UPS CONVERSION

[(unknown)]

Hi All,

  I'm looking for any information re: converting a 1400VA APC UPS to a battery Bank powered wind/ Solar charged inverter system. I'm planning on using two 12v Deep Cycle batteries wired in series (UPS needs 24Vdc) , and charging will be done with a 40v Ametek and Solar supplemented with about 10 watts power. My BIG 2 questions are has anyone used this type of UPS and if so how did they disable the ON/OFF feature when plugged into AC only? and also how can i manage to charge BOTH 12v batteries at the same time using my 12v Wind/Solar power with the Batteries hooked in series?

              Thanks for any input,

                           Macguiver2

[drdongle]

Firstly 10 watts of solar will never fill your needs, think more like 500 watts.

secondly I'm not sure I understand you on/off question regarding the inverter. Most UPS's will come on automatically as soon as the 12 or 24 DC is connected, though some want to see 120 VAC first then disconnected to work.

As for charging a 24 volt bank from 12 volts, there is no simple way to do this, except to use a 12 to 30 volt converter between the generator and batteries, or to switch batteries from series to parallel ( which means when charging you can't use them).

Carpe Vigor

Dr.D

[edy252]

another question about ups conversion (or usual inverters) is how to disable the auto switch-off feature when using deep cycle batteries...since we can take more power from a deep cycle battery without harming it...and usually ups systems are made to use lead-acid batteries.

[(unknown)]

Thanks for some feedback,

I didn't quite give enough info before. The combined Wind/Solar wattage will be something around 110-180 watts. The disconnect question was to enable the UPS to be turned on with a switch instead of the automatic ON feature when disconnected from AC line.

[ghurd]

I have done quite a few of these types of set ups.

First, I am assuming that 1400VA (1400 watts-ish) is a lot more than you really need, and therefore, you are wasting a LOT of power to run this monster (unless you have a power hungry laser printer). Example my Sony Vaio, 17" flat panel, inkjet printer, cordless phone, and fax will run eaisly from a US$45 Vector 400W inverter (mid-quality, more efficient than most, easy to get, and cheap).

Second, forgive me, but I don't know anything about a 40V Ametec, but you said 12 volts, so I'll go with it.

You are going to find it cheaper and better to start over.

Get a 12 volt battery the right size, and a little bigger. Wet is much cheaper, but any sealed is nicer in the home. Battery sizing information is available and specific to you situation. Deep Cycle only, look for AH or amp hour rating. If it lists 'Cranking Amps', it's probably a half-breed or just a car battery with a different sticker. If you have the Ametek, you probably alredy have enough batteries.

Figure how much power you really need to keep your equipment running, multiply it by 1.2 (20% extra). Maybe go up a step for future expansion. Most run about 90% efficient at 90% capacity, too big is a Huge waste, and too small won't work. Get the inverter.

Connect it all together. Almost plug and play.

Here is why I say to start over.

1. st- 12 to 24V is not too easy, cheap, or efficient.
   
2. nd- Most 12 volt stuff is readily available, and cheaper.
   
3. rd- I think the efficientcy of going 12 to 24V rules it out, not to mention cost and reliability (more fancy parts = more failures).
   
   

Big 4th- you may have the chargers and batteries already. You need a $40 inverter with a switch. You can sell the UPS.

About the 10 watt panel. It's going to make about 0.58 amps, or about 7.4 watts, almost negligible. In comparison, your UPS is probably using 18 to 25 watts when it's not even running anything. If you already have it, or if it's free, by all means hook it up! But here (US), for about double the money, you can get a panel 5X bigger that will count for something. A 10 watt panel into batteries used often, or over say 40 AH, won't even need a regulator, just a diode (use the diode, the diode discussions about not using it are flawed).

I've seen this dozens of times. Someone has plenty of solar, but can't keep up with there needs. Turns out they are running a 1000, 1200, and once even a 2000 watt inverter to recharge drill batteries needing 32 watts peak, for 8 hours. The inverters were actually using several times more power than the batteries! A $30 inverter fixed the problem. The guy who sold them the inverters, said they needed $thousands more of his solar panels.

