Comments on: diy dual conversion ups

By: carlton

carlton — Wed, 20 Jun 2007 20:20:04 +0000

@2: nope, for a heck of a lot of reasons, namely, all the power losses. power factor losses (current and voltage not in phase on input or AC output stage), core losses and winding losses in the transformer, switching losses in the inverter, the list goes on and on. if you spent a good deal of time/money, you *may* be able to get above 80, maybe 85% efficiency. If you're really good, know the theory, simulate and build a really solid design, that efficiency can get up past 90%, maybe up to 92-93% (as with top-of-the-line UPS systems, which are mucho expensive).

@3: for the above reasons, you would be using more volt-amps then you would be getting out.

By: Dark_Photon

Dark_Photon — Wed, 12 Jul 2006 12:37:24 +0000

I like #9′s idea a lot. I’ve wondered myself how to get something together that would do that – and it wouldn’t have to last very long, either – 5 mins at the most, screw the monitor. I just need enough directly fed power to hit ctrl-S on my keyboard and then hit hybernate. Can anybody point me in the right direction? I can’t be only the second person to have ever thought of doing this.

By: Phill Kenoyer

Phill Kenoyer — Sun, 14 May 2006 00:22:56 +0000

I’ve got a good UPS setup for my servers.

First I have 8 350A/hr batteries. Then I have an Iota 12vDC/75amp charger, with the smart IQ module. Then I purchased a bunch of 12vDC power supplies from Mini-Box.

I pulled out the power supplies that were in my servers, then put in the new DC power supplies (each PS is 100Watt). I have 7 servers that can run for about 10 hours without power.

By: tha_bommer

tha_bommer — Wed, 15 Mar 2006 20:18:05 +0000

I have one of these setups running.

A heavy duty car battery charger (you know one of those 3′ tall standing models with all of the overdraw and overheat protection built-in)
6 1000 Cold Cranking Amps (850 Amp) lead acid 12 volt batteries connected in parallel with an isolator on the charging end.
2 inverters 450 and 400 watt.
2 3.06 GHz PCs with 450 watt power supplies.
1 toshiba A70 laptop running 3.2 GHz mobile P4 (draws just over 2 amps @ 120 volts charging while on)
I have a few meters on the rig at all times, overheat protection on the wiring, charger, and inverters. Low-voltage shutdown.
So far the longest unpowered test of the system was 2 days.
My next upgrade I think will be finding a good way to connect the thing to a computer or all of the computers so they will shutdown, or at least hibernate when the voltage gets near the danger zone with the CRT off. As well as maybe an audible warning for heat or voltage related shutdowns.
Only thing is I need to watch the charger and periodically check the temperatures and acid levels of the batteries and top em up.
I would have used deep-cycle batteries but at the time I made my rig the 1000 CCA car batteries were free for me from work.

So far no fires or overheats.

By: Colin

Colin — Thu, 28 Jul 2005 19:44:30 +0000

Re: 24 You can usually replace the internal UPS battery with a bigger one without problems – although the UPS may wonder why the new battery is taking longer to charge, that should be OK. DON’T attach any extra shit (battery float charger), it may confuse or damage the UPS.

By: AK

AK — Wed, 27 Jul 2005 22:18:55 +0000

what do you guys think of this: i have a 800va belkin ups with a worn out battery running my computer network. i want to replace the worn out (gel-cell?) battery with a good optima sla and also attach a battery float charger to maintain the optima battery. anyone see any problems with running my ups this way?? thanks

By: Jay

Jay — Wed, 13 Apr 2005 16:41:17 +0000

strider_mt2k: Current isn’t “pulled” from
batteries. A chemical reaction in the battery
causes electrons to build up the surface of one
electrode. The other electrode ends up losing
electrons as they’re moved by the chemical
process. The excess electrons on one terminal
repel each other so they spread out. They spread down the conductive plate and
out of the negative terminal of the battery.
On the other terminal the reverse happens.
The chemistry in the battery drives the whole
thing. The load does nothing to drive this
process.

By: Jimmy the Clown

Jimmy the Clown — Thu, 17 Mar 2005 10:46:18 +0000

It is best to use “deep cycle” batteries, as car batteries aren’t meant to be completely discharged. Car batteries are meant to provide a ton of current for a short period. Discharging them completely damages them. Deep cycle is the opposite.

By: digitalFX

digitalFX — Fri, 18 Feb 2005 06:31:52 +0000

#14, I agree 100%. I swapped out my 7.5 AH in my belkin battery backup for a 33 AH sealed lead acid and have had no problems for the past 6 months. In tests I went from 30 minutes before the low battery light came on to over 2 hours. All I did was get more connector and make “extender” wires for the new battery sitting behind the UPS.

By: CDE

CDE — Fri, 11 Feb 2005 00:57:58 +0000

#19: No.

By: nr19

nr19 — Thu, 10 Feb 2005 23:56:55 +0000

just to get a more quiet computing experience could something like this be used as an replacement for the pc power-supply?

By: strider_mt2k

strider_mt2k — Thu, 10 Feb 2005 01:57:51 +0000

#16
Current isn’t SENT through a system it’s PULLED through the system by the device drawing it.

Batteries hooked up that way will merely have more capacity for doing work: It will run longer, not use more energy.

how’s that?

By: Eric Cox

Eric Cox — Wed, 09 Feb 2005 17:31:59 +0000

A far cheaper solution is to do what I did: get yourself a cheap “off the shelf” 12V UPS, and simply replace the battery with something not quite so pathetic. I bought an APC 12 volt UPS (about $60 US), and a deep-cycle marine battery from Optima (http://www.optimabatteries.com). The battery is a lead-acid battery, but the lead-acid is in the form of a thick paste, so no leaking. Then I simply invested in a few connectors and a length of (very heavy) wire, and drilled a hole in the UPS case for the wire to go through (remember to put a rubber grommet in it!). I then soldered up the connectors to the wire, and had myself a great UPS (made for that purpose) only with a beefy battery on it.
My setup is 2 rackmount PCs, a KVM switch, a wireless router, 2 17″ LCD monitors and a large stereo amp. Last year the trasformer behind my house blew up, and this UPS ran my entire setup for 2 days. (1 PC was on 24/7, 1 was on only during the day)

By: CDE

CDE — Wed, 09 Feb 2005 01:28:04 +0000

#15: and your lack of any evidence to back up your claims is staggering

By: casual observer

casual observer — Tue, 08 Feb 2005 23:37:50 +0000

#8 your ignorance is showing