re: "But there are execeptions. ... it's not hard to put enough charge/discharge cycles on a set of batteries to see differences in life between high quality batteries and the lesser quality ones. I'm going on 8 years on one set of GC that are typically discharged to 30%SOC then recharged at 65-90A close to 50 times/year or more."
sigh, ... "exceptions" -- certainly, but we don't govern out lives by exceptions. Is there some sort of reason why generalities and normal have to be countered with exceptions, no matter how extreme? Is using an exception as a counterpoint to established norms really a service to the readers here?
how do you measure the quality of a battery? how do you measure the end of life? Neither of these has decent objective and empirical measure in real world situations and both are highly dependent upon circumstances, environment, and other factors that are difficult to define or control.
A 30% SoC leaves no room for error, no margins, no reserves, and needs a good 8 to 12 hours under best conditions to completely and fully recharge the battery. A habit of such deep discharge is hard on the batteries and gets into the area where temperature, age, cycle to cycle variation and so forth can leave you in the morning without any usable battery capacity.
Typical RV reserves are for a battery to handle 3 days - that means about a 30% DoD (depth of discharge) rather than a 30% SoC (state of charge).
Then there is the fact that 50 cycles per year times a nominal 5 year battery life is only 250 cycles. Many SLI batteries will handle that in lab conditions. It isn't cycle life that is an issue with typical (or even in the extreme case presented) usage.
All I hear about for the Trojan batteries is the 6V T series. Anyone tried the T-150 12 V series? I've been running two of these for over 5 years. Never a problem when dry camping and we do that a lot. In cold weather never a thought of running out of power running the heater at night. I also have 240W Solar so the battery bank is brought up the next day. Only problem is their weight, the batteries. I have a custom diamond plate box on the tongue of my TT for them. When I've lifted them in or out of the box they weight about 85 Lbs each. I check them regularly. Hope to get more years service and when they eventually reach end of life I would replace with the same thing.
When I bought them through a Trojan commercial dealer they were called a "floor machine battery" but fit the bill for a 150 AH each battery. I do run a small sine wave inverter along with my ham gear when we are out. I also have a couple of EU2000's so we can run the air but seems we never really need anything other than the 12V.
2004 F-150 XL Supercab.
HD, 4.10 Gears, Magnaflow, Airaid, Troyer Performance Tuned Xcal I. 2006 Aljo 225LT.
240 Watt Solar, Dual T-150's, Solar Boost.
Kenwood TS-480SAT , Sierra 1800, Ten Tec Hercules II,
Dell Laptop with SL-1 soundcard interface.
Some folks get confused when I say this because well they can look and SEE the pair of six volt batteries in their RV but in truth, there are no six volt RV battery systems. The two six volt batteries, together, make one big 12 volt,
So what is the big advantage of six volt pairs? Cost, mostly. I will explain.
The standard GC-2 size six volt battery (t-105) is mass produced for golf cars from coast to coast, thousands of them are sold every year, it is very likely the single most popular lead acid battery on the planet. Thus the cost of production is lower.
They are also a true deep cycle battery.
Two of them, in series, is roughly equal to a size 8D 12 volt battery.
Now.. You can get 12 volt DEEP CYCLE, some golf cars do use them (in fact more and more they are using them now days) but they are still more costly per amp hour capacity.
And that's why they remain so popular (The six volt types that is)
That said. No reason not to use a 12 volt deep cycle battery if you have 'em.
Nothin adds excitment like something that is none of your business
Kenwood TS-2000 housed in a 2005 Damon Intruder 377
It is easier if you think of 2 6 volt batteries as a single battery. You will always have to have 2 6 volt batteries in series to make a 12 volt battery. You can then hook up as many of these 12 volt "batteries" in parallel as you want.
so if you go with 6V's, do you only run 2, or 2 in series with an additional 2 in series, all paralleled together? id love to get the higher aH ratings, since im primarily a boondocker (i did switch to LED's recently, tho), but never figured out if the 6V guys are using 2 or 4. 4 would be an awful lot of weight added to my tongue. never actually saw a trojan 6v, are they the same size as a typical 12v?
thanks in advance!
mikey
So let me get this straight in my old hard head, 2 6 volts in series (rated at 220 amp hours) are still going to be 220 amp hours , if you add 2 more 6 volt in series, then paralel, you will end up with 440 amp hours??
