Percival P. Cassidy wrote:

But are you saying that the "Automatic - Deep Cycle" setting on an
"ordinary" battery charger (it's one I bought originally for the car
batteries, but the "Deep Cycle" setting seemed like a bonus) is not a
reliable way of keeping the batery in good shape?

Perce

Aside from attempting to rescue his battery, the OP has got
to fix or replace that charger
^^^^

We already have strong evidence that the charger you used
cooked the electrolyte. I made no reference to the "universe"
of ordinary chargers - I was thinking specifically of yours.
But you raise a good point, expanding the question - and others
have answered.

Whatever charger you use, you need to verify that it is
doing the job properly. Consider building an add-on
monitoring/control circuit. Perhaps a comparator with
a sonalert to notify you that something is wrong with
automatic charger shut-off when the voltage exceeds
some level. I built a comparator into an ordinary
10 amp charger to turn it on and off automatically.
A 339 works fine - 4 comparators in one chip, so you
can have a voltage too low output turn the thing on,
and a voltage too high turn it off. Still have two
comparators left over to use as you like. Add a couple
more 339 chips and you could add a 10 step led
voltage monitor, for example.

Ed

On 08/18/05 04:47 pm ehsjr tossed the following ingredients into the
ever-growing pot of cybersoup:

But are you saying that the "Automatic - Deep Cycle" setting on an
"ordinary" battery charger (it's one I bought originally for the car
batteries, but the "Deep Cycle" setting seemed like a bonus) is not a
reliable way of keeping the batery in good shape?

Aside from attempting to rescue his battery, the OP has got
to fix or replace that charger

^^^^

We already have strong evidence that the charger you used
cooked the electrolyte. I made no reference to the "universe"
of ordinary chargers - I was thinking specifically of yours.
But you raise a good point, expanding the question - and others
have answered.

Well, we don't know how much the charger contributed to the problem,
because the electrolyte level wasn't checked for more than a year
because I hadn't realized that it's not a "maintenance-free" battery.

Whatever charger you use, you need to verify that it is
doing the job properly. Consider building an add-on
monitoring/control circuit. Perhaps a comparator with
a sonalert to notify you that something is wrong with
automatic charger shut-off when the voltage exceeds
some level. I built a comparator into an ordinary
10 amp charger to turn it on and off automatically.
A 339 works fine - 4 comparators in one chip, so you
can have a voltage too low output turn the thing on,
and a voltage too high turn it off. Still have two
comparators left over to use as you like. Add a couple
more 339 chips and you could add a 10 step led
voltage monitor, for example.

While looking for a hydrometer today, I noticed "Vector" brand "smart"
chargers (10/6/2A and 6/4/2A) that claimed to have 3-stage charging
circuitry and to be suitable for car batteries, deep-cycle batteries,
and gel-cell batteries. Are these likely to be any good?

The battery was still warm, and each cell was still bubbling slightly
after the thing had been disconnected from the charger for about 3
hours. The SG of each cell was pretty much the same at approx. 1.1175,
and the voltage across the whole battery was 12.4. When I put it back on
charge, the voltage rose to 13.3.

What do you think?

Perce

The battery was still warm, and each cell was still bubbling slightly
after the thing had been disconnected from the charger for about 3
hours. The SG of each cell was pretty much the same at approx. 1.1175,
and the voltage across the whole battery was 12.4. When I put it back on
charge, the voltage rose to 13.3.

What do you think?



I think the battery is bad. I may be remembering wrong, but I seem to
recall that SG should be around 1.230 for lead acid cells, I think. Also,
nominal open circuit voltage on a freshly charged battery ought to be at
LEAST 12.8 volts.


Ed K7AAT

On 08/19/05 12:19 am Ed tossed the following ingredients into the
ever-growing pot of cybersoup:

The battery was still warm, and each cell was still bubbling slightly
after the thing had been disconnected from the charger for about 3
hours. The SG of each cell was pretty much the same at approx. 1.1175,
and the voltage across the whole battery was 12.4. When I put it back on
charge, the voltage rose to 13.3.

What do you think?

I think the battery is bad. I may be remembering wrong, but I seem to
recall that SG should be around 1.230 for lead acid cells, I think. Also,
nominal open circuit voltage on a freshly charged battery ought to be at
LEAST 12.8 volts.

