Solar System Update 2012

http://www.atbatt.com/product/22088.asp

My diminutive 20w Mono-Si based solar power system is getting a proper storage battery. Learn more about it by clicking "read more" 
For the last 2 years it has been operating using my car's old 36Ah FLA battery. The battery was made in Dec 2004 in Japan and now after thousands of cycles it is barely functional in my solar system : fills up too quickly and discharges too quickly : this dramatically reduces the performance of the system. After some light online research I located a suitable replacement designed for solar :) 

Amstron VRLA Deep Cycle Gel Cell Batteries are maintenance free, easy to handle, rugged and economical. It has a characteristic of high discharge rate, wide operating temperature, long service life and deep discharge recover. GENERAL FEATURES • Superior Deep Cycle Design • High Power Density • Thick Plates and High-density Active Material • Longer Life in Deep Cycle Applications • Excellent Recovery from Deep Discharge • Designed for Solar Energy Applications Amstron AP12-40DG Rechargeable Sealed Lead Acid Deep Cycle Gel Battery is designed with advanced gel technology, high performance, heavy duty plates and electrolyte to produce 100% Depth of Discharge at extreme temperatures with over 10 years of float service life. This battery uses a state of the art, heavy-duty, calcium-alloy grid that provides exceptional performance in cyclic discharge use perfect for  use in solar power applications.  Voltage per unit 12 Volts : Cell per unit 6 cells Nominal Capacity (10.50 Volts) 20 hr. 2.02A / 40.4Ah 10 hr. 4.0A / 40Ah 5 hr. 6.47A / 32.35Ah 1 hr. 24.6A / 24.6Ah Approximate Weight 29.5 lb / 13.38 kg Energy Density 1.39 W-h/in3 (84.97 W-h/l) Specific Density 16.1 W-h/lb (35.42 W-h/kg) Internal Resistance (Approx.) 9.2mΩ Max Discharge Current 100.0A (5 mins.) Max Short-Duration Discharge Current 400A (5 sec.) Shelf Life 1 Month 3 Months 6 Months 12 Months 97% 91% 82% 64% Operating Temperature Range Charge -4°F (-20°C) to 122°F (50°C) Discharge -40°F (-40°C) to 140°F (60°C) Type R Terminal Charging Voltage (25°C) Cycle Use 14.4-15V(-30mV/°C), Max. Current 10A Float Use 13.6-13.8V(-20mV/°C) Size  L: 7.8 inch (19.81 cm)  W: 6.54 inch (16.61 cm)  H: 6.73 inch (17.09 cm) ** Update 4/20/2012 : The battery Arrived early on 4/19 so I got it all hooked up just before darkness set in when my panel was pushing a meager 7.38 volts. It had a resting charge of 12.61 when it arrived. So today on 4/20/2012 it will get its first day of solar charging :) Unfortunately, the weather consists of thick rain clouds.... fortunately, the mono-si panel works exceptionally well under diffuse overcast light conditions....