That's exactly right. Four six volt jars in series/parallel will create a battery bank of twelve volts @ 440 amp-hours.
rustycopperballs wrote: So let me get this straight in my old hard head, 2 6 volts in series (rated at 220 amp hours) are still going to be 220 amp hours , if you add 2 more 6 volt in series, then paralel, you will end up with 440 amp hours??
You want the biggest battery cells you can get. Each lead acid cell is about 2 volts. 6 volt batterys have 3 cells, 12 volt batterys have 6. If you can you only want 6 cells in series. That gives the best performance. Now, getting cells big enough may not be easy, practial or cost effective. As has been stated before, the T105s are generally the most cost effective.
re: "The standard GC-2 size six volt battery (t-105) is ... very likely the single most popular lead acid battery on the planet. Thus the cost of production is lower."
The data I have seen does not support this, either in census or in significant cost efficiencies in mass production. All one needs to do to see for themselves is to go to a local battery retail outlet and examine inventory and battery costs there.
re: "They are also a true deep cycle battery." -- if you can find any objective decision based on some measure commonly available for batteries that will clearly separate "true deep cycle" from other types, please let me know.
The biggest problem on these 6v or 12v questions is the myth mongering. The only solution is to watch out for platitudes and marketing hype and, instead, use warranty, price, and specifications as your primary decision criteria.
"The structural difference between deep cycle batteries and cranking batteries resides in the lead battery plates. Deep cycle battery plates have thicker active plates, with higher-density active paste material, and thicker separators. Alloys used for the plates in a deep cycle battery may contain more antimony than starting batteries. The thicker battery plates resist corrosion through extended charge and discharge cycles." {From Wikapedia}
If you don't need a starting battery why give up the enhanced performance of deep cycle in a "House Bank" type of application found in many RV's. Six volt or twelve, take your pick but you will get more amps per $ with a pair of 6 volt GC's and yes T-105's (my personal favorite), are an excellent choice. As always....opinions and YMMV
Most folks probably intuitively realize this, but two 65 lb. 6 volt deep cycle batteries in series will have no more lead in their plates (total) than two 65 lb. 12 volt deep cycle batteries have in their plates (total).
For the above situation (and related situations), the plates in each of the two 6 volt batteries are thicker because over the life of the battery set they would have to had carried about twice as much lifetime current as the plates carried in the 12 volt battery set. For the plates in the the 6 volt batteries to last as long as the plates in the 12 volt batteries - since the 6 volt batteries are always carrying twice as much current during use - they would have to be about twice as massive as the plates in the 12 volt batteries.
Hence, "in general" the more massive plates in a 6 volt battery system are not automatically guaranteeing overall longer battery life than in an equivalently sized 12 volt battery system. You can't get around the electro-chemical physics of the situation.
rustycopperballs wrote: It is easier if you think of 2 6 volt batteries as a single battery. You will always have to have 2 6 volt batteries in series to make a 12 volt battery. You can then hook up as many of these 12 volt "batteries" in parallel as you want.
Gee that sounds like what I keep saying Do you get criticized for saying it like I do?
Oh in case you wonder. I fully agree.
"Can I replace just one six volt battery if it goes bad?"
Would you want a 12 volt battery where half of it was new and half of it 2 years old?
Can I put in one of a different size?
Would you want a 12 volt battery that was half one size, half another.
And so on.
Thinking of the two paired six volt as a single 12 volt answers simply makes all those questions... Vanish.
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Do you get criticized for saying it like I do?
