12v Cigarette power lead for cooling camera

[Andyb90]

Hi Everyone, 

I've just bought an asi1600mm cool camera. It has a 2.1mm 12v dc input. The spec says 2A max.

If anyone has recently bought a good quality cable of this spec and could provide a link that would be great. I'm looking for one about 2m in length.

Also this may be a silly question and forgive my ignorance here, some cables are listed as 3a, 5a etc. Is that just the fuse inside the cigarette plug? Could I use one of those cables, if I just replaced the fuse with a 2A one?

Andy.

[Uplooker]

Its the voltage you need to pay attention to.Any appliance will just draw the current that it requires, depending on what it happens to be doing at the time.

If something says 2A you are best to fit a 3A fuse as you may get slight spikes and would end up replacing the fuse every 5 mins.

You also say that the asi1600mm has a 2.1mm 12v dc input, you need to know if it is tip +ve or not. Others with the same camera on here should be able to confirm that.

Tip +ve means that the end / hollow bit is +ve and the "outer" part is -ve.

What are you going to run the camera from - mains or leisure battery?

Have a look at FLO for cables etc. or contact them

https://www.firstlightoptics.com/astronomy-cables-leads-accessories/skytron-power-supply-cable-skywatcher-eq3-2-eq5-heq5-eq6-series-mounts.html

 

[Andyb90]

1 hour ago, Uplooker said:

Its the voltage you need to pay attention to.Any appliance will just draw the current that it requires, depending on what it happens to be doing at the time.

If something says 2A you are best to fit a 3A fuse as you may get slight spikes and would end up replacing the fuse every 5 mins.

You also say that the asi1600mm has a 2.1mm 12v dc input, you need to know if it is tip +ve or not. Others with the same camera on here should be able to confirm that.

Tip +ve means that the end / hollow bit is +ve and the "outer" part is -ve.

What are you antingto run the camera from - mains or leisure battery?

I'll use a 3 amp fuse then. The input on the camera is stated as center positive on the specs. The camera has these symbols on the back.

Does that mean the Skywatcher cable would be okay ?

I'll be using a tracer battery for power with a female cigarette type socket.

Andy.

[SonnyE]

It sez in the manual up to a 3 amp supply is recommended.

http://astronomy-imaging-camera.com/manuals/ASI1600 Manual.pdf

See Page 10.

If in doubt, consult ASI to be sure.

Bear in mind that the fuse is to protect the wiring, not the device being fed. If a device (Camera, Mount, etc.) blows the fuse. It usually has a serious problem and should be a warranty return.

[Sargs]

On 16/09/2016 at 22:18, Andyb90 said:

I'll use a 3 amp fuse then. The input on the camera is stated as center positive on the specs. The camera has these symbols on the back.

Does that mean the Skywatcher cable would be okay ?

I'll be using a tracer battery for power with a female cigarette type socket.

Andy.

Yes, that's a centre positive connector and I reckon the cable will work well for you. I've an ASI1600mc and use the same Skytron cable- technically mine was for a Nexstar 6se, but I've also used it to run a SkyWatcher NEQ6 and an Atik One 6.0. Connector size is same for all the above- 5.5mm outer, 2.1mm centre, tip-positive, and a 3A fuse will do the job. I suspect the SkyTron cables with this tip are really all the same cable (note they're the same specs and price) but are labelled separately to reassure people that they're getting the right cable for their mount. Good bit of wire- I'll certainly buy another if I ever manage to kill this one; I've had it four years and it's still going strong!

 

 

[Tiny Small]

The fuse doesn't protect the camera. It's there incase the camera goes wrong and spikes the circuit. It stops the camera from ruining anything else that's plugged in to the same circuit. All my other bits of equipment have fuses in the cables but I didn't bother fitting one to my camera cooler. I would suggest if you want to fuse it, use a 5 amp fuse as the cooler can draw up to 3 amps, as suggested above. Why not make your own cables? I use euro sockets for everything. Far better than the fag lighter sockets: http://www.ebay.co.uk/itm/like/201474523572?lpid=122&chn=ps&adgroupid=27378760866&rlsatarget=pla-181484359986&adtype=pla&poi=&googleloc=1006976&device=c&campaignid=620865095&crdt=0

[Gina]

Never use a connector that's meant for mains use for low voltage circuits!!  You are asking for serious trouble if you do and anyone can get confused.  In fact you risk your life .   There are plenty of very good connectors recommended for low voltage power supplies.

[Tiny Small]

10 hours ago, Gina said:

Never use a connector that's meant for mains use for low voltage circuits!!  You are asking for serious trouble if you do and anyone can get confused.  In fact you risk your life .   There are plenty of very good connectors recommended for low voltage power supplies.

The earth connection is removed and it's connected directly to a 12 volt regulated power supply permenantly. Its just a plastic plug with two connectors inside, exactly like a cigarette lighter but doesn't fall out. 

[Andyb90]

I ended up getting one of these 3m Skywatcher/Celestron cables:

http://www.rothervalleyoptics.co.uk/rother-valley-optics-power-cables.html

It looks to be a good quality cable.

