pianotuna
Regina, SK, Canada
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Hi LScamper,
Going for the greatest number of amp-hours is always the way to go!
LScamper wrote:Hi painotuna,
If the 6-volt plates are twice as thick and the same number as the 12-volt battery then the current is twice that of the 12-volt battery as you say and the two should perform about equal. I suspect they are not twice as thick but more of them. The result may be that everything cancels out and they perform the same. Energy density should be about equal no matter what the configuration. So we still don't see a major difference between 6 or 12-volt batteries. Still interesting to think about it.
For me the choice of 6 or 12-volt was the footprint of the battery. The 6-volt configuration stores about 50% more AHs (about 80 AH x 2 = 160 AH > 232 AH) for the same floor space as my old group 24 batteries but is about 2 inches higher, which I have.
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
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pnichols
Santa Cruz Mountains
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Joined: 04/26/2005
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I'm not sure all liquid acid batteries have "plates" - some may have plates perforated enough such that they may be more "grids" than plates.
Anybody know for sure?
If so, perhaps the very common combination Marine/Starting or Deep Cycle/Starting batteries in fact have some type of grid arrangement (just like a pure starting battery may have) instead of solid plates. I seem to remember reading somewhere that a grid arrangement in batteries (but containing the same amount of lead as a plate battery would contain) can deliver higher currents for short periods, hence some starting (or combination?) batteries may in fact have grid arrangements instead of solid plates.
When comparing the commonly available combination 12V batteries - if they in fact have "grids" instead of solid plates - to true solid plate deep cycle 6V batteries ... the 6V batteries will indeed win every time on long term reliability in RV use.
Has Don claimed that his 12v batteries are true deep cycle 12V batteries and thus probably have solid plates? What he's talking about regarding current densities versus lead mass electro-chemical deteriation over time for 6V batteries and 12V batteries only has merit if both battery types being compared have similar (solid) plate structure.
Phil, 2005 E450 Itasca 324V Spirit
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bill h
coastal reconquista
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Joined: 08/02/2001
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pianotuna wrote:Hi time_to_go_now,
Provide proof. When you do, I'll shut up about the myth that 6 volt deep cycle batteries are better than 12 volt deep cycle batteries.
For my own purposes, I need to compare apples to apples per dollar.
As an example, Trojan makes a couple of 12 volt batteries that use the same plates as their 6 volt GC batteries. Neither battery should be better than the other. The problem for me is that they cost more per amp hour, so that makes the 6 volters better for my pocketbook.
Quote:It seems folks only have anecdotal evidence. That's not proof.
One person's anecdotal evidence is another's experience. My experience with the deep cycle 12 volters sold by most outlets do not last as long as golf cart batteries.
Many golf cart companies lease their carts, batteries included, to the courses for three years. The batteries have to last three years. They almost all use six volt batteries.
A battery salesman convinced a buyer at the airline that his 12 volt CCA rated deep cycle batteries would be good for both starting and electric powered vehicles, lifts, etc. He offered a really good price, as the purchase would be very large and all the same battery.
Guess how it played out. At least all our trucks started.
Several posters here have gotten 9 year or more out of a set of golf cart batteries. I wonder what the longest reported life of a size 24 or 27 WalMart 12 volt battery is.
OOPS! Anecdotal.
84 Barth 30 tag powered by ht502/Thorley, Gear Vendors OD
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sh410
Northwest
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Don,
When you make statments like "Provide proof. When you do, I'll shut up about the MYTH that 6 volt deep cycle batteries are better than 12 volt deep cycle batteries." it sounds like your challenging other peoples beliefs with yours. We all like to think our beliefs are in some way "facts".
For those of us who have room for only a two battery set, we will never have enough Ahrs run our AC. In addition I think there is only one way to hook up 2-6vs set to balance. In the case of a two 12v set there is only two ways to hook up--one of them is preferable and the other less preferable will not make a significant difference.
I beleive that you are talking to a different audience when you are taking about 6-8 battery setups than many of us who have but two batteries and that is where the challenge comes from.
Enjoy your setup, maybe asking folks to prove their belief could be left out and then those of us who are interested can learn and also enjoy your experience.
John
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pianotuna
Regina, SK, Canada
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Hi sh410,
I apologize for reacting to what I saw as a personal attack by time_to_go.
Balanced wiring on twelve volt batteries affects the following:
output capacity
charging
life span
I don't think the above is in question. Wiring two batteries correctly to take advantage of those benefits is simple and costs no more than doing it incorrectly. Mostly it is not done correctly which is sad.
For many years I had only two 12 volt batteries. They served me in a spectacular manner, and were charged with ancient technology on 115 volt side, an isolating diode on the alternator side, and 30 watts of solar with an old style "on/off" charge controller.
