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The battery pack that I use claims that a radio or TV can be
operated for 20 hrs. On several occassions, by freshly charged
battery went dead driving the G-11 with DSC. I couldn't understand
this at first, and later concluded that a fine layer of bubbles
formed over the battery plates made it appear dead. So when it
happened again, I simpley shook the battery as hard as I could but to
no avail. Any comments, or does the G-11 draw about 5 times the
current of a radio or TV

I use a 34 amp hour marine battery (a small battery, about the
size used in rider mowers) for my G-11 /w DSCs and it lasts all
night long even in the winter.

I use marine batteries because unlike car batteries, they are
designed to be discharged almost completely without harming
them.

I also use two other 34 amp batteries to run my laptop and
CCD camera but I'm fixing to upgrade to two 68 amp hour
batteries because the smaller batteries are just borderline enough.

I have noticed something about marine batteries (don't know which
kind you have), that if you charge them up after a few weeks of
sitting, they don't have as much capacity. The longer they have
sat, the lower their capacity is.

However after I cursed at them for running completely down
in say 1/2 the time they should have and charge them up
fully again. Then they have full capacity and last much longer.

So what I now will do if I haven't been out for a month or so is
charge them up, run them down, and then charge them
up again before I go out.

This is called "cycling" by NiCad users. I don't know if the
concept applies to these batteries or not, but it definitely
makes a big difference.

Rockett Crawford


havriliak@... wrote:

The battery pack that I use claims that a radio or TV can be
operated for 20 hrs. On several occassions, by freshly charged
battery went dead driving the G-11 with DSC. I couldn't understand
this at first, and later concluded that a fine layer of bubbles
formed over the battery plates made it appear dead. So when it
happened again, I simpley shook the battery as hard as I could but to
no avail. Any comments, or does the G-11 draw about 5 times the
current of a radio or TV

----------------------------------------------------------------------------

Capella's Observatory (CCD Imaging)

The G11 should consume less than 1 amp per hour, but for safety's sake,
estimate that rate. The DSC's consumption should be negligible but again,
play it safe and estimate 0.5 amps per hour. If you estimate 1.5 amps per
hour total consumption, you'll be very safe. It's probably about half that
in reality.

Was your battery fully charged before you used it? What is the amp-hour
rating?

Deep cycle batteries such as this should be recharged immediately after
use, no matter how low you've run them. Running them all the way down
and/or letting them sit in a partially or fully discharged condition
shortens their life.

They have no memory and can be discharged to any point before recharging.

I use a hefty Marine battery rated at 105 AH along with a smaller "Gates
Cyclon" 24 AH battery. The pair can run my scope, CCD camera, autoguider
and laptop for four nights without recharging, as I learned this past June
on Mt Lassen in California. Fortunately, I didn't have to use my dew
straps, as they are some of the biggest consumers of electrical power.

Paul Sterngold

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I doubt it, most likely your battery pack is not in good shape. What kind of
batteries and how big is the pack made off?

I sometimes use a 5ah lead-acid gellcell and its good for two nights.

Herm


havriliak@... wrote:

The battery pack that I use claims that a radio or TV can be
operated for 20 hrs. On several occassions, by freshly charged
battery went dead driving the G-11 with DSC. I couldn't understand
this at first, and later concluded that a fine layer of bubbles
formed over the battery plates made it appear dead. So when it
happened again, I simpley shook the battery as hard as I could but to
no avail. Any comments, or does the G-11 draw about 5 times the
current of a radio or TV

Astropics

this does no good to lead acid batteries, all you are doing is shortening its
life. Its definitely good for nicads but does not apply to lead acid batteries.

All you have to do is to promptly recharge the battery with a good automatic
charger, or float it at 13.8v...keep the electrolyte topped off etc..

all you possibly could want to know about rechargeable batteries, all types,
check it out here:



Herm

Rockett Crawford <Rockett@...> wrote:

This is called "cycling" by NiCad users. I don't know if the
concept applies to these batteries or not, but it definitely
makes a big difference.

Astropics

--- In Losmandy_users@..., hermperez@w... wrote:

this does no good to lead acid batteries, all you are doing is

shortening its

life. Its definitely good for nicads but does not apply to lead

acid batteries.

All you have to do is to promptly recharge the battery with a good

automatic

charger, or float it at 13.8v...keep the electrolyte topped off

etc..

all you possibly could want to know about rechargeable batteries,

all types,

check it out here:



Herm

Rockett Crawford <Rockett@a...> wrote:

Thanks to all of you who responed. The battery is a lead-acid
battery sold by Pep Boys for boosting your car battery when needed.
The amp-hr rating is not listed. It was alway fully charged as
indicated by the pilot light (green) when the button was pressed.
Over charging may be the cause because I tend to leave the wall unit
charger plugged in all the time. In any case when used three days in
a row, it is recharded overnight and the third night failed after
about 4 hrs. I assume that the battery is a dud and leaving for
Sam's to buy another. Once again thanks.

This is called "cycling" by NiCad users. I don't know if the
concept applies to these batteries or not, but it definitely
makes a big difference.

Astropics

Paul Sterngold wrote:

The G11 should consume less than 1 amp per hour, but for safety's sake,
estimate that rate. The DSC's consumption should be negligible but again,
play it safe and estimate 0.5 amps per hour

The DSCs have a display heater which takes about 1/2 amp, but
only when the temperature drops below freezing. The digital drive
pulls about 1/2 an amp.


