Adding Second Battery to My Existing Solar System :::

Hi centerline,

Used telecom jars were about $0.77 per amp hour including tax. ($424 Cdn dollars).

All things being equal is an impossible statement. The batteries I got 11 years of use from were Marine cycle from Walmart.

The reason I changed to sealed jars is I no longer wished to lay down on the snow to check electrolyte levels in temperatures of -37 c (-34 f).

centerline wrote:
in addition, I dont know exactly what model of battery you have, but I I highly doubt they carry the cycle life of twin 6v batts of the same composition... im going to step out on a branch here and say that all things being equal, 2 12v batts can never reach the cycle life of 2 6v batts have... that why 2 6v batts is usually the better way to go.

I will agree that your batts are good, and special.. but so are my 3 12v 185HC batteries that offer me 660ah @20hr rate, but im not trying to salute them or compare them to the common ones that I wrote about... and if I did, it would throw things in the same direction you went when comparing your batteries to the common ones..

and although you say yours are used telecom batts, one has to wonder what you or someone else will have to pay when you need to replace them....

pianotuna wrote:

centerline wrote:
here are a few facts...

Some of your facts are myths.

they are all absolutely true and NOT false. BUT when one takes things out of context, and picks it apart, it can be twisted to seem that way..

as you say yourself, you are comparing the special batteries you have to the most affordable and common 6v and 12v batteries available eveywhere, all the time..
in defense of what I wrote, your batteries are NOT in the same class and cant even be compared to the common ones.
in addition, I dont know exactly what model of battery you have, but I I highly doubt they carry the cycle life of twin 6v batts of the same composition... im going to step out on a branch here and say that all things being equal, 2 12v batts can never reach the cycle life of 2 6v batts have... that why 2 6v batts is usually the better way to go.

I will agree that your batts are good, and special.. but so are my 3 12v 185HC batteries that offer me 660ah @20hr rate, but im not trying to salute them or compare them to the common ones that I wrote about... and if I did, it would throw things in the same direction you went when comparing your batteries to the common ones..

and although you say yours are used telecom batts, one has to wonder what you or someone else will have to pay when you need to replace them....

its rare that the common person would even consider spending as much on batteries as we have... and i belive my facts need to stand as written about the batts I was writing about...

buying, selling, and knowing batteries are a part of my world... and educating those that dont know in simple terms without throwing all the special stuff in that can only cause confusion... until they get a grasp of the basics.

and if you want to reconsider and edit what you wrote, I will do the same here... :-)

centerline wrote:
here are a few facts...

Some of your facts are myths.

centerline wrote:
for normal sized batteries. 2 6vGC batts will have a much longer life than 2 12v batts will

Myth. It depends on how they are cared for. I generally get 10 to 11 years of service from my heavily used battery bank.

centerline wrote:
2 quality 6vGC batts will give more measurable/advertised amps, and many more usable amphrs than 2 12v deep cycle batts will

Myth. My 12 volt jars are 139 amp-hours each, two yield 278 amp-hours. 6vGC are about 240 amp-hours

centerline wrote:
wet cell batteries, which have the most affordable initial cost, can last as long as any new tech battery with proper care, and usually does.

Myth. LI for example although costly are already cheaper on a per cycle basis than flooded jars. They may last 5 times as long as a regular flooded jar.

centerline wrote:
quality batteries are not always at the top of the price range, but its true that a quality battery will outperform a budget battery

Surrette Jars may last 20 years, with proper care. They are not inexpensive. Edison batteries after they are "worn out" only require the electrolyte to be replaced for another life span to happen.

