The
boat (1972
Morgan Out Island 41,
on the hard, new to me) has a
battery 'tray' with two dead 4D
batteries in it. Was going to replace them when I noticed that it seems three Group 31 will fit that space also(?).
Aside from having to make some jumpers and lengthen a few wires that go to the terminals, what are the pros and cons of having three
batteries, vs two, feeding a standard OFF-1-2-BOTH
battery switch?
I guess with three, two will have to be in parallel and one on its own? Will this create problems? Or is this better so two can feed the house and leave one in reserve for starting the
engine?
Both batteries are of the same brand and line:
"EXIDE NAUTILUS
MARINE & RV BATTERIES - DEEP CYCLE"
Spec sheet covering both batteries:
http://www.exide.com/portal/server.pt/gateway/PTARGS_0_0_405_221_16527_43/http%3B/WINAPAQLOG1.Inside.Exide.ad%3B7089/publishedcontent/publish/exide_corporation__public_/transportation/north_america/images/specs_marine.pdf
All the advantages in the specification department seem to be in favor of the Group 31s:
Price:
Group 31: 3 x $89 = $267
4D: 2 x $149 = $298
20 hr Ah rating:
Group 31: 3 x 115 = 345
4D: 2 x 160 = 320
Marine Cranking Amps:
Group 31: 3 x 900 = 2700
4D: 2 x 850 = 1700
Reserve Capacity:
Group 31: 3 x 205 = 615
4D: 2 x 250 = 500
Questions:
- How can the three Group 31s seemingly offer so much better specs over the two 4Ds, when their footprint is about 25% smaller and their height is over an inch less?
- Why does a Group 31 DC have more MCA than a 4D DC?
- Less cost, less size, less weight, more MCA, more Ah, more RC... How can this be - am I missing some important factor here?
Any comments will be appreciated.