Absorbed Glass Mat (AGM) Batteries
AGM batteries (Absorbed Glass Mat) also known as VRLA (Valve regulated Lead Acid) or Sealed Maintenance Free batteries, have the most mischief surrounding them of any battery category.
Some folks routinely call them GEL batteries, which is not correct, but GEL batteries are also Sealed Maintenance Free batteries. GEL batteries are more difficult to correctly charge than AGMs.
A lot of folks will tell you maintenance free means you don’t have to pay attention or do anything to them. Not so at all. All lead acid battery cells “stray” in voltage (it’s the nature of the beast) and when you have unequal cell voltage some cells “hog” the charge.
Voltage checks will indicate when you need to “Condition” (overcharge) the bank to bring the cells to equal voltage again. . If you buy your AGM batteries from The Solar Biz™ we’ll help you to set up your system (Inverter/Charger and Charge Controller) correctly.
Another Myth is AGMs don’t last as long as Wet Cell Batteries They’re all lead acid batteries so if they’re the same size weight and Amp Hours they will live the same length of life.The real differences are AGMs won’t freeze even when discharged and the self-discharge rate is significantly less than a wet cell (meaning they will “sit” charged longer)