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Equipment Discussions >> Mounts

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Raldo
member


Reged: 03/24/11

Loc: PR
Cg5 and celestron 7amps powertank new
      #5505021 - 11/05/12 07:28 AM

How much estimate operating time I can get out of celestron 12v 7amps powetank on my cg5. Is the cg5 a power hungry mount? Thanks in advance for the replies.

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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #5505033 - 11/05/12 07:38 AM

Yes it is. Moreso than my NexStar 11 GPS. As for how long a 7ah battery will last, that depends on how much slewing you do. Once in a while and you should be able to do all night. Do much zipping around the sky, and it won't go more than a few hours. Do yourself a favor and get a 17ah jumpstarter.

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Raldo
member


Reged: 03/24/11

Loc: PR
Re: Cg5 and celestron 7amps powertank new [Re: rmollise]
      #5506107 - 11/05/12 10:37 PM

Thanks uncle Rod, I will follow your advise.

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Phil Wheeler
Carpal Tunnel


Reged: 12/31/05

Loc: 3 miles WNW of Celestron
Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #5506162 - 11/05/12 11:19 PM

Another approach might be some number of smaller units. I use three 14 A-h devices. Easier to handle and one is in use while the others can be on charge -- and for field trips all three go.

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Raldo
member


Reged: 03/24/11

Loc: PR
Re: Cg5 and celestron 7amps powertank new [Re: Phil Wheeler]
      #5506218 - 11/06/12 12:39 AM

Thanks for the reply. Can you please elaborate more on that.

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TopherTheME
sage
*****

Reged: 02/11/11

Loc: Rochester, MI
Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #5506800 - 11/06/12 12:24 PM

I use a 18.5V 5Ah Lipoly pack (and a 12V regulator) and it powers my mount for about 3 nights or about 9 hours of operation. Although this is mostly tracking, not slewing.

You can estimate your mounts run time rather easily. The average current draw from my CG-5 is about 1.5 Amps, although this numbers a bit high but I'm assuming you're doing a good amount of slewing. So a 7Ah battery will operate around 4.5 hours roughly. Taking into account battery life and you never want to completely discharge a lead acid battery you're looking at around 3.5 hours.


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rmollise
Postmaster
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Reged: 07/06/07

Re: Cg5 and celestron 7amps powertank new [Re: TopherTheME]
      #5507070 - 11/06/12 03:22 PM

Yep..."roughly" is the watch word. A 7ah battery won't come close to supplying 7ah. BUT...as you say, if you're mostly tracking, you are good. Again, IMHO the perfect battery for this mount is a 17ah jumpstart battery (from Wal-Mart or Pepboys or Harbor Freight). Reasonably light and inexpensive, built in or included charger, cool stuff like a light. Can't go wrong. If you don't observer long or don't slew much, abotu 17ah is still desirable, since it will allow you to power dew heaters, etc. from one battery.

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Raldo
member


Reged: 03/24/11

Loc: PR
Re: Cg5 and celestron 7amps powertank new [Re: rmollise]
      #5508804 - 11/07/12 06:14 PM

Thanks a lot for all the replays.

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andysea
Pooh-Bah
*****

Reged: 09/03/10

Loc: Seattle, WA
Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #5509293 - 11/08/12 01:15 AM

If you are a crafty person you can buy two 12Ah UPS replacement batteries on Amazon for a grand total od about $30 and then connect them in parallel. That would give you a total capacity of 24Ah. You can add a voltage regulator that can be had on ebay for about $7 including shipping from across the world I recommend always supplying through a regulator for all critical components i.e. mount, CCD etc. If you use a dew heater, that should be on its own battery.
I use two 105 Ah deep cycle batteries in the field and will probably add a third one dedicated to the mount alone.
Just a thought.

Edit: I found a 18Ah 12V Battery for about $35 on Amazon. Should work fine for most smaller mounts and for my Mach1.

Andy

Edited by andysea (11/08/12 08:17 PM)


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Raldo
member


Reged: 03/24/11

Loc: PR
Re: Cg5 and celestron 7amps powertank new [Re: andysea]
      #5510623 - 11/08/12 09:43 PM

Thanks a lot to all the ideas. Clear sky's for all of you.

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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #5511517 - 11/09/12 12:11 PM

My problem is Astro Physics indicates I need to get to 12V 40Ah to run a Mach 1 GTO all night- so there are levels of power demand.

-Rich


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rmollise
Postmaster
*****

Reged: 07/06/07

Re: Cg5 and celestron 7amps powertank [Re: Starhawk]
      #5511816 - 11/09/12 03:01 PM

40 ah to run the Mach 1 one night? Never heard that.

