Power for out in the "field"

At home I have the luxury of 110v convet/12volt which powers my dew heaters and slewing demands, however I find that out in the field (Star party) my viewing time is limited to my "Power Tank" which usually flashes the yellow light after several hrs. of observing. does anyone have any suggestions to an alternative power source? thanks again, John M in Astoria, OR.

Bottom line.....for those long sessions or perhaps a weekend of long sessions I pull the large deep cycle batteries out of my boat. Two of them.....Not only do have plenty of power on hand I keep my batteries in use during the winter months.

A Powertank should last more than a few hours......

Be that as it may, the next step up is an RV Battery. You may want to go there, but it is significant overkill for most applications that do not involve imaging, etc.

Alex

Hi john,
For what it is worth, the "powertanks" don't seem to last long. Get a deep cycle marine battery for about the same price. It will last easily all night, or two nights or more even with lots of power demand for accessories. Draw back is they are lead acid and heavy to carry, but they can keep you in full power for a couple nights. Go for the most 'Amp Hours" you want to lug around. I've had a 75 amp hour for three years now and only recharge it after an all nighter or two good nights, and then it is still over 11 volts when I charge it. Full charge is about 14 volts, which is well within the operating limits of most 12 volt systems. I recharge it after it has dropped below 12 volts. Tried a standard car battery, but they don't like to be discharged much and don't last long. Weighs 50 pounds but worth every penny and pound. Get a deep cycle charger to match the battery and it should perform for years with proper charging.
Powerfull clear skies,
Brad

Although I have the big heavy battery out of my boat when I need it, I rarely use it. I have three of the smaller sealed lead-acid battery packs with built-in chargers and cig. lighter plugs. (Two from Harbor Freight and one from Walmart.) They're much handier and if one poops out, I've got a spare. These always seem to do the job for powering my scope mount and laptop (via a small inverter).

My favorite power saving invention is my reading/writing/chart lamp. It's a cheap clamp-on headboard reading lamp from Walmart. I removed the standard 110v socket and wiring and replaced the lamp with a round red 8 LED truck clearance lamp from an auto parts store, diffused by a piece of white translucent Lexan. I bought a curly cord cable with cig. lighter plug from Walmart to replace the old wiring. I set one of my battery packs on my table out in the field, clamp the lamp to its handle and plug it in. The LED's draw so little current that the battery only requires occasional recharging.

John Meiners said:

At home I have the luxury of 110v convet/12volt which powers my dew heaters and slewing demands, however I find that out in the field (Star party) my viewing time is limited to my "Power Tank" which usually flashes the yellow light after several hrs. of observing. does anyone have any suggestions to an alternative power source? thanks again, John M in Astoria, OR.

Two:

Larger capacity power tank...unless you are really suckin' it down a 17ah should last more than a few hours, but 21ah models are easily available. I do use two: one for the scope, one for the dew heaters. Make sure you charge the thing for 12 hours after every use, and charge it once a month if you don't use it.

Trollin' motor battery (aka deep cycle marine battery). If you need a lot of current, including power big laptops, etc., this is the way to go. Way less portable than a jumpstart battery, and without a built-in charger, of course.

John Meiners said:

At home I have the luxury of 110v convet/12volt which powers my dew heaters and slewing demands, however I find that out in the field (Star party) my viewing time is limited to my "Power Tank" which usually flashes the yellow light after several hrs. of observing. does anyone have any suggestions to an alternative power source? thanks again, John M in Astoria, OR.

This spring, when I get my astronomy shed moved up to the observing location, I'm gonna put a solar powered battery charger on my Deep Cell Marine battery.

These solar chargers are available for around 80 bucks. Hoping to be able to just leave the battery up there and forget about it.

Good Seeing, Walt