#1  
Old 27-02-2008, 06:17 PM
Zuts
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SBIG External Power Help

Hi Guys,

I have an SBIG ST2000 XCM. I want to use it away from mains. I already have a 24 amp hour battery. The SBIG has the standard 90 to 240 volts AC adaptor.

What is the best way to use the battery power without destroying the camera

Thanks
Paul
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  #2  
Old 27-02-2008, 06:22 PM
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skwinty (Steve)
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Hi Paul
I would use an inverter.
They are reliable and stable as well as being reasonably priced.
You would select one based on output wattage required.
Regards
Steve
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Old 27-02-2008, 08:20 PM
Dennis
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The SBIG mains adapter for my ST7E delivers both 12Vdc and 5Vdc so I’d second Steve’s recommendation of a good quality inverter.

Cheers

Dennis
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  #4  
Old 27-02-2008, 10:19 PM
Zuts
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Originally Posted by skwinty View Post
Hi Paul
I would use an inverter.
They are reliable and stable as well as being reasonably priced.
You would select one based on output wattage required.
Regards
Steve
Thanks Steve, I was thinking of that but hopefully a SBIG user will chime in and tell me what they do.

Paul
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Old 28-02-2008, 12:02 AM
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Originally Posted by Zuts View Post
Thanks Steve, I was thinking of that but hopefully a SBIG user will chime in and tell me what they do.

Paul
Hi Paul
If your sbig camera requires 2 voltages then your only other option is 2 batteries wired directly to the camera. If the camera requires one voltage then you would have to wire one battery directly to the camera.
See Dennis's post 3.
The advantage of using an inverter is that you dont have to connect anything other than the original plugs and power supplies to the camera.
This will minimise any undue damage to the camera.
A battery will not have any short circuit or over current protection should something go wrong whereas the sbig power supplies should at least be voltage and current regulated affording you some level of protection.
(unless you purchase a suitable powertank which may or may not have this protection)
IMHO a decent quality inverter is the only sensible solution to operating away from the mains supply.
Regards
Steve
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Old 28-02-2008, 04:35 AM
gbeal
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Sorry mate, I only use AC, as where I image there is power, and this powers the mount, and the PC. SBIG do make a 12 volt power supply.
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Old 28-02-2008, 05:00 AM
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I use a generator. Honda 2000i far from cheap but perfect for this equipment. It is bigger than I need. Honda make smaller ones at the same quality level.

You could consider a $100 Bunnings generator. Despite what many say, I got a year and a half of work from one and the computers/cameras weren't upset by it as long as you didn't introduce large sudden loads to the generator such as switching on a monitor or tv while imaging.

Get a couple of those cheap 25m extension cords too and put the generator 50m away and the already reasonably quiet exhaust from the generator is not an issue. You will need to mix 2 stroke oil for the cheap gen sets.

You could buy one, try it with all your equipment connected and if it doesn't suit you, quickly return it. Basically if you are getting in to serious CCD's and you want to go all night, batteries are no longer the answer.
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Old 28-02-2008, 10:55 AM
Zuts
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Hi Guys,

Thanks for all the replies. I may go with the field unit from SBIG, but a bit exe.

Another alternative would be a 1800va UPS as sold for pc's (142 bucks from MSY). What do people think about this option. Also my current battery pack is 12 amp hour. For a 1800 va UPS does this mean it is 18 amp hour and are the batteries inside a UPS the same as the standard car starter batteries with the same charging and power supply characteristics?

Thanks Paul
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Old 28-02-2008, 12:27 PM
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I'm sure someone else which chime in, but the risks of an inverter could be a bit of a problem. If they don't generate a good true sine wave, you could screw with the electronics. SBIG cameras are not the cheap $50 TV from your local discount store.

I'd ring/email Peter Ward @ atscope and get his advice directly. Many years ago I asked the same question, and was put off an inverter (but don't have the details handy). Don't skimp with this stuff unless you're happy to risk a very expensive paperweight.