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cameron12x
sage


Reged: 11/10/10

Re: Cg5 and celestron 7amps powertank new [Re: rmollise]
      #6060724 - 09/03/13 09:46 AM

Does Celestron or a 3rd party sell the necessary cable to run from a 12V battery to the mount?

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Starhawk
Space Ranger
*****

Reged: 09/16/08

Loc: Tucson, Arizona
Re: Cg5 and celestron 7amps powertank new [Re: rmollise]
      #6060751 - 09/03/13 09:58 AM

Talk to AP and that's where you're headed. From another thread it would seem they base this on cold weather performance stacked with max use, some margin, some more margin, and an allowance for battery life. They even go so far as to advise against something like a 17AH battery.

A 7AH power tank seems to work handily, and it can have it's battery replaced and return to service at half the cost of a new one. I did this with one powertank and one of the Orion version.

What I have not been able to get to work, and I don't know why, is plugging in a USB car charger to be able to run mobile stuff off of a powertank on non-astronomy nights. Insufficient battery power?

-Rich

Quote:

40 ah to run the Mach 1 one night? Never heard that.




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RTLR 12
Post Laureate
*****

Reged: 12/04/08

Loc: The Great Pacific NorthWest
Re: Cg5 and celestron 7amps powertank new [Re: Starhawk]
      #6060978 - 09/03/13 12:27 PM

Celestron makes this one...

http://www.celestron.com/astronomy/celestron-car-battery-adapter-for-all-nexs...

or youcan get these from Radio Shack...

http://www.radioshack.com/product/index.jsp?productId=3889594

Stan


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Eddgie
Postmaster
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Reged: 02/01/06

Re: Cg5 and celestron 7amps powertank new [Re: Raldo]
      #6061320 - 09/03/13 04:45 PM Attachment (4 downloads)

The CG5 draws about .35 amps when tracking, so that is not all that much.

Slewing both motors at top speed, the mount draws about .71 amps.

I use a 10 battery pack of Eneloop 2500ma rechargeable AA batteries, and I get about 3 to 4 hours of run time if I am not doing long, across the meridian slews every time.

In a normal session, I will do maybe 2 hours and maybe 30 slews, but I tend to work "Linearly" with my observing, moving short distances for each slew and this pack has never let me down.


I run my XX12G Go-To dob for about the same amount of time, and the 8SE also, so to me, it does not seem like the CG5 is less efficient than these other mounts. All will run several hours if you are efficient with your slewing.

All of them measure pretty closely on current draw, with .3 to .35 amps for tracking, and .7 to .8 amps for slewing.

I also made a cable with two 9Vdc type connectors so I can either double up my pack for over twice the run time, or I can hot-swap out... Put in a second pack in parallel to the first and pull out the first pack. The mount never stops or looses settings.

Lots of people told me that this did not work and I could only run 21minutes or something, but I had been using this and was happy enough with it as a solution. I don't observe all night though, so I would not suggest that this is a solution for marathon events.

For "Grab and Go" type observing of 2-3 hours though, it has been working quite well for me personally. I have not hooked up to a house or car battery since doing this.

With the hot swap, I could run for days if I wanted. I have a 12 position charger and the batteries charge at 1 amp, so turnaround on a pack is less than 2 hours normally, depending on how low I let the pack get. The plastic pack itself costs about $2 each ( I only have two) so you could make as many packs as you wanted, but I rarely go so long that I need to put in the second pack.

I use all rechargeables these days. The trick to making this work is use the highest quality AA pre-charged you can get. That would be Eneloop XX 2500s.

But even the Eneloop 2000s run my XX12G for a normal 2 hour session without any problem. I was out a few nights ago with the XX12 Go-To dob and did about two and a half hours on the 2000ma pack and I still had about 1/3rd capacity remaining. About 30 slews by motor. I do my across the sky slews by hand though, which of course you can't do with the CG5 or the 8SE, The motors have to run to reposition the scope. The XX12G though can be moved manually at any time to save battery. Just let go and it starts tracking again at the position you leave it. I manually slew on very long slews to about where I need to be, then Go-To for the final slew. It goes longer on a pack then the CG5, but again, most of my slews the other night were pure motor-drive Go-Tos. I only manually slew when I am moving maybe a quarter of the way across the sky.

Anyway, to answer your question, I find the run time of the CG5 to be similar to the run time of the 8SE and XX12G, so I would say that it is "typical" of mounts in this class.


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