Battery Equalization Strangeness
 

I have (2) 8D lead acid batteries that I just tried to equalize using
my ProSine inverter/charger. Based upon a battery temp of 70F and the
documentation supplied by the manufacturer I specified a maximum
equalization voltage of 15.5V and a maximum charging rate of 22A (5%
of 440 AH capacity). Upon starting the equalization the charging
voltage rose to 14.7V at 22A. It stayed there for about 5 hours and
then the charging voltage dropped to 14V at 22A. The battery temp
rose from 73F to 75F during the period. After 2 hours at 14V I
aborted the equalization. Upon switching back to normal charging mode
batteries started charing at 27A at 14.3V and have been at that charge
rate for about 1/2 of an hour.

Any ideas as to what's going on? I expected to see the voltage rise
during the equalization and not drop. I certainly didn't expect to
see the batteries charge at the 27A following the aborted
equalization.

-- Geoff

Battery Equalization Strangeness
 

GeoffSchultz wrote:
I have (2) 8D lead acid batteries that I just tried to equalize using
my ProSine inverter/charger. Based upon a battery temp of 70F and the
documentation supplied by the manufacturer I specified a maximum
equalization voltage of 15.5V and a maximum charging rate of 22A (5%
of 440 AH capacity). Upon starting the equalization the charging
voltage rose to 14.7V at 22A. It stayed there for about 5 hours and
then the charging voltage dropped to 14V at 22A. The battery temp
rose from 73F to 75F during the period. After 2 hours at 14V I
aborted the equalization. Upon switching back to normal charging mode
batteries started charing at 27A at 14.3V and have been at that charge
rate for about 1/2 of an hour.

Any ideas as to what's going on? I expected to see the voltage rise
during the equalization and not drop. I certainly didn't expect to
see the batteries charge at the 27A following the aborted
equalization.

-- Geoff

Batteries should be fully charged BEFORE starting equalization. Fully
charge the batteries then test with a hygrometer to see if equalization
is needed
krj

Battery Equalization Strangeness
 

On Feb 24, 5:35 pm, krj wrote:

Batteries should be fully charged BEFORE starting equalization. Fully
charge the batteries then test with a hygrometer to see if equalization
is needed
krj

The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer. The batteries are 1.5
years old and have never been equalized and have gone through 2
cruising seasons.

-- Geoff

Battery Equalization Strangeness
 

"GeoffSchultz" wrote in message
ups.com...
On Feb 24, 5:35 pm, krj wrote:

Batteries should be fully charged BEFORE starting equalization. Fully
charge the batteries then test with a hygrometer to see if equalization
is needed
krj

The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer. The batteries are 1.5
years old and have never been equalized and have gone through 2
cruising seasons.

-- Geoff


I'm guessing that you had at least one sulfated cell that broke-free during
your aborted equalization, and that now the charger is able to bring the
whole battery up to full charge. I'd watch the temperature, but let it do
it's thing unless it starts to boil.

Battery Equalization Strangeness
 

On 24 Feb 2007 14:45:32 -0800, "GeoffSchultz"
wrote:

The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer.

I'm opposed to the use of sealed batteries for deep cycle house banks
for exactly that reason. How do you know that your batteries are not
half dry? I'd be almost willing to bet on it.

Battery Equalization Strangeness
 

On Feb 24, 7:19 pm, Wayne.B wrote:
On 24 Feb 2007 14:45:32 -0800, "GeoffSchultz"

wrote:
The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer.

I'm opposed to the use of sealed batteries for deep cycle house banks
for exactly that reason. How do you know that your batteries are not
half dry? I'd be almost willing to bet on it.

Clearly I don't know. The problem is that my battery boxes are under
the sole and have no venting. I wanted AGMs, but the only thing
available in Guatemala was lead acid. Based upon conversations that I
had with highly respected boat builders and a relative who designs
batteries for a living, they suggested the use of a sealed battery to
avoid the build-up of hydrogen in this space. As is usual, boats are
a series of compromises. I took the advice of people who have far
more expertise than I do in this field.

