Generators for portable?

[garymck]

Hi,

wondering if there is any low cost generator suitable for imaging at remote locations? My understanding is that cheap generators produce waveforms that are not conducive to running computers and imaging equipment, but the generators that produce good clean power are VERY expensive. Is there any way to clean up the power of a cheap generator and make it suitable? I know deep cycle batteries are an option, but they are hugely heavy, and very expensive as well...

cheers
Gary

[Tandum]

You could plug the genny into a UPS and run the gear off the the UPS.
You would want a line interactive UPS, something like this (http://www.computeralliance.com.au/parts.aspx?qryPart=11105), that type of ups fixes the input wave.
Cheap option is to run a battery charger off the genny and charge a car battery.

[ZeroID]

APC put out a small line conditioner that might refine the rough wave form but don't know if it big enough or clever enough to make a difference. Line interactive UPS's are normally pretty large beasties wired into server rooms and even the small versions are pretty expensive. Over a thousand dollars or thereabouts ( my wife is in the UPS business, specs and sells APC gear) and if you want good sinusoidal wave form then it is not going to be cheap.

[Barrykgerdes]

The wave form from the cheap alternator type AC 230 v generators is reasonable. They are regulated in speed to keep the frequency at 50 Hz. If you use this to the drive a lower voltage power supply to get your 12 volts there should not be any problems. Their big drawback is the audio noise level (100 db+).

The more expensive (quiet less than 60db)) generators run at higher speed and convert the AC to DC which is then used to drive an inverter to supply 230 v AC at 50 Hz. This type of supply is subject to electrical noise but the supply is normally well filtered before being available for use. The one I use cost $600, has remote electric stop/start.

The main thing to remember if you want to avoid spikes is to start the generator before you connect it to your equipment and turn on and don't let it run out of gas or stall while connected to your equipment. ie turn of your equipment before you stop the generator.

I use a quiet 2.5 KVA generator in the field all the time. It also sits in a soundproof shelter. It runs a TV, PC, 4 laptops, Telescope, CCDs and a full imaging set up. Powers the caravan (does groan a bit when I turn on the toaster with a heavy load) but does not affect the imaging. During the day when the cameras are not working It drives power tools. drill, grinder, chainsaw etc (not quite enough power for the welder)

Barry

PS when you look at the cost of Deep cycle storage batteries and a cheap generator for charging $600 for a generator doesn't look too bad.

[DavidTrap]

I think you're going to be looking at batteries for night-time use and recharging with cheap generator during the day as the lowest cost option.

DT

[garymck]

Thanks for the suggestions, will look at getting a cheap generator and a form of ups to filter it.....
cheers
Gary

[gregbradley]

I have used a Honda 20iu generator for running my laptops, CCD cameras, mounts and everything with never any problem. I have done this for several years. It is not very loud and the engine has a happy idle sound to it. I use it at my dark site which has no connected power.

It has very clean power and runs TVs, DVDs - anything without any trouble.

I also have a Chinese Generator with an inverter and whilst it runs everything OK I notice that a TV does not get a good picture on some stations when using it so the power is a bit dirty or it gives off interference.

Honda also makes a 1000iu which would be adequate for astro gear which does not require much power.

I find a full tank lasts about 8 hours so usually I fill it up just before dusk and then a top up before I go to bed and it is still running in the morning at 8am.

You need to change the oil frequently (its very easy to do though) and also it may need to be revved hard with the eco throttle off for 10minutes every now and then as I have been told they in earlier models formed glazed cyclinders if idling too long (which it will do with astro gear as that represents very little load for it). Mine started blowing smoke after 2 years use (about 800 hours worth).

I have found Castrol magnatec oil cured that to a large degree. Apart from that it has been very reliable. The pull cord broke once. I have used it now for about 5 years. The Chinese 3300 kva one has broken down about 6 times in 2 years and is largely a hunk of junk.
Go for the Honda, pay a bit more, but you'll get a nice piece of gear that will make imaging more pleasant and reliable. You can run a whole weekender off it, astro gear, lights, TV, DVD, fridge and electric blankets at the same time without any strain. You could run a little heater for yourself as well but I find anything that heats or cools draws a lot of power. Fans don't use much. I use a little gas heater I leave under my table and I turn it on in winter to warm me up a bit when tending the laptop for an imaging session and its 5C or so.

Greg.