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Power to the obs--Generator, solar or wire?

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#1 RogerRZ

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Posted 18 February 2013 - 02:07 PM

Hi all, in an effort to get away from local light pollution sources and be able to leave the telescope for longer periods during astrophotography, I'm thinking of building a roll off roof building that's in a clearing behind my house, where no local lights reach at all.

I will be 600 feet away from the house, and the AC power that comes along with it.

What would you suggest one use, keeping in mind a max $1000 budget (the lower the better).

A solar panel array, 1000 watt generator or hard wire it to the house (copper or aluminum)?

This will be used to power a laptop, mount, CCD camera, dew heaters and a couple of lights, for a couple of hours, no more than three nights per week.

Thanks

#2 Alex McConahay

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Posted 18 February 2013 - 02:42 PM

600 feet is a long wire run. The difficulty of digging the trench would vary a lot on the type of soil, etc.....You will need oversized wire, which would be expensive.

On the other hand, once in, it is in and reliable. So, I would opt for that.

Alex

#3 zawijava

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Posted 18 February 2013 - 02:52 PM

If you haven't already read this Thread you may want to take a look. -Tim

Hi all, in an effort to get away from local light pollution sources and be able to leave the telescope for longer periods during astrophotography, I'm thinking of building a roll off roof building that's in a clearing behind my house, where no local lights reach at all.

I will be 600 feet away from the house, and the AC power that comes along with it.

What would you suggest one use, keeping in mind a max $1000 budget (the lower the better).

A solar panel array, 1000 watt generator or hard wire it to the house (copper or aluminum)?

This will be used to power a laptop, mount, CCD camera, dew heaters and a couple of lights, for a couple of hours, no more than three nights per week.

Thanks



#4 RogerRZ

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Posted 18 February 2013 - 03:20 PM

Thanks for the link.

I've been looking at solar setups, but I don't know what I'm doing. and am a little scared to make the commitment and find that I'm running out of power, and then having to fork over more $$$.

As far as the trenching, I have a backhoe, so no worries there, but to borrow some New England terminology, wire is "wicked expensive". If I have to fork over $2k for wire, it will be of no use, there will be no building to run it to. :shocked:

I have a 2600 watt Yamaha generator, but I find it a bit loud, and I'm also concerned about getting it started on those 15 below nights. Can't beat the price, though. I'd connect it to a UPS, in order to get clean power out of it...

One option is those nice little 1000w Hondas or Yamahas, and keep it indoors until I need it, where it will be nice and warm for easy starting.

Hmmmmm......

#5 zawijava

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Posted 18 February 2013 - 04:01 PM

Perhaps a properly sized battery bank(figure out your power demands) with a small pure sine wave inverter and a small generator. If sized properly the battery bank would get you through an entire nights observing. Then you could run the generator for charging at a time when your not using the observatory so you won't have to listen to it. At a later date you could easily add a solar panel or two and a charge controller so as to possibly not need the generator. -Tim

Thanks for the link.

I've been looking at solar setups, but I don't know what I'm doing. and am a little scared to make the commitment and find that I'm running out of power, and then having to fork over more $$$.

As far as the trenching, I have a backhoe, so no worries there, but to borrow some New England terminology, wire is "wicked expensive". If I have to fork over $2k for wire, it will be of no use, there will be no building to run it to. :shocked:

I have a 2600 watt Yamaha generator, but I find it a bit loud, and I'm also concerned about getting it started on those 15 below nights. Can't beat the price, though. I'd connect it to a UPS, in order to get clean power out of it...

One option is those nice little 1000w Hondas or Yamahas, and keep it indoors until I need it, where it will be nice and warm for easy starting.

Hmmmmm......



#6 RogerRZ

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Posted 18 February 2013 - 04:06 PM

I hadn't thought of that. It would be a good and cost efficient way of building a system that could eventually become fully solar powered, without going all in at the start...

#7 Bob Moore

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Posted 18 February 2013 - 05:38 PM

I would do the wire, it fact we just did that. see the link for the project. http://www.cloudynig...4896352/page...

we ran 760' of #4-0 3 wire 760' of #2 for the ground and 760' of fiber for out data. Here is a photo from today

Bob

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#8 zawijava

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Posted 18 February 2013 - 05:48 PM

Looks nice Bob! I'm curious as to when you laid that wire and at what cost? Just trying to compare to what today's prices might be for that 760' :question: -Tim

I would do the wire, it fact we just did that. see the link for the project. http://www.cloudynig...4896352/page...

we ran 760' of #4-0 3 wire 760' of #2 for the ground and 760' of fiber for out data. Here is a photo from today

Bob



#9 Bob Moore

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Posted 19 February 2013 - 01:42 AM

we did the wire in july i think we got an 800'roll and i thing it was 1.25 per foot

#10 YetAnotherHobby

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Posted 19 February 2013 - 12:58 PM

You can get several hours from a big marine battery. That is what I use in the field. I can power a laptop, goto mount, camera, etc. using an inverter as needed.
I suppose you could charge the battery with a small solar array since you could take days to recharge. Or lug the battery back in the house for a recharge at the end of a session. Inverter + charger probably less than 25% the cost of wire. And you have a portable solution for dark site work.

#11 RogerRZ

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Posted 19 February 2013 - 01:26 PM

I probably don't need much more that four hours at a stretch, so maybe a couple of heavy marine batteries might do.

I am fortunate that this observatory will be under fairly deep skies (SQM 21.3), so whenever I travel, it's usually with my travel trailer on social outings...

