Battery Glossary

Lithium Batteries

Lithium batteries are actually single-use, non-rechargeable batteries, found in small devices like calculators or timers, and known for their long service life. They are also referred to as lithium-metal batteries. RPC does not sell any lithium-metal batteries for that matter. The term ‘Lithium Batteries’ is sometimes incorrectly used to designate the various chemistries of rechargeable Lithium-ion batteries.

Lithium-ion Batteries

Buy Li-ion Batteries

Lithium-ion batteries, or Li-ion for short, are rechargeable batteries with a very high energy density. This results in smaller and lighter batteries when compared with other battery technologies or chemistries. They also have a very low self discharge rate, which means they have a long shelf life. Lithium-ion batteries will stay nearly fully charged even after several weeks of storage, however manufacturers recommend charging them at least every six months. One of their biggest advantages is their high charge and discharge capacity: they can deliver up to 100% of their nominal capacity.

There are a number of types of Lithium-ion batteries, with different chemistry and characteristics. RPC recommends Lithium Iron Phosphate for off-grid solar systems.

Lithium Iron Phosphate Batteries (LiFePO4 Batteries)

Lithium Iron Phosphate, or LiFePO4 Batteries, are a type of Lithium-ion battery with an energy density that is slightly lower than that of other Li-ion chemistries (e.g. LiCoO2) as they have a lower operating voltage. However, due to their Iron Phosphate cathode chemistry, LiFePO4 batteries are practically incombustible, even when rapidly charged or discharged. This safety aspect gives Lithium Iron Phosphate the edge over other chemistries, as spikes of high currents are common in households. In addition, LiFePO4 can deliver higher peak currents than other Li-ion batteries.

Lead Acid Batteries

Lead Acid Batteries are one of the oldest forms of rechargeable battery. They are made of lead plates submerged in an acid solution.

Despite having a very low energy-to-weight ratio and a low energy-to-volume ratio, their ability to supply high surge currents means that the cells maintain a relatively large power-to-weight ratio. These features, along with their low cost, make them attractive for use in motor vehicles to provide the high current required by automotive starter motors.

Depending on the intended use, the lead plates are manufactured differently to allow for deep discharge or shallow discharge. Read more about the difference between car batteries & deep cycle batteries which are better suited to power a household.

License: Some of the information on this page was gathered from Wikipedia and is therefore released under CC-BY-SA License.

Wet Cell or Flooded Batteries

A wet or flooded cell battery operates by means of a liquid electrolyte solution covering all internal parts inside of an unsealed container, requiring that they are kept upright and the area is well ventilated to ensure safe dispersal of the hydrogen gas produced during overcharging. 

Valve-Regulated Lead-Acid Batteries

A valve-regulated lead-acid battery (or VRLA battery) is an improved type of liquid electrolyte battery. They recombine the oxygen produced at the positive plates with the hydrogen from the negative plates, which can create excessive pressure that must be released to prevent explosion. As the name says, even though they are referred to as sealed lead-acid batteries, they always include a safety pressure relief valve. As opposed to flooded batteries, a VRLA battery cannot spill its electrolyte if it is inverted. Because of their construction, VRLA batteries do not require regular addition of water to the cells and are commonly advertised as 'no maintenance' batteries.

VRLA batteries are further classified as:

  • Absorbed Glass Mat (AGM) batteries
  • Gel batteries

Absorbed Glass Mat Batteries

Absorbed glass mat (AGM) batteries were originally developed for the military as a temperature tolerant and vibration resistant power source. These batteries hold the electrolyte on the glass mat separator.

Gel Batteries

A gel battery is a VRLA battery with a 'gelified' electrolyte. Chemically they are the same as flooded batteries except that the antimony in the lead plates is replaced by calcium.