Celestron Power Tank As Laptop Power Source

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Date: 20 Jul 2007 14:48:18
From: John Nichols
Subject: Celestron Power Tank As Laptop Power Source

Looking down the road to when I purchase a goto SCT, I recently purchased a
Celestron Power Tank. Obviously I plan to use it instead of relying on
batteries, but I'd also like to use it as a power source for more laptop
when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
hours), but without some sort of adapter (cigaretter?) I don't see a way of
doing so. Surely I'm not the only person out there who would like to, or
actually does, do this?

Any recommendations?

Date: 21 Jul 2007 20:14:29
From: canopus56
Subject: Re: Celestron Power Tank As Laptop Power Source

On Jul 20, 8:48 am, "John Nichols" <be...@worldnet.att.net > wrote:
> Looking down the road to when I purchase a goto SCT, I recently
> purchased a Celestron Power Tank. Obviously I plan to use it
> instead of relying on batteries, but I'd also like to use it as a
> power source for more laptop when I'm trying to do astrophotography
> (my laptop's battery only lasts 1.5 hours), but without some sort
> of adapter (cigaretter?) I don't see a way of doing so. Surely I'm not
> the only person out there who would like to, or actually does, do this?
> Any recommendations?

You are talking about long-session imaging - 4 to 6 or 8 hours. Think
about the power requirements in terms of amp hour ratings. Determine
the draw of your equipment and divide into the rated amp hours.

Amp hours can be a less than accurate rule-of-thumb. First, the rated
capacity changes by temperature. Second, your mount will stop working
when the voltage drops to below about 10.3 volts. Powering a laptop
with low voltage can hurt it. So plan on actually getting less than
the amount of time that a raw amp hours divided by draw rate will
show.

The Celestron power tank is a 17 amp hour device. A typical mount
will draw 1 or 2 amps, giving an ample life of around 6 - 8 hours.

A modern wide-screen bright laptop will draw 2-4 amps. With the power
draw of your mount, you are suddenly down maybe 3 or 4 hours,
excluding the initial draw down of your laptop battery (an additional
reserve of 1 1/4 hours). When you get into October or November and
are adding dew heaters - then you are looking at 1 1/2 to 2 hours.

Partially for this reason, imagers and some visual users go for an
automotive or marine battery with an amp hour rating of around 54
hours. But they are heavy and a nuisance to lug around.

The next consideration in making a selection is battery life and
replacement cost. Batteries, even rechargeable batteries, can only
handle a limited number of recharges - internal heat during recharge
is the principal enemy. It recharges the battery by also degrades its
useful life. Depth of discharge is also an enemy of long battery
life. The deeper the discharge state, the hotter the battery gets on
recharging - shortening its life. For example, you can power your
laptop on its battery - repeatedly recharging its on board battery.
But this shortens the rechargeable battery's life.

But a more economical approach is to always run the laptop - or any
other device dependent on a rechargeable battery - from the power
converter and only slighty discharging the battery. This is how your
car battery works - it is always in a constant state of slight
discharge and constant recharge. Because it only is slightly
discharged is why it lasts for several years.

Some batteries - like deep cycle marine batteries - are more resistant
to degredation from recharging than other batteries - like standard
automotive batteries.

All of these factors, excepting weight, favor using large deep cycle
marine batteries. But these batteries are heavy and expensive.

If you are principally a visual observer and normally only use a
powered mount for 2 or 3 hours at a time, something like a
lighterweight Powertank probably is better selection. Fully discharge
it during each session, but plan to replace it every couple of years.

If you are principally an imager - or just like to stay up all night -
probably the heavier marine or automotive battery with a separate
power inverter is the better route.

What I personally do is I use an standard automotive battery rated at
55 amp hours. It is cheap enough to replace once a year or every two
years, considering it gets discharged more frequently. A typical 2-3
hour visual session does not really discharge it that much. In order
to protect my equipment, I also invested in some decent inverters (a
12VDC-120AC and a separate 120AC to 12VDC regulator) that always
maintain the same voltage level dispite the level of battery
discharge.

For a third "emergency" 120AC power source, I also do have a small
inexpensive cigarette lighter power inverter, but I do not use it
much.