I put a 3 amp fuse in and connect it to a tracer battery via a hub.

That's okay isn't it?

Andy.

[Tiny Small]

11 hours ago, Gina said:

Never use a connector that's meant for mains use for low voltage circuits!!  You are asking for serious trouble if you do and anyone can get confused.  In fact you risk your life .   There are plenty of very good connectors recommended for low voltage power supplies.

I should add that I'm not using mains wiring either. I'm using 16 gauge wire which over the distance I'm operating (50 feet), delivers (IIRC) 10 amps at 12 volts, which is a couple of amps over what my entire system draws at maximum.

8 minutes ago, Andyb90 said:

I ended up getting one of these 3m Skywatcher/Celestron cables:

http://www.rothervalleyoptics.co.uk/rother-valley-optics-power-cables.html

It looks to be a good quality cable.

I put a 3 amp fuse in and connect it to a tracer battery via a hub.

That's okay isn't it?

Andy.

Yes. That will be fine so long as you don't run the cooler at maximum. Not that you would if you're following a sensible cooling and warming cycle. Fuses are not as accurate as you would think so it's always best to be slightly over what you need. The manual for the camera says it can draw up to 3 amps so I would have gone with a 5 amp fuse, however, when I run the cooler on my 178 (same rating), even on a fairly quick cooling cycle, it never goes above about 60% so if you take it steady, you may be fine. But if the fuse goes pop, put a 5 amp one in there as a replacement.

[RayD]

220v mains AC is low voltage and 12v DC is classified as ELV (extra low voltage).  The problem with using connectors such as kettle type (Euro) is that they disconnect + and - at the same time when unplugged, which on DC circuits, particularly if disconnected whilst on load, can draw a significant arc across the contacts, which technically could raise the risk of fire, which is unlikely at these low loads, but most likely could cause damage your equipment.  Well designed DC specific plugs and sockets are typically designed such that + or - is removed sequentially (look at the design of cigar sockets).

There are plenty of connectors which are designed for both AC and DC circuits, so worth having a look for what suits your needs, but I personally wouldn't use Euro plugs (kettle) on DC supplies as they are generally designed for use on AC supplies, although it is perfectly feasible that there are DC specific ones available.

[Andyb90]

1 hour ago, Tiny Small said:

Yes. That will be fine so long as you don't run the cooler at maximum. Not that you would if you're following a sensible cooling and warming cycle. Fuses are not as accurate as you would think so it's always best to be slightly over what you need. The manual for the camera says it can draw up to 3 amps so I would have gone with a 5 amp fuse, however, when I run the cooler on my 178 (same rating), even on a fairly quick cooling cycle, it never goes above about 60% so if you take it steady, you may be fine. But if the fuse goes pop, put a 5 amp one in there as a replacement.

I'm using SGP for camera control and see the TEC Power Level is displayed next to the current temperature so I'll keep an eye on it to ensure I'm not running too close to max.

Andy.

[Tiny Small]

1 hour ago, RayD said:

220v mains AC is low voltage and 12v DC is classified as ELV (extra low voltage).  The problem with using connectors such as kettle type (Euro) is that they disconnect + and - at the same time when unplugged, which on DC circuits, particularly if disconnected whilst on load, can draw a significant arc across the contacts, which technically could raise the risk of fire, which is unlikely at these low loads, but most likely could cause damage your equipment.  Well designed DC specific plugs and sockets are typically designed such that + or - is removed sequentially (look at the design of cigar sockets).

There are plenty of connectors which are designed for both AC and DC circuits, so worth having a look for what suits your needs, but I personally wouldn't use Euro plugs (kettle) on DC supplies as they are generally designed for use on AC supplies, although it is perfectly feasible that there are DC specific ones available.

Thanks for the explanation. You learn something new every day. I did wonder what the issue might have been.

I very rarely disconnect anything though and whenever I go near any of it, it's always turned off at the mains first (power to the PSU) and if I'm turning stuff on, it's always all plugged in before turning the power on. I never connect or disconnect anything from a live circuit. But it's certainly something to think about next time I decide to improve the system.

[hughgilhespie]

Hi,

Just a teensy bit of physics. When you break a DC connection, it doesn't really matter which 'pole' disconnects first. As soon as the contact is broken one side becomes the positive pole and the other becomes the negative. You will always get some amount of arcing - as indeed you do with AC unless you happen to break the connection at the exact moment when the alternating voltage is at zero. Contact arcing is not much of a problem provided that the connection is broken quickly enough and the contacts moved a sufficient distance apart.

There is a potential problem with using AC connectors for DC signal connections when the DC signal is small and very low current. Connectors (and switches) designed for power use usually need a MINIMUM current flow to operate reliably. This is known as the wetting current. Very low power circuits should always use connectors and switches that are suitable. I think this means they will be using gold plated contacts.

Regards, Hugh

[RayD]

44 minutes ago, hughgilhespie said:

Very low power circuits should always use connectors and switches that are suitable.

All circuits should use connectors that are suitable.