Inverter or laptop power adapter?

krw wrote:
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Parties? Did he finally get the permit from the EPA?

Stephen wrote:
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WTF does that have to do with APC UPS in the < 1 KVA range? Have you always had a reading comprehension problem, or is it from excessive drinking and old age?

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Falcon SG series from 800VA true on-line XP Energy Systems MSX series from 700VA true on-line Liebert GXT2 Series from 500VA true on-line AEC T1 Series from 500VA true on-line Sinetech MHC Series from 700VA true on-line
Plenty of true on-line double conversion UPSs under 1kVA.
I have no comprehension problems, your 'these' could have referred to any of the UPS ranges mentioned in the thread so far from my point of view. So what I gather you were actually referring to were your UPSs. I apologise for misunderstanding, but take issue with the rather unfriendly manner in which you decided to point out my error, are you always that rude?
I don't drink, and young enough thanks.
As for APC, no-one has mentioned APC before you did. We used some APC UPSs years ago, which were 500VA, and we were able to start them without line power. I can't remember the model though. They looked a bit like the APC Smart-UPS range, but were cream rather than black, in a 2U 19" rack format.

Stephen wrote:
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The ones I am talking about are for PCs, Why would you want a rackmount UPS on a small boat? S 100 VA inverter would make more sense, and wouldn't need to be hacked.

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Most will run from the moment their main switch is activated if their battery is up, and there is no AC detected.
Thank you for the confirmation.

Bungalow Bill wrote:
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IME, for modern UPS, *some* will do something similar but certainly not most - as due to what I can only assume is a cost-saving measure, they often don't have a "test" or "start" button. So they just sit there doing absolutely nothing until connected to a supply, no matter what position the main switch is in.
I haven't actually come across one that runs immediately on operating the main switch, with no power connected. A make and model of one that does so would be appreciated. The nearest to that I have seen is one with a "start" button, right next to the main switch.
Another thing for the OP to consider is that UPS tend to use several 12v batteries in series, to create an internal dc supply of 48v or higher. Whereas an inverter is usually designed to run off 12 or 24v. So an inverter can be a whole lot easier to hook up to the odd big deep discharge battery, or even a car battery or two, at a push.
Also many small UPS have been designed only to run for the length of time determined by their internal batteries. On high load they get very hot internally, but the battery energy runs out before the internal temperatures rise to unsafe levels. Mod those to run off an external battery supply and they trip thermal (often non-resettable) fuses - if you are lucky..
Me, I like to use a genny and an inverter and batteries- especially these tiny ones that use electronics to produce the output sine wave and allow the motor speed to change with load. Even a small one will work well with a battery/ inverter combination. Whereas you need a much larger regular genny to do that, because of the voltage peak truncation effect of load on small gennys.

On Sun, 16 Sep 2007 07:33:00 -0400, "Michael A. Terrell"
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Bullshit. I have UPSs that will turn on in backup/recover mode when there is no AC power detected, and if it ain't plugged in, guess what, asswipe... no AC gets detected, dipshit.
Another power supply that YOU made a retarded ASSumption about.
Par for the course with a weenie fucktard like you.

Bungalow Bill wrote:
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Yawn. None of the APC I have will work the way you describe.

On Sun, 16 Sep 2007 07:33:00 -0400, "Michael A. Terrell"
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Note where I said it was only good for a couple of hours, and not even if under full load.
Fuck off, asswipe. It ain't for your house lights.

Bungalow Bill wrote:
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Yawn.

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I tried using one of those small, cheap UPS's to power my cordless phone during a power outage. When the power finally went out (stupid me didn't do a proper test beforehand) I found the UPS died after just a few minutes. With the biggish battery (12v 7.5mah) compared to the load (110v 500ma), it should have lasted several hours, if not days. Evidently it automatically turns itself off after a very short while, since it was really meant for computers with heavier loads. This makes sense, since it was designed to be cheap, not efficient, so instead of monitoring the load and battery, it just had a simple timer.
The batteries in most UPS's, especially those designed for home or office use, have sealed lead acid batteries. Not quite deep cycle, but they're usually good for three to five years. (No doubt somebody's ready to fire back that they have SLA's or AGM's that have lasted 15 years...good for you, but their rated life is roughly 5 years or less in terms of reliability) In most UPS's, you can change out the batteries after a few years at a small fraction of the cost of a new UPS.
Some UPS's are designed to be directly connected to larger, automotive type batteries, so if you need very long running time and/or high power, these are the way to go. Typically, you would use deep cycle marine type batteries, and some can run on anything from 12v to 48v.
CS

