A suitable U.K. mains to 12V DC supply to run my various equipment

[choochoo_baloo]

Hello all,

As per the title I am unsure about what type of mains to 12V DC power supply to look for to run my astrophotographic gear on my garden pier. I ask because I have been getting some conflicting advice. I will be running 3 things from the supply:

Mount, rated 3.5 A

DSLR's 12V power supply in place of the Canon battery, rated 1.5 A
Focuser, rated 1 A

Thus maximum current draw would be 3.5 + 1.5 + 1.0 = 6.0 A. However virtually every sensibly priced power supply I find for the amateur astronomy market is rated at 5.0 A. So I'd like to ask what types of power supply other astroimagers use for mains running.

Thanks in advance.

[Bubbles82]

I was recommended this it 13.8v, 200 watts and upto 15 amps it's available several places online about£38. I have tested it with my mount and dew bands and it wasn't even close to the amps it can deliver

[damnut]

Hi There,

Maplins have a number of 12v psu's http://www.maplin.co.uk/p/moonraker-375w-switched-mode-dc-variable-voltage-compact-bench-power-supply-n87jn

[Tinker1947]

The Fusion Twin PSU's work ok but do have a fan running 24/7 they come is various sizes 

[SnakeyJ]

Linear or switched >

[Astroboffin]

Linear or switched >

Should always go for linear, for astro gear in my opinion

The Fusion one shown above is the one I use and find it superb, it does have a fan running, but for my set up being on a pier and the power runs underground from the fusion transformer which is in my warm room in the garage,so,the noise from the fan is not an issue, it is around 8m away and drops from 13.8v in warm room to 13.2v at the pier, so no problem at all.

They can be bought for as little as £35 have a look here where I bought mine from

http://www.tantronics.co.uk/acatalog/fusion_15A_13.8V_200W_Bench_Top_Power_Supply_Twin_Output_PS200T.html

Regards

AB

[choochoo_baloo]

Should always go for linear, for astro gear in my opinion

The Fusion one shown above is the one I use and find it superb, it does have a fan running, but for my set up being on a pier and the power runs underground from the fusion transformer which is in my warm room in the garage,so,the noise from the fan is not an issue, it is around 8m away and drops from 13.8v in warm room to 13.2v at the pier, so no problem at all.

They can be bought for as little as £35 have a look here where I bought mine from

http://www.tantronics.co.uk/acatalog/fusion_15A_13.8V_200W_Bench_Top_Power_Supply_Twin_Output_PS200T.html

Regards

AB

Can you explain to me what the advantages of switched vs linear are please, and also what these descriptions physically mean!

[Astroboffin]

Hi,

A switched supply, or a PWM supply (pulse with modulation) is basically the voltage is supplied by switching the power supply on and off very fast, so for example if you have a 12v supply coming in and you want 6v coming out, then the power supply will switch on and off equally 50% on and 50% off this will give 6v overall. The on's and off's will be equal in length.

If you wanted 3v output then it would have to be switched off 3/4 of the time and on for 1/4 of the time,

So, the on's will be shorter than the off's, these switches are extremely fast and not noticeable, but will reduce the voltage accordingly, and work very well for the right applications, such as dew controllers where you need to adjust the voltage to make the dew strap warmer or cooler.

The down side for astro imaging is that you can get a lot of radio frequency interference from them which can play havoc with your kit, especially cameras and thing with data cables, they can get corrupted by the interference. You can help them a little by fitting ferrite beads to all your cables, these just clip on the cable near to either end, and can help a lot with RF interference. When you but a good quality USB cable you will have what looks like a bulge in the cable at one or both ends, these are ferrite beads to help stop RF interference.

The linear supplys, supply a constant voltage, by the use of electronics to lower the incoming voltage to whatever is needed, this voltage is then constant with hardly any interference, and so in my opinion much better for astro kit, others may not agree, some others may, it may be a personal thing.

Hope,that helps explain a little , I am by no means an expert with electronics, and someone may be able to explain a little better than me as to the differences.

Regards

AB

[Demon Barber]

Hi All  i have used these for 5years with no problems:http://www.rapidonline.com/electrical-power/rapid-smps-25a-40a-65063 

hope this helps,i run my entire obsy from this and have not had any supply problems.

Regards

Mike

[choochoo_baloo]

Thanks all for the suggestions and information.

[Physopto]

I would go for a battery and charger. No problems with blackouts or brownouts.

If possible a LiFePo battery! But costs are high then.

Derek