Capella's Observatory (CCD Imaging)

hermperez@... wrote:

this does no good to lead acid batteries, all you are doing is shortening its
life.

No, you are definitely wrong about the batteries I am using.
It does do a lot of good. I discovered this by accident. I noticed that
every time I went out for more than one night, the second night the batteries
had almost twice the capacity as they did the night before.

Finally I wised up and started cycling the batteries before a star
party rather than just charging them up.

Its definitely good for nicads but does not apply to lead acid batteries.

All you have to do is to promptly recharge the battery with a good automatic
charger, or float it at 13.8v...keep the electrolyte topped off etc..

I do charge it with a good automatic charger designed specifically for
marine batteries. I also charge them immediately when I get home to
leave them in a charged state.

all you possibly could want to know about rechargeable batteries, all types,
check it out here:

This is a good page, but it appears to only apply to small R/C packs
that go into models.

----------------------------------------------------------------------------

Capella's Observatory (CCD Imaging)

Rockett, I'm sorry but I cant explain my argument better, lead acid batteries
have a finite number of times that they can be discharged to zero, also they
don't suffer from a "memory effect". I really don't know why you are noticing an
improvement but if it works for you...

Herm

Rockett Crawford <Rockett@...> wrote:

hermperez@... wrote:

this does no good to lead acid batteries, all you are doing is shortening its
life.

No, you are definitely wrong about the batteries I am using.
It does do a lot of good. I discovered this by accident. I noticed that
every time I went out for more than one night, the second night the batteries
had almost twice the capacity as they did the night before.

Finally I wised up and started cycling the batteries before a star
party rather than just charging them up.

Astropics

hermperez@... wrote:

Rockett, I'm sorry but I cant explain my argument better, lead acid batteries
have a finite number of times that they can be discharged to zero,

All batteries do, not just lead acid.

The cycling does not waist a discharge since the batteries are no good
to me on that first charge/discharge cycle because they will die on me
1/2 way through the night.

also they
don't suffer from a "memory effect". I really don't know why you are noticing an
improvement but if it works for you...

I didn't say anything about them having "memory effect" and my description of
the problem doesn't fit the definition of the memory effect. That is caused by charging
nicads over and over without fully discharging them. I am familiar with this
phenomena because I also fly RC planes.

My problem is charging my marine batteries fully after sitting for weeks
and them having just 1/2 of the capacity when discharged. After the next
charge however they have full capacity.

Cycling them before the first night solves this problem.

take care,
Rockett Crawford

----------------------------------------------------------------------------

Capella's Observatory (CCD Imaging)

Hi Rockett,

From personal experience and some knowledge of the subject I will
have to Agree with you! IMHO the life reduction from repetitive
discharging and recharging has a far greater effect on the sealed gel
lead-acid cells than the wet type that you and the poster are using.

Wet cells are designed for much higher current loads than the 1 amp
or so required by the initial poster and tend to increase internal
resistance under such low loads. Discharging such a cell under a
moderate load of say 10 amps or so and then immediately recharging
the cell would restore its performance and help to "wake it up".

If you have an old tired lead-acid battery, it is sometimes possible
to restore some of its performance by forcing a positive flow of
current through the cells but you have to be very careful doing
this. You need to use a controllable bench power supply and monitor
the battery temperature closely. When the voltage across the cells
stabilises, stop and then immediately recharge the battery. This
action can help to partially restore the chemistry of the electrolyte
but in the end the best solution under these circumstances would be
to simply replace the battery.

Regards,
Ian.


--- In Losmandy_users@..., Rockett Crawford <Rockett@a...>
wrote:

hermperez@w... wrote:

Rockett, I'm sorry but I cant explain my argument better, lead

acid batteries

have a finite number of times that they can be discharged to zero,

All batteries do, not just lead acid.

The cycling does not waist a discharge since the batteries are no

good

to me on that first charge/discharge cycle because they will die on

me

1/2 way through the night.

also they
don't suffer from a "memory effect". I really don't know why you

are noticing an

improvement but if it works for you...

I didn't say anything about them having "memory effect" and my

description of

the problem doesn't fit the definition of the memory effect. That

is caused by charging

nicads over and over without fully discharging them. I am familiar

with this

phenomena because I also fly RC planes.

My problem is charging my marine batteries fully after sitting for

weeks

and them having just 1/2 of the capacity when discharged. After the

next

charge however they have full capacity.

Cycling them before the first night solves this problem.

take care,
Rockett Crawford

--------------------------------------------------------------------

--------

Capella's Observatory (CCD Imaging)

I go thru one or two large marine batteries in a year, I fly electric powered RC
planes (24 nicad cells, 30amp currents), plus I have a bass boat and then
telescopes with a large amount of dew heaters and fans. Large marine batteries
are cheap, $43 for 105ah...

Don't forget, lead acid batteries can explode and spew acid all over the place,
keep them away from you and don't make sparks near them.

Herm

"Ian Betts" <ian.betts@...> wrote:

If you have an old tired lead-acid battery, it is sometimes possible
to restore some of its performance by forcing a positive flow of
current through the cells but you have to be very careful doing
this. You need to use a controllable bench power supply and monitor
the battery temperature closely. When the voltage across the cells
stabilises, stop and then immediately recharge the battery. This
action can help to partially restore the chemistry of the electrolyte
but in the end the best solution under these circumstances would be
to simply replace the battery.

Regards,
Ian.

Astropics