taking your laptop to a dark site

[graham.hobart]

Ok I have decided to find a darker site, I can run the telescope off a power tank but I need advice about my lap top.
It's a sony viao the black box on the lead says 19.5 volt ac adaptor, I have googled and found nothing for the road except a new battery,
any bright ideas?

[RobF]

What size screen Graham, and does it have a DVD drive?
My 17" Acer (few years old) draws about 1.5A, so you generally need a pretty decent battery (unless you have a baby Atom based lappy).

For example, say 10hrs imaging, that's 15 Amp hours, and for a deep cycle battery not going below 30% means you would want at least a 22AH battery to start with for a single night. Generally you have to add in a bit for your mount (say 0.5A/hr), your dew control, camera, etc too though.

[midnight]

Graham,

I regularly use my laptop (a Dell) with a 19.5VDC requirement and I ended up getting a DC-DC converter. Jaycar sell them and you select the voltage on the front and it comes with a standard 12V "cigarette lighter" plug and about 5 DC plugs which you pick the one that fits your laptop at the other end.

If you're into building electronics, here is an article from this month's Silicon Chip.

http://www.siliconchip.com.au/cms/A_112454/article.html

The Jaycar one is here :

http://www.jaycar.com.au/productView.asp?ID=MP3472&CATID=20&form=CAT&SUBCATID=922

Both work very well so you only have to worry about your 12V battery capacity and charging.

Good luck!

Darrin...

[frolinmod]

I have a Dell Latitude E6510 laptop computer. I was shocked to find that the Dell supplied auto/air adapter for my laptop nothing more than a cigarette lighter plug and cord; no DC-DC boost converter. So apparently my laptop runs off either 19.5V or ~12V. Handy!

[midnight]

Yes those line of business laptops are nice - I wish mine was like that as they are 11.1V spec so can readily accept 12VDC without any conversion.

The only reason I've kept mine is it has a DB9 rs232 port on the back - rare for laptops these days. But everyone is heading for USB so I'd take the 12VDC option over a DB9 port spec anyday. I did try mine with 16V and it booted but locked up - just unreliable. Probably pays to check if one's laptop is already spec'ed for 12VDC otherwise one would be wasting money on a DC-DC converter.

Cheers,
Darrin...

[RobF]

Heck - that's my work computer. I didn't know any laptops could do that!

[tonybarry]

Jaycar was selling 650W UPS for $140 - a great way to run the laptop without issues. I take my laptop (an Apple Macbook Pro) and run it from the UPS with no troubles. The 12V battery for the scope and camera is separate.

Regards,
Tony Barry

[steve000]

ebay is your best friend!.

just go to ebay and search for sony vaio car adapter.. then look for the models. its about $20

[RobF]

Unless you have a 2nd car battery in mind, I wouldn't recommend running off your cigarette lighter connection for more than an hour or two maximum. Not unless your car is a manual and it will be pointing downhill for a push start in the morning. Not much fun when you can't get started out in the middle of nowhere, and car batteries are designed to produce a lot of power over a short period, not a long slow draw-down. I've already had to use my "astronomy" jump starter pack for a morning rescue (albeit because the car stereo was going most of the night...!).

[frolinmod]

I bought the Dell Latitude specifically for in-field use to run my Paramount ME, focuser and camera. I chose it for a few reasons:

1. It can be plugged into three different types of expansion dock, one of which is slim form fitting and has a real serial port, parallel port, two PS2 ports and two extra USB ports on it. I use the serial port to connect a GPSR with 1PPS as an NTP Stratum-0 time source. I power the GPSR off the 5V pin on one of the PS2 ports.

2. It has both ExpressCard and PCcard slots. I wanted to be able to plug in a Firewire 800 Expresscard for my Flea 3 camera.

3. Reasonable CPU power and modern OpenGL compatible video chipset for running TheSkyX.

[frolinmod]

Here is what powers my mount and laptop in the field. It's two 220 AH 6V lead acid golf cart batteries in series for a total of 220AH @ 12V. I've left the top of the battery box off in one picture so that you can see the batteries. These are extremely heavy. I have to use a battery strap to lift them one at a time. Needless to say I don't set up more than 100 meters or so from my car!

Note the Anderson connectors on the power distribution panel. I'm a proponent of using Anderson connectors. Also note the 5V USB power ports so that I can charge my cellphone too.

[graham.hobart]

Thanks everyone for the suggestions, and Darrin (midnight) I was in Jaycar as my 12 v 1.5a adaptor for my video cam got chewed up accidentally so whilst there I purchased one of those laptop multi adaptors for 79.95, will let you know how it runs off the Celestron 17Ah power tank with the mount. I will be using spare batteries in my DSLR as they are cheap and the power adaptor I bought off ebay for it only works sporadically (Booh!!)
Now just have to organise a dark site trip....
regards
Graham

[Louwai]

I have 2 x 100ah Gel 12v batteries. I can operate 3 x GO-TO scopes + my Lappy all simultaneously for several nights without recharging.

When I'm away for an extended time I run a 12v fridge 24/7 as well.
When the fridge is being used I need to top-up the batteries daily with the Solar Panels.

All is permenantly fitted into the scope trailer & I run 20m long 12v supply cables to each of the scopes.

[RobF]

Sounds like Ernie and Bryan are living the dream to me....:)

[astrospotter]

If you go to a star party out at a dark site or with other observers try to beforehand cut some pieces of red plastic or get a plexiglass dark red sheet the size of your screen.

You will find that even when dim the crt will destroy your own night vision and that of others around you. If you want to see galaxies and also not upset other viewers, pick up some dark red plastic for the screen.

Besides the huge battery approach I was amazed to find that I can run MegaStar program on a 10" netbook screen for 8 hours as long as it has LED backlight. This is amazing but true as long as you have an extended battery pack on your netbook (a netbook is a little bit smaller laptop).

Just mention this since led backlights are generally used on most all laptops these days but older pcs use way more power so then get the gel cell or other approach. I use an old car battery and a 12V adapter made for my pc if I have to use my non netbook pc. Something to think about down the road if your current laptop ever needs replacement.