Here is some information on battery mass and heat, and pictures of my poor old house batteries.
My old Trace DR 2412 charged at 120 amps, my new Magnum charges at 140 amps, so I bought the optional battery minder.
http://tinyurl.com/4cu7vaq
For optimum battery charging, a unique temperature compensation circuit utilizes an optional remote probe to automatically adjust charge voltage to battery temperature. In the inverter mode, if your batteries run seriously low, an adjustable over-discharge protection circuit automatically turns off the inverter to protect your batteries. Other design features protect against undercharging, overload, and accidental connection of an AC source to an AC outlet.
Thermal mass means that because they have so much mass, they will change internal temperature much slower than the surrounding air temperature. A large insulated battery bank may vary as little as 10 degrees over 24 hours internally, even though the air temperature varies from 20 to 70 degrees. For this reason, external (add-on) temperature sensors should be attached to one of the POSITIVE plate terminals, and bundled up a little with some type of insulation on the terminal. The sensor will then read very close to the actual internal battery temperature.