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Define "better solution."
A laptop adapter that connects directly to 12v is more efficient, requires less parts and cables that can fail, and can be used in practically any vehicle. I got one on Ebay that works great, but it's only for the low power laptop. My big pretty laptop requires more power than most of the adapters I've found.
However, your friend lives on a boat, so having a handy source of 110v would be useful for other things without the need for more adapters. Years ago I got a good inverter at a truck stop, but if you want to go fancy, tripp-lite makes some really nice ones which can be wired into an entire circuit or two throughout the boat using marine Romex.
By the way, avoid Radio Shack unless you want a cheap battery or something. Practically everything they have now is pure garbage. Even a cheapo inverter should shut itself off or trip a breaker when overloaded. Buying anything else from them is a waste of time and money.
CS

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Good feedback, thanks. I have the same opinion of RS and wanted to steer my friend clear of them in the future. What about power quality of the inverter output? Should one be concerned or do modern inverters provide a clean enough output for laptop and other uses? Any problems driving motors (refrigerators, fans, etc) within the wattage limitations of the unit?

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Laptops and anything else with a switching power supply will be perfectly happy with just about any inverter.
Some motors, on the other hand, might not be so easygoing. I haven't had a problem so far, but I don't run much of that stuff on mine.
Instead of the curvy pretty sine wave you (should) be getting in the house, an inverter will spit out what's called a modified sine wave, which kinda looks like rectangles. Most things don't care, but I'm told some do, especially motor type stuff. As I said, I don't do much more than running a TV and whatnot off my inverter. You can always do the buy-and-try method, where you buy something, try it out on the inverter, and if it doesn't work, take it back.
If you want the pretty-sine-wavy inverter that'll run anything, it'll cost you roughly double or more, and in my opinion, just isn't worth the expense or trouble.
What you and your friend need to do is sit down, make a list of everything you want to run, then do some research into what's available and what power it requires. You can get quite a few things to run off 12v, like a fridge, fan, coffee maker, and buying a huge, beefy inverter to run that kind of stuff is a waste of money and power.
Oh, and when you see a 500 watt inverter for sale cheap, chances are almost 100% that it'll barely handle 200 watts or so for any length of time. Sometimes they beef up their advertising by claiming Peak Watts or Surge Power, and sometimes they just lie their tails off. Even if it can handle 500 watts, and you have something like 450 watts you need to run, better move up to a higher rated model. It's best to have plenty of wriggle room for start-up loads, unexpected demand, and the fact that few inverters take kindly to being pushed closer to 80% of their max rating for any length of time.
CS

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Thanks for the input; I was concerned that the square wave outputs could cause stress on the load device but you have convinced me that that should not be a concern with this application.
I agree with you that if it appears to be too good a price then it probably is!
Ron

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I saw somebody suggest a generator. These can be very small and handy, but they can be hard on your gear. Typically, the cheaper or junkie the generator, the nastier the output, usually in the form of messy sine waves and voltage spikes. I had one do this, and it wasn't even cheap or junky. Evidently it wasn't designed for 110v AC, but to run A/C units and recharge the batteries on a 24v bus (the generator had it's own battery and used 12v). It tended to blow fuses on 12v adapters, such as cell phone chargers, and killed a wall wart powering my DVD player. The conversion was done by good mechanics, but the generator just wasn't built for this stuff.
Another problem with gas generators, especially if kept strictly for emergencies, is fuel. If you leave it in there for months or years at a time, it can do damage to the carbs, and you may be out of luck when you really need it. The fuel can also go bad if you don't use stabilizer, and eventually even that will go if not used. If you use a generator on a regular basis, however, it should be pretty reliable.
Anyway, a small generator might not be a bad idea. You said elsewhere the boat was too small, but if your thinking of a small refrigerator, it's probably big enough for a smallish generator to power it. Higher power gear, such as a fridge and fans, won't be bothered by a generator's output as much as electronics, and you can still use an inverter for the more delicate stuff. This would be handy if you go camping or have an emergency.
I still prefer an inverter, and eventually I'll get a more powerful one for emergencies unless I get a great deal on a diesel genny. An inverter can sit ignored for years and still fire right up. All you need is a fully charged battery (or two, or several) which can be had with any car or truck. This makes more sense for my lifestyle.
CS

no_one wrote:
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Check out this company:
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no_one wrote:
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The 12V laptop supply will probably be more efficient and less prone to incompatibilities between a 115V PS and an inverter.
A good (not Radio Shack) inverter will provide more flexibility in the event 115 VAC is needed for other gizmos. It will, of course, be more expensive.

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My friend decided to go with the 100W Anyplug adapter from Targus; It will run from 110VAC, 12VDC, and whatever DC is used on commercial aircraft. I appreciate all the info and opinions; I knew going in that there were several ways to skin the cat and wanted to hear what others might do.
Again Thanks Ron