That's just my 2c worth - ask someone who knows the gear inside out!
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Old 28-02-2008, 04:15 PM
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Hi Paul
If you go the UPS way remember that the UPS is basically an inverter.
With regards to the sine wave issue the points to remember are:
1. 24amp/hr DC battery powers the inverter producing 220VAC.
2. 220VAC powers the standard SBIG power supplies.
3. The standard SBIG power supply produces the DC voltages for the camera.

Hence any variation the sine wave quality of the inverter would have no impact on the DC voltage produced by the SBIG supplies. The inverter could produce a square wave or a saw tooth wave and still not affect the DC voltage produced by the SBIG power supply.

Good Luck in your quest for field power.
Regards
Steve
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Old 28-02-2008, 05:01 PM
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Hi Paul
I looked at the SBIG field power supply and for peace of mind you should rather use this.
12VDC Power SupplyThis optional power supply converts 12VDC from a battery to the 5VDC and 12VDC required by the camera. It is for operating your ST-7/8/9/10/2000 camera from a battery in the field, or anywhere there is no convenient AC power. Part # 50388

I dont know what the cost is but this power supply does not use an inverter.
It will use voltage dividers and regulators as it only needs to convert DC to DC.
Regards
Steve

Another reason for suggesting an inverter was because you could use it to power other accesories (such as laptop etc) as well as the camera. Inerters are not as risky as some would suggest unless it is heath robinson.
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Old 28-02-2008, 06:07 PM
Zuts
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Hi Steve,

Thanks, yes, as I said in a previous post I am considering the SBIG field converter but is is rather exe at 230 AUD.

I really dont want to damage/lessen the life of my camera so I am trying to find out what other SBIG users use in the field.

Failing this i will probably get the SBIG converter.

Paul
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Old 28-02-2008, 07:01 PM
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Quote:
Originally Posted by Zuts View Post
Hi Guys,

Another alternative would be a 1800va UPS as sold for pc's (142 bucks from MSY). What do people think about this option. Also my current battery pack is 12 amp hour. For a 1800 va UPS does this mean it is 18 amp hour and are the batteries inside a UPS the same as the standard car starter batteries with the same charging and power supply characteristics?

Thanks Paul
Hi Paul
Some more info re: your questions (albeit from a non sbig owner).
VA means a ratio between volts and amps.
1800VA means that at 1800 volts the current will be 1 ampere.
At 180 volts the current will be 10 ampere.
The battery will not be the same as a car battery which is a lead acid battery. It would probably be a Lithium , Cadmium , Nickel or Metal based battery.

A 12amp/hour battery of any type means that the battery will provide 12 ampere for 1 hour or 1 ampere for 12 hours.
The charging rates will differ from battery type to battery type.

Hope this is of some use to you.
Regards
Steve
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Old 28-02-2008, 08:14 PM
Karls48 (Karl)
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This is true only for resistive load. If there is any inductance or capacitance in the circuit then it has to be calculated as I x U x cos phase angle. VA rating alone does not give you information how much power it can supply or for how long.
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Old 28-02-2008, 08:29 PM
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This is true only for resistive load. If there is any inductance or capacitance in the circuit then it has to be calculated as I x U x cos phase angle. VA rating alone does not give you information how much power it can supply or for how long.
Hi Karl
This is true only for resistive loads refers to which statement?
Agreed the impedance of a alternating current circuit plays a significant role in circuit analysis but at the end of the day ohms laws still apply.
Regards
Steve
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Old 29-02-2008, 07:50 AM
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I have an ST-8E and ST-9E. The ST-8E has a mains supply adapter and the ST-9E has a 12v/Battery power supply adapter both from SBIG.
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  #17  
Old 01-03-2008, 11:28 AM
Zuts
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I have an ST-8E and ST-9E. The ST-8E has a mains supply adapter and the ST-9E has a 12v/Battery power supply adapter both from SBIG.

Hi Guys,

Thanks for all the replies. I should get the SBIG field unit but I cant wait the month it will take. So i will get a 300 watt sine wave inverter from Jaycar and another battery pack. If anyone thinks this is really dumb please tell me quick as i will be going soon to pick one up.

Thanks Paul
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