Oops! I got an extra "1" in there for the SG. It should have been 1.175.

Anyway, I did a random series of charging -- sometimes on the 12A
setting (although the ammeter never read that high), sometimes on the 2A
setting -- and resting cycles, adding water as needed. The SG came up to
1.265 (the bottom of the green on my hydrometer), but the "fully
charged" indicator on the charger did not come on.

I then bought a "Vector" 2/6/10A microprocesor-controlled "smart"
3-stage charger (on clearance for a good price) and hooked that up.
After a few hours, it showed "FUL"[ly charged], then switched to
"FLO"[at]; in the latter mode, it is supposed to monitor the battery
voltage (currently 13.8) and "top it up" as needed.

So perhaps this ill-treated battery is not a goner after all.

Thanks for your help.

"Perce"
(aka Alan NV8A)

Percival P. Cassidy wrote:
On 08/18/05 04:47 pm ehsjr tossed the following ingredients into the
ever-growing pot of cybersoup:

But are you saying that the "Automatic - Deep Cycle" setting on an
"ordinary" battery charger (it's one I bought originally for the car
batteries, but the "Deep Cycle" setting seemed like a bonus) is not a
reliable way of keeping the batery in good shape?


Aside from attempting to rescue his battery, the OP has got
to fix or replace that charger


^^^^

We already have strong evidence that the charger you used
cooked the electrolyte. I made no reference to the "universe"
of ordinary chargers - I was thinking specifically of yours.
But you raise a good point, expanding the question - and others
have answered.


Well, we don't know how much the charger contributed to the problem,
because the electrolyte level wasn't checked for more than a year
because I hadn't realized that it's not a "maintenance-free" battery.

Whatever charger you use, you need to verify that it is
doing the job properly. Consider building an add-on
monitoring/control circuit. Perhaps a comparator with
a sonalert to notify you that something is wrong with
automatic charger shut-off when the voltage exceeds
some level. I built a comparator into an ordinary
10 amp charger to turn it on and off automatically.
A 339 works fine - 4 comparators in one chip, so you
can have a voltage too low output turn the thing on,
and a voltage too high turn it off. Still have two
comparators left over to use as you like. Add a couple
more 339 chips and you could add a 10 step led
voltage monitor, for example.


While looking for a hydrometer today, I noticed "Vector" brand "smart"
chargers (10/6/2A and 6/4/2A) that claimed to have 3-stage charging
circuitry and to be suitable for car batteries, deep-cycle batteries,
and gel-cell batteries. Are these likely to be any good?

The battery was still warm, and each cell was still bubbling slightly
after the thing had been disconnected from the charger for about 3
hours. The SG of each cell was pretty much the same at approx. 1.1175,
and the voltage across the whole battery was 12.4. When I put it back on
charge, the voltage rose to 13.3.

What do you think?

Perce

I can't comment on the chargers you mentioned - I don't know
anything about them. But I wouldn't trust any charger until
I have verified that it 1) does charge the battery, and
2) does not overcharge the battery. And even that has the
possibility of error. A charger that works fine at 50 F ambient
may not work right at 80 F. So my testing, at 50 F, may
not reveal a flaw that occurs at 80 F. (Or vice versa.) The
terminal voltage - the voltage across the battery at which the
charge should terminate - varies with temperature.

Concerning your battery's SG: either your SG tester or the battery
is bad. The SG reading is too low. To verify, check the specs
on your battery with the manufacturer to see what they say the
SG should be. I believe the battery is bad, as there is
corroborating evidence from other facts besides the SG reading

Regarding my comment that there is strong evidence that your
charger is bad: the electrolyte level didn't go down due to
leakage. The alternative is that it went down due to evaporation,
which is a result of heat, which in turn can be caused by
overcharging. As you point out, we don't know how much of the
electrolyte loss was caused by the charger - but the only
possibility that can be linked to what you have posted thus far
is overcharging. Perhaps there are other factors you haven't
mentioned?