Finally, a modern laptop has a pretty heavy wattage requirement. If
you buy an automotive inverter (12VDC-120AC) resist the tempation to
buy a small 100W-200 Watt model. Get something that will handle 400W
or 800W. This is also the limitation of small cigarette inverters.
They may not be able to provide the wattage to run your laptop,
considering your car's electronics.

If you do go the marine or automotive battery route, get one that is
smaller than a standard marine battery plastic case. I have a marine
battery case (available at most trailer stores for about $20), but put
a smaller battery in it. That leaves room to stuff the power inverters
into the same convienent carry case. Some stout webbing and a clasp
from an outdoor or climbing stuff keeps the lid on and provides a
handle for carrying.

Hope that helps.

Clear skies - Canopus56

Date: 21 Jul 2007 02:29:30
From: G
Subject: Re: Celestron Power Tank As Laptop Power Source

Buy a new Toyota truck. They can come with a AC outlet in the truck bed.
Problem solved, nice truck to :)
I now this cause I have one, 750amp deep cycle battery in the truck...
last all night and it starts up fine. Then the drive home recharges the
battery...

"John Nichols" <bejay@worldnet.att.net > wrote in message
news:SW3oi.178136$Sa4.43964@bgtnsc05-news.ops.worldnet.att.net...
> Looking down the road to when I purchase a goto SCT, I recently purchased
> a Celestron Power Tank. Obviously I plan to use it instead of relying on
> batteries, but I'd also like to use it as a power source for more laptop
> when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see a way
> of doing so. Surely I'm not the only person out there who would like to,
> or actually does, do this?
>
> Any recommendations?
>

Date: 21 Jul 2007 12:02:37
From: William Hamblen
Subject: Re: Celestron Power Tank As Laptop Power Source

On Sat, 21 Jul 2007 02:29:30 -0400, "G" <your@smart.net > wrote:

>Buy a new Toyota truck. They can come with a AC outlet in the truck bed.
>Problem solved, nice truck to :)
>I now this cause I have one, 750amp deep cycle battery in the truck...
>last all night and it starts up fine. Then the drive home recharges the
>battery...

It's a long walk when it doesn't start.

Bud
--
The night is just the shadow of the Earth.

Date: 22 Jul 2007 03:09:22
From: John Nichols
Subject: Re: Celestron Power Tank As Laptop Power Source

"William Hamblen" <wrhamblen@comcast.net > wrote in message
news:c0f4a35jo9vnkfo6o08hps06eudj8ipvdd@4ax.com...
> On Sat, 21 Jul 2007 02:29:30 -0400, "G" <your@smart.net> wrote:
>
>>Buy a new Toyota truck. They can come with a AC outlet in the truck bed.
>>Problem solved, nice truck to :)
>>I now this cause I have one, 750amp deep cycle battery in the truck...
>>last all night and it starts up fine. Then the drive home recharges the
>>battery...
>
> It's a long walk when it doesn't start.
>
And while I'm likely to buy a Toyato when I buy my next vehicle, it's not
going to be a truck. :)

Date: 20 Jul 2007 21:56:13
From: thad@thadlabs.com
Subject: Re: Celestron Power Tank As Laptop Power Source

On Jul 20, 7:31 pm, jeffbullard <jeffbullard.e73...@spacebanter.com >
wrote:
> [...]
> In retrospect I should have gone for a marine battery, which you can
> get at your local outdoors store such as Academy or whatever. I looked
> at them recently and they go for about $60 plus another $50 for a decent
> charger. Then add a power inverter and you can use your regular laptop
> AC power chord.

"Chord"?

Would that be A-flat or a G-string?

:-)

Date: 20 Jul 2007 23:59:03
From: John Nichols
Subject: Re: Celestron Power Tank As Laptop Power Source

Date: 20 Jul 2007 13:52:36
From: RMOLLISE
Subject: Re: Celestron Power Tank As Laptop Power Source

On Jul 20, 9:48 am, "John Nichols" <be...@worldnet.att.net > wrote:
> Looking down the road to when I purchase a goto SCT, I recently purchased a
> Celestron Power Tank. Obviously I plan to use it instead of relying on
> batteries, but I'd also like to use it as a power source for more laptop
> when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see a way of
> doing so. Surely I'm not the only person out there who would like to, or
> actually does, do this?
>
> Any recommendations?

