Can you power a ATik camera and FW from a 17A, 12V battery?

[kirkster501]

^^

I have two such batteries. My thoughts were to power my mount from one and the camera stuff from the other. Any thoughts regarding that please? Does this Atik kit come with 12V cigar plug?

Thanks, Steve

[andyo]

^^

I have two such batteries. My thoughts were to power my mount from one and the camera stuff from the other. Any thoughts regarding that please? Does this Atik kit come with 12V cigar plug?

Thanks, Steve

Yes the Atik comes with a 12v cigar plug.The Atik 314L+ uses 0.8amps and the EFW2 uses 0.3 amps so I would imagine the batteries would be ok.

[Merlin66]

Yes,

I do it all the time.

20Ah gel cell batteries.....

[kirkster501]

Any sort of fusing required guys or just plug in and go? A fag plug seems somewhat inappropriate with a £2000 camera hanging off it!

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[andyo]

Any sort of fusing required guys or just plug in and go? A fag plug seems somewhat inappropriate with a £2000 camera hanging off it!

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The fuse is in the gigar plug.Oh a massive yes to do I think a cig plug is inappropriate I really don't like them the connection is poor and is always prone to any bump or knock but this type of connection seems to be almost universal for many astrophotography items surely a din type connection would be better.However I use cig connections myself because the equipment Ive bought adopts them anyway I feel a rant coming on so enough said

[Gina]

Yes, you definitely need fuses - those batteries can pack a fair old punch and could set fire to something if you get a short - or blow up expensive equipment. I can't stand those horrible cig plugs and never use them. I use standard XLR connectors. They're professional connectors and very reliable.

[NickK]

I power my whole lot from a 100Ah 12V Bosch S5 battery!

I switched to a set of these connections: http://www.maplin.co.uk/4-pole-speakon-connector-1389 and now it's just push in and twist lock. They're rated at 250V 40A. When you twist them they will electrically disconnect before they physically disconnect.

[kirkster501]

Thanks for your thoughts guys.

How would the waranty work on that? You get a new Atik 314 or 460, chop the cigar plug off and attach/solder on a new type of power plug? Hmmm, how would a warranty claim made to Atik be construed if you did that?

EDIT - spelling

[bluedandelion]

Except for the 383L+. Get a DC-DC regulated power supply for this one. It is very finicky about voltage drops below 12 vots and the nouse wil render your subs unusable. I set my regulated sypply at 12.8V

Ajay

[DrRobin]

Hi,

I power my Atik16 from a small sealed leaf acid battery, works just fine. Batteries have a very low impedance and therefore under fault conditions can deliver very large currents, so you should always fit a fuse. It is a common misconception that the fuse is there to protect the equipment, it isn't. The fuses only job is to protect the wiring, mostly against short circuit.

Electronics, if they go wrong will go bang long before a fuse blows, the fuse will blow to stop the wiring/device from catching fire, but that is about all.

Having spent all my life designing electronic circuits (and a fair few power supplies) you will always be better powering sensitive electronics from a properly rated battery, it is the quietest thing around. A switch mode PSU or DC to DC converter is always going to be noisy in comparison and depending on how smooth the output and how much smoothing there is in the camera power supply, you may or may not get a problem. The other potential problem of a power supply or DC to DC converter is the prospect of it going wrong and stuffing 20+ volts in to your camera, something that can never happen with a battery.

I have ciggy plug and multiway block, but the plugs have a little locking collar and hen this is slid down, they never pull out by mistake and I have never had a problem with them. The little DC plug that plugs in to the equipment is even more susceptible to fall out than a ciggy plug.

Robin

[Gina]

I protect my expensive equipment against PSU failure with an overvoltage crowbar and fuse.

[DrRobin]

Yes, that will do it Gina. I used to design those as well when I worked for a company making standby power systems.

Robin

[kirkster501]

Is there an adapter that allows you to power the EFW2/CCD from one car battery plug? Sure, could do this with a 12v car plug doubler but I'd like the "Y" closer to the camera to keep the number of long leads down a bit.

[ollypenrice]

I think the warranty would work provided there were no evidence of an incorrect power supply having caused the problem. Atik's manual describes the power supply required by the camera. It is not mandatory to feed this supply in via a cigar lighter socket. (The larger Atik cameras come with mains power supplies.) Cigar sockets, as others have been quick to point out, are not suitable for astronomical purposes because the connections are far too tenuous and the loss of time arising from a momentary glitch doesn't bear thinking about.

I'm not sure about sharing a cable between the EFW and the camera. We need an electronics expert. It is quite a nice idea, certainly, if it had no implications for the continuity of supply to the camera. Maybe a question to the Atik helpline? (It strikes me that the EFW only draws current when the camera isn't imaging, unless you are after DJ-style special effects by slurring from one filter to the next during an exposure!! )

Olly

[DrRobin]

Hi,

I don't think there would be a problem with a Y cable, the only things to consider are the following:

1) The cable is of sufficient cross sectional area, important for the common cable;

2) The filter wheel doesn't put excessive noise back on to the cable.

When you run two devices like this on the end of a single cable, if one of the devices is noisy then it tends to inject noise back in to the cable and the other device. If they have their own cable then the noise is sent back to the power supply/battery where it is absorbed. I suspect a filter wheel and a camera would be fine from a single cable, the filter wheel draws the most amount of power when it is moving and at that point the camera isn't taking any pictures, so it doesn't look like it would be a problem.

