Mains Power supply

[Abitofsense]

Hi,

Just got a Celestron CPC 800 yesterday and I want to connect the mount to the mains. Just wondering can I just use any cheap 12v 1.5A plug (that's what's in the manual) like from Amazon or eBay? Or is there a risk doing this? 

I see some people recommend system like this https://www.firstlightoptics.com/batteries-powerpacks/nevada-ps-08-6a-8a-regulated-linear-power-supply.html

Is there a reason for this over connecting a standard plug? 

Thanks

[Cornelius Varley]

A cheap 12v 1.5amp psu would probably cause the mount to operate erratically. Cheap wall mounted PSUs tend to be non regulated so that when the load is increased on the mount (slewing at fast rates) the psu might not be able to deliver sufficient volts to the mount. A regulated psu will always supply a constant voltage when the load increases whereas a non regulated psu will drop the volts when placed under load. A lot of problems associated with goto mounts are down to using an inadequate psu. Using a bigger psu such as the one in the link will ensure the mount will operate properly and it could also be used for powering dew strips etc.

 

 

 

[RayD]

Yep, totally agree with Peter.  Power supply adequacy is critical for goto.  I have one of the linked PSU's from FLO and for the money it really is excellent.

[Abitofsense]

Ok, perfect it makes sense now. I'll pick one up in maplins tomorrow. Thanks 

[Stargazer33]

Just make sure you get +ve and -ve round the right way. There isn't any reverse polarity protection on mount PCBs.

[Cosmic Geoff]

Power supplies are a regular topic on this forum. The requirements of the mounts don't vary much, other than that the bigger and heavier mounts require a bit more current capacity than the small ones. They all need a regulated mains supply of adequate rating, or a battery of the right voltage that is of adequate capacity for the job, which will depend on whether you are powering just the mount, or an array of dew heaters, laptops etc as well, and how long you can tolerate standing around in the cold.

Be aware that AC mains voltage is potentially lethal, and if you are sufficiently careless you can kill yourself or a member of your family.  All mains equipment should be kept dry, protected from damage and preferably protected by an ELCB.

If you buy a cheap mains PSU, should it fail there is no guarantee that it won't take your expensive mount electronics with it.

If in doubt, it is wise to err on the side of more current capacity rather than less. It is also necessary to ensure that the power plug connection is secure and restrained so that it cannot pull out or wiggle around as the mount moves. And that the DC connection is the right way round.

[PeterCPC]

I would recommend fitting an external RCD box to connect up to rather than just relying on an in-line RCD. Something like this

Also put a cover over the connections - like a plastic box - to stop dew forming.

Peter

[Geoff Lister]

I have used, without any problems, a selection of 12V 1.5A & 2A plug-top supplies on my Skywatcher Skymax 127 Mak, Heritage 90P Virtuoso, & Skyliner 250PX Dob, and Celestron Skyprodigy 70 & Cosmos 90 WiFi. The ones sold to go with the 12V LED, flexible, stick-on, strips, are easily available, on eBay, from China. Before using, I check polarity & voltage, but, so far, I have not found any duds. They use switch-mode circuitry, run cool, and seem to have good voltage stability. 

I have found it useful to extend the 12V cable with a couple of metres of stout, white, bell-flex. This avoids cord-wrap, and shows up better, than the standard black, in the dark. I usually add a little plastic clip to the rotating part of the mount; this acts as a strain-relief for the lead, and stops it trying to pull the plug out of the mount's socket.

To avoid dew problems, as mentioned by Peter, above; I use a mains extension lead with the plug-top supply, and mains socket end of the extension lead, in an old shoe box.