Standard Flooded Deep Cycle Battery (maintenance free or not maintenance free)

There’s the regular standard “flooded” lead acid battery with the first kind being “maintenance free” and the second kind being “not maintenance free” - has caps that you screw off so you can add distilled water when necessary. Some people think that the maintenance free ones last about as long as the warranty and not as long as the one requiring a tad of “maintenance”, which is pretty easy.  These are likely the least expensive comparatively. (This is not to say these can’t get to be pretty costly as well depending on your idea of what “pretty costly” might be.)

Gelled Electrolyte Deep Cycle Battery

You’ll see gelled electrolyte deep cycle batteries. While the liquid inside the standard flooded battery looks like water, the liquid in a gelled deep cycle battery looks like jello and they’re sealed. The whole concept of spilling, a hazard, is removed so that’s really nice in addition to the no maintenance. But, a disadvantage of these is that a regular automotive type charge could easily damage them. The charging current has to go by the manufacturers recommendations. Too much current too fast will damage the battery. If you see yourself putting a nice pump up charge on your battery before (or even during) your battery use “solar season” or some intermittent charging over the off season, this could be an added hassle factor.  These batteries also typically cost more.

AGM Deep Cycle Battery (Absorbed Glass Mat) also sometimes called “dry” or “starved electrolyte”

AGM batteries are newer and have advantages over the previous types but also cost two or three times more than the standard flooded type. They’re more efficient than the standard flooded batteries and don’t have the issues of the gel. There’s a fine fiber between the plates holding the acid. They’re sealed, maintenance free, more efficient, can’t spill, don’t freeze easily - lots of great qualities. Some applications need these features. But, again, AGM deep cycle batteries are pricey.


Battery Size -  Page 3


Three General Types
Of those batteries most commonly used, there are three general types of Deep Cycle batteries you might run into. In the Deep Cycle category, virtually all batteries used with solar set ups are Lead-Acid. The difference between them is in their construction, so their qualities are a bit different. They’re still Lead Acid batteries.