Is a solar powered observatory possible?

[Astronut1982]

Hi guys,

I've recently started to build my roll off shed observatory & have started to consider power sources for it. This got me to wondering if a solar powered observatory is feasible. I was thinking that I could use batteries to power my kit & that those batteries could be recharged by solar power during the day to keep the batteries topped up.

Does anyone know if this idea is possible or am I hoping for too much? If it is, could anyone give me an idea of what would be involved & what I'd need to do it? The kit I'd be powering using this method would be a PC, an NEQ6 pro, my dew heaters & a camera [at first a DSLR but later on a CCD].

Thanks in advance for any advice offered.

Jeff

[madatter]

My caravan as a 18w panel that charges the battery during the day, it only requires light to charge, not sun, so it should be possable but you might require a larger solar panel.

[JB80]

I would say so but I have no idea how it works, my Dad can run his houseboat on solar power, or could at least and I imagine things have moved on from then.

I'm definitely curious and hopefully someone can share more info.

[upahill]

Shouldnt be a problem, but im not an electrician, and its been 10 years since i studied electricity so everything that follows could be wrong. I would have a few leisure batteries inside the observatory and then panels on the roof.

Based on a 5 hour session I think you would be using about 620watt-hours, equivalent to 52amp hours for a 12v system.

Ive taken this bit from another site:

On an average British day, the power you need could be produced by a solar panel array of approximately251 watts. However, you do of course get more power in the middle of summer than in winter. In summer you could produce that power with only 124 watts of solar panels. In winter you would need 620 watts of panels to produce enough power.

So in summer, a single 250watt panel should recharge the battery, but in winter you would need three of them to do the same thing, http://www.ebay.co.uk/itm/250W-solar-panel-kit-for-charging-12V-24V-battery-in-motorhome-caravan-boat-/111019437499?pt=UK_Gadgets&hash=item19d9462dbb should do the trick for the summer time.

As for winter, it depends how many days you would be using the observatory, if it was every 3 days then the single panel would still suffice I guess, if it was everyday then you might need to tripple up on the panels. Likewise you would need more panels if you stay out for 10 hours a night

at 52ah though for a 5 hour session you could get away with say a 110ah leisure battery.

With the relatively low cost of batteries compared to the 400-1200 you would need for a great solar setup it may be better just to buy 2 leisure batteries with handles and swap them out as and when you need to, charging them in the house.

[The Sailor]

If I were to run an observatory by battery alone I would have a bank of batteries, each battery charged by a solar panel and a switch to run each battery in turn as they run down, basically no different fron running batteries on a boat. This system would ensure that a full nights stargazing would be possible using all equipment.

Jim

[JamesF]

Sticking a finger in the air fairly wildly, could we say you'd need about 50Ah for a night's imaging? At 12V that's 600Wh. A 100W peak PV panel is probably around 1.2m x 0.8m, so you could probably fit three on a 2x2m square obsy, giving 300W peak. Assuming 50% output you'd need four hours between imaging sessions to get your 600Wh. That sounds so utterly reasonable that I'm sure I must have made an error somewhere

Combine it with a small wind turbine and use a leisure battery with, say, twice the required capacity and I reckon you'd be sorted. You could even perhaps use a dehumidifier as a dump load once the battery is charged.

James

[JamesF]

Blimey. It's like someone was reading over my shoulder

James

[Astronut1982]

Thanks for the replies guys.

So it does look like it should be feasible. I'll need to do a bit more research but I think that I'll be fitting solar panels to charge the batteries up.

When I get a system set up I'll post on here incase anyone else is interested.

Jeff

[shirva]

Hi Jeff...I've done my shed solar powered.I use a high amperage truck battery linked to a blade fuse box then it powers two four feet led strips, 1 have two power outlets one to a step up voltage adapter for laptop as a back up to laptop battery..the other is extension cabled to a durite connector for power scope and equipment. I have a solar panel trickle charger from maplins on roof (this only needs light to work not direct sunlight) if partss are ordered from Hong Kong via eBay its a cheap set up.if you had a larger solar panel and an other battery could run a small inverter for 240 volts.

[Steep]

I have a couple of panels charging a single standard car battery (not ideal but it works), one risk is over charging the batteries if you don't use them for a few days, especially during the summer months so with the set up you plan you should budget for a charge controller and sump to take up any excess power.