Anyhow, this is what I have and I'm trying to figure out what's going
on. I suspect that there's a short in a cell.

-- Geoff

Battery Equalization Strangeness
 

GeoffSchultz wrote:
On Feb 24, 7:19 pm, Wayne.B wrote:
On 24 Feb 2007 14:45:32 -0800, "GeoffSchultz"

wrote:
The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer.
I'm opposed to the use of sealed batteries for deep cycle house banks
for exactly that reason. How do you know that your batteries are not
half dry? I'd be almost willing to bet on it.

Clearly I don't know. The problem is that my battery boxes are under
the sole and have no venting. I wanted AGMs, but the only thing
available in Guatemala was lead acid. Based upon conversations that I
had with highly respected boat builders and a relative who designs
batteries for a living, they suggested the use of a sealed battery to
avoid the build-up of hydrogen in this space. As is usual, boats are
a series of compromises. I took the advice of people who have far
more expertise than I do in this field.

Anyhow, this is what I have and I'm trying to figure out what's going
on. I suspect that there's a short in a cell.

-- Geoff

AGM's are lead-acid also. They just have a glass mat that is 95%
saturated with acid vs a "flooded" cell
krj

Battery Equalization Strangeness
 

On 24 Feb 2007 16:49:58 -0800, "GeoffSchultz"
wrote:

Clearly I don't know. The problem is that my battery boxes are under
the sole and have no venting. I wanted AGMs, but the only thing
available in Guatemala was lead acid.

The best bet for deep cycle batteries with difficult access are the
Rolls or Surettes with the recombinant caps, also known as HydroCaps.

Supposedly the cell caps contain a catalyst which turns escaping
hydrogen back into water if my understanding is correct.

http://www.rollsbattery.com/

If nothing else, they have a great warranty.

Battery Equalization Strangeness
 

The best bet for deep cycle batteries with difficult access are the
Rolls or Surettes with the recombinant caps, also known as HydroCaps.

Clearly you haven't tried to buy batteries in Guatemala...

-- Geoff

Battery Equalization Strangeness
 

On 24 Feb 2007 14:45:32 -0800, "GeoffSchultz"
wrote:

On Feb 24, 5:35 pm, krj wrote:

Batteries should be fully charged BEFORE starting equalization. Fully
charge the batteries then test with a hygrometer to see if equalization
is needed
krj

The batteries were fully charged. Unfortunately these are sealed lead
acid and can't be tested with a hygrometer. The batteries are 1.5
years old and have never been equalized and have gone through 2
cruising seasons.

-- Geoff

I believe that it is widely recommended that maintenance-free
batteries MUST NOT be equalized, as equalization DOES boil off some
water, which can not be readily replaced in a sealed battery.

The equalization instructions for my Xantrex charger say :

"An equalization charge should be performed /only/ on vented, flooded
(non-sealed or "wet") batteries. It should be performed only if
recommended by the battery manufacturer and only as often as
specified."

(I will admit that some "maintenance-free" batteries are actually
"maintenance-resistant" - a determined user can remove the caps, to
check and replenish fluid levels.)

--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

Battery Equalization Strangeness
 

The best bet for deep cycle batteries with difficult access are the
Rolls or Surettes with the recombinant caps, also known as HydroCaps.

Clearly you haven't tried to buy batteries in Guatemala...

-- Geoff

Battery Equalization Strangeness
 

On 24 Feb 2007 19:16:42 -0800, "GeoffSchultz"
wrote:

The best bet for deep cycle batteries with difficult access are the
Rolls or Surettes with the recombinant caps, also known as HydroCaps.

Clearly you haven't tried to buy batteries in Guatemala...

Thought you were in the states right now for some reason.

There is a Rolls dealer in Miami that offers good discounts.

I just bought a standard 8D at NAPA auto parts for $160 which
surprised me as being fairly reasonable. It goes into a difficult but
not impossible location, so it does get checked and refilled once in a
while.

Battery Equalization Strangeness
 

"GeoffSchultz" wrote in
ups.com:

they suggested the use of a sealed battery to
avoid the build-up of hydrogen in this space. As is usual, boats are
a series of compromises. I took the advice of people who have far
more expertise than I do in this field.


