[Constantin]

Don,
The life of any battery is a function of its duty cycle, the quality of its construction, and the maintenance it received. Some flooded cells like the CS series from Rolls/Surrette will last longer than AGMs under ideal conditions.

However, the many benefits of AGMs (little self-discharge, high efficiency, no spill, low chance of fumes, little maintenance, etc.) have made me convert over.

Particularly if you use your main engine to recharge your banks and bulk charge each day, will the higher charge acceptance and efficiency of AGMs end up making them a cheaper option than flooded cells. More on that on my web-site: http://www.vonwentzel.net

I go through the benefits of AGMs and also have a bulk-charging battery model available that you can customize to compare batteries based on your specifications.

 

[Constantin]

The amp hour capacity of AGMs per unit volume is usually the same if not higher than premium flooded cells. Only the cheapest of flooded cells will have higher Ah capacities (due to very thin Pb plates) but will have correspondingly shorter lifespans.

AGMs are a premium energy storage system. As such, they deserve a charge system that is worthy of them. I''d make sure the system on board is capable of dealing with AGMs and that the charging voltages are set correctly. These voltages do not differ very much from flooded cells (unlike Gel) and thus even a "flooded" setting on a regulator is unlikely to damage an AGM.

The primary difference is the bulk stage where AGMs can be recharged up to 18x faster than flooded cells. Not too many people have that kind of charging capability on board... Anyway, see my website mentioned above for sizing and other considerations.