The PC will be the killer as far as power requirements go so strip it to a bare minimum, you won't need fancy graphics so don't fit a high end gfx card and keep the peripherals to a mimimum, case fans won't be very important either working at night.

[JamesF]

Looks like 12V dehumidifiers do exist, so using one as a dump load might be feasible.

Depending on what's available it might be tempting to stick with a laptop for control and image capture in the obsy, transferring to a more powerful machine indoors for processing?

James

[Gina]

Yes, you don't need much power for capturing and controlling - I use a netbook running XP. Quite adequate though XP still crashes very occasionally. It will run for 8 hours on its battery

[urbanastro]

I know I'm replying to an old post but here's my two cents

The Lima Astronomical Society www.limaastro.com operates a roll-off roof observatory at dark sky, rural site. The observsatory houses a 10 inch Meade RCX400 with cameras, laptop and lighting. The solar setup is very simple. We use a 45w solar array (from Harbor Freight), a 12v 60 amp hour deep cycle battery and a 400w inverter. In the four yearss since this was set up, power has never been a problem even in winter. In fact the inverter in not really needed since everything is now running directly from the battery. Since most commercial astronomical telescopes and equipment is designed with remote use in mind, power requirements are not really as critical as you may think.

[Starlight 1]

I run my set-up on just 54v on 2 car batterys. in the uk you be luck to get more then 2 nights in plus winter nights I am only go out side for 3 or 4 hours, but I still have main back up.

[Scorpius]

I have a solar powered set up at my remote site which powers my camp building and this is also where my future obsy will be located. So just a couple suggestions: You'll need a charging controller and the smaller ones usually come in 15 or 30 amps so I'd suggest 30 to provide some headroom for future expansion/equipment. Plan on using LED lighting which is a lot less power hungry than standard incandesant. I would plan on an inverter so you can have 110 v available to run computers and the mount with an A\C adapter. And finally, I wouldn't even try this without an auxillary hook-up for a gasoline generator which can not only be used to power everything when the batteries get low but can also recharge the battery bank at the same time. This involves a battery charger powerful enough to recharge the entire battery bank, an RV style transfer switch to change from solar to battery power and an exterior weather proof receptacle where the generator power cable plugs in. I plan to install a separate system for my obsy - rather than use the system serving the camp building but either way, the key to an effective solar system is having enough batteries of the right type and the right number of panels (based on their output in amps) to keep the batteries charged. It's important to remember that solar panels don't work on cloudy days hence the reason for an auxiliary generator to ensure there will always be power available when you need it or at least that's been my experience...

[Scorpius]

Quick correction - the transfer switch is to change from battery power to generator power not solar to battery as I indicated in previous post...

[Gina]

Interesting thread and gives me ideas   I don't need solar power for my main observayory as it's well within cable reach of the house but I also have a field with really good views about 300 yards away from the house.  The problem would be comms - there's no telephone line as well as no mains power at the site.  Anyone know if it's possible to run Wi-Fi over 300 yards?  Sound impossible to me but you never know   Or is there another form of comms that would give me remote control and at least a webcam.  I guess quite a slow link would be usable as the observatory could be mostlly automatic.

Maybe I should start a new thread as this is diverging a bit from topic...

[carastro]

I know some-one who has actually done this, but I am not quite sure if it's enough on it's own, but then I think he has possibly powered the warm room for overnight accommodation as well, but if you want me to put you in touch with him as I don't think he's a member on here, send me a PM.

Carole 

[JonC]

Interesting thread and gives me ideas   I don't need solar power for my main observayory as it's well within cable reach of the house but I also have a field with really good views about 300 yards away from the house.  The problem would be comms - there's no telephone line as well as no mains power at the site.  Anyone know if it's possible to run Wi-Fi over 300 yards?  Sound impossible to me but you never know   Or is there another form of comms that would give me remote control and at least a webcam.  I guess quite a slow link would be usable as the observatory could be mostlly automatic.

Maybe I should start a new thread as this is diverging a bit from topic...

Yes Wifi can do longer ranges, needs to be line of sight with nothing in between. You also need directional antennas at each end and a good wifi unit.

[Gina]

Thanks Jon