I don't know about Guatemalan batteries, but wetcell lead acid batteries,
either those "sealed" (which all have gas vents to prevent pressure
explosions) or liquid wetcells, haven't gassed hydrogen during NORMAL
charging since manufacturers stopped using antimony grids to hold up the
soft lead in the grid. Modern lead-acid batteries use an alloy that
prevents gassing by the grid structure and reduces local battery action
to nearly zero. (The old batteries used to discharge themselves quite
rapidly because the antimony and lead formed a weak battery with the
electrolyte that was shorted because the antimony and lead were bonded
together. This ate the electrolyte over a short time. Remember "dry
charged" batteries way back? That was why.)

BOATERS, as a charging group always in a terrible hurry to speed up a
very slow chemical reaction (charging) against all the rules of chemistry
and physics, create hydrogen gas by hugely overcurrenting their battery
banks with massive alternators, giant chargers, overvoltage charging,
etc. in many ways. This causes a chemical reaction at the surface of the
plates that breaks down the electrolyte's diluting water into oxygen,
which creates lead-oxide coating on the plates, plus hydrogen gas, which
vents, no matter whether the electrolyte is a jelly, soaked in a guaze
AGM rolled up between the plates or in liquid solution. Of course, this
consumes the electrolyte's water supply, which requires replenishing.
This is not a problem on batteries charged properly, SLOWLY, which don't
bubble at all because their hydrogen and oxygen ions recombine back into
water not being driven hard apart by the overcharging.

All boaters know you can charge the house batteries in 20 minutes engine
time if you charge them at 250A, right? Your manufacturer's advise took
this into account...(c;

Larry
--
http://www.youtube.com/watch?v=fEJmc...elated&search=

Battery Equalization Strangeness
 

Somehow or another my post to this with an update didn't make it.
Anyhow...

The problem was my Morningstar Tristar voltage regulator. According
to the manual if you push the (only) switch for 5 seconds, the unit it
supposed to drop into manual equlaization mode until you push the
switch for 5 seconds again. I did this, but it seems that it didn't
go into manual equalization mode. It was diverting any voltage above
14.2 V to the water heater. I found out the hard way that I can boil
water in my water heater!

I haven't had a chance to re-run the equalization. I'll do that in
the next day or two. I'm busy installing a new water maker.

-- Geoff

P.S. Larry, thanks for the info regarding hydrogen production in new
batteries. I didn't know that.

Battery Equalization Strangeness
 

"GeoffSchultz" wrote in
oups.com:

P.S. Larry, thanks for the info regarding hydrogen production in new
batteries. I didn't know that.



Next lesson, we'll be discussing steam explosions in overheated hot water
heaters and its effects on boat humidity and mold production. Read pages
286 through 348 in your text book and complete the Chapter Eight section in
your workbook before class.....(c;

You're quite welcome. Let's all charge the house batteries at 250A and
turn the electrolyte water into hydrogen to fuel the genset....(c;



Larry
--
I have a new strategy to protect the Mexican border. From the border
to inside the USA, 1 mile, we turn it into our OPEN PIT nuclear
waste dump, turning it into a no-mans-land for tens of thousands
of years. Anyone attempting to cross will simply be eaten alive
by neutrons! Problem solved!

Battery Equalization Strangeness
 

Unfortunately these are sealed lead acid and can't be tested with a hygrometer.

I thought SLA should not be equalised - taking them above 14.4 volts
will have them gassing without any way of topping them up??

Battery Equalization Strangeness
 

(I will admit that some "maintenance-free" batteries are actually
"maintenance-resistant" - a determined user can remove the caps, to
check and replenish fluid levels.)

--
Peter Bennett, VE7CEI

I'll concur with this. I've met a number of maintenance resistant
batteries whose owners thought were maintenance free. Somtimes it
meant pealing off a decal to access the pry off caps. Sometimes the
caps come off as one piece for the whole six cells. Often there is a
way in if there are wet cells.