Return to the Cloudy Nights Telescope Reviews home page


Telescope Specific Forums >> Celestron NexStar

Pages: 1 | 2 | (show all)
mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Running the CPC off my car battery new [Re: rigelsys]
      #6000909 - 08/01/13 01:58 AM

All true but for the small issue that all Nexstar controlled scopes/mounts use servo and not stepper motors (your comments could easily lead someone to believe the opposite). There are indeed differences between servo and stepper motors in the way they draw current when loaded down but it's probably not enough to make a difference in this discussion.

The point about scopes/mounts requiring a bit more current as they age is often true. Gears loosen up a bit with age but the lubrication does dry out and pick up dirt which causes things to tighten up. With the scopes I've been around over the past 10 years I've never seen that situation really make a big impact on the power requirements ... at least not enough to cause real obvious problems.

Nexstar hand controllers are usually fine with voltages down to around 10.5v or so. Below that and they will start to do strange things (slew to widely incorrect positions for example). Batteries usually have to be depleted well below 50% to end up with voltages below 10.5v.

AC 12v power supplies rated at 2.5amps should normally be fine for CPCs, even old ones. Celestron used to supply a 1.5amp power supply for the NexStar GPS scopes, but this often caused problems. The power supply also wasn't of very good quality and the scopes would draw enough current to cause those older power supplies to consistently run hot, which really shortened their lifespans.

The bigger electrical issue though is usually the physical connection of the power plug/socket. That problem tends to show up as a reset of the hand controller rather than just strange operations.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Gastrol
Pooh-Bah


Reged: 11/04/11

Loc: los angeles
Re: Running the CPC off my car battery new [Re: rigelsys]
      #6001805 - 08/01/13 05:56 PM

Would a 35AH golf cart or wheel chair battery be a good choice for running the CPC for several hours? I'm thinking of picking one up at Harbor Freight.
I don't take my CPC out in the field that often and I didn't want to spend $100 on a marine/deep cycle battery.


Post Extras: Print Post   Remind Me!   Notify Moderator  
David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: Running the CPC off my car battery new [Re: Gastrol]
      #6001991 - 08/01/13 07:41 PM

Quote:

Would a 35AH golf cart or wheel chair battery be a good choice for running the CPC for several hours? I'm thinking of picking one up at Harbor Freight.
I don't take my CPC out in the field that often and I didn't want to spend $100 on a marine/deep cycle battery.




These batteries (golf cart and motorized wheelchair batteries) tend to be deep-cycle, so they should work for running your scope if their voltage is right. A 35 amp-hr battery fully-charged should run your CPC scope easily for at least a full night if not a couple of nights if the battery is in decent condition. Clear skies to you.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
4 registered and 11 anonymous users are browsing this forum.

Moderator:  Brian Risley, panhard, Mitchell Duke, mayidunk 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1074

Jump to

CN Forums Home




Cloudy Nights Sponsor: Astronomics