The RV industry uses golf cart batteries with two 6 volts in series with Trojan T-145s kicking out 205 AH in a six hour period. They don't look like your grandpa's battery but they are made for non-starting loads but they weigh in at 71 pounds a piece. I use them in my RV where size and weight isn't a factor and they last twice as long as any marine battery. The Costco version costs about the same as the marine batteries.
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01-03-2011, 08:22 PM #111998 Mobius
310 HP PCM
01-03-2011, 08:26 PM #12
I actually considered the 2 6v battery route as I have experience With them having had a cart in the past. So since its been brought up, can anyone elaborate on the pros and cons, side from the size, of going this route? also taking into consideration my existing dual bank charger, and charging all 3?
01-03-2011, 09:09 PM #13
Con would be the alternator and entire boat is a 12V system.
Wouldn't you have to wire those batteries to be 12V outputs some how because nothing on the boat will work other wise.Malo <--- Means--Evil or Mean One. This explains a lot.
2013 Mojo 2.5 Skylon Tower. Bestia < Beast >
01-03-2011, 09:21 PM #14
01-03-2011, 09:21 PM #15
You would only use two of the 6 volt models in series for the stereo bank which would equal 12 volts. The starting battery could be a conventional marine Group 24 12-volt lead acid.
The only reason to avoid golf cart batteries is if you have already had a history of back problems.
Depleted amp/hour capacity will be the same issue relating to the alternator and shore charger load as with any other batteries of the same capacity.
The dimensions are a consideration. Golf cart batteries certainly are a great amp/hour per dollar value.
01-03-2011, 10:05 PM #16
And with these 2 6v cart batteries wired in series, to act as one 12v battery, regarding charging, the second bank on my charger would be coinnected to the + or 6v batt 1 and the - of 6v batt 2. Correct? This would then charge the batteries equally? And with this method, I just increased my amp/hour with 2 6v over the 2 12v accesory batts and made a true "dual" 12v setup for the charger to work as designed?
I mean, am I missing something, or am I appropriate in wondering why on earth people would go with 2 12v batteries for accesory with lets say a 115 amp hour rating each when they could use 2 6v batts rated at approx 205 amp hours each?
I feel like the dual 6v in series makes more sense and is so simple it's brilliant, however, David, I have seen several of your installs and have seen no trace of 6v batts. Which makes me wonder what I am overlooking.
01-03-2011, 10:19 PM #17
In a series configuration you don't sum the amp/hours as you would in a parallel configuration.
We don't like handling the extra bulk and different dimensions on an everyday basis. But don't let that influence you as I really don't have any reason to discourage the use of GC batteries.
01-03-2011, 10:45 PM #18
Ah, so for simplicity sake, and for black and white:
1) 2 6v batts rated at 205 amp hours each will provide only 205 amp hours total once wired in series?
2) 2 12v batts rated at 115 amp hours each will provide 230 amp hours total once wired in parrallel?
Is that correct?
01-03-2011, 11:11 PM #19
01-04-2011, 11:03 AM #20
Just to keep this topic fresh, I've been reading a bit more about a dual 6v set up this morning.
Taken from this link: http://www.marxrv.com/12volt/12volt.htm
A lot of RVers have switched from the "standard" group 24 or 27 12 volt batteries to the larger 6 volt golf cart batteries. If you have room for at least 2 of them, they are a good choice. They are true deep cycle batteries and will last a lot longer than most common 12 volt batteries in your RV. They are physically larger, so you must measure carefully before buying them, but I recommend you use them if you can. I have a set of Trojan Golf cart batteries that are going on 5 years old and they still have almost all of their original capacity. They are priced about the same as (or a bit lower than) the common 12 volt deep cycle battery. Golf cart batteries have a higher capacity than group 24 and 27 batteries... a pair of group 24 12 volt batteries only provide 140-170 amp/hours of capacity, where a pair of golf cart batteries provide 180-220 amp/hours. There are other deep cycle batteries available, such as the L-16 and AGM types, that are extensively used in large solar and alternate energy systems, but their physical size and added expense make them a less attractive choice for the average RVer.
I guess my next step is to call ProMariner directly and confirm with them that my ProSport 12 charger will meet this application and will charge my Crank battery as well as the dual 6v.
The site above has tons of useful battery info, good read regardless of what you intended use is.