Battery price question...

6V is $89.88 at Sam's Club and they are true deep cycle and may last longer.

kfp673 wrote:
Seems to me I could just buy 2 12V and have similar Ah. So I guess I am just not seeing the cost savings. What am I missing? Thanks

you are missing nothing.
bumpy

we do about the same ,not real hard on the battery. I,ve bought mine at wal mart ,the biggest deep cycle that will fit the box. battery life depends on how you take care of it. when we return from a trip I charge the battery ,then put my battery tender on the battery ready for the next outing. mine are four years old still in great shape.p.s check water few times .

6V is not about the cost, as two inexpensive 6V still cost more than most 12V batteries. 6V or GC2 batteries take more abuse and have larger power reserves.

Beyond cost,space is also a consideration. 2 GC2s take up less space than 2 Group 31s which would be required to get the same capacity.

philh wrote:
6V is not about the cost, as two inexpensive 6V still cost more than most 12V batteries. 6V or GC2 batteries take more abuse and have larger power reserves.

This is a "depends" situation.

If you compare 2 Group 24 or Group 27 "RV/Marine" batteries, to two 6V GC2 size batteries on price alone then you are sort of correct.

HOWEVER, 2 group24 or Group 27 "RV/Marine" batteries will not give you not as much Ahr capacity of one pair of 6V GC2 batteries.

Group24 has roughly 60Ahr of capacity, costs about $60 for one, two would be $120 and you get 120Ahr of capacity.

Group 27 has roughly 70Ar of capacity, costs about $70 each, two would be $140 and 140Ahr of capacity.

6V GC2 batteries can be found at Sam's Club or Costco for around $90 each and have roughly 210 Ahr of capacity! 6V batteries when wired in series to get 12V don't add capacity but with 210Ahr that is far more capacity than Group24 or group 27. One PAIR of 6V GC2s costs about $180.

To get near the same Ahr capacity of one pair of GC2s you would need FOUR group 24s ($240) or THREE Group 27s ($210).. Plus lots of additional interconnect cables.

Another issue with group24/27 or any "RV/Marine" battery is they are a "hybrid" between "starting" and "deep cycle", they have "trade offs" which make them not as good for starting and "deep cycle" use..

Group24/27 RV/marine batteries should not be discharged very deep if you want any hopes of getting much life out of them. The shallower discharge, the better life you get from them.. Basically 20%-50% of the capacity is usable..

GC2 batteries on the other hand are designed to be able to withstand as much as 80% of the capacity being used and suffer no harm in life. So you can use GC2 batteries much longer than Group24/27 RV/marine batteries between charges.

As far as OPs question of where to find GC2 batteries, look up your nearest Sam's Club or Costco club, they typically will have them in stock for the lowest prices you are going to find..

Barring that, look up a Batteries Plus store or a NAPA store (although you will pay top dollar at those stores, they will be able to get GC2 batteries for you).

Now, I am sure someone will mention another 12V battery, a Group31, sure you could go that route, but they are insanely priced $240-$300 EACH) and with 135Ahr of capacity it still would take TWO of those to be equivalent to one pair of GC2s in Ahr. Not to mention two group31 would cost a mere $480-$600 and you would have same discharge limitations of the group24/27 RV/marine batteries..

Just because it says "RV/marine" doesn't mean it is a good choice if you need max discharge capacity and max life.

Bumpyroad wrote:

kfp673 wrote:
Seems to me I could just buy 2 12V and have similar Ah. So I guess I am just not seeing the cost savings. What am I missing? Thanks

you are missing nothing.

Not likely to have similar Ah rating OR the similar price.

Golf cart batteries are specifically designed to put out "modest" amounts of current as opposed to hugs amounts for a starting battery) over long periods of time. They will last longer.

Gdetrailer wrote:
Another issue with group24/27 or any "RV/Marine" battery is they are a "hybrid" between "starting" and "deep cycle", they have "trade offs" which make them not as good for starting and "deep cycle" use.

