Converting an old Uninterruptable power supply

[Titantornado]

So I have an old APC 1000va UPS with dead batteries, and was considering making it into an inverter.  Surely enough, as has been reported here before, it won't turn on without household power present.  So I took it apart to see what makes it tick, and was surprised to see so much solid state in there.  For me, it's more than I can grasp or understand how to modify.  But, I know a little.  Like, I know that when the house power goes off, a relay(s) click, and it is running on batteries.

OK, suppose I were to manually close the correct relay(s) to make it run as if on battery backup.  Could it be that easy?  I'm not interested in the battery charging portion of the circuit board, which means I can remove the power cord, eliminating the hazard of powering it with the relay bypassed.  I just got to try find the simple way to do this, if possible. ICs knowledge is on the outer fringe of my mind's capability.

A side note, if used for continuous power, there are two nice spots for pancake fans on each side of the transistor heatsinks.

Thoughts welcome

[Phil Timmons]

This sounds like a really interesting hack to me.  I have a small pile of old UPS(s) that would/should/could work good for this.

As you observed the basic hardware is all there.  My concern in doing on line hacks like this may lead someone else into doing something unsafe.  Other than writing a whole lot of "do not do this," on a Do It Yourself site, such as this, how can we do this safely for everyone?

As interesting side note, I was interviewing for a job (EE) with APC last year.  Started chatting with their engineers about the company history.  Seems they started out of MIT as a Solar Energy Inverter company during the last "energy crisis."  As that market fell off in the 80's they switched to mostly UPS's (same innards), and they caught the climb of the computer/network/data center growth and that demand for UPS's.

[TomW]

Phil;

I, also, feel these kind of "help me" stories are very dangerous. Especially when the poster admits to not knowing what he is looking at as evidenced by this statement:



For me, it's more than I can grasp or understand how to modify.



Dangerous stuff but any time you try to note the danger in this kind of stuff the "free info" folks get all uppity.

T

[Titantornado]

Well, I admit I was trying to make myself sound a bit dumber than I am to avoid getting into a whole discussion about how to build a circuit for an inverter, and deviate from the original question of this thread.  Yes, I know a resistor, from a capacitor, from a transistor, etc. I also know what not to touch. (yes I realize there's 120 volts on portions of the circuit board, and all the relays on the board have 120v to the contacts)  

Barring any such concerns, I can tell you I'm quite competent, just a bit less when dealing with ICs.  I can (and have) build an ICB from plans, but I will have difficulty explaining how it works.  Credentials:  I was an electrician for eight years, with three years schooling before that.  I'm halfway into building an axial flux wind turbine. (see my files for evidence)  I've built a kitplane (see link in my info bar above) And I'm not a 16 year old punk either.  (34 to be exact)

Just looking for peoples thoughts.  No offence taken.  (besides, unless someone says, "that won't work because . . . . .", I'll be giving it a try anyhow)  ;-)

[Phil Timmons]

Oh sure, for me the concern was nothing to do with you, (Titantornado) at all.  This is your thread, I figured we would beat the topic back and forth to the point that we were working safely between us.

On boards such as this, there are usually MANY more "lurkers" -- guys who read and follow stuff -- than there are in any given conversation.  Typically 10 times or more.  And on this site, information sits here for years to be "mined" by others, as well.

So my pondering was how do this as a Do-It-Yourself topic and make it safe for them, too?  I know I do not have that answer, up front, but was thinking that as an engineering ethics thing, we should consider it.

[BT Humble]

...I can (and have) build an ICB from plans...

I'm so glad there was no "M" at the end of that acronym! ;-)

BTH

[scottsAI]

Hello Titantornado,

I have several Smart UPS 1000. If you have the APC PRO 1000, then this will not work.

The rumor the Smart UPS can't be turned on without 120vac is false.

Get the manual for your unit and read it:-)

In the back the Smart UPS may be labeled "cold star" or:

There is no utility power and the UPS is off. I cut this from manual.

120/230 V models: Use the cold start feature to supply power to the

connected equipment front the UPS battery(s).

Press the test button for one second and release. The UPS will beep briefly.

Press and hold the button again for about three seconds. The unit will

emit two beeps. Release the button during the second beep.

Pressing the test button will stop the unit from beeping while in off line mode.

