On Fri, 17 Apr 2009 21:10:59 -0400, "Flying Pig"
wrote:

I suspect that this has already been discussed, but since I don't have
access to the archives, I beg your indulgence...

We have new, L16H batteries in our 880AH house bank, flooded cell. In a
perfect world to make them last longest, I know that they'd never be
allowed to drop below 100% capacity - but then, what's the point of
having a battery?

I also know that running them down to 20% on a regular basis will make
for a short life span.

So, the question (well, maybe two) is:

What is the recommended, real-world cycle? That is, how low do you
take your flooded batteries on a regular basis? Related, is there a
readily available source for information on the numbers of cycles to a
given percentage of discharge in a battery life span? I.e., 500
cycles to 50% and back to 100% but only 100 cycles to 20% and up to
75%, or the like (recognizing that these numbers have no relation to
any battery made)?

Second, what do those of you with flooded cells, not connected to the
shore power all the time (that is, full-time cruisers or rarely
connected to the utility-based power cord) have as a practice? What
charge regime, and how, do you observe? Never below X%, seldom above
Y%/Always more than Y% of capacity?

We have a variety of charging sources and differing loads which makes
for days when we may see close to 50%, and days when it never leaves
"full" - and since we can't "force" "full" reasonably, we want to make
sure we're not unreasonably asking for our batteries performance.

Knowledgeable assistance appreciated, and your practice, whether
empirical or just "is" would also be appreciated.

Thanks.

L8R


Batteries should never be run below 50% if you want decent life from
them. Further, no battery likes to remain below 100% for extended
periods. They should be recharged promptly after being run down.
Similarly, batteries not being used should be kept at or very near
fully charged at all times.

You can, of course vary from this, but it will be at the expense of
battery life and capacity.