I have to agree.Regular car type batteries should not be used inside a
home,to dangerous.
cuhulin

I use small bench supplies because I have a lot of small bench
supplies. You set it up for 13.8VDC, and the current limit cuts in if
the battery wants more. Gell cells don't like excessive voltage, so I
avoid the cheaper car battery chargers. My bench suplies range from 1A
to 8A, no where near as heavy duty as a car battery charger.

You could buy a "cyclic" charger if you want faster charging. For
instance, for the np7-12, you could hit it with 14.5V to 15V at
1.75Amps to charge it. I personally don't like doing this, and rather
just set up the float voltage (13.5 to 13.8V). I only mention the
np7-12 because I have one next to me. The one I use in the field is
much larger, and unfortunately not handy. [I put it in a West Marine
battery carrier, so it's all locked up so to speak.] Note that you can
float a SLA (sealed lead acid) at the float voltage forever. That is
how you use the battery in backup mode.

The charge time at the float voltage won't be linear. As the battery
charges, it draws less current. If you want to quickly charge the SLA,
you can buy a cyclic charger. As I said, I use my infrequently, so the
bench supply works for me. http://www.xantrex.com/ has chargers meant
for SLA, but I still suggest getting two batteries and just floating
one on a good bench charger (HP, Labda, Sorensonmetc.] The only problem
with a bench supply is some jerk could crank up the voltage.

You can drain the SLA down to 10.5V (i.e. 1.75V/cell). In the field, I
use a cheap Harbor Freight DVM. No use getting a good meter all
scratched up.

I don't like the idea of using car batteries for this application. The
outgassing can ruin electronics or your lungs. SLA batteries are safe
enough to install inside electronics gear. I've use noise measuring
gear that would disconnect from the mains when making a measurement,
using an internal SLA to power the electronics.

bpnjensen wrote:
M...sushi.com wrote:

I suggest getting a gell cell to avoid battery acid spills or fumes. I
only use mine when in the field, so I don't have a set up as you
suggest. I charge my battery from a bench supply using 13.8v as a
float voltage.

Thanks, also to RHF and Cuhulin. I just took a look at these gel cells
on a couple of websites, incluidng the one recommended by RHF and some
others. This, of course, raises more questions :-)

How big a charger must one have? Must the current available on the
charger be some minimum fraction of the amp-hours of the battery, or
can one use a smaller charger and just leave it on longer?

Also, is the charge time a simple proportion between the charger
current and the battery amp-hour value? i.e., to recharge an 18
amp-hour battery with a 10-amp charger, the charge time is 1.8 hours -
?

Is it OK to drain a gel cell until it loses almost all of its charge?
Or is there some minimum level at which one must stop (25%, 50% or
etc)?

Finally, once the gel cell battery is fully charged, how does one know,
and will it hurt if the charger is kept on without checking? Does a
charger have a device to shut off when full charge is reached?

Thanks,
Bruce

Wet cell car type batteries.Back in the 1950's or 1960's,I read in one
of my Popular Science or Popular Mechanics magazines if you will drain
the acid out of the battery into a porcelain or glass container and
flush the crud out of the battery with a water hose (no nozzle on the
water hose and the water turned on at low pressure) and then pour the
acid through a piece of cloth (to filter out crud in the acid) and pour
the acid back into the battery,that will extend the life of the
battery.Pure Sulphuric battery acid has a chemical burn equal to 735
degrees temperture,same as a red hot poker at 735 degrees.I used to work
at a factory that manufactured auto/truck/lawnmower batteries and
believe you me,,, I do know about that pure sulphuric battery acid! One
drop of it on your hide will make you jump ten feet high! The acid in
the car type batteries is very,very watered down.
cuhulin

Dear Bruce,

I own a Century Electri-pac Model BPIP-99 (Portable Electric Power -
Cordless and Rechargeable) which meets all your requirements. I bought
it several years ago from THE SPORTSMAN'S GUIDE catalog ($75.00 at the
time). I do not know if this model is still available, but you could
investigate. Similar items are available at THE PEP BOYS.

In fact I have powered my AOR AR7030 Plus and my Wellbrook ALA 330S
from this unit. Everything worked fine.