[RatOmeter]

Your solution might be addressable through the APC's configuration software (PowerChute I think) by setting the dropout voltage to a lower value.

For the original question, maybe this can be accomplished through the 9-pin serial communications connector.

To shutdown the UPS, hold the Receive line (pin 2) at RS-232 high level for 4.5 seconds.

To power up the UPS, there's another pin on the connector that you can tie to some voltage (another RS-232 level?) for 4.5 seconds.  Unfortunatly I can't remember and haven't yet found (by google) those details yet.

Here's the one hitch in the plan, I'm not sure if it will agree to turn on if no mains power is present.  It certainly will not power up via the front panel button under those conditions.

Beyond that, pretty much everything is under the control of the firmware, so it's not readily modifiable.  One of my APC UPSs is controlled by an Intel 87C51 microcontroller and I happen to have an EPROM version of the same type of chip.  However, APC secured their firmware EPROM so there went my plan to copy and modify the code to make it RE-friendly (I will probably never find the time to program it from scratch).

I'll post again later if I can firm up some of this info.

[drdongle]

Well if the RS 232 connector dosn't fix you problem just aad a switch ( of proper power handling capablity) in series with the + line from the batteries.

Carpe Vigor

Dr.D

[tecker]

   The UPS does waste power but if you want good clean pwr it's a good idea .

 As for charging 24 with 12 you can use two regulating supplies at the 12 volt legs of your batery bank.  

[tecker]

 that's battery

[(unknown)]

I appreciate all the feedback i'm getting. Ultimately what i'm trying to do is lower my electrical costs by powering all of my security lighting (about 500Watts),with my wind generator and solar panel. I want to charge two 12volt deep cycle batteries at the 12v rate although they need to be connected in series to supply 24volts to the UPS. The UPS is going to be used to supply the 120vac for the security lights. This UPS is rated at around 1000watts so 500watts (absolute max), should be safe. If my calculations are correct the A/H capacity of the 2 deep cycle batteries should be enough to run the UPS powering the security lights all night and maybe the next night as well ,(on one full charge). The problem that i'm considering is ,how will i be able to turn on the UPS at night (automatically) ,to power the lights. Charging of the batteries seperately, when they are hooked in series is the last problem. My Ametek 40vdc Tape drive motor is capable of putting out 24vdc and higher but only at winds of around 20 mph or more. The average wind speed in my area is around 10 to 12 MPH ,which gets me output of 14 to 16vdc consistently. This is why i want to charge both 12v batteries seperately with 14vdc adding a little help from 10 watts of solar . I have already built one 12v charge controller/regulator and i think i will probably have to build another one to do the seperate charging of the two batteries from the same source.

What i really need is a bigger wind generator and 2 more batteries, BUT, i'm limited on the cash for this project. If this works well i'll buy more batteries and another 1400va UPS , put up another ,BIGGER, wind generator and power my workshop from it, (saving more on my electric bill).

The reason i'm using the UPS as the inverter is the cost. I get these 1400va APC UPS's for $25.00. they are used but in great (tested), condition. Three of these adds up to 3000watts and $300.00 less than 1 single inverter of the same wattage.

Modifying them to do what i want is where the information runs low. This is where i need the biggest help from everyone out there. If i can use a old computer to turn on the UPS through the RS232 at the right time of the night , that may be an option !

 I've also thought of using a timer to shut the AC input of the UPS off thus turning on the lights at night. Except they would be on during the day too if there's no "daylight OFF" sensor. AHHHH, my brain's starting to hurt again. Help me if you can , Thanks !!!!

                            Macguiver2

[drdongle]

I suggest a photo electric control, it's simple, inexpensive, and can interface with the inverter unit directly WITH OUT A COMPUTER.

Carpa Vigor

Dr.D

[tecker]

   Yep use the photo if you need them on all night or constant on for a given period at night motions on zones with the ups inabled after dark . get a couple of Altronix smp 7

and  power them with your charging system hook one to each battery and there you go.

 With the motions turning on  with activity around the area that is covered by that zone fixture you should conserve Quite a bit . The photo cell will shut down at dawn and  drop the charging relay back in to charge up with your syatem .