I have a thirst for knowledge. If some one comes up with why six volts are better I'll be the first person to jump on the six volt band wagon. What I won't accept is anecdotal emotional appeals.
sh410 wrote:Don,
When you make statments like "Provide proof. When you do, I'll shut up about the MYTH that 6 volt deep cycle batteries are better than 12 volt deep cycle batteries." it sounds like your challenging other peoples beliefs with yours. We all like to think our beliefs are in some way "facts".
For those of us who have room for only a two battery set, we will never have enough Ahrs run our AC. In addition I think there is only one way to hook up 2-6vs set to balance. In the case of a two 12v set there is only two ways to hook up--one of them is preferable and the other less preferable will not make a significant difference.
I beleive that you are talking to a different audience when you are taking about 6-8 battery setups than many of us who have but two batteries and that is where the challenge comes from.
Enjoy your setup, maybe asking folks to prove their belief could be left out and then those of us who are interested can learn and also enjoy your experience.
John
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sh410
Northwest
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"What I won't accept is anecdotal emotional appeals."
Fair enough! Neither will I
John
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DeweyClawson
Enon Valley, PA
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Joined: 09/22/2007
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Pianotuna's argument about 6 vs 12 volt batts may or may not be correct. However his argument is based on the 6 and 12v batts being built the same. If this is not true, then his argument is simply irrelevant as there are too many variables introduced.
Most of the 6 vs 12v argument centers around different battery construction: 6volt deep cycle vs 12volt starter or combo batts. Most of us generalize these descriptions as 6 or 12 volt when we really mean deep cycle or starter/combo batts.
From the Wikipedia article on lead acid batteries:
Starting batteries
"Lead acid batteries designed for starting automotive engines are not designed for deep discharge. They have a large number of thin plates designed for maximum surface area, and therefore maximum current output, but which can easily be damaged by deep discharge. Repeated deep discharges will result in capacity loss and ultimately in premature failure, as the electrodes disintegrate due to mechanical stresses that arise from cycling."
Deep cycle batteries
"Specially designed deep-cycle cells are much less susceptible to degradation due to cycling, and are required for applications where the batteries are regularly discharged, such as photovoltaic systems, electric vehicles (forklift, golf cart, electric cars and other) and uninterruptible power supplies. These batteries have thicker plates that can deliver less peak current, but can withstand frequent discharging."
Combo batteries
"Marine/Motorhome batteries, sometimes called "leisure batteries", are something of a compromise between the two, able to be discharged to a greater degree than automotive batteries, but less so than deep cycle batteries."
Hopefuly this removes a little of the muddy water.
The fool learns from his own mistakes.
It is the wise man who learns from the mistakes of others.
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pianotuna
Regina, SK, Canada
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Hi DeweyClawson,
I agree 100%. Battery type must be the same for any fair comparison. i.e. both marine or both deep cycle.
DeweyClawson wrote:However his argument is based on the 6 and 12v batts being built the same. If this is not true, then his argument is simply irrelevant as there are too many variables introduced.
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bill h
coastal reconquista
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Joined: 08/02/2001
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pianotuna wrote:Battery type must be the same for any fair comparison. i.e. both marine or both deep cycle.
Yes. However, the market enters into the pricing, and (at least with Trojan) the six volters offer a lower price per amp hour than the 12 volters using the same plates, which should make them equal in every other way.
The demand for GC batteries makes the production cost cheaper, and the competition in the marketplace keeps prices lower.
So, even though I wave the six volt flag, it is for cost reasons only.
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pianotuna
Regina, SK, Canada
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Hi pnichols,
Here is a picture (old old old however)
plates
pnichols wrote:I'm not sure all liquid acid batteries have "plates" - some may have plates perforated enough such that they may be more "grids" than plates.
Anybody know for sure?
If so, perhaps the very common combination Marine/Starting or Deep Cycle/Starting batteries in fact have some type of grid arrangement (just like a pure starting battery may have) instead of solid plates. I seem to remember reading somewhere that a grid arrangement in batteries (but containing the same amount of lead as a plate battery would contain) can deliver higher currents for short periods, hence some starting (or combination?) batteries may in fact have grid arrangements instead of solid plates.
When comparing the commonly available combination 12V batteries - if they in fact have "grids" instead of solid plates - to true solid plate deep cycle 6V batteries ... the 6V batteries will indeed win every time on long term reliability in RV use.
Has Don claimed that his 12v batteries are true deep cycle 12V batteries and thus probably have solid plates? What he's talking about regarding current densities versus lead mass electro-chemical deteriation over time for 6V batteries and 12V batteries only has merit if both battery types being compared have similar (solid) plate structure.
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