Mains power supply for dew bands?

[Swoop1]

Hi all,

I am exploring what I need to get to power some dew bands I am going to get soon.

All dew controllers I have found so far are powered through a cigarrette lighter plug. Is there anyone out there who does a controller that is powered from the mains?

If not, can anyone recommend a power supply that isn't going to go all sparky on me when I use it outside? My set up is currently temporary and everything runs off an extension lead plugged into an outdoor socket. I am thinking something like this that won't complain because it isn't mounted in a nice, dry, cosy obsy.

Thanks

[Budgie1]

How about one of THESE (there's a 5 amp version as well) stored in a Dri-Box?

[pete_l]

6 hours ago, Swoop1 said:

I am thinking something like this that won't complain because it isn't mounted in a nice, dry, cosy obsy.

Even that has a standard domestic "kettle socket" supplying it with mains power. So it isn't rated for outside use.

[fifeskies]

If all you are powering is dew bands the supply can happily live indoors and use a long 2 core cable from the 12v outlets to the dew bands. There will be a small voltage drop over a long cable but this will not significantly affect the dew bands. I would use as a minimum 2 x 0.75mm cables unless you have a very long distance to go (over 50m).

0.75mm is about 1.5 ohms for the return loop if all 50m is used

 

So with a 25m cable (0.75 ohms loop) and  with say 2 dew bands at 1 amp each (about 4 inch OTA size) the voltage drop at full power is around 1.5 volts , which will only drop the heating by a small amount and is likely to be around the usual setting in any case

(dew heaters rarely get used at full output , normally dialled down a bit with a controller)

With a 13.8 style power supply , you actually hit around 12v at the scope end with this type of load so its a perfect match.

There is enough spare capacity for powering a handy red led lamp as well.

You can easily make a small splitter box in a hobby case for multiple 12 v outlets.

 

A reel of 2 x 0.75mm cable is relatively cheap purchased online , 50m PVC is about £13 , or the better option of rubber cable is £25 for 50m.

 

NOTE   If you are using this for powering your mount , this will not work as well , the high current draw when slewing will drop the voltage too far , you could overcome this by using far thicker cable  (eg 1.5mm2) , but the cost rises significantly

[SimM]

On 17/12/2020 at 03:26, pete_l said:

Even that has a standard domestic "kettle socket" supplying it with mains power. So it isn't rated for outside use.

If you are going to put a PSU in a drybox, then it makes sense to put all the mains plugs and sockets in the drybox as well e.g. no point in the PSU being dry if the plug is in an extension reel that is outside.

Edited December 21, 2020 by SimM

[Swoop1]

I just found this power supply on RVO- 8 amps output and a splitter to a cigarette lighter kack included. Might fulfil my needs.