Best,

Joe

Most auto parts stores and truck and marine supply/parts stores sell
Portable Electric Power units.Check out the pawn shops too,you might
find a good deal there.Looking in my November 2005 issue of Popular
Science magazine I see a two page ad for Black & Decker Portable Power
Solutions.The ad says Wal Mart stores sells them and there is a website
to check out www.vectormfg.com
cuhulin

Joe wrote:

I own a Century Electri-pac Model BPIP-99 (Portable Electric Power -
Cordless and Rechargeable) which meets all your requirements. I bought
it several years ago from THE SPORTSMAN'S GUIDE catalog ($75.00 at the
time). I do not know if this model is still available, but you could
investigate. Similar items are available at THE PEP BOYS.

In fact I have powered my AOR AR7030 Plus and my Wellbrook ALA 330S
from this unit. Everything worked fine.

This sounds promising - nothing like simple and effective! I will stop
at a Pep Boys and look into this type of thing.

Do you recall, offhand, what the amp-hour rating is, and how long it
takes to do a full recharge?

Thanks,
Bruce

Dear Bruce,

Specifications on the back of the unit read:

Ratings: 115V Output 300 Watts (2.3 Amps) @ 60Hz
12 Volt Output 20 Amps
12 Volt Input 8 Amps Maximum

I do not remember how long the initial charge took. I leave it plugged
in when it is not in use so it is always charged and ready to use. I do
not use it often. I keep it as a backup power supply. But it worked
just fine when I tried it with my radio and antenna.

Best,

Joe

Hi Joe...

I'm curious, do you find that the inverter generates noise, as
suggests it would?

Joe Analssandrini wrote:
Dear Bruce,

I own a Century Electri-pac Model BPIP-99 (Portable Electric Power -
Cordless and Rechargeable) which meets all your requirements. I bought
it several years ago from THE SPORTSMAN'S GUIDE catalog ($75.00 at the
time). I do not know if this model is still available, but you could
investigate. Similar items are available at THE PEP BOYS.

In fact I have powered my AOR AR7030 Plus and my Wellbrook ALA 330S
from this unit. Everything worked fine.

Best,

Joe

On 29 Oct 2005 20:24:26 -0700, "junius" wrote:

Hi Joe...

I'm curious, do you find that the inverter generates noise, as
suggests it would?

I'm not Joe however I have use radios in the vicinity of [inexpensive]
inverters and have found them to be very effective noise generators.

Joe Analssandrini wrote:
Dear Bruce,

I own a Century Electri-pac Model BPIP-99 (Portable Electric Power -
Cordless and Rechargeable) which meets all your requirements. I bought
it several years ago from THE SPORTSMAN'S GUIDE catalog ($75.00 at the
time). I do not know if this model is still available, but you could
investigate. Similar items are available at THE PEP BOYS.

In fact I have powered my AOR AR7030 Plus and my Wellbrook ALA 330S
from this unit. Everything worked fine.

Best,

Joe

Cheap inverters put out square waves (not quite, but good enough for
this discussion). They make a ton of racket, so I can't see how anyone
would consider them suitable for use around radios. Further, if your
radio runs off of 12VDC, why take a 12V battery, invert it to 117V AC,
then step it down and rectify to 12VDC.

For devices that run off of 12V, note that the 12V is nominal. Just
about everything can run from the 13.8V float voltage, with margin. The
only pain in the arse is the Wellbrook pre-amp, which is positive
ground. Touch the case to to a negative ground and you pop the internal
fuse. When I use the device in the field, I place it in a zip lock bag,
poking a hole for the cable. They really should have insulated the
thing. Of couse, you need to build a special postive ground cable
(cigarette lighter adapter) and make sure you only use it with the
wellbrook.

In the future, I'm going to build a 12V distribution box using cannon
connectors. Those cigarette lighter connectors are really crap.

wrote:
On 29 Oct 2005 20:24:26 -0700, "junius" wrote:

Hi Joe...

I'm curious, do you find that the inverter generates noise, as
suggests it would?

I'm not Joe however I have use radios in the vicinity of [inexpensive]
inverters and have found them to be very effective noise generators.

Joe Analssandrini wrote:
Dear Bruce,

I own a Century Electri-pac Model BPIP-99 (Portable Electric Power -
Cordless and Rechargeable) which meets all your requirements. I bought
it several years ago from THE SPORTSMAN'S GUIDE catalog ($75.00 at the
time). I do not know if this model is still available, but you could
investigate. Similar items are available at THE PEP BOYS.

In fact I have powered my AOR AR7030 Plus and my Wellbrook ALA 330S
from this unit. Everything worked fine.

Best,

Joe