Power supply to goto's

hotspur (Chris) · #1 12-09-2010, 09:47 AM

Hi Folks.

I have a 'powertec' power supply unit,its a very elite DC unit from mains power.

It has 0-24 volts,and up to 3 amps,it has digital displays and fine and course settings,it can power 2 items at once-it has individual settings and display for each item.it cost me $400,I used it power antique train set.

But no longer use it for that,I am wondering could I use this for my goto mount and dew heater as my batteries die in the observatory-leaving them in cold is one of the best ways to shorten their lives-so I am told.

If I put this power supply unit in a cupboard in observatory,and set voltage to 12 volts DC,and put cables under carpet to goto and dew heater,It should be fine?

Is there any cavets here?,the cable to goto has a fuse in it.I will try and post a pic of this unit,its vVERY heavy,and I would never be able to sell it.

So hopping to use it in another hobby like astronomy.

Any advice would be great thank you.http://www.iceinspace.com.au/forum/s...ad.php?t=65158

Chris PS here is a link to photos of the unit

BlackWidow (Mardy) · #2 12-09-2010, 01:17 PM

Hi Chris... I am no expert on Astronomy, but do have a bit to do with electronics so I think I can help. This power supply would be perfect for your scope. As these power supplies were often used as a lab supply they have very stable voltage supply once selected. Also the Amp rating is hight and more than enough to supply your scope and heaters. Goto Scope use very low current to help with battery life. You will get good clean supply with you power supply and all will be good...

Cheers
Mardy

rally · #3 12-09-2010, 01:50 PM

Chris,

If the output is only 3 amps I suggest you work out the maximum current draw of your gear first.

3 amps is not a lot to spread across many devices, especially at peak load
Thats only 36 watts at 12v.
Some dew heaters can draw more than that depending on their size and how many straps you are using.
So add up the mounts power, heater power and see what you get.

However why not use the unit to trickle charge your battery when its in use if you have 240v power available ? - that way the battery wont go flat in the first place.

Rally

hotspur (Chris) · #4 12-09-2010, 01:54 PM

Thanks Mardy.

Yes,this power supply unit is the type that would be found in a scientific lab or technicians workshop.It would be highly calibrated to give a good clean power.It was certainly very expensive-but looks and sounds like I will be able to put it to good use in my observatory.

Cheers Chris

Louwai (Bryan) · #5 12-09-2010, 03:50 PM

Sunds like a perfect unit Chris, but i agree with Rally. 3 amps is not huge & so you'd need to check your total peak demand.

My go-to with heaters & motor focus has a peak demand of about 4.5amps.
My Kendrick heatr ctrlr has a built in 5amp fuse.

I have a 7.5amp main fuse & when I plug the lappy in as well I blow the main fuse.

The old girl draws a bit.

B

hotspur (Chris) · #6 12-09-2010, 05:00 PM

I think some of you may have miss read info,the PSU I have has two different units in the one case-see photos in link.

I can operate two items individually.i.e they will not affect each other,that is

one item can be set to 15 volt DC draw up to 3 amps,another to 8 volts DC

So I imagine I can set one to 12 volts for SS2K and it draws the amps it needs,and the other to 12 volts for dew heater-largest strip heat is for a 4 inch refractor the other 1and 1/4 inch for eye piece,I am no electronic whiz,but I feel this unit should be able to cope with this.

I currently use 2 5 year old second hand 12 volt 7 amp batteries which are almost cactus,for the above two items,one battery each.I will do some checking

michaellxv (Michael) · #7 12-09-2010, 05:20 PM

Does the 3 Amps equate to a 3A fuse on your 240V supply line i.e. roughly 720watts?
Or is it 3 Amps on the output at whatever voltage you select?

BlackWidow (Mardy) · #8 12-09-2010, 05:39 PM

Hello again Chris. As I mention in my first post this power supply is ideal for your needs. In all situations you can exceed the output by adding too many items. However I have a Meade LX200 and use a stip dew heater on mine. I just tested its draw with my multi meter and it only draws 0.49 MA.. Very Very Low for the heater only. Not sure what the scope draws, but it would be in the MA Range. You will have plenty of current for your current needs. I would not use the power supply as a charger for batts as it will charge too fast and will not stop once charged. Most Gel cells batts are best charge with a special logic chargers that can be purchased for around $40 at Jaycar Electrical. they also condition the battery and stop plate build up...

Nice talking with you

Mardy

hotspur (Chris) · #9 12-09-2010, 07:10 PM

Hi Michael.it is up to 3 amps to whatever voltage I set,i.e most of the old trains are 12 volts,but draw different amps-some .5 some 1.5

I looked at specs in SS2K manual it said 12 volts and 2 amps or more,thats all it said.

Thanks Mardy for advice-nice avatar pic you have,can you post that pic in terstrial items,it looks interesting.

regards Chris

BlackWidow (Mardy) · #10 12-09-2010, 08:24 PM

I did notice Chris that you also have an Aviation Avitar... I have been a pilot since about 18 years of age. I did not have the money to keep up the sport, so a few years ago I invested in sports aviation and purhchased a Microlight. Love flying it as well as the odd flight in 3 axis sports aircraft...

You can get a better look at my aircraft on my Youtube video when I took up my brother In Law after 3 years of trying to advise him that he was not going to die

Here is the link if you would like to have a look http://www.youtube.com/watch?v=TL7MGfO2PYY

regards
Mardy

hotspur (Chris) · #11 13-09-2010, 11:43 AM

Great video clip Mardy!

I liked the beginning-take off,

does look a bit scary!-I thought a Cessena 172 was scary,but that looks more so!

Still I would be keen to try.

cheers Chris