Powering laptop in the field?

I am going to order one of the orion autoguiders from anacortes tomorrow. I already have a decent laptop BUT will need to figure out the best and cheapest way to power it in the field..... Anyone have ideas or how to you supply power to your laptop at your darksite? Mine is an IBM Thinkpad I1300, ac adapter I have now is outputting 16v, 3.36a, I would like to power it for up to 8 hours if at all possible.

Chris

Do a Google search for "12v Travel adapters" I found really nice 12v travel power supplies for my Toshiba and Dell laptops. As I remember I only paid about $40 for one and $20 for the other. I power everything from 2 100A AGM batteries and charge with 45w solar panels during the day. The batteries make great ballast for the tripod. I spent a week out in the dark skies near Datil, NM and the system worked great.

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You can also use a power inverter and your automobile's cigarette lighter socket or just connect it straight to the battery. Not sure if it will give you 8 hours though.

I just bought a power inverter to power my C8 drive motor while in the field. Paid $24 for it. Havn't had a chance to try it yet.

I bought a small, cheap 350 watt inverter (12v/110v) at WalMart for about $40. I just lift the hood on my Ford F150 pickup, set the inverter on a towel on the radiator and use the supplied short cables & clamps to connect it directly my pickup's battery. I then run a standard 20' extension cord from the inverter back to my pickup's tailgate where I place my laptop. I sometimes power a 7 watt/110v red lamp, clamped to the tailgate support, from the same power source. This easily powers my laptop and lamp all night long with no ill effects on the battery. Been using it for 5 years now.

Note 1. I don't believe powering a laptop with a cigarette lighter type inverter is a good idea. You get a voltage drop between the battery and cig. lighter socket, the electrical connection isn't very secure, it wasn't designed for long term use and tends to overheat, possibly blowing a fuse. Connecting the inverter directly to the vehicle battery eliminates these problems.

Note 2. The inverter I use is rated for 350 watts continuous and 700 watt peak power. It is thermally protected, fused, has a built in cooling fan, green power-on LED, a red overload/low battery warning LED, two 3-prong 110v receptacles, and an on/off rocker switch. It has a footprint about the size of a DVD box and stands about 2.5" tall. The power capacity and built in safety features help avoid potential problems.

Large Deep Cycle battery, with adapters for your laptop. The scope and camera and laptop can be run from a large battery for quite a while. I use a 115 amp hour Trolling Motor battery that I bought at Wal-Mart for about $65 and it has a carry handle and 1/4" wing nut connectors which makes it easy to wire for your connections required.
I rarely use mine for more than one night of imaging before recharging it, but 6-8 hours of continuous running is typical for me. Never get below 12v on the battery, even though I run a large 17" laptop, G-11 mount and ST2000 camera.

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If you can skip the inverter, do so.

Every time you convert (or invert) energy, you lose something. SO, inverting a 12 volt from an RV, car, or special stand alone battery, into 110, and then back into 18, runs the battery down faster.

Of course, with a big enough battery, you can probably do one night easily whether you use a 110 inverter or not--but if you want to stay a few nights, etc. try skipping the 110.

Alex

IBM AC/DC Combo Adapter P/N 22P9003 is what I use
(just google IBM and the number). As others have said,
don't run it on your car's battery, if you want a working
car in the morning. Get a couple big (>=55 AH) auto/marine
batteries, instead.

Chris Roten said:

I am going to order one of the orion autoguiders from anacortes tomorrow. I already have a decent laptop BUT will need to figure out the best and cheapest way to power it in the field..... Anyone have ideas or how to you supply power to your laptop at your darksite? Mine is an IBM Thinkpad I1300, ac adapter I have now is outputting 16v, 3.36a, I would like to power it for up to 8 hours if at all possible.

Chris

Chris....

Large, deep-cycle marine batteries are the way to go of you need lots of power. However, if you want something ready-made check out www.xantrex.com. Their portable power units are well constructed, though they include extra features that you may not need.

I have a Xantrex 600HD (28 amp-hr) and a Xanrex 200 Plus (12 amp-hr). Both have modified sine-wave inverters. The 600HD has three AC outlets, while the 200 has one. Each also has one cigarette lighter style 12VDC port.

I bought the 600HD several years ago to run a CPAP machine for astro-camping. Most CPAPs are sensitive to the quality of the AC power, and the sine wave from the Xanrex passes muster. I can get two full nights out of it, which is what I usually need. I also used the 600HD to run my Celestron CPC-800, my laptop, and my DSLR for the Mercury Transit, and I had power to spare. The 600HD should be able to paower the typical laptop for at least 8 hours.

When I am just operating the CPC-800, I use the Xantrex 200 Plus, mainly because it's lighter. I have even used the air compressor once.

Fred