Here’s some things you should know about batteries!
As a battery discharges power, its voltage level will decrease. A fully charged “12 volt” battery should read at about 12.7 volts. However, a fully charged battery on a charger or in a running vehicle is typically at 14.7 volts. A discharged battery usually reads 11.1 volts depending on the type of battery and its application.
Amp Hours (AH) - Ampere hours are the amount of amps a battery can produce for one hour. The larger the AH rating, the longer the battery can produce power and the longer it will take to recharge.
Cranking Amps (CA) - A rating stating that the battery can produce a certain amount of amps at a temperature of 32° F for 30 seconds.
Cold Cranking Amps (CCA) - A rating stating that the battery can produce a certain amount of amps at a temperature of 0° F for 30 seconds.
Vented Battery - Vented batteries release water vapor when the battery's internal pressure increases due to heat, sealed batteries do NOT have a pressure relief valve.
Deep Cycle - Deep cycle batteries are affordable and the most popular battery for solar energy storage. Deep cycle batteries are designed to discharged up to 80% of its charge before its battery life is effected. Thus a 12 volt deep cycle battery can discharge over 9 volts before damage occurs to the battery.
Starting - Starting batteries are used primarily in cars to power the engine starter. They can deliver short, high amp bursts quickly, but are not designed to produce power for a long duration. From some starter batteries, their life span will rapidly decrease if their voltage drops below 11.8 volts. Starting batteries are NOT recommended for solar applications.
Marine - Marine batteries are a hybrid between deep cycle and starting batteries. They are not as efficient as deep cycle batteries but can handle the energy discharge better than a starting battery can.
Types of Batteries
Lead Acid batteries contain lead plates submerged in fluid battery acid. These batteries are very common in vehicles, they should NOT be drained below 80%, and are typically low in cost. https://batteryuniversity.com/learn/article/lead_based_batteries
Gel Cell batteries contain lead plates submerged in a battery acid gel. These batteries do not have to be kept upright. https://batteryuniversity.com/learn/article/bu_201b_gel_lead_acid_battery
Absorbent Glass Mat (AGM) batteies are similar but not the same as a gel battery. The electrolyte is in a mat form that is very light, durable, and reliable. https://batteryuniversity.com/learn/article/absorbent_glass_mat_agm
Lithium-Ion batteries are some of the highest quality batteries. They are lightweight, can store charge for a very long time, and can be completely discharged without causing damage. https://batteryuniversity.com/learn/article/lithium_based_batteries
If you would like to increase your battery bank lifespan, battery balance equalizer is recommended to connect to all of your batteries. This will insure all the batteries in the bank will charge and discharge at the same rate.
Here is how to connect batteries in series and parallel to create different voltage and amperage to properly power your devices.