On Mon, 1 Jun 2015 10:58:48 -0400, "Tom" wrote:

Hi Gents

Sorry for offtopic question in your forum, but you folks know more about
marine batteries than any of the boating newsgroups, for my purpose anyway.

I have a half dozen marine deep cycle batteries. I get about 8 years
usefullness from them when I store them properly, I slow charge them once
per month while in my garage for winter storage and I try and never leave
them sitting without being charge. I try to never drain them completely, I
keep them filled with RO water and don't over boil them. Etc etc etc.

My question is I am coming up on the 8th year and might have neglected this
winter's long storage time. I have two that are my concern. Two Nautalis 12v
Deep Cycle, they are the bigger ones. One only holds the 12v charge for
about an hour. Battery charger "intelligent automatic charger" Will charge
them both, and shut off automatically when fully charged, then a week later
one is still 12v, the other is 10v. I needed to fill about 15% or 20% of
the fluid with RO water.

My question is about de-sulfating. I bought the one for $20.00 bucks that
connects and blinks the red light while it is desulfating with an electronic
pulse (reverse) and while I did this for about 2 months now on the
batteries, one shows very very good response but one still only holds the
12v charge for a week then goes down to 10v.

What I want to try is replacing the sulfuric acid. I think that could super
charge the lead acid reaction. The auto stores in Ontario no longer sell the
replacement battery acid (sulfuric acid) but just over the border in NY
state they all do. Very cheap. So I want to know what you folks think about
doing a 2 month de-sulfation then replacing the very grey and thick old acid
with some very clear and new sulfuric acid.

Replacement batteries would run me about $300.00. The Sulfuric Acid is about
$12.00 per gallon.

The folks at the Auto Supply Stores say it is good idea to do, but some say
not good idea. I am happy to hear you folks opinion of the matter. Feel free
to fling the mud. Just give me lots of advice.

I ended up having to replace the entire Fish Finder Extension for
Transducer, took about 2 days. I didn't end up splicing like I thought,
however when I removed all the panels to replace the old transducer cables
(there were 2 old ones in there) one was simply a regular hunk of coax for
mobile ham radio. With splices, with electrical tape. So for years I have
been using the old fish finder (Eagle Supra) 170mhz with a 25 foot piece of
radio coax spliced into the old transducer. O well.

But thank you folks for any advice on the sulfuric acid replacing in deep
cycle marine batteries. I live in Ontario so we store these batteries for 6
or 7 months per year.


That's how our grandpas did it:

https://www.youtube.com/watch?v=5qA-pqBffWg


w.