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 Post subject: Power supply unit
PostPosted: Sun Feb 03, 2013 12:17 am 
Hi all,
I'm looking at switching to 240v to power my EQ5 GOTO mount.
I've seen the celestron/skywatcher offering or £30. http://www.scopesnskies.com/prod/astroe ... upply.html
I've read conflicting stories,
A they shouldnt be used at all
B that they're not great & I need a minimum of a 13.8v that can juice up to 5amps to ensure a regulated constant supply to save any damage to the electronics in the mount.
Can anyone confirm this or recommend a solution?
Cheers
Andy


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 7:26 am 
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Location: Bolton
Andy, when calculating your DC power-budget, don't forget to factor in the dew-heaters - they will need a few amps too on a damp night. So look for something with at least 10A capability, maybe like this:
http://www.ebay.co.uk/itm/12V-10A-DC-Transformer-Switch-Power-Supply-Adaptor-For-Multi-CCTV-Cameras-/390529677462
But if you're planning to operate it outside, get something that's waterproofed, and earthed.

However it would be safer to keep the mains indoors and use some fat (i.e. low-resistance) cables to bring the DC out to your telescope. Remember that Ohm's Law hasn't been repealed yet, so for every ohm of resistance in the cables you'll lose 1V for each 1A of current.


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 8:37 am 
Thanks for that Ross, it wasn't really what I had in mind. I was after something like a laptop charger, something robust that I could use outside. I'm not overly worrying about voltage drop as it would be outside on an extension lead.
It's worth bearing in mind for when I (eventually) get a fixed setup & for the price it's almost too good to be true.
The hunt continues!
Cheers
Andy


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 10:11 am 
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Amartin wrote:
it would be outside on an extension lead

It's never a good idea to use mains equipment designed for indoor use only out of doors.
But if you feel that you must, at least use an RCD plug and keep all the mains stuff inside one of these:
http://cpc.farnell.com/festive-lights/fl-1859-bf/dri-box-330-ip55-weatherproof-black/dp/EN82293


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 10:42 am 
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Andy Ross

Homebase were selling a similar water proof enclosure before Christmas, might be worth a look to see if there going cheep now Christmas is over


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 11:03 am 
Hi Andy,
have a look at Modern Astronomy, see 2nd one from the top in the link
http://www.modernastronomy.com/accessories.html#accPSU

As Ross has said make sure and use a RCD with it.

Ian


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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 1:34 pm 
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Location: Bury
What Ross Suggest in terms of building your own isn't a bad idea

If you over build, it gives you more options if you want to drive more than a mount, and trust me having built mine I've already reach my limits in terms of physical plugs. But I know I have the ampage to drive allot more and can expand quite easily.


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Celestron 11" Telescope
Eq6 Pro Mount
Eq5 Mount
EQ Mod
QHY5 Guide camera
Cannon 1000D SLR Camera

I choose to image with an 11" SCT Celestron in this decade and do the other things, not because they are easy, but because they are hard......
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 Post subject: Re: Power supply unit
PostPosted: Sun Feb 03, 2013 3:09 pm 
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Location: Adlington
We saw this power box at Kelling Heath a couple of years ago. It seems to have 6 switched 12v supplies and a USB hub. Not sure what the DIN plug is for.


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