More info on AGM batteries.
The AGM battery (absorptive glass mat battery) also known as VRLA ( valve regulate lead acid) battery is a internally recombinant battery. Hydrogen and Oxygen generated during charging/boosting are recombined at the negative plate. To effectively achieve recombination two items are critical.
1 - Acid saturation in the plates and separators need to be below 98%.
2 - The battery needs to operate under pressure of 1 PSI and higher. (valve regulated)
Opening the battery should not be done. Removing the vents can comprimize the vent seals and allow air to enter the battery during use. Air leakage into the battery will effect the negative plate and can reduce reconbination resulting in dry out - shorten life.
Adding any liquid, water or acid, will create an inbalance as David Roden indicated. It is not beneficial to add any liquid even at end of life. The addition will not mix uniformly and create variation in the acid contration in the plates and that create unbalances in the cells. The glass mat separator does not alow acid mixing that occurs in a typical flooded battery such as an automotive battery.
AGM batteries are not spillable, If damaged they will not leak any substantial amount of acid. Adding liquid, acid or water, will create a flooded battery condition. Shipping flooded batteries is restricted. Requires a hazardus material clean up contact number. Acceptance of the truck driver or boat driver is required. Flooded abtteries are phrobited form shippment by plane,( just like lithium batteries)
I converted my E12 from 6 golf cart batteries to two paraller strings of 3, 12 volt 75 amp hour Gr 24 AGM deep cycle batteries. The have been working great and require no maintence. The only chalange is the lift motor which is 18 volt. I have the motor connected to 24 volt and use a power resistor to drop the voltags to 18 under lift operation.
The only maintance I do at the end of winter and end of the cutting season is boost each battery separately to bring all the voltages up to the same 12.9 volt at open circuit to balance all the batteries.
Dave Thuerk
Manager of Battery Design
--- On Fri, 4/16/10, David Roden <etpost drmm net> wrote:
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