I want to make a small UPS, one that would be able to run my
PC for a little while if the power failed (enough so it can
shutdown it self down properly).
2 ways I have thought of doing it.
1st would be a 240V to 12Vbattery back to 240V that can be run
in series with the incoming supply.
2nd would be to modify the existing switch mode computer power
supply to include the battery.
I would like to do the second method as that sounds easier :)
Any suggestions or pointers to websites that may help me out?
I think the best way is to build a dc-dc psu parallel to 12v/10Ah battery
and to use any ups software as I use.
modify it with 2 relays (for shutdown) and you have a simple solution.
> I want to make a small UPS, one that would be able to run my
> PC for a little while if the power failed (enough so it can
> shutdown it self down properly).
>
> 2 ways I have thought of doing it.
> 1st would be a 240V to 12Vbattery back to 240V that can be run
> in series with the incoming supply.
> 2nd would be to modify the existing switch mode computer power
> supply to include the battery.
>
> I would like to do the second method as that sounds easier :)
>
> Any suggestions or pointers to websites that may help me out?
I'd suggest you buy one. Making one generally is more work then it is
worth, and dangerous to boot. Small UPSs can be found very cheaply these
days. TTYL
Hmm, APS? I haven't heard of that one, might you mean APC? If not I
apoligize in advance. I myself have an APC and I love it, not many frills,
but it gets the job done. TTYL
There was a 700VA UPS at Fry's. (now AKA Outpost.com) They were selling
them for $58 with a $50 rebate. You might want to keep an eye on them for
that deal again. It was a Joe-Generic UPS and did not have a serial port to
indicate that it was running on battery. You should be able to modify the
design with a pic and add that feature. It barely has enough time on my
system to keep it alive long enough to shut down, but very seldom does my
power go out for more than a few seconds anyway, so I just use it to bridge
the brown outs.
Peter Mcalpine wrote:
>
> Hi Herbet,
> supposed had not really looked at small UPS as though the
> cost was a bit much, will do some web searching.
>
> Can anyone recommend a good small UPS?
> (Would actually prefer rack mount also :)
> > I want to make a small UPS, one that would be able to run my
> > PC for a little while if the power failed (enough so it can
> > shutdown it self down properly).
I'd try something a little different, use 3x 6v
gell batteries, I think 18v is about right, then
2 simple smps buck regulators to give 12v and 5v
at the decent amps. Maybe you could run 12v battery
and no/minimal 12v regulation?
It could be a good system if you can charge the
thing from a car battery or truck (24v) battery,
or even solar.
But what about the monitor?
-Roman
-- http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
I dunno if it is of value to you or not, but I am almost done with a new
DC UPS design. HW is done, SW is nearly done, working on some time
totalizers in it.
It has
85-265VAC input
24VDC @ 800mA output
one 12V gel cell or lead acid battery you attach
Adjustment to match AH
Full charge cycle control in software
Modbus serial port allows access to all control parameters
I designed it for the remote telemetry location application where they
do not want to put an office rated UPS in the box. This one is a rail
mounted device.
I plan a 100W version, but that takes custom magnetics, so I gotta
finish the 800mA version first.
-- http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
> Peter Mcalpine wrote:
> >
> > Hi Herbet,
> > supposed had not really looked at small UPS as though the
> > cost was a bit much, will do some web searching.
> >
> > Can anyone recommend a good small UPS?
> > (Would actually prefer rack mount also :)
>
> > > I want to make a small UPS, one that would be able to run my
> > > PC for a little while if the power failed (enough so it can
> > > shutdown it self down properly).
>
>
> I'd try something a little different, use 3x 6v
> gell batteries, I think 18v is about right, then
> 2 simple smps buck regulators to give 12v and 5v
> at the decent amps. Maybe you could run 12v battery
> and no/minimal 12v regulation?
>
> It could be a good system if you can charge the
> thing from a car battery or truck (24v) battery,
> or even solar.
>
> But what about the monitor?
Use a small 100va 12vdc->120vac inverter and power it right from the
battery supply.
