Power Supply Question

[step_hen]

Since i mostly observe from just outside the garage door, I would like to run the mount, dew control etc from the mains socket in the garage. Obviously i'd need and RCD and some sort of PSU to give a 12V output- but which one exactly would you recommend?

Thanks

[barkis]

Hi Stephen,

I use Maplin PSU's I have 2 of the 10 Amp ones in my Obs.

Check out these and see if one is suitable for your needs.

Ron:)

http://www.maplin.co.uk/module.aspx?moduleno=231

[SteveL]

Seconded on the 10A unit (which is really rated at 7A continuous). I used one for a long time until I upgraded to something a bit bigger.

[daz]

Thirded - although I only the 5a version

[step_hen]

so do these work safely outdoors then?

[SteveL]

if you protect them from direct moisture, yes. I ran mine under a plastic box on the garden table (along with all the mains powered stuff, all protected by a RCD lead)

[step_hen]

so something like a large tupperware container with a few holes drilled for cables etc?

[daz]

Yep

[SteveL]

you have to allow SOME airflow, the power supply will get quite warm if you are pulling a heavy load. Just ensure the holes are near the bottom of the sides, or actually come in from underneath if possible.

[step_hen]

Thanks folks, sounds good. think i'll go for a 10amp PSU then, and raid the wifes cupboards for a suitable box!

[Psychobilly]

20A Ripmax Pro Peak is my Weapon of choice Beloved of the RC Racing Fraternity I use the second set of terminal to "float" a 110AH Leisure battery so that I can ride through any power problems...

Moor Models Ripmax Chargers

The £39 one handy current output digital display on the front as well and its a Switch mode design so doesn't chuck out all the heat the linears do and is a lot lighter...

Billy...

[step_hen]

Well thanks for throwing a spanner in there Peter- i had my mind made up! So what is the value in having the greater ampage? is it worth the extra cost or is 5A going to be sufficient?

[SteveL]

If you are going to be running a mount and multiple dew straps, you could easily pull at least 5A when slewing around. I still remember the horrible noises my NS8GPS made fully loaded up with the 7A unit (WO66 on top, plus telrad, dew straps on the C8/WO66/telrad) and when I slewed the mount, you could hear the PSU buzzing and struggling. Turned the dew controller off, problems went away.

Bigger should be better (all other things being equal)

[Gerrymac]

I also used the maplin PSUs, and there's no doubt that they are very good, but even with an RCB in line, it's not safe to have them outside and exposed to the risk of a rainshower. The RCB, assuming it's recently tested and working will cut the power if there's earth leakage, but even so, this is not the safe and approved way to provide external power, especially when there's 240V around. I think that this should be done with batteries or a properly designed external power supply.

If the DC cable run is not too long, the cable is of suitable guage, and because the Maplin PSU's output 13.8V, the voltage drop may not be too bad if the PSU is kept indoors and DC cable used to run to the mount.

[Tinners]

Aye. Your best bet is to keep it all indoors and just run the low voltage dc outside. The thicker the conductor in the cable you use, the less voltage you will lose at the telescope end.

The voltage drop for 5m is about about 1% for a 3mm dia conductor (@10 amps) : 2% for a 2mm Dia : 8% for 1mm Dia.

[MishMich]

Hi,

Apologies for chipping in and reviving a not-so-old thread. Recent events have led me to look at changing my power source (HEQ5 threw a wobbly with low powertank). At home, I don't need a powertank, and for off-site I have the SLT mount, which doesn't draw much power. I looked at other tanks, and various alternatives. But, I set up the scope right outside the conservatory, and the mains runs right to a socket near the door where I put the laptop, etc. So, I'm thinking an AC->12vDC converter would be best for my needs.

I could probably get away with the Maplins one for now (no dew-heaters yet). I'm not electrical - I could be, but I'm not, not with DC anyway. Also, I hate exposed connections and wires hanging around (H&S thing). So, I'm assuming I could just connect a lighter socket to the terminals (I have one, intended for Bongo-camper use which I found a different solution to), and run the HEQ5 lighter plug into? I also have a 3-lighter-socket-into-1-lighter-plug adapter I go for the Bonger. Would that be sufficient for running a couple of other bits (like the CCTV camera I use sometimes) if I need them? Or would I need to rig up some kind of mounting for a series of sockets?

I should be able to run the 12v cables into the conservatory, and keep all the 240v stuff safely indoors.

Thanks,

M.

[MishMich]

It's OK, I think I've had my answer on the thread where this came up (in connection with power tanks).

M.

[dph1nm]

Has anyone tried this sort of thing:

Anything-LED 12V 5A 60W

They seem to be for LED lights and the like, but they deliver 5A at 12V and are rated for outdoor use.

NigelM