Saw a battery blow up once when I worked in a lumberyard years ago. Guy was jumping a fork lift, and when the clamp touched the terminal there was a spark, and BOOM! Hydrogen gas from the discharged battery had accumulated in the battery box, and it blew the top off the battery. Pure luck that nobody was hurt.

here are a few facts...

all batteries have the potential for explosion

two batteries are better than one in most cases, but that is providing both batteries are good.

pairing a new battery with an old one does not make the old battery better, but will quickly bring the new one down to the level of the old one.

two perfectly good batteries in a single bank, and one goes bad, it has the potential to ruin the other one if not discovered and removed in time

one good battery and one bad battery in the same bank will almost always offer less power than one good battery by itself.

if a battery that is being fully charged regularly, is giving noticeably less performance, its failing.

for normal sized batteries. 2 6vGC batts will have a much longer life than 2 12v batts will

12 marine "deep cycle" batteries are not really deep cycle batteries at all.

2 quality 6vGC batts will give more measurable/advertised amps, and many more usable amphrs than 2 12v deep cycle batts will

there are such a thing as true 12v deep cycle batteries, but the entry level battery is about $210 each, but 2 of them offer less advertised amps than 2 6vGC batteries will at about $100 ea... and they still wont have as many potential charge cycles as the 6v batts do

in a 12volt bank of 2 12v batts, if one goes bad, you can remove it and go on until you can replace it...
in a 12volt bank of 2 6v batts, if one goes bad, the system is down until it gets replaced.

wet cell batteries, which have the most affordable initial cost, can last as long as any new tech battery with proper care, and usually does. ....this is only true because most people ruin batteries by neglect or misuse, long before the full potential battery life can be realized.... and they dont even know they caused the demise of their batteries..

ANY battery can fail without any apparent reason, at ANY time...

trojan batteries are good, but they are not necessarily the best.
(us battery and deka produces excellent batteries at less cost than trojans)

quality batteries are not always at the top of the price range, but its true that a quality battery will outperform a budget battery.

spend the money and buy right the first time and it will be a long time before you have to buy again.. as paying half as much for the lower priced items twice, isnt cheaper...

there are many more Facts that could be given that would help in maintaining the bank in the best condition for the longest possible time, but these few will allow you to make a decision on what you want to buy...

pyoung47 wrote:

Matt_Colie wrote:
Surviver,

As long as you really are stuck buying two new batteries, you might as well save a lot of grief and buy a pair of 6V golf cart batteries. These will give you better than any pair of 12V jars and the likelihood of a battery explosion is greatly reduced.

Matt

I have actuallly witnessed a battery explosion. Pretty dramatic. Golf cart.

I blew the top off a 12V battery in an old car I had. I had used the old trick of running a screw into the terminal and cable to increase connection. I didn't know until I returned to the car after work and noticed that there was a tell-tale burn mark on the hood, that the whole top was blown off. Lesson one: make sure the screw is short enough so that it doesn't contact the hood when you close it.

I dropped an open end wrench across a gang of 6V's in a golf cart. The 36V and power from the batteries melted one end of the wrench. No explosion and no noticeable effects on the batteries. I'd bet a guy could weld with a gang of batteries like that.

Matt_Colie wrote:
Surviver,

As long as you really are stuck buying two new batteries, you might as well save a lot of grief and buy a pair of 6V golf cart batteries. These will give you better than any pair of 12V jars and the likelihood of a battery explosion is greatly reduced.

Matt

I have actuallly witnessed a battery explosion. Pretty dramatic. Golf cart.

Thanks guys... M

Matt_Colie wrote:
you might as well save a lot of grief and buy a pair of 6V golf cart batteries.

When battery is inside, it has to be AGM or Lithium.

Get 2*100 AGM. Stay away from less reputable brands like UPG or unknown/littleknown boxes from Walmart etc.

Hey Morgan,

Like others have suggested, I feel that you would be better off replacing both at the same time.

But, if it will make you feel any better, tomorrow, I am replacing my four (seven year old) 6 volt golf cart batteries because of one lousy cell in one battery. Bummer, but I would rather have all the capability that I can get rather than drag around weight that not only isn't helping but is also loading the other three batteries down. Life in RV land I guess.

See you in a few weeks.

Steve