I've got a two year old house bank of two Group 27B's. (the 27B's are
supposed to be a little bit better than a plain Group 27) Last summer
they seemed to loose their ability to keep my refrigerator and anchor
light working as long as they used to and I'm wondering if they are shot
or not. They have gotten a lot of use these last two years, so I won't
whine too much if they are gone, but I would hate to replace them if
they aren't.

How do I check this out?

Is there some way to de-sulpher the plates or something to re-energize
them and save me a $130 trip to Sam's Club?

Capt. Jeff

You don't mention if these are deep cycle batteries.. IMHO, if your getting
them at Sam's Club, the chances are that they are automotive with the
"Marine" or "RV" label..

If this is true then the two years heavy service you got out of them is
about all you can expect. The main performance difference between
cranking/automotive and true deep cycle is the vast difference in the number
of "Deep" cycles.. The deep cycle batt. can handle hundreds while an
automotive will be less than 100. Battery mfgs don't advertise the number or
cycles unless they can claim several hundred cycles.

If your running refrigeration, you should invest in true deep cycles because
of the frequency of lowering the battery charge to less than 50%.

Sams Club does sell a 6volt golf cart battery that bares a striking
resemblence to the Trojan T-105 but for a little less.. I'm not sure of it's
performance rating..

If you invest in deep cycle batteries, then you can further improve their
performance by getting a good 3 stage battery charger that allows for an
absorption charge periodically. I think that is what you were refering to as
"de-sulpher...".

Sorry to say, I think your existing batteries have seen their best days.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

What Steve writes in a separate reply to you is true, but he has assumed
you have inapropriat batteries to begin with. Before disgarding the
batteries;
Make sure the the water is topped up in each cell of each battery.
Make sure the connections are clean and tight.
Make sure the alternator belt is tight.
Make sure the specific gravity of each cell is the same...whether high or
low they should all be the same. If not the lowest one will limit the
current flow of all the rest of the cells.
Make sure they are true deep cycle batteries. the weight is the key.
Trojan Golf cart batteries i bought for $100 each have lasted me 12 yrs!
All i do is keep the water level up in them and never let them sit
uncharged for any more then a few hours or they will 'sulphate' and loose
the ability to recharge.

rick

On Sun, 15 Feb 2004 22:29:37 -0600, Messing In Boats
wrote:

I've got a two year old house bank of two Group 27B's. (the 27B's are
supposed to be a little bit better than a plain Group 27) Last summer
they seemed to loose their ability to keep my refrigerator and anchor
light working as long as they used to and I'm wondering if they are shot
or not. They have gotten a lot of use these last two years, so I won't
whine too much if they are gone, but I would hate to replace them if
they aren't.

How do I check this out?

Is there some way to de-sulpher the plates or something to re-energize
them and save me a $130 trip to Sam's Club?

Capt. Jeff




--
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

For whatever it's worth, I took a poster's suggestion and bought a 4 amp
Battery Minder for $100, which the Battery Minder folks say might solve
our problem. (What do you think they would say?) These are deep cycle
batteries that were only taken down to 0% only a couple times by
refrigeration and fans in hot weather and charged right back up again
with the engine. I tested them for voltage after a full charge and they
appear to hold it well.

If this doesn't improve their capacity, at least I will have the system
for my next set. For those who care, the 4 amp charger will handle two
different types of batteries (two Group 27Bs for house and one Group 24
starting, hooked up to a combiner) and will supposedly charge and
maintain the set and can be plugged in all the time to keep them happily
de-sulfated, even all winter. I don't take my batteries out of the boat,
ever. They seem to like it just fine, as long as they are charged.

I'll find out soon whether it brings them back, as I'm trailering it
from COLD Minnesota to WARM Florida in two weeks.

Capt. Jeff

Messing In Boats wrote:
I'll find out soon whether it brings them back, as I'm trailering it
from COLD Minnesota to WARM Florida in two weeks.

Battery capacity will be higher in Florida, capacity is
temperature-dependent.

From Trojan website:

"How does temperature affect the performance of my batteries?
At higher temperatures (above 77oF) battery capacity generally
increases, usually at the cost of battery life. Higher temperatures
also increase the self-discharge characteristic. Colder temperatures
(below 77oF) will lower battery capacity and prolong battery life.
Cooler temperatures will slow self-discharge. Therefore, operating
batteries at temperatures at or slightly below 77oF will optimize both
performance and life."

"How do I determine my battery capacity when it is colder/hotter?
Battery capacity is basically a linear relationship. A good rule of
thumb is that for every 15oF above 77oF, capacity is increased by 10%
and for every 15oF below 77oF, capacity is reduced by 10%."