AGM battery question

[bruceknee]

I am using AGM's, do I need the batteries to be enclosed in a sealed compartment that is vented or are they ok in the same bay as the gen. and inverter will be in? Gen will be isolated.

[Nick Badame Refrig/ACC]

Bruce,

This is all I found on AGM,

AGM TECHNOLOGY - THE DIFFERENCE

Some of the main differences between the old vented lead acid batteries and the LIFELINE AGM valve regulated sealed lead acid batteries are:

- The electrolyte is absorbed in a glass mat (AGM) separator in the LIFELINE and it is spillable in the flooded or vented type.

- The cells have pressure relief valves in the LIFELINE that are designed to keep positive pressure in each cell. The older vented or flooded type battery cells are open to atmosphere through the vent cap holes (should the vented battery be tilted or inverted, the result can be electrolyte (sulfuric acid/water mixture) spilled all over your equipment, a highly corrosive and potentially dangerous condition).

- The cell groups in the old vented type batteries are loosely packed and thus have high plate separation. In contrast, the LIFELINE AGM marine battery has every square inch of positive and negative plate material tightly packed and compressed with the AGM and supported by the walls of each cell. With this type of construction, LIFELINE offers much lower internal resistance ... greater starting power (particularly in cold temperature) ... and a much higher degree of protection against shock and vibration than the old flooded type

From What I hear, They use them in aircract that Fly Upside Down!!

Hope this helps!
Nick-

[Nick Badame Refrig/ACC]

Battery Comparison Chart

Gel Cell
Better for rough service environments
Leak proof
Can be installed on its side with small drop in performance
Less susceptible to low temperatures
When charged correctly does not vent much gas
Low self discharge rate
Higher initial cost than Liquid Cell
Electrolyte cannot be replaced 
Charging tolerances are tighter; cannot be charged over 14.2V without damage
Not ideal for use with automotive or unregulated chargers
NOTE all lead acid batteries sulphate if left discharged and require maintenance charging

AGM
Maintenance-free
Leak proof when tipped or if case is cracked 
Used for both deep cycle or starting batteries
Can be installed at any angle (except upside down)
Shock and vibration resistant
Minimal gas release when
charged properly
Low self-discharge rate
Can be submerged in water without internal damage (battery terminals will corrode)
Many charge cycles when properly charged
Better performance for DC loads
Highest initial cost of all three types
More weight per Ah than wet cells
Electrolyte cannot be replaced 
NOTE all lead acid batteries sulphate if left discharged and require maintenance charging


Liquid Cell - also called Flooded Lead Acid

(FLA)
Lowest cost to purchase by amp hour
Less sensitive than the other two styles in accepting higher charging voltages and less expensive / less regulated charging methods 
Good deep cycle performance
Can spill corrosive battery acid
Must be installed upright
Requires regular maintenance 
More quickly damaged if left discharged
NOTE all lead acid batteries sulphate if left discharged and require maintenance charging
Not suitable for high vibration environments

Hope This helps-
Nick-

[H3Jim]

Bruce,
I mounted my AGM's in the engine compartment.  Basically they are sealed batteries, and should not ever outgas.  There is as caveat there, in that if you do overcharge /abuse them to the extent that internal pressure builds excessively, they can vent by design to prevent them from blowing up.  In that case there would be plenty of explosive gas in the batterey copartment.  If you have a 3 stage charger, and do not excessively overcharge, you could go the entrie life of the batteries or even the conversion and never have an issue.