OK Shadow,
Here ya go, a sneak preview of what I been working on this summer.
Site is incomplete and will launch soon.
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Some good comments on battery facts so far but I will add my 2 cents.
If your looking for a bigger gas tank such as trolling time then consider the reserve capacity rating.
This number tells you the minutes under 25 amp load and still maintain certain voltage.
This is how to measure capacity of deep cycle batteries, but only one of several rates given, such as CA, CCA, MCA, AH.



Product Comparison

Product Details
Product D31M 8052-161, Optima BLUE TOP Marine Deep Cycle Battery 31MDC, Exide Nautilus Marine & RV Deep Cycle Battery 8A31DTM, 12 Month Deka Intimidator Deep Cycle AGM Battery
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Price $0.00 $110.00 $228.00
Model OPT D31M 31MDC 8A31DTM
Brand Optima Exide Deka
Availability 2 - 3 Days In Stock In Stock
Rating
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Summary Optima BLUE TOP D31M 12 Volt 900 CCA/1125 MCA Marine Deep Cycle 8052-161 Ultra high-performance SPIRALCELL TECHNOLOGY® AGM (absorbent glass mat) dual-purpose battery for marine and RV. BLUETOP®.. Exide 31MDC 12 Volt 725 CCA/900 CA Deep Cycle .. Deka 8A31DTM 12 Volt 800 CCA/1000 MCA AGM Battery ..
Weight 59.80lb 0.00lb 69.00lb
Dimensions (L x W x H) 12.19in x 6.56in x 9.38in 13.00in x 6.81in x 9.88in 12.94in x 6.75in x 9.38in
Power Rating
Voltage 12 12 12
Cold Cranking Amps (CCA) @ 0°F 900 725 800
Marine Cranking Amps (MCA) @ 32°F 1125 900 1000
Reserve Capacity Minutes @ 25A 155 205 210
Amp Hours (20 Hr Rate) 115 105
Characteristics
BCI Group Size 31 31DC 31
Manufacturers Part Number 8052-161 31MDC 8A31DTM
Battery Type Sealed AGM (Absorbed Glass Mat)- Marine Deep Cycle Deep Cycle Lead Acid Sealed AGM (Absorbed Glass Mat)-Deep Cycle
Terminal Type M, Top Post & Stud (5/16P 5/16N) M1 Post w/Stud (3/8P 5/16N) M, Top Post & Stud (5/16P 5/16N)
Core Unit Value 1.5 1.5 1.5
Manufacturer Warranty
Free Replacement Period 24 Months 12 Months 12 Months