Hi:

As you've been told, the Powertank doesn't have the oomph you need to
run a laptop for long. My solution? What I've used for several years
is a 75ah trolling motor battery (aka "deep cycle marine battery") and
an inverter (a Black and Decker). The battery is a little on the heavy
side, but it does have the power I need, and is priced about the same
as a jump start pack like the Powertank.

Be further advised that the Powertank has had quality problems. If you
want a battery like that, check Wal-Mart's automotive section instead.

Unk Rod

Date: 21 Jul 2007 03:31:23
From: jeffbullard
Subject: Re: Celestron Power Tank As Laptop Power Source

RMOLLISE;809500 Wrote:
> On Jul 20, 9:48 am, "John Nichols" be...@worldnet.att.net wrote:-
> Looking down the road to when I purchase a goto SCT, I recentl
> purchased a
> Celestron Power Tank. Obviously I plan to use it instead of relyin
> on
> batteries, but I'd also like to use it as a power source for mor
> laptop
> when I'm trying to do astrophotography (my laptop's battery only last
> 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see
> way of
> doing so. Surely I'm not the only person out there who would like to
> or
> actually does, do this?
>
> Any recommendations?-
>
> Hi:
>
> As you've been told, the Powertank doesn't have the oomph you need to
> run a laptop for long. My solution? What I've used for several years
> is a 75ah trolling motor battery (aka "deep cycle marine battery") and
> an inverter (a Black and Decker). The battery is a little on the heavy
> side, but it does have the power I need, and is priced about the same
> as a jump start pack like the Powertank.
>
> Be further advised that the Powertank has had quality problems. If you
> want a battery like that, check Wal-Mart's automotive section instead.
>
> Unk Rod

I used a small 7Ah lead-acid rechargeable for my scope and laptop. To
many of my all-night astrophotography sessions were cut short
especially with dew-zapper added. (Many nights I wished for
dew-zapper for the laptop)

In retrospect I should have gone for a marine battery, which you ca
get at your local outdoors store such as Academy or whatever. I looke
at them recently and they go for about $60 plus another $50 for a decen
charger. Then add a power inverter and you can use your regular lapto
AC power chord

--
jeffbullard

Date: 20 Jul 2007 14:44:40
From: William Hamblen
Subject: Re: Celestron Power Tank As Laptop Power Source

On Fri, 20 Jul 2007 14:48:18 GMT, "John Nichols"
<bejay@worldnet.att.net > wrote:

>Looking down the road to when I purchase a goto SCT, I recently purchased a
>Celestron Power Tank. Obviously I plan to use it instead of relying on
>batteries, but I'd also like to use it as a power source for more laptop
>when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
>hours), but without some sort of adapter (cigaretter?) I don't see a way of
>doing so. Surely I'm not the only person out there who would like to, or
>actually does, do this?

You can get for most laptops adapters that plug into a 12 V cigarette
lighter socket. I've got one for a ThinkPad.

You can get cheaper versions of the Celestron Power Tank at auto parts
stores where they are sold as jump starters. They don't have
flashlights or radios built in, but they do supply power for about
two-thirds of the price. If you need more power you can roll your own
from a wheelchair battery.

Bud
--
The night is just the shadow of the Earth.

Date: 20 Jul 2007 13:51:03
From: Joe S.
Subject: Re: Celestron Power Tank As Laptop Power Source

"John Nichols" <bejay@worldnet.att.net > wrote in message
news:SW3oi.178136$Sa4.43964@bgtnsc05-news.ops.worldnet.att.net...
> Looking down the road to when I purchase a goto SCT, I recently purchased
> a Celestron Power Tank. Obviously I plan to use it instead of relying on
> batteries, but I'd also like to use it as a power source for more laptop
> when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see a way
> of doing so. Surely I'm not the only person out there who would like to,
> or actually does, do this?
>
> Any recommendations?
>