You do not need to cut the power cord. Power is NOT back feed to utility.

I have several UPS as back up power to my whole house. Use 8, 6v golf cart batteries.

I use the whole UPS, charger and all.

If the UPS will not cold start, maybe consider a small inverter, Sams club $28 for 400w, plug UPS into it, get UPS going and turn off the small inverter.

May not be as nice as just turning it on, but should be safe, and quick.

My experience the efficiency is low on the UPS. Inverter is better. When you get it going see how long it last, do the math. You may consider sticking with the inverter.

Have fun,

Scott.

[dinges]

You mean like this guy?

http://www.interestingprojects.com/cruisemissile/

Not an ICBM, just a cruisemissile, but still. Way too many creative people around with too much time on their hands

Peter.

[nothing to lose]

" I was an electrician for eight years, with three years schooling before that."

Sorry to say that does not really mean much sometimes. I don't mean you though.

 I got about a 58 year old life time Electrician with lots of schooling always trying to tell me how I am wasting my time building wind gennies because they simply don't work

HE beleaves that for real!

He may know how to wire up a factory and handle 480V, but he don't know squat about about inverters, magnets, magnet wire, etc...

Anyway, have you looked for a manual for the UPS and see if anything is there about hard starts or cold starts, whatever they called it. Most of the ones I been playing with DO startup off batteries. About 650watts-1000watts for the small home type UPSs.

May need to hold the ON button for a few seconds. May need to hold it till the UPS beeps and let go DURRING the beep. May be the TEST button to use instead of the ON button. Some are trickey to start on batteries, but so far all of mine have.

The 2200 rack mount ups, 1750watts sinewave, I have to hold the Test button till it beeps and let go durring the beep. Let go before the beep or after the beep it does not turn on. Have to let go DURRING the beep! I think I tried to startup about 5 times on batteries before I got it just right the first time. I was staring to think oh crap it ain't gonna do it, but once I got it the first time I now get it everytime easy. Just had to figure the system. I think I only got it right after downloading the manaul for that one and several tries.

A side note on Sinewave UPS started on batteries. I noticed with at least one UPS about 1000watts that the window fan I was testing with ran slower on the UPS when started on the batteries, I pluged UPS into the grid and the fan speeded up to full speed, unplug the grid and fan stayed running at full speed.

I don't know why, but it SEEMS like the fan was running slower like on a modwave inverter to begin with. When I connected the grid and it ran full speed and continued to run full speed after unplugging the grid it made me wonder if there is something there that senses the grid to kick it into proper sinewave operation?

I was testing about 5 UPSs that I had bought as junk for parts cheap (4 worked fine) and only had one set of batteries. I should have went back and further tested that one like with a digital clock and seen if it kept time, but I didn't do that yet.

[Phil Timmons]

Super answer, Scott >>>

"If the UPS will not cold start, maybe consider a small inverter, Sams club $28 for 400w, plug UPS into it, get UPS going and turn off the small inverter.

May not be as nice as just turning it on, but should be safe, and quick."

That is safe, cheap and anybody can repeat it without danger to themselves or others.

Good job!

========

Regarding other folks observations about inverters and UPS and their cyclic rate -- (which sometimes varies from the nominal 50 Hz or 60 Hz).  The cyclic rates and voltages can vary depending on the intended use -- as only back-up v. grid tied v. who knows?

We just put in an SMA system for a customer about 2 months ago, that uses seperate inverters for the grid tied portion and combination inverter/chargers for the battery back-up system.  They (SMA) sure made their rig complicated.  So that it can verify that it is "off-grid" when the grid power is off, it shifts the cyclic frequency to about 59 Hz.  But then, so that clocks and motors do not go too slow in the cumulative, it speeds up in pulses to about 61 Hz.  And it does this talking back and forth between the equipment.  Just crazy complicated, in mho.

Of course, the Electrical Gods were not amused by we mortals and such nonsense, and sent lightning and toasted the entire control system.  Something like $30,000 damage.  That was a good day to not be the insurance company.  Nature is a Mother.  

[BT Humble]

Yeah, I've read about him before.  It seems his life has taken a turn for the worse since he announced that project.  

I can't say that I'm surprised!

BTH

[Titantornado]

You were right on Scott.  She started right up on the cold start procedure.  That saves me a lot of trouble experimenting.

Many thanks!