-- Mitch
-- http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
>Hmm, APS? I haven't heard of that one, might you mean APC? If not I
>apoligize in advance. I myself have an APC and I love it, not many frills,
>but it gets the job done. TTYL
That's what a loss of a night of good sleep does to us. Sorry :o(
This is something I've always thought about. Essentially what the PC
requires are +/-12Volts, and +/- 5V. Why dont they come out with a standard
for a 'power supply port'? Since the current requirement for the -ve
voltages is minimal, wouldnt it make a lot of sense to just connect the
motherboard to a battery thru proper rectifiers to block current when the
power is present? The most expensive electronic stage in a conventional UPS,
the inverter, could be completely eliminated. The battery could have an
external charger, or the 'port' could have a source trickling back from the
SMPS to charge it. The negative voltages could be derived from the battery
as well.
I do have a feeling i am missing something here, but what is it?
> This is something I've always thought about. Essentially what the PC
> requires are +/-12Volts, and +/- 5V. Why dont they come out with a standard
> for a 'power supply port'? Since the current requirement for the -ve
> voltages is minimal, wouldnt it make a lot of sense to just connect the
> motherboard to a battery thru proper rectifiers to block current when the
> power is present? The most expensive electronic stage in a conventional UPS,
> the inverter, could be completely eliminated. The battery could have an
> external charger, or the 'port' could have a source trickling back from the
> SMPS to charge it. The negative voltages could be derived from the battery
> as well.
>
> I do have a feeling i am missing something here, but what is it?
>
> Anand
>
The newer motherboards (ATX) generally start out on 250W power supplies
which provide up to:
+5v at 27A
-5v at 0.5A
+5v at 1A (Always on)
+12v at 9A
-12v at 0.5A
+3.3v at 14A
The thing you're missing is that to supply 27 and 14 amps requires a
good bit of design in a switching power supply. Of course, your
particular setup may require less, but the cost in time and money to
design it is much more than the cost of a decent external 120V UPS -
which can also power your monitor.
Given that you probably aren't about to create a new PS for your
monitor, and the computer is useless without the monitor, you may just
think twice about making an internal system, instead of external.
>This is something I've always thought about. Essentially what the PC
>requires are +/-12Volts, and +/- 5V. Why dont they come out with a standard
>for a 'power supply port'? Since the current requirement for the -ve
>voltages is minimal, wouldnt it make a lot of sense to just connect the
>motherboard to a battery thru proper rectifiers to block current when the
>power is present? The most expensive electronic stage in a conventional UPS,
>the inverter, could be completely eliminated. The battery could have an
>external charger, or the 'port' could have a source trickling back from the
>SMPS to charge it. The negative voltages could be derived from the battery
>as well.
>
>I do have a feeling i am missing something here, but what is it?
>
>Anand
>
> The newer motherboards (ATX) generally start out on 250W power supplies
> which provide up to:
> +5v at 27A
> -5v at 0.5A
> +5v at 1A (Always on)
> +12v at 9A
> -12v at 0.5A
> +3.3v at 14A
>
> The thing you're missing is that to supply 27 and 14 amps requires a
> good bit of design in a switching power supply. Of course, your
> particular setup may require less, but the cost in time and money to
> design it is much more than the cost of a decent external 120V UPS -
> which can also power your monitor.
>
> Given that you probably aren't about to create a new PS for your
> monitor, and the computer is useless without the monitor, you may just
> think twice about making an internal system, instead of external.
>
> -Adam
>
> Anand Dhuru wrote:
>
> >This is something I've always thought about. Essentially what the PC
> >requires are +/-12Volts, and +/- 5V. Why dont they come out with a
standard
> >for a 'power supply port'? Since the current requirement for the -ve
> >voltages is minimal, wouldnt it make a lot of sense to just connect the
> >motherboard to a battery thru proper rectifiers to block current when the
> >power is present? The most expensive electronic stage in a conventional
UPS,
> >the inverter, could be completely eliminated. The battery could have an
> >external charger, or the 'port' could have a source trickling back from
the
> >SMPS to charge it. The negative voltages could be derived from the
battery {Quote hidden}
> >as well.
> >
> >I do have a feeling i am missing something here, but what is it?
> >
> >Anand
> >
> >----- Original Message -----
> >From: "Peter Mcalpine" <@spam@pmcalpinKILLspamBIGPOND.NET.AU>
> >To: <KILLspamPICLISTKILLspamMITVMA.MIT.EDU>
> >Sent: Wednesday, January 02, 2002 5:55 AM
> >Subject: [EE]: Small UPS
> >
> >
> >>Hi All and happy new year :)
> >>
> >>I want to make a small UPS, one that would be able to run my
> >>PC for a little while if the power failed (enough so it can
> >>shutdown it self down properly).
> >>
> >>2 ways I have thought of doing it.