Robin

[DrRobin]

Hi,

Something like this would do the trick.

http://www.ebay.co.uk/itm/CCTV-2-way-Power-Splitter-12V-DC-2-1mm-/170824868889?pt=UK_CCTV&hash=item27c5f4a419

Robin

[bluedandelion]

A switch mode PSU or DC to DC converter is always going to be noisy in comparison and depending on how smooth the output and how much smoothing there is in the camera power supply, you may or may not get a problem. The other potential problem of a power supply or DC to DC converter is the prospect of it going wrong and stuffing 20+ volts in to your camera, something that can never happen with a battery.

I was being specific about a particular model of Atik - the 383L+. Not all their cameras are built alike. See these links ...

http://www.atik-cameras.com/forum/index.php?topic=126.0

http://www.cloudynights.com/ubbthreads/showflat.php/Number/5332810

http://stargazerslounge.com/topic/154063-powering-a-atik-383l-and-keeping-noise-away/

I have personally lost several hours worth of subs from trips to dark sky sites. The solution is either an AC-DC or DC-DC regualated supply that consistently keeps the voltage above 12 V. Most people have found that keeping the voltage somewhat above 12 V works best with the 383L+. Lead acid batteries do not provide a steeady voltage in cold weather or under load. WIth the DC-DC regulated supply, the camera is a dream to use.

I've also got to ask thie following question. Several manufacturers provide AC-DC regulated supplies or built in voltage regulation with their cameras. If regulated supples are dangerous, why woud they do that?

Ajay

[DrRobin]

Hi,

If you use a DC-DC converter or switch mode AC-DC converter then I would recommend fitting a 'crow bar' device like Gina. The failure mode on a switcher can send excess voltage in to the load if the feedback circuit in the power supply fails. An even better solution would be to float charge a battery. Use a battery of say 18Ahr and float charge at say 10%, that way the voltage will be about 13.8V. The capacity of the battery will ensure that you never go much higher and will provide fantastic smoothing. You also have the advantage that if you loose the mains, the battery keeps the load powered.

The assumption that [sealed] Lead Acid batteries do not provide a steady voltage in cold weather is not quite accurate, the capacity at low temperature is reduced as is the peak output current. Therefore the battery appears to discharge faster at low temperatures for the same load and hence the terminal voltage does decrease slightly, but it is very minimal. Most SLAs are quoted for operation at 20C, but manufacturers show data down to -20C and some down to -40C.

Further the assumption that battery voltage goes down as a function of load is also misleading. Battery terminal voltage stays fairly constant for a range of loads for over 70% of the rated capacity, there is a slight drop in voltage, but you are talking about a fraction of a volt for loads varying from 5% up to 50% of the recommended load. Of course at higher loads the battery will discharge faster and once you discharge over 70% of capacity you will see a voltage reduction.

You are probably more likely to see a volt drop in the cables used to power your camera/dew heater than you are in the battery voltage.

Finally, why are the regulators built in to cameras safe? The designer of the camera spent quite a lot of time designing and testing the complete design, they test under a range of conditions before they can certify and release a camera and are prepared to back this up with a warranty. The designer of the £9.99 PSU you bought from Ebay didn't know what you were going to use it for or the temperature range and therefore couldn't put all that design effort and testing in to the product combination, that is why the total solution from the manufacturer is safe and when an individual puts the solution together they taken on some of that responsibility.

Robin

[Gina]

I'm running all my kit except the mount off a PC PSU (with overvoltage crowbar and fuse) and about 4-5m of 6A cable and with the 460EX camera on I'm seeing noise lines from the Lodestar that I've never had before. It could be the extra current (though it's alright with two 314L+ cameras on at the same time) or it could be that the 460 is passing interference to the Lodestar through the common USB hub. It doesn't cause any problems though. I'll do some checking with digital multimeter and hand held oscilloscope.

Running off a battery with mains charging seems a good idea.

[DrRobin]

Knowing that you use XLR connectors, they should be okay with the current and I doubt that a 460 takes significantly more current than a 314L at 12V, so noise on the power leads might well be the answer. Have a look with your scope, close to the camera (if you can). If it is noise on the USB, then it must be on the USB power lines, is your Lodestar USB powered, I think they are? Have a look on the 5V on the USB, again with the scope. I am guessing your USB hub is powered by the same 12V?

I am not sure if a 460 draws any current from the USB, it might for the camera part, only using the 12V for the cooling, whereas the 314L might draw all it's power from 12V, might be worth checking the specs on the 460, if they detail it.

I reckon your big problem (tongue in cheek) though is just too many cameras and you should flog one of your 314Ls to me.

Robin

[Gina]

Thanks for your reply Robin Yes, the Lodestar is USB powered. The USB hub is powered from the 5v o/p from the PC PSU.

I suppose £800 or £900 might secure one of my 314L+s but I don't really want to sell Mind you, I might sell a 314L+ later on to help fund an upgrade to a secomd 460

[kirkster501]

I aim to power the cameras and FW from one 17A battery I think for now. That should last plenty of time; I cannot leave stuff going all night since I have no obs. My guide cam is powered from my PC.

All that said, I am thinking of building a 100A power box with a leisure battery to power the whole shebang - PC, mount, cameras etc with an inbuilt inverter. This will also have the better power sockets too.

[bluedandelion]

Robin,

Thank you for that detailed reply. Part of the problem is that when you go to the field the energy one can pack into lead-acid is limited. I have an 85AH lead acid batery, but with a laptop, cameras, mount and an occasional dewheater that is not enough for long. What bothers me and many Atik 383L+ users is that the designers did not take this possibility into account. Even at 12V some samples (mine included) of theis camera shows considerable noise. Other KAF8300 based cameras from SBIG or QSI have not shown this complaint.

I do have fuses upstream and downstream from the DC-DC regulator. I understand now that this will not offer over-volt protection. I will look into the crow-bar circuit. Thanks again.

Ajay