Newbie with battery question

mjmaddox wrote:
I can't speak for others but that's just too much detail for most newbies like me. Maybe appropriate in another thread but not necessary for the questions being asked in the Beginning RV thread...

Which is precisely what I was trying to say all along.

I'm really sorry that things like that have to clutter up threads where people are just looking for basic advice and information.

I apologize for my contribution to things getting out of hand.

Original poster here - WOW, just wow !! this simple question got way out of hand..

First off thanks go to:
- the responses that I haven't killed my battery yet.
- everyone who suggested just get a battery tender. Sad part of that is that I have multiple tenders in the basement previously used with motorcycles - I just didn't realize the phantom draw against the battery in addition to the self discharge. Will definitely hook it up in the future.

Wing - thanks for the simple instructions regarding the disconnect switch. I'll look for it at the next opportunity

Gopackgo- wins the award for most helpful response to an RV newbie in the Beginning RV thread. I do keep the trailer at my home however I work out of town so not always at home with the trailer easily accessible. Battery was fully charged when left as you assumed.

Vulcan, Piano and Harold - While your initial responses were informative, may I suggest you take these deep technical discussions and disagreements to the PM communication process next time. I can't speak for others but that's just too much detail for most newbies like me. Maybe appropriate in another thread but not necessary for the questions being asked in the Beginning RV thread...Again, just my opinion so please don't go off on your disagreements with my opinion.

Moderator - thanks for trying to keep some sanity in this thread.

2112 - thanks for staying with the thread long enough to ask if I got some resolution.

Looking forward to my next trip!!

Did OP ever find that disconnect switch?

Dupe removed.

pianotuna wrote:
So far as I am aware, yes. If you research the history of lead acid

THANK YOU.

Just the tiny bit of information you supplied about antimony gave me just enough information for a Google search that actually was productive.

http://www.battcon.com/PapersFinal2009/ClarkPaper2009FINAL_12.pdf

I haven't read beyond the second page but THIS looks like a really good general reference for most all things battery.

I'll read through it all later to see if it says, or hints at, all deep cycle varieties having a higher self-discharge rate.

So far as I am aware, yes. If you research the history of lead acid you'll find that up until about 1954 all of them were designed to be what we now call deep cycle units. After that other chemistries started to be used. It kind of coincides with the introduction of the alternator vs a generator for cars.

Deep cycle batteries at 85% state of charge have an acceptance rate of about 12.5 amps per 100 amp-hours of capacity. Any more than that and they start to gas instead of charge. This is one reason why for boondocking a modest solar system can be a huge benefit--no one in their right mind is going to run a generator to charge at such a low rate. (163 watts per 100 amp hours)

Vulcan Rider wrote:

pianotuna wrote:
Flooded deep cycle batteries have more antimony to start with, that is one reason that their self discharge rates are higher than a car jar.

Now maybe we are getting somewhere.

Is that true of ALL flooded deep cycles ?

pianotuna wrote:
Flooded deep cycle batteries have more antimony to start with, that is one reason that their self discharge rates are higher than a car jar.

Now maybe we are getting somewhere.

Is that true of ALL flooded deep cycles ?

Vulcan I've spent the last 15 years reading every thing I can from a scholarly dissertation from 1927 to the latest and greatest stuff at Battery University.

Unless the tops of batteries are kept scrupulously clean it may contribute to self discharge.

As cycle life increases self discharge rates increase as a result of antimonyial poisoning of the plates. Flooded deep cycle batteries have more antimony to start with, that is one reason that their self discharge rates are higher than a car jar.

I've managed to get 10 years of life out of Walmart jars under conditions where I draw 275 amps, which most folks don't, so I'm doing a few things right.

pianotuna wrote:
But that is for a brand spanking new battery. An old deep cycle could easily be 1% per day.

I hear YOU saying that. That makes two "non-experts" who hold that opinion.

The Wiki article was NOT specifically talking about "deep cycle" batteries and the original post claimed a 10% difference at the high end of conventional versus deep cycle rates. Nothing was said about battery age or temperature.

I was and still am trying to get a handle on this claimed higher discharge rate for deep cycles.....in general. It is the first I've head this and am honestly trying to verify it.

No offense and nothing personal but I do NOT take the word of people I don't know posting anonymously on the Internet and if you know how Wiki works, it isn't much better in some cases.

pianotuna wrote:
"Self-discharge rate 3–20%/month". But that is for a brand spanking new battery. An old deep cycle could easily be 1% per day.

Quote from wikipedia

Good article. The only thing it does not address is the effects of being stored at high temperatures. As I stated earlier, shelf life diminishes progressively as temperatures rise and so does its service life.
The smaller the physical size of the battery the more susceptible it is to the effects of high temperature.