Originally Posted by Bill_E
Regarding batteries: I am beginning to see the advantages of good golf cart batteries. I'm wondering if two of them will be sufficient. When considering batteries, what are the most important parameters? Amp hours? My Optimas are only 55 Ah each and there are lots of golf cart batteries at 150 and more Ah. Or is the Reserve Capacity a more useful parameter? Again, there are lots of golf cart batteries with high reserve capacities. I'm going to have to do a whole lot more reading on this issue.
It's not just Ah's or reserve capacity it is a combination of cycle life, Ah's and cost.
Keep in mind that Group 24, 27 & 31 batteries are not
really a true deep cycle battery, in flooded designs. When compared to their sister cases, in starting or dual purpose types, they appear to be "deep cycle" but when compared to an actual deep cycle battery, such as a GC2 6V or a GEL or a premium
battery, they are not really deep cycle
Trojan for example rates their entire 12V SCS "deep cycle" line up at just half the rated cycles of their GC2 6V / T105. Half the rated cycles! How many know this when buying
the Trojan 12V SCS "deep cycles" batteries? Probably less than .5%, if I had to guess.....
What's the better value, 200Ah's of Trojan 12V batteries or 200 Ah's or Trojan 6V batteries when the 6V batteries will deliver double
the cycles of the 12V, in the lab
What's the better value a Deka GEL battery rated at 1000 cycles vs. a Deka AGM
rated at 300 cycles? Even if the GEL cost $50.00 more this is a steal, if you charge them correctly.
Most Group 24, 27, 31, 4D & 8D 12V flooded batteries are all what I call "imposter deep cycles" including the Trojan SCS series 12V G-24, G-27 & G-31... Some flooded 12V deep cycles will give more cycles than others, in these group sizes, but none compete directly with a true deep cycle battery such as a GC2 6V in terms of cycle life..
Battery buyers should always try to understand they are are not just buying Ah capacity
they are buying expected cycle life
too. The trouble is it is nearly impossible to compare cycle life claims, between manufacturers, because most don't rely on independent labs that test to a standard. Within a brand
the cycle life data is useful guidance
but brand to brand is not...
12V deep cycle golf cart batteries such as the Trojan T1275, and they do have the same cycle life as a 6V T105, but they are also taller, like the GC2 6V, and a built to use the same plates as a GC2 battery. They are also pretty darn pricey compared to T 105's due to lower volume. This is why most just use the GC2 6V case in a series or a series parallel configuration for 12V...
G-24, 27 & 31 flooded batteries simply do not have the plate thickness a GC2 6V battery does because they are adapted
battery case sizes from the 1950's automotive world......
For example in the Deka / Sea Volt / West Marine
line you have starting, dual purpose and deep cycle
G-24, 27 & 31 12V batteries which all share the same case
. However they are only really deep cycle
when compared to the starting or dual purpose batteries with which they share the identical case
. They are not "deep cycle" when compared to the GC2 6V or other actual deep cycle
batteries. Deep cycle? Compared to what? This is what needs to be asked....
Here's the data across the Deka / East Penn / West Marine line up:
Flooded Batteries - Group 24, 27, 31 4D, 8D & 6V GC2
12V Starting - Cycles to 50% = Not Rated
12V Dual Purpose - Cycles to 50% = 200 (4D & 8D)
12V Deep Cycle - Cycles to 50% = 350 (G24, 27, 31)
6V Golf Cart - Cycles to 50% = 700-1000 (GC2, L16 etc.)
AGM - Cycles to 50% = 300 (all case sizes)
GEL - Cycles to 50% = 1000 (all case sizes)
*Note: The above are LAB RATED cycles. Expect less in the real world..
As can easily be seen the 12V "deep cycle" battery is only a "deep cycle" when compared to the starting or dual purpose batteries it shares a case with. If you absolutely must buy a 12V G-24, 27 or 31 buy the deep cycle version. In many cases this is all that will fit. It is easy to see that these are not really deep cycle when compared to a truer deep cycle battery.
The only ones that have lab rated cycles the same or close, to their own brands 6V batteries, are Lifeline AGM's. I know of no other brand that will rate their G-24, G-27 or G-31 at even half the cycles of their GC2 6V flooded batteries. The Deka / East Penn / WM product is less than half...
It should be noted that West Marine, for all the crap they take, is actually honest
in their labeling of the Deka 4D and 8D flooded batteries and they don't lie and call them deep cycle like many other re-sellers of those identical Deka/East Penn batteries do.
Sadly the term "deep cycle" has been grossly bastardized, diluted and abused by the marketing
teams. A Deka AGM at 300 cycles, or flooded 12V battery at 350 cycles is not what I would consider a deep cycle battery
. A Deka GEL at 1000 cycles, or a GC2 6V are a deep cycle battery. I have one GEL bank that just entered its 15th season.. The 6V GC2 at 700-1000 cycles or L-16's etc. are also deep cycle batteries.
Remember its not just Ah capacity you are buying.. Cycle life is where the returns are... Still most batteries are murdered
by their owners and lots get les than 20% of the lab rated cycles, in the real world... GC2 golf cart batteries almost always win when you look at $$ per Ah and $$ per cycle...
If you want the ultimate in deep cycling lead acid there are always 2V batteries such as those by Rolls.....
The GC2 6V market is extremely competitive and most brands, even the JCI (Johnson Controls) built 6V's, are pretty darn robust..