Battery Type

[RickDavis]

Originally Posted by mello mike

Hi Soyboy,
If you like anecdotes, here's one for you. For eight years I, too, believed that 6v Golf Cart Batteries were the best batteries to use for boondocking (more amp hours and more robust with heavier plates). They worked great for me for eight years until last April when one of the battery posts separated on one of my two 6v batteries, leaving me no 12v power on the last day of my trip. It really sucked. So, from now on if I have room for only two batteries I go with Size 27 12v batteries. The 6v batteries are superior, IMHO, for RVs but I would only use them If I had room for 4 or more batteries (if one pair fails you still have two more to get you by).

I have thought about that also, as I start year 8 on my 6 volt batteries. I finally decided that if that happens I can run off the truck until I can get to the battery store. Actually since the truck has 2 batteries I could probably get away with borrowing one for a day or two

[Mexray]

Have you guys noticed that stuff never breaks on your AS when it's in storage back home...it's always when you're out using it like it's designed...

I'd say eight years on a set of GC type 6 volt's is ahead of the 'curve', so to speak! Those critters are built stout inside, and usually they finally need replacement when the capacity gets so low that they just won't run you 12 volt stuff very long anymore - rarely do they suffer from internal cell failure.

On older 6 volt batteries, check out the ends of the battery case - if the ends become 'bulged out' and 'hard' when tapped with your hand - it's time to think about replacements...that 'bulging' is a result of the internal sulfateion process of the plates as they expand sideways as the deposits built up - this 'ageing' process makes most batteries fail due to the plates rubbing a hole through the separator, and touching each other - the 6 volt's are fairly immune due to the thick waffle-type rubber separator that's used in their construction...

That 'post failure' is really rare - perhaps there was a stress crack in the lead that was aggravated over the years by the cable connector...or it could be a small 'crack' was formed when the posts were 'burned' on, at the factory - or guy doing the 'burning' made a 'cold' joint on one part of the post that finally allowed a crack to form with age...I have seen post failures when the post has been abused, such as using a hammer to pound on the cable connector when installing - a BIG no-no in battery guy circles...

I know, more info that you probably needed...

Ray

[Soyboy]

Mike I hear ya, but think about it, a lot of folks out there are running their RVs on 1 12V battery and would be in the same spot if a post broke etc. While anything can and will happen (and I am not saying you didn't do this), I try to maintain my batteries and would hopefully notice if a post was coming loose. Of course one would could just go dead too. My point wasn't so much use 6V batteries, but rather by good, commercial, heavy duty deep cycle batteries that can take abuse both physical and electrical. Trojan does make group 27 batteries, but I don't know how they compare to the traditional brands. I just know that I had no luck with those and have had very good luck with the Trojans. Now I have jinxed myself and will loose a battery this weekend while camping at Cunningham Falls SP. I will come back and cry on your shoulder if that happens! Of course there are also always AGMs and gelled styles.

Mexray, I will heed your advice and keep an I on them.

You know I read once that if you could take a lead acid battery apart and clean it, the lifetime would be extended multiple times. Don't know if that is true, but it seems to make sense.

For the OP or anyone else that is not familiar with it, I would highly recommend visiting the 12 Volt Side Of Life Website: http://http://www.marxrv.com/12volt/12volt.htm It has been around for years and was a great resource when I started RVing years ago. I still visit it for a refresh from time to time.

[dljosephson]

There really isn't much mystery here, if you poke past the marketing hype. Yes, you can use a car battery in an Airstream. You will be happier with a deep cycle battery *because* it will provide more capacity in low current use, and more charge/discharge cycles before it doesn't hold enough charge. The difference is in how the battery maker uses up the given volume inside the case. A starting battery has thick inter-cell jumpers and maximum plate area, so it can produce the most current for starting. In a deep cycle battery, the plates can be a little smaller so more space is left at the bottom of the battery case for the deposits that form when the battery is just sitting there (and every time there is a deep discharge). If you use a starting battery in deep cycle service, the bottom of the battery soon fills with deposits and shorts out one or more cells. If you use a deep cycle battery in starting service, you might not get enough amps to crank your engine on a cold day. It's not a matter of better or worse, but a different set of design compromises.

[bryanl]

re: "A starting battery has thick inter-cell jumpers and maximum plate area, so it can produce the most current for starting" -- not so much any more in modern batteries. There are differences which one can see in any manufacturer's line card where cost, life, and capacity are traded off to round out the line. The fact is, though, that the differences tend to get lost in the way RV batteries are used and in the inherent variances in available battery capacity due to use profile, temperature, age, cycle to cycle variance, and so on.

It's not a matter of better or worse, but a different set of design compromises.

and it is a mature technology where those differences are not really that significant in typical RV applications. Look at the line cards and you'll see this.

re: "If you use a starting battery in deep cycle service, the bottom of the battery soon fills with deposits and shorts out one or more cells." -- no lead acid battery last very long if put into 'deep cycle service' and the issue isn't shedding but rather sulfation. The biggest shedding problem is over charging in float service. As one paper I saw concluded, shedding in properly used and maintained batteries is more an indicator of battery life being exceeded than anything else.

re: "I like to read folks anecdotal stories." -- the problem is that many looking for advice are not after entertainment but rather effective and reliable advice. Many times, anecdotal stories do not offer that and, especially when it comes to batteries it seems, leads people away from good cost effective solutions to their problems.