Ed

On 08/20/05 01:37 am ehsjr tossed the following ingredients into the
ever-growing pot of cybersoup:

Regarding my comment that there is strong evidence that your
charger is bad: the electrolyte level didn't go down due to
leakage. The alternative is that it went down due to evaporation,
which is a result of heat, which in turn can be caused by
overcharging. As you point out, we don't know how much of the
electrolyte loss was caused by the charger - but the only
possibility that can be linked to what you have posted thus far
is overcharging. Perhaps there are other factors you haven't
mentioned?

But won't an unsealed (i.e., NOT "maintenance-free") battery lose water
by evaporation even if it's not overcharged? Otherwise why the need to
check the electrolyte level regularly?

Perce

But won't an unsealed (i.e., NOT "maintenance-free") battery lose water
by evaporation even if it's not overcharged? Otherwise why the need to
check the electrolyte level regularly?



Not meaning to get this tread off on a tangent, but the above comment
prompts me to point out that even "maintenance free" batteries AREN'T,
necessarily. On many occassions I have found it necessary to peel back the
paper cover on automotive maintenance free batteries, remove the exposed
cell caps, and add water, especially after a year or two operating in a hot
climate. I don't believe marine type batteries would be any different in
this regard.


Ed K7AAT

On 08/20/05 05:06 pm Ed tossed the following ingredients into the
ever-growing pot of cybersoup:

But won't an unsealed (i.e., NOT "maintenance-free") battery lose water
by evaporation even if it's not overcharged? Otherwise why the need to
check the electrolyte level regularly?

Not meaning to get this tread off on a tangent, but the above comment
prompts me to point out that even "maintenance free" batteries AREN'T,
necessarily. On many occassions I have found it necessary to peel back the
paper cover on automotive maintenance free batteries, remove the exposed
cell caps, and add water, especially after a year or two operating in a hot
climate. I don't believe marine type batteries would be any different in
this regard.

Just to complicate matters, I eventually found the Web site for these
batteries (the only marking on it is "Stowaway Tournament"; I had bought
it at Sam's and assumed it was a "store brand," but it's made by -- and
acknowledged by -- Exide). Somewhere in the FAQ they say that they are
"maintenance free" but also "maintenance accessible." How's that for
confusion?

Perce

On Sat, 20 Aug 2005 21:06:12 GMT, Ed wrote:

Not meaning to get this tread off on a tangent, but the above comment
prompts me to point out that even "maintenance free" batteries AREN'T,
necessarily.

Some of us refer to such batteries as "maintenance resistant".

With regard to three-stage charging:

I use at Size 31 - 100 AH - gel-cell battery as the main power
source for my radio equipment. Gel-cells are REALLY sealed and can
be operated in any position. They do not have vent caps, hidden or
exposed, and as the name implies, has a gelled electrolyte rather
than a liquid electrolyte. Truly maintenance-free discounting the
need to check the connections for tightness and corrosian from
outside sources.

I recently put a new charger designed for gel-cell charging into
service. This is a professional type charger, not an automotive
charger (with price to match), and it has a specific setting
(dip-switch on control board) for gel-cells. It was recommended as
the proper companion to the battery by the local industrial battery
supplier.

In addition, if the current drawn by the load while the battery is
being charged is greater than 2A (which it is here) a jumper has to
be added on the control board to change it to a two-stage charger
or else the control circuitry will see the load current as charging
current and adjust the voltage upwards to compensate.

I have also found that when in "charge" mode, the DC output has a
60 Hz component which needs to be filtered between the battery-charger
junction and the load. One more thing that "they" don't tell you
in books or teach in courses.

--
73 de K2ASP - Phil Kane
(Regsitered Professional
Electrical Engineer)

I concur with Phil. Gelcells are the true maintenance free battery of
choice for a ham shack. I have run my ham shack off 12V gelcell battery
banks for at least 25 years. I have always simply floated the battery
with a regulated 13.6V 4A power supply. It charges the battery as needed
and floats it at 13.6V when the battery becomes charged; no danger of
overcharging. If the power goes out, there is no need for switch over . .
.. shack is still running off the battery. About every 6 or 7 years I
replace the battery(s).

More recently I have pulled the AC power supply off in favor of 55watt
solar panel with home brew regulator ..... set for 13.6V max. Still works
like a dream.



Ed K7AAT