#12 tclehman1969

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Posted 20 February 2013 - 12:35 AM

Running a power line looks like it could be expensive. I've been doing a lot of thinking on this myself for a future project and I am leaning toward a deep cycle battery, a good sized one. I don't know exactly what size as I haven't calculated my power needs as yet, but something that would give me a good six hours observing time. During daylight, have a trickle charge to bring it back up off solar. That may not be enough time to get it fully charged up, so a little generator could likely do that.

Of course I could break the system up having one battery for the scope (scope drive, illuminated reticles, camera power, dew strip) and another for the misc. equipment (laptop, lighting). Overall my goal is to be completely self contained.

Has anyone ever added up wattage requirements for their systems?

#13 Alex McConahay

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Posted 20 February 2013 - 09:11 AM

I think I did. Not wattage--amps. It was under 5 amps for everything running, including focuser. This does not include lights in the obs or other obs facilities.

Those of you thinking of running generators, etc. remember that you will also run heat, maybe air conditioning. ALl this can be done with alternatives, but it is so much simpler by biting the bullet and running wire.

Alex

#14 RogerRZ

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Posted 20 February 2013 - 10:41 AM

I looked into wire, and to run sufficient gauge to have 15A at the observatory, I'd be in for over $2000.

I would be left with a nice wire poking out of the ground, and no building to connect it to.

Batteries are looking better and better, especially since I don't need to run any heat or AC (I won't be building a warm room, and it doesn't really get hot enough, for long enough, to warrant an A/C unit...)

#15 Bob Moore

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Posted 20 February 2013 - 11:54 AM

Roger, are you saying it would cast you 2k to do it your self? that does not sound right. we ran 700+ feet of 4-0 so we would have 50 amps and it cost us $1,000.00. for you 600' run in copper you would need #4 wire and in Aluminum you would need #2. I can't see how it would cost $2,000.00 to run 600' 0f #4

#16 frolinmod

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Posted 20 February 2013 - 12:59 PM

Two pairs of very cheap lead acid 6V golf cart batteries wired serial / parallel (two wired together in serial, in parallel with another two wired serial) will give you all the power you need for several days. Just run the generator for a few hours once a week or put some solar panels up.

#17 RogerRZ

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Posted 20 February 2013 - 02:55 PM

I need to find out where you people buy your wire! With scrap copper at $3-ish/lb, that 4-0 is worth close to $500 as scrap...

Aluminum, #2 (service) is about $400/Mft, but this isn't really the ideal stuff for this application. (They only want to sell me a 2Mft coil too...)

#18 Peter L.

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Posted 20 February 2013 - 03:32 PM

Roger,

I see you are just across the Strait from me in NB. After you use your Obs for one winter, you'll want a warm room. Factor that into your design now. And with heat, comes higher electricity needs. I echo others' suggestions to bite the bullet and run the wire. If the budget can't support it, delay your build and save.

Just my opinion...

Peter

#19 RogerRZ

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Posted 20 February 2013 - 04:06 PM

I've been using my existing observatory for six Winters now, and have not needed a warm room yet. I will be keeping my dome for visual use (for now), this new one is going to be used mostly for unattended (except for opening and closing the roof) photography, shielded from local LP, and no "off limits" trees. I don't have Mrs. RogerRZ's permission to cut trees around the house. The new spot can be cleared as needed (it's already quite open, but I might mow a few more trees down to the North).

#20 Mary B

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Posted 20 February 2013 - 05:42 PM

@ of these solar panels will give you 240 watts at 12 volts, http://www.solarblvd...-Panels/c1_2...

Add 2 golf cart batteries at $200 each, and a $100 charge controller. 12 volts at 120 amp hours. Add up all your power needs by looking at the amp draw and adding them together. Multiply by how many hours a night you will use it and you have your daily amp hour draw.

My golf cart batteries are 232 amp hour so 2 in series is 232 amp hour at 12 volts. You only want to use half your battery capacity maximum to extend battery life. so divide the 232/2 for you available daily power from the battery.

Batteries give off acid fumes so you will need a sealed container vented to the outside.

#21 jazle

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Posted 20 February 2013 - 06:25 PM

laptop = 60W,
mount = 50W,
CCD camera = 40W,
dew heaters = 30W,
and a couple of lights = 80W,
Total ~= 260W? Make it 500W just for any future luxuries.
I assume these are mostly 12V devices or run on universal switching power supplies capable of going down to 90VAC. Let's assume worst case 110V at the house and no more than 100V at the observatory. You can do that with 12ga wire, 10ga if you want to feel better about the voltage drop.
For your budget, you can buy a 600' length of SOOW or SJOOW cable -- both are rated for outdoor use and make a plenty-long extension cord. I did this with a 150' length of 10/3 and ran all of my equipment on one leg of the 240V and a 1500W heater on the other leg.
Make sure you run it on a GFCI outlet, however. That cord is long and extremely durable, but if you snag it with a tool or lawnmower enough to nick the insulation and it rains, you want to know that puddle is safe on your walk out to the observatory.
And if these are your power needs, I definitely recommend this over a permanent installation if that means the difference between a permit versus no permit required (which -- only counting paperwork -- is costing me more than $1000 for my roll-off so far).

#22 Mary B

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Posted 21 February 2013 - 05:32 PM

For solar that would be about 25 amps per hour so a 8 hour stint would be 200 amp hours from the battery if you go solar. Lighting could be dropped considerably with led dropping it to about 20 amp hour or 160 amp hour for 8 hours.

#23 ahopp

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Posted 21 February 2013 - 06:04 PM

I power my mobile observatory with a 3Kw Honda EU3000is generator and a 3Kw inverter so that I can run my gear at 12V DC native.

Tony






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