As I am now in the market for a battery upgrade I read a long thread of the same subject on a 4runner forum and found the following Quote to be the clearest explenation of the features and benifits?
"Just thought I might add some light to the battery chat. Batteries fall
into 3 main catagories...with some variations.
Standard automotive, rv marine and deep cycle.
Standard automotive need a large available amperage for a short duration,
usually under a minute until the vehicle is started, after which the
battery is immediately recharged.It is constructed with thinner lead
plates. Typically doesn't discharge more than 10%. Full deep cycling
of this battery, 70% or more, will kill this battery if done 8-10
times.Usually rated in cold cranking amps which is the number of amperes a
battery at -18C(0 F.) can deliver over 30 seconds without falling below a
voltage of 1.2v per cell (7.2v combined)
Deep cycle batteries are designed to deliver a smaller amperage over a
longer period of time, with longer periods between recharging.It
incorporates thicker lead plates and denser active material and typically
will discharge to 70% or more.It is capable of doing this 400-600
times.Usually rated in reserve capacity, which is the number of minutes a
new fully charged battery can deliver 25 amps @ 27 C., (81 F.), while
maintaining a voltage of 1.7v per cell.
R.V. Marine fall somewhere in the middle, having to be capable of starting
an engine, and power accessories found on larger boats, as well as being
constructed more ruggedly for the vibrations of marine life.
These are my choice for off-roading with accessories, such as winches &
lights, and large stereos, as they have the best of both worlds."
if your interested the link is
http://www.barneymc.com/toy_root/techtalk/electric/battery.htm
I am fairly confident in going with a red top for now. another battery was mentioned called Black Panther which are sealed, and smaller dimensions (they talked about fitting two in a stock tray) , is anyone here running these?