Several other replies have told you that the Power Tank does not have the
capacity to run both the scope and a laptop.
Let me address the power adapter question. My laptop is an HP. HP sells a
power adapter, power supply, battery eliminator, or whatever you want to
call it, that operates off either house current (110VAC) or 12 volts DC. It
comes with two power cords -- well, three power cords, actually. One power
cord is permanently affixed to the power adapter and that cord goes to the
laptop. The other two cords have plugs that plug into the end of the power
adapter and these are the input cords -- one of them plugs into the wall for
using house current, the other has a cigarette lighter plug for plugging
into the cigarette lighter or 12 VDC outlet of a car (truck, whatever).

I have seen after-market power adapters that work the same way if you don't
want to spend the $$$ for an OEM power adapter. While mine is an HP, I
suspect every other laptop maker has the same thing. This is what the HP
device looks like:
http://www.shopping.hp.com/product/notebook/notebook_hp/batteries/1/accessories/PC628A%2523ABA
(the photo shows only one power cord but the description tells you that it
comes with both AC and car power cords.)

Date: 20 Jul 2007 11:10:02
From: Dave Jessie
Subject: Re: Celestron Power Tank As Laptop Power Source

John Nichols wrote:
> Looking down the road to when I purchase a goto SCT, I recently purchased
> a Celestron Power Tank. Obviously I plan to use it instead of relying on
> batteries, but I'd also like to use it as a power source for more laptop
> when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see a way
> of doing so. Surely I'm not the only person out there who would like to,
> or actually does, do this?

Hi John,

I'm afraid your Power Tank doesn't have nearly the capacity you'll need for
a laptop let along for a laptop with your goto scope. For that you're going
to need a much higher capacity deep cycle marine battery available for a
reasonable price at an auto parts store. I'd suggest at least a 50Ahr
capacity along with a 12VDC power supply for your laptop and NOT a power
inverter to convert your deep cycle 12VDC to 110VAC then back to 20VDC (or
so) for your laptop. Did I make myself clear here? Starlord isn't the only
diabetic on this board with low bloodsugar difficulties - I'm currently at a
40mg/dl reading ;^(

Clear Dark Steady Skies,
Dave Jessie (a neighbor of yours!)

Date: 20 Jul 2007 15:02:15
From: Chris L Peterson
Subject: Re: Celestron Power Tank As Laptop Power Source

On Fri, 20 Jul 2007 14:48:18 GMT, "John Nichols"
<bejay@worldnet.att.net > wrote:

>Looking down the road to when I purchase a goto SCT, I recently purchased a
>Celestron Power Tank. Obviously I plan to use it instead of relying on
>batteries, but I'd also like to use it as a power source for more laptop
>when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
>hours), but without some sort of adapter (cigaretter?) I don't see a way of
>doing so. Surely I'm not the only person out there who would like to, or
>actually does, do this?
>
>Any recommendations?

I hope you got the bigger model... 7Ah is marginal even for running your
scope, let alone a scope and laptop. Remember, these things don't like
to be deep cycled.

Some laptop manufacturers provide 12V power supplies for their products.
Check for that first. Otherwise, the standard approach (in spite of some
inefficiency) is simply to use a power inverter, with a 12V lighter
adapter on the input and 120VAC output. You then plug your regular
laptop power supply into that. Suitable inverters run around US$50.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

Date: 20 Jul 2007 15:01:31
From: Terry A Haimann
Subject: Re: Celestron Power Tank As Laptop Power Source

On Fri, 20 Jul 2007 14:48:18 +0000, John Nichols wrote:

> Looking down the road to when I purchase a goto SCT, I recently purchased a
> Celestron Power Tank. Obviously I plan to use it instead of relying on
> batteries, but I'd also like to use it as a power source for more laptop
> when I'm trying to do astrophotography (my laptop's battery only lasts 1.5
> hours), but without some sort of adapter (cigaretter?) I don't see a way of
> doing so. Surely I'm not the only person out there who would like to, or
> actually does, do this?
>
> Any recommendations?

The power Tank (sic) doesn't have the horse power to run a goto and a
laptop. You should consider a Marine Battery.