This is called sulfurization, and it reduces the efficiency of the battery.  To combat this there is a way to tell the inverter to set the generator to ‘equalize’ the batteries.  This basically winds the voltage in the batteries up to a high level for 3-4 hours, which gets the chemistry so hot and vibrational in the battery that the sulfur is literally shaken off.  We always notice a jump in our battery storage capacity after doing this so we try to do it every month, but really it happens every 4-6 weeks.

Next week we’ll talk about the generator, probably our least favorite part of the system.