| Batteries are separated into two categories, by | | | | battery with the thickest plates will last the |
| application (what the battery is used for) and | | | | longest |
| construction (how the battery is built. Automotive, | | | | A battery cycle is one complete discharge and |
| deep-cycle and marine are the major applications. | | | | recharge cycle. Usually its considered to be |
| There are others, but those three categories | | | | discharging from 100% (fully charged) to 20% |
| make up the bulk of battery applications. | | | | and then back to 100%. How deep a battery is |
| Deep-Cycle batteries are the battery of choice | | | | discharged directly affects its life span. A battery |
| for most installations because of the way they | | | | that is discharged to only 50% capacity every |
| are made. Deep-cycle batteries are made to be | | | | day will last twice as long as a battery that is |
| run completely down relatively fast, and | | | | drained to 10 or 20% every day. |
| recharged just as fast, constantly. The major | | | | Battery Life |
| applications for deep-cycle batteries are solar | | | | There are many variables to deep-cycle battery |
| electric (PV), backup power source, and boat/RV | | | | life. Overcharging, extreme heat, extreme cold, |
| batteries. | | | | lack of use can all lead to a premature death for |
| There are 3 main construction types at this time: | | | | even the heartiest of batteries. All things being |
| - Flood (wet) | | | | equal, if the battery is maintained, not |
| - Gelled | | | | overcharged, in a relatively cool area, a good |
| - AGM | | | | gelled deep cycle will probably last around 3-5 |
| Flooded batteries are what most people think of | | | | years. An AGM deep cycle will probably go around |
| when thinking of batteries of this size. They are | | | | 6-8 years. The standard flooded battery 1-6 |
| the standard battery with removable caps, or | | | | years. Again there are MANY variables so its |
| they might even be the 'maintenance free'. | | | | pretty hard to give a precise time |
| Gelled Batteries or Gel Cells are sealed, and some | | | | In the deep-cycle family of batteries, the AGM |
| are valve regulated. They contain gelled acid that | | | | has one advantage over the other two types in |
| was gelled by adding silica gel, making like a | | | | it's class. Of all 3 of the deep cycle types, AGM is |
| battery acid jelly. If you have the space and | | | | the only one that can actually withstand freezing. |
| especially the ventilation, the valves actually do | | | | However when frozen, the output is 0, but it will |
| help out on battery life. But ventilation is | | | | be undamaged and use able when thawed out. |
| extremely important. However they have to be | | | | Your needs for batteries may be a little different |
| charged at a slower rate to prevent excess gas | | | | than someone else's. Buy according to your needs |
| from destroying the cells. Usually, solar systems | | | | and do the proper homework on the |
| charge relatively slow, so this isn't really an issue, | | | | manufacturer before making this investment. |
| but if you have a aux. generator on your system, | | | | There is a myth that you shouldn't store batteries |
| you have to limit the current. Most of the better | | | | on concrete floors. It is just that, a myth. The |
| made inverters handle this without a problem. If | | | | reasoning for this story originates back when |
| they are overcharges they will die quick. | | | | battery cases were made of wood and asphalt. |
| AGM (Absorbed Glass Mat) batteries are similar to | | | | The acid would leak from them and if they were |
| the gelled batteries but they also have fiberglass | | | | sitting on a concrete floor, there would be a slow |
| mat between the plates of the batter, which is | | | | discharging circuit forming in the now moist floor. |
| then filled with gel. These batteries are the | | | | Battery Quick Facts |
| premier choice if you have any concerns about | | | | * Almost all batteries have to be cycled 10-20 |
| spilling of battery acid. While spills can still happen | | | | times before being able to reach full capacity. A |
| with AGM batteries, because of the viscosity of | | | | brand new battery will actually have a capacity |
| the gell, it takes a little more than just a hole in | | | | thats about 10-15% less than rated capacity. |
| the battery to come in contact with you or the | | | | * Always keep vent caps on your flooded |
| floor. | | | | batteries when charging. This prevents water loss |
| The main difference in deep-cycle batteries is | | | | and splashing when they bubble during the charge |
| thicker plates. The thicker plates allow the | | | | cycle |
| deep-cycle battery to be discharged down as | | | | * Lead-Acid batteries do not have a memory. |
| much as 80% over and over again. The main | | | | They do not need to be fully discharged to avoid |
| difference between a TRUE deep-cycle and other | | | | having a memory. This will only lead to early end |
| wannabes is the presence of solid lead plates, not | | | | of battery life. |
| sponge. Thicker plates mean longer life. The | | | | |