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GM 8 power supply

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#1 SkyRanger

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Posted 02 February 2011 - 08:34 AM

I just traded my Tak 76 for a TV102 and bought a used GM8, which is coming shortly. I will use it mostly where I can run an extension cord to AC, but wondering if a 12V "power tank" might be more convenient. I will be visual only.
Have you felt the need for the Losmandy regulated power supply for visual use or has a 12 power tank been all that you need? I will be using the scope for public star parties and the absence of long power cords is an advantage.

Thanks,

Gordon

#2 hudson_yak

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Posted 02 February 2011 - 08:55 AM

I only have first-hand experience with the non-Gemini version. Any 12V power tank will work fine with those.

And yes, it'll be much more convenient.

Mike

#3 Eddgie

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Posted 02 February 2011 - 09:09 AM

These scopes draw VERY little current. A big battery pack is overkill. Max draw is only 500 milliamps, and when tracking, probably only a couple hundred ma.

What this means is that you can run it off of a small battery pack using rechargable AA batteries, or a small battery like used for home alarms and the mount will run all night.

So, unless you are running other equipment, the power tank is overkill.

My own experience with power tanks (I have had two) is that the batteries only seem to last a couple of years.

They are also bulky.

For my non-Go-To mounts, I usually prefer to run them off of small battteries or battery packs because they are far more compact, cheaper, and I can just recycle the batteries when they die rather than tossing the big power tank.

Something like this: http://www.google.co...d=0CIUBEPICMAA#

Or this. You can buy a small charger, and you can make a custom cable that just clips on: http://www.buy.com/p.../208713948.html

#4 SkyRanger

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Posted 02 February 2011 - 09:20 AM

Just what I needed to know!

My GM8 has encoders installed. I have access to a Sky Commander which I want to try to see if I want a "push to" system.

Looks like I have no need for an expensive power supply!

Thanks,
Gordon

#5 Dave M

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Posted 02 February 2011 - 09:45 AM

No need to buy the expensive one from Losmandy, you can get
the same exact thing from many places on the net.
I use one to run my G11..
For example you can get one here, shipped for $33
http://tinyurl.com/4lnabob

#6 Eddgie

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Posted 02 February 2011 - 01:17 PM

Well, the Sky Commander runs off of its own battery which resides in the Controller, so again, you udon't need a power tank to run that either.

A home alarm backup battery will run the scope for a long time.

Heck, I had a freind that used to run his Meade LX90 off of a home alarm backup battery. Would easily run the scope a couple of hours unless he was slewing.

Even my Meade LXD-750 only draws 400ma when ticking over. It is the slewing that sucks current.

One of the really nice things about mounts like the GM8 and C11.

I have often thought of going back to a Ci700 for my 6" APO. I had a DSC on it, and push to was fine for my use. Fast and Quiet. Mount would run for hours off of AA battery pack.

So, a battery pack will do you.

#7 Richard McC

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Posted 03 February 2011 - 01:07 AM

The Sky Commander can also use external power (it draws vanishingly little current). I power my GM8 mount and Sky Commander unit with a 12V sealed battery.

#8 Lew Chilton

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Posted 03 February 2011 - 06:40 PM

I've used a GM-8 (digital drive version) since 2003. The Losmandy 13.8VDC regulated power supply is the exact same one that was/is sold at Radio Shack for less.

I also have used the Celestron 12V/7AH Powertank for visual use since 2003 and have never been let down at a star party. (But I finally did replace the Powertank's battery a year or two ago with an identically spec-'ed one from a local hobby shop, and it only cost $18.)

#9 SkyRanger

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Posted 03 February 2011 - 08:24 PM

Thanks for all the suggestions. I will definitely go for a cheaper power supply option!

Gordon






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