replacing batteries

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albertaangler

albertaangler

Active member
Joined
Jan 16, 2010
Posts
31
Location
Banff Alberta
My two group 27 12v batteries are weak to nfg and need to be replaced.
Seen and heard lots of chatter about 6v versus 12v.
So .... what's the definitive answer???
I probably have room for 4 6v's in the box I built.
I could maybe go 4 6v; 2 6v or 2 12v again.
We typically dry camp and from 4 to 18 days (with intermittent access to groceries and fuel).
We have a small generator and a small solar panel to help along.



 
Don,
What's your typical dc load on the batteries?  If it's just lights, gas fridge, water pump, and a little tv, then 2 six golf should do fine.

But if you have a sat receiver on all day long & a lot of tv, like me, then 4 six volt golf cart bat are the way to go.  Mine are connected in a "H" pattern where the two middle connections of each 6 v are connected together to keep the individual battery load & charge equal.  My Trojan T125 are 7 yrs old and holding up fine....although I really don't know how much capacity has dropped off over time. 
The longevity of the batteries depends on the sophistication of the charger.  My Dimensions charger has 3 stages of charging with bat temp sensing.  And it has an equalization mode that supercharges periodically (every 20th charge cycle).  This reduces bat sulfation. 
Check out how sulfation kills batteries at Wikipedia here:
http://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery#Sulfation_and_desulfation

To answer your question, there is no one definitive answer to the 6 vs 12 and wet vs sealed.  There are many variables and $$ involved. 
 
It's all about amp-hours, space, and cost. In other words, how many amp-hours can you cram into the space available and how much is it going to cost. Typically 6 volt wet cell batteries get you the most  for the least, but if your system came with 12 volt batteries then you should at least look at that option. Just be sure the batteries are true deep,cycle. Some batteries labeled "marine deep cycle" are not true deep cycle but rather a hybrid, not recommended.
Two 6 volt batteries will give you about 215-230 amp hours. Compare that to two 12 volt is parralell, both power and cost.
 
As Selah says, voltage is not the concern - it is amp hours per amount of space and cost. Golf cart batteries are top quality deep cycles and often available at attractive prices, so a worth considering.  They happen to be 6v (or 8v, but that's not relevant here), but that's not the reason they are good batteries. There are excellent 12v deep cycles available - Trojan is the premier manufacturer of them - but they are a specialty item and thus tend to be pricey.

Given that you dry camp for extended periods, you no doubt want plenty of amp-hours and batteries that will hold up well under repeated deep discharge cycles.  4 x 6v GC2 (golf cart) batteries would deliver about 450 AH at a likely cost of around $400 and should last several years with reasonable care and a good quality multi-stage charger. I suspect that 4 x 12v Trojan deep cycles would cost at least double that, but Sam's Club has a private label 12v deep cycle (Duracell) that would be about the same AH and price as golf cart batteries. If you are  a Sam's member, check it out on their website.
 
Duner We're pretty frugal power users. Have changed out lights to LED's. No TV. What we really need is reliable power for furnace as most use is June and September/early October at 3500 to 4500 feet. Nights are long and chilly. Waking up to frost is not unheard of.
$$ is not an obstacle within reason.

Thanks for the input.
Checked on 6v 2300 series GC2 are $170.00 each. I'll check other sellers tomorrow.
 
There's a reason most top of the line RV manufacturers put in 4 or more 6 volt deep cycle batteries. It's not because they're cheaper and it's not because they're lighter. It's because they work best. While you're buying new batteries you may as well get the best setup. Four 6 volt batteries are exactly what you want.

Ken
 
Don, if $$ is not an obstacle, check out the latest Lithium-Ion RV batteries. 450 amp-hours in a single 141 lb 12 volt battery. Just google  lithium ion RV batteries
Just think what you could do with two of them..
 
Selah said:
Don, if $$ is not an obstacle, check out the latest Lithium-Ion RV batteries. 450 amp-hours in a single 141 lb 12 volt battery. Just google  lithium ion RV batteries
Just think what you could do with two of them..
Click to expand...

Wow, that's a tremendous amount of energy in a smallish package!  I wonder what their target market is at $5,448 ea? 
Link: http://www.erv.us.com/lithionics-series-l400-12v-400a-engine-starting-and-deep-cycle-lithium-battery/

Seems like there would be some LiO battery used in the hybrid car business that would be a lot more cost effective.
 
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