This has been stated HUNDREDS of time on this forum !

If you plan on HEAVY inverter loads then 12 volt have an edge.

If you just use a 300 watt inverter then twin six volts have the edge.

Capacity is king. Judge by cost per amp-hour at the 20 hour rate.

If you boondock and will need lots of battery power then two batteries will be much better. If you will not need much power boondocking or just boondock overnight then one 12 is fine.

One reason for two 6's and not 2 12's is the 6's can be run in "series", which means they work together to make 12 volts. If one battery is of less capacity then it will not drain the other one down trying to "level" the charge between the two.
With 12's if one battery is lower, lets say one maxes out at 13.4 volts and the other at 13.6, then the 13.4 will always be draining the other down to 13.4 yet never increase the charge. It gets worse the lower the low battery is.
WIth a pair of 12's you always want to buy them as a pair of the same age, and replace them as a pair. WIth 6's you are free of this. It will not matter.
6's are easy to find anywhere, auto parts store, big box store all over the nation. finding a true deep cycle 12 anywhere is much harder to find. When traveling on the road this will matter if one battery needs to be replaced.
You DO NOT want a "marine" battery for an RV, esp for boondocking. These batts are meant for boating, not camping.

Gdetrailer wrote:

philh wrote:
6V is not about the cost, as two inexpensive 6V still cost more than most 12V batteries. 6V or GC2 batteries take more abuse and have larger power reserves.

This is a "depends" situation.

If you compare 2 Group 24 or Group 27 "RV/Marine" batteries, to two 6V GC2 size batteries on price alone then you are sort of correct.

HOWEVER, 2 group24 or Group 27 "RV/Marine" batteries will not give you not as much Ahr capacity of one pair of 6V GC2 batteries.

Group24 has roughly 60Ahr of capacity, costs about $60 for one, two would be $120 and you get 120Ahr of capacity.

Group 27 has roughly 70Ar of capacity, costs about $70 each, two would be $140 and 140Ahr of capacity.

6V GC2 batteries can be found at Sam's Club or Costco for around $90 each and have roughly 210 Ahr of capacity! 6V batteries when wired in series to get 12V don't add capacity but with 210Ahr that is far more capacity than Group24 or group 27. One PAIR of 6V GC2s costs about $180.

To get near the same Ahr capacity of one pair of GC2s you would need FOUR group 24s ($240) or THREE Group 27s ($210).. Plus lots of additional interconnect cables.

Another issue with group24/27 or any "RV/Marine" battery is they are a "hybrid" between "starting" and "deep cycle", they have "trade offs" which make them not as good for starting and "deep cycle" use..

Group24/27 RV/marine batteries should not be discharged very deep if you want any hopes of getting much life out of them. The shallower discharge, the better life you get from them.. Basically 20%-50% of the capacity is usable..

GC2 batteries on the other hand are designed to be able to withstand as much as 80% of the capacity being used and suffer no harm in life. So you can use GC2 batteries much longer than Group24/27 RV/marine batteries between charges.

As far as OPs question of where to find GC2 batteries, look up your nearest Sam's Club or Costco club, they typically will have them in stock for the lowest prices you are going to find..

Barring that, look up a Batteries Plus store or a NAPA store (although you will pay top dollar at those stores, they will be able to get GC2 batteries for you).

Now, I am sure someone will mention another 12V battery, a Group31, sure you could go that route, but they are insanely priced $240-$300 EACH) and with 135Ahr of capacity it still would take TWO of those to be equivalent to one pair of GC2s in Ahr. Not to mention two group31 would cost a mere $480-$600 and you would have same discharge limitations of the group24/27 RV/marine batteries..

Just because it says "RV/marine" doesn't mean it is a good choice if you need max discharge capacity and max life.

You could probably close this thread as everything that needs to be said about comparing 6v to 12v has been said very well right here. These are the reasons I went with 6v last year.

Now, the only issue is the OP said single 12v battery, and with 6v you must have 2.