> >>1st would be a 240V to 12Vbattery back to 240V that can be run
> >>in series with the incoming supply.
> >>2nd would be to modify the existing switch mode computer power
> >>supply to include the battery.
> >>
> >>I would like to do the second method as that sounds easier :)
> >>
> >>Any suggestions or pointers to websites that may help me out?
> >>
> >>Thanks!
> >>Peter Mcalpine
> >>
> >>--
> >>http://www.piclist.com hint: To leave the PICList
> >>RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu>
> >>
> >>
> >>
> >
> >--
> >http://www.piclist.com hint: PICList Posts must start with ONE topic:
> >[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
> >
> >
> >
> >
> >
>
> --
> http://www.piclist.com hint: The list server can filter out subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
>
>
>It could be a good system if you can charge the
>thing from a car battery or truck (24v) battery,
>or even solar.
>But what about the monitor?
Hmm, LCD? :o)
Far far away from this galaxy, in a long time ago ;o) I had a "laboratory on a van", that had a complete PC running in a No-Break, with 2 150AH batteries being recharged at night, when I was back home. It was an interesting experience ;o)
Pretty simple actually... the monitor. You'd still probably need an inverter
for the monitor, and even if you didn't there are still a variety of
peripherals that have different voltages, ie. printers, scanners, etc. While
this may sound crazy the easiest solution is an inverter, all of these
devices work with 120V AC. Aside from that inverter technology has
progressed amazingly in the past couple decades, it is no longer the huge
bulky, noisy and wasteful device it used to be. TTYL
There is a chance that you could use a DC/DC converter to switch the DC
up to about 100VDC. If the power supply is a simple off line switch
converter, it simply rectifies the line to DC and uses that. Just a long
shot. Last time I took a PC power supply apart, that is how they worked
(AT supplies). A 12V to 100V DC/DC converter ought to be much simpler to
build.
Herbert Graf wrote:
>
> Pretty simple actually... the monitor. You'd still probably need an inverter
> for the monitor, and even if you didn't there are still a variety of
> peripherals that have different voltages, ie. printers, scanners, etc. While
> this may sound crazy the easiest solution is an inverter, all of these
> devices work with 120V AC. Aside from that inverter technology has
> progressed amazingly in the past couple decades, it is no longer the huge
> bulky, noisy and wasteful device it used to be. TTYL
>
Some years ago I made some dc-dc converters for this purpose for the local
power company here. They ran off 48v dc and powered the normal computer
power supply and monitor off about 280 V dc. You had to disconnect the de
guassing coils in the monitor though. It was a very cheap way of doing it.
We also made a 12V version.
George Tyler
> > > > I want to make a small UPS, one that would be able to run my
> > > > PC for a little while if the power failed (enough so it can
> > > > shutdown it self down properly).
> >
> >
> > I'd try something a little different, use 3x 6v
> > gell batteries, I think 18v is about right, then
> > 2 simple smps buck regulators to give 12v and 5v
> > at the decent amps. Maybe you could run 12v battery
> > and no/minimal 12v regulation?
> > But what about the monitor?
>
> Use a small 100va 12vdc->120vac inverter and power it right from the
> battery supply.
Hmm, it still bugs me that the PC requires
mainly +5v and +12v dc, and having to use an
inverter to go from battery to AC then back
to DC in the PC PSU. And most TVs and monitors
have a main 110vdc rail that supplies the
whole device, i've often wondered about solar
systems etc that have a high voltage DC rail.
It can be very handy haveing a 120v dc battery
system...
-Roman
I have seen SMPS for PC with built in batteries, its charging circuit &
12VDC-330VDC inverter circuit. Good for 2-3 mins for PC. But that maynot
feed your monitor. So in case power fails, your monitor will turn-off but PC
will be alive. then you can initiate shuttdown.
Probably you have a PC with such power supply but external batteries. OR may
be its SMPS with 12VDC output for poweing external devices for same SMPS!
Hitesh Mahant wrote:
>I have seen SMPS for PC with built in batteries, its charging circuit &
>12VDC-330VDC inverter circuit. Good for 2-3 mins for PC. But that maynot
>feed your monitor. So in case power fails, your monitor will turn-off
>but PC will be alive. then you can initiate shuttdown.
Where did you see this ? I would be interested in a type number, price
etc. If you have any info please forward it.
tia,
Peter
-- http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads
mitvma.mit.edu
