http://www.google.co.uk/search?q=sealed+lead+battery&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=GoG3TJ3VO4ez4Abg2rWZCg

http://www.google.co.uk/search?q=sealed+lead+battery&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=GoG3TJ3VO4ez4Abg2rWZCg

http://www.google.co.uk/search?q=lead+aciid+battery&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GGLT_en&redir_esc=&ei=YYG3TNfpLMfc4Aadk5CuCQ

taken from battery stuff.com

http://www.batterystuff.com/tutorial_battery_gel_agm.html

GEL vs. AGM Sealed Batteries

AGM (absorbed glass mat) is a special design glass mat designed to wick the battery electrolyte between the battery plates. AGM batteries contain only enough liquid to keep the mat wet with the electrolyte and if the battery is broken no free liquid is available to leak out.

Gel Cell batteries contain a silica type gel that the battery electrolyte is suspended in, this thick paste like material allows electrons to flow between plates but will not leak from the battery if the case is broken.

More often than not AGM Batteries are mistakenly identified as Gel Cell Batteries. Both batteries have similar traits; such as being non spillable, deep cycle, may be mounted in any position, low self discharge, safe for use in limited ventilation areas, and may be transported via Air or Ground safely without special handling.

AGM Batteries outsell Gel Cell by at least a 100 to 1. AGM is preferred when a high burst of amps may be required. In most cases recharge can be accomplished by using a good quality standard battery charger or engine alternator. The life expectancy; measured as cycle life or years remains excellent in most AGM batteries if the batteries are not discharged more than 60% between recharge. There are some AGM batteries we sell that offer excellent 80%+ deep cycle abilities.

Gel Cell Batteries are typically a bit more costly and do not offer the same power capacity as do the same physical size AGM battery. The Gel Cell excels in slow discharge rates and slightly higher ambient operating temperatures. One big issue with Gel Batteries that must be addressing is the CHARGE PROFILE. Gel Cell Batteries must be recharged correctly or the battery will suffer premature failure. The battery charger being used to recharge the battery(s) must be designed or adjustable for Gel Cell Batteries. If you are using an alternator to recharge a true Gel Cell a special regulator must be installed.

Yes, the aforemention post contain great information, BUT how do you tell what type of battery it is if the manufacturer does not identify on its case and labels what it is?

Case in point, I have two 12 VDC batteries I use for lawn tractors and neither ID what battery type it is. I recently bought a BATTERYMINDER maintaining/charging unit and per the written instructions it is imperative that I know the battery type before attach the unit to a battery.

What visual clues would help me in distinguishing between the various types of cells? Any ideas?