Marine Battery? Jump-Start Battery? Power Inverter?
Russ
I am not an electronics buff, and I am confused by all the different
posts that I have seen regarding this. In addition to the scope, I
want to power a video camera, monitor, & VCR. What kind of portable
power supply do I need? Do I need to be concerned with amps, volts,
watts, wobbelators, kenuten valves? AND, where does a power inverter
fit in to all this? Do I need one of those too?
Thank you in advance.
** If you want to send me e-mail, remove the NOSPAM from my address **
Al
and maybe a dew heater, one of the small jump start batteries would do well
(these are usually 17 AH batteries). However, the other stuff you wish to
power complicates things. If you absolutely need to power all this stuff in
the field, I would suggest 2 batteries...a small jump start battery for your
telescope and a marine deep cycle battery for the rest of the accessories.
You could buy both at a membership store such as Costco or Sams for $50
each. BTW, a power inverter simply changes DC current to AC.
Al
"Russ" <ru...@NOSPAMepcinternet.com> wrote in message
news:3fa146a5....@news.det.sbcglobal.net...
sdastroguy
power drain and recharging. The power inverter will allow you to run
the VCR, etc on 110v off the marine battery. Get a good size battery
that is gel filled. It should withstand 300-500 charge/discharge
cycles. I use one rated 585 CCA and for what you want to run, you will
want one this size. Everything should be rated for 12 volts. As for
the amperage, it will be important for the inverter. Add up the amps
requried for all the equipment you want to run at the same time and
then add 20% or so to that total to get the size of the inverter you
need.
On Thu, 30 Oct 2003 17:14:58 GMT, ru...@NOSPAMepcinternet.com (Russ)
wrote:
Kipper
"Russ" <ru...@NOSPAMepcinternet.com> wrote in message
news:3fa146a5....@news.det.sbcglobal.net...
Inverters convert DC to AC. The ones you might be interested in also
convert the car battery voltage to domestic mains voltage. I use a power
inverter when at a dark spot to keep all my stuff in juice for the duration
because I drive to a dark spot. I plug the inverter into the cigarette
lighter socket of the car and have mains voltage to plug things into (like
VCRs).
Yes you need to watch your WATTS. Simply add up all the Watts that
everything you want to plug-in uses and the power inverter has to be more
than that (the more the better). One thing you need to watch is your car
battery! It may be worth a periodic engine run to keep it charged. For
example, monitor: 80watts, VCR 60 watts, scope power supply 25 watts; total
is 165 watts. You'd really be looking at a 200+watt inverter, but that's
just an example. Always read the VA value or Watts value at the mains
voltage (ie input voltage), not, for example in a power supply, the output
watts or VA value.
You might want to ensure your wabbelators don't drop off in the cold...
Cheers
--
K.
Chuck Taylor
periods of use (discharging) better than typical auto batteries.
Auto/starting batteries are made for short periods of high current use
followed by recharging. If they are repeatedly used for long periods as with
a scope, they will not last as long as a marine battery.
Clear Skies
Chuck Taylor
Do you observe the moon?
Try the Lunar Observing Group
http://groups.yahoo.com/group/lunar-observing/
"Russ" <ru...@NOSPAMepcinternet.com> wrote in message
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Michael A. Covington
"Russ" <ru...@NOSPAMepcinternet.com> wrote in message
news:3fa146a5....@news.det.sbcglobal.net...
> I am not an electronics buff, and I am confused by all the different
> posts that I have seen regarding this. In addition to the scope, I
> want to power a video camera, monitor, & VCR. What kind of portable
> power supply do I need? Do I need to be concerned with amps, volts,
> watts, wobbelators, kenuten valves? AND, where does a power inverter
> fit in to all this? Do I need one of those too?
The LX90 runs on 12 volts direct from the battery.
An inverter will give you 120 volts AC, probably needed by your video
camera, monitor, and VCR. It is inefficient. If possible you should find
12-volt-operated equipment instead.
Yes, you have to know about volts, amps, and watts. Briefly:
Volts are the pressure of the electrons. A power supply delivers a fixed
voltage (e.g., a 12-volt battery).
Amps are the rate at which electrons are actually flowing. A power supply
has a maximum number of amps that it can deliver. Connect it to something
that requires the same number of volts but fewer amps, and everything's
fine.
Watts are volts times amps -- a measure of the rate of energy consumption.
The maximum output of an inverter is often measured in watts rather than
volts.
Never ask an inverter or power supply to deliver more amps or watts than
it's rated for. Things will fry.
--
Michael Covington
Author, Astrophotography for the Amateur
www.covingtoninnovations.com
drdrb
synonym for "deep cycle battery", manufacturers also make marine
starting batteries which are not deep cycle. Starting batteries (such
as jump start batteries) have high cold cranking amp ratings, but do
not tolerate deep discharge without damage. A marine starting battery
is just a starting battery built to be resistant to the pounding
sometimes experienced in boats, and is no better than any other
starting battery for deep cycle use.
