Which Battery is better?

Aug 2, 2009
637
Catalina 315 Muskegon
I am so glad to see a reply in this thread from MaineSail. Truly makes my day.

Andiamo, my advice to you, and it's excellent advice by the way, pay attention to what MaineSail has told you. If you can find a better source for battery information, I want to know about it.
 
May 24, 2004
7,129
CC 30 South Florida
Any battery that doesn't overcapitalize it's features.
There is a difference between denominated Marine Deep Cycle Batteries and what are True Deep Cycle Batteries. True Deep Cycles wet cell batteries do not take kindly to movement or motion and are mostly used in stationary battery banks to serve as back-up power for computer rooms or medical equipment or for storage in land based solar installations. Such batteries could not withstand boat movements without damage. Those known as Deep Cycle apt for marine use are more of a middle of the road battery design between Deep Cycles and Starting Batteries of even Dual Purpose Batteries. Their plates are thicker and as such their weight. New Lithium Ion smart batteries are revolutionizing the weight, size, capacity and applications of batteries but at this time are a little pricey for general recreational boating use.
 
Jun 11, 2004
1,621
Oday 31 Redondo Beach
There is a difference between denominated Marine Deep Cycle Batteries and what are True Deep Cycle Batteries. True Deep Cycles wet cell batteries do not take kindly to movement or motion and are mostly used in stationary battery banks to serve as back-up power for computer rooms or medical equipment or for storage in land based solar installations. Such batteries could not withstand boat movements without damage. Those known as Deep Cycle apt for marine use are more of a middle of the road battery design between Deep Cycles and Starting Batteries of even Dual Purpose Batteries. Their plates are thicker and as such their weight. New Lithium Ion smart batteries are revolutionizing the weight, size, capacity and applications of batteries but at this time are a little pricey for general recreational boating use.
So are you saying that something like a Trojan T-105, sold as a Marine/RV battery, is "...more of a middle of the road battery design between Deep Cycles and Starting Batteries..." and is not a true deep cycle battery?
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Trojan T-105, sold as a Marine/RV battery, is "...more of a middle of the road battery design between Deep Cycles and Starting Batteries..." and is not a true deep cycle battery?
No. The battery as defined by the manufacturer is a "Deep Cycle Battery".

T-105 Deep-Cycle Flooded
Capacity MinutesCapacity Amp-HoursEnergy (kWh)Dimensions inches (mm)Weight lbs. (kg)

@25 Amps
447
@75 Amps
115
5-Hr Rate
185
10-Hr Rate
207
20-Hr Rate
225
100-Hr Rate
250
1.50Length
10.30 (262)
Width
7.11 (181)
Height
11.07 (281)
62 (28)

Note the Battery weight. 62LBS. Compare that to a Marine RV Battery like those in AutoZone and you'll find the weight significantly less. Why? Less Lead in the battery. Thin plates.

A Deep Cycle Battery will have thick plates. There are 3 cells providing 6 volts.
 
Jan 18, 2016
782
Catalina 387 Dana Point
Yup. Lotsa manufactures/retailers (I'm looking at you WM) have figured out if you stick a label on the battery with the word "marine" on it you can double the price. It's still a crap battery.

For a house bank you want max AH. You don't care about CCA or anything else. Read MaineSail's battery articles. He's spot on.

AGMs for most sailors are not a good choice. As mentioned above, the bang for buck sweet spot is GC-2 golf car batteries.