What you want is a deep cycle battery, marine or otherwise. Wheelchair
batteries (available at Sears, etc.) are deep cycle batteries and come
in various sizes which would probably meet your portability
requirements.
Al Arduengo
My solution was a Marine Deep Cycle battery from WalMart ($48) rated at
115aH (115 amp hour). I bought a 350Watt inverter and a 1-to-3 12V
receptacle splitter. Connect both the inverter and splitter to the
battery (make sure to add fuses if necessary!) and I am able to run my
scope, dew heater, laptop and music source for a few nights. The
battery is quite heavy but worth it. In your case, you may not get as
much time as I do simply because of all the extra stuff you want to
power. Add up all the power usage (watts) for you equipment (should be
printed on the box/tag/instructions/case and make sure you get an
inverter that can handle all the power combined of the stuff you want to
run on AC. Be careful not to use the PEAK power output of the inverter
as your guide. Inverters usually have a peak and nominal rating and
nominal is usually half of peak. USE THE NOMINAL!! or you might burn
something up. :-/
Email me if you have specific questions and I will be glad to assist.
Best,
-Al A.
ru...@NOSPAMepcinternet.com (Russ)
writes:
--
~/.signature
Al Hall
<chucktaylo...@speakeasy.fishing> wrote:
>Marine batteries have the advantage of being able to repeatedly handle long
>periods of use (discharging) better than typical auto batteries.
>Auto/starting batteries are made for short periods of high current use
>followed by recharging. If they are repeatedly used for long periods as with
>a scope, they will not last as long as a marine battery.
Any reason not to use a deep cycle marine battery in the car in place
of a regular auto battery?
Al
"Al Hall" <alh...@despammed.com> wrote in message
news:eu85qvkdk7gim749v...@4ax.com...
Seems like a very good question to me. I asked this very question when I
was buying some batteries for astronomy use and I'll paraphrase what I was
told...
A boat and a car place different requirements on a battery and it's a good
idea to buy a battery that's made for those requirements. As an example,
it's very important for a car to have a big reserve of cold cranking power,
while this is not too important in a boat that is used during the warm
weather months. On the other hand, it's common to draw small amounts of
power from a boat battery while the engine is shut down and the system is
not charging. Of course, when you're ready to go home, it's important that
the battery has enough power to get you home.
In spite of the superior marine batteries available today, you should see
some of the batteries going into boats these days. I have a huge 75 pound
battery for each of the engines, plus a bank of 3 deep cycle batteries to
operate accessories. Not too many gas stations out there. These days,
boatmen pray that they never need a tow, as a tow could cost you a thousand
dollars or more.
Al
Mike Richmann
A minor note: no need to look specifically for wheelchair batteries at
Sears. The conventional Diehard brand marine deep cycle batteries will
do the job nicely if you don't mind handling lead-acid models. For all
of my power-hungry hardware, a couple of them (Diehard part number
27494) cover my requirements and they usually go for about $60 per pop
in the automotive department...
---
Mike
http://www.concentric.net/~richmann/
Al Hall
wrote:
>
>"Al Hall" <alh...@despammed.com> wrote in message
>news:eu85qvkdk7gim749v...@4ax.com...
>> Any reason not to use a deep cycle marine battery in the car in place
>> of a regular auto battery?
>>
>
>Seems like a very good question to me. I asked this very question when I
>was buying some batteries for astronomy use and I'll paraphrase what I was
>told...
>
>A boat and a car place different requirements on a battery and it's a good
>idea to buy a battery that's made for those requirements. As an example,
>it's very important for a car to have a big reserve of cold cranking power,
>while this is not too important in a boat that is used during the warm
>weather months. On the other hand, it's common to draw small amounts of
>power from a boat battery while the engine is shut down and the system is
>not charging. Of course, when you're ready to go home, it's important that
>the battery has enough power to get you home.
>
>In spite of the superior marine batteries available today, you should see
>some of the batteries going into boats these days. I have a huge 75 pound
>battery for each of the engines, plus a bank of 3 deep cycle batteries to
>operate accessories. Not too many gas stations out there. These days,
>boatmen pray that they never need a tow, as a tow could cost you a thousand
>dollars or more.
>
>Al
>
Hi Al,
Makes sense. OTOH, if you were planning on using the car battery to
power a scope through the cigarette lighter outlet maybe a deep cycle
battery would be better as long as it would start the car too. A few
years ago I had a small camper van that I set up with a second deep
cycle battery to run accessories when the engine was turned off. It
was isolated from the starter battery with a diode based battery
isolator that I got from a camper outlet. When the primary [starting]
battery went bad one time, I switched it with the deep cycle and ran
the van for weeks with no problem until I got around to buying a new
primary battery when they went on sale. Since then I've always
wondered if the deep cycle battery wouldn't be a better choice for
those amateurs who use their car battery to power their scopes.
[the other] Al
Tom Randy
Or get 2 golf cart batteries and wire them together. More bang for your
bucks.