Any electrical engineers on this forum? : LUSENET : TimeBomb 2000 (Y2000) : One Thread

I recently came in possession of a UPS backup system. We replaced the backup on one of our mainframes because the battery pack was aged and weak. It comes in two boxes. One box has the inverter, 1500 watts and the controller. The batteries are in a seperate box that attaches to the inverter box via a cable.

My question is if I replace the batteries can I use this package plus one or more solar panels and have a working solar power package? If so would I have to do anything more than attach the panels to the batteries? Also which pole should I attach the panels to and would it need to be done in series? Almost forgot; what do I need to do about the inverter / controller wall plugin? What was an AC charging source must become a DC charging source.

Any help would be very much appreciated. I am a code head and this is a hardware problem.

Respectfully, Ed Stevens

-- Ed Stevens (, November 22, 1998



Yes you can. Basically, you should use a charge controller between the solar panels and the batteries. You have options with the 'built- in' charger. I'd use it to charge the batteries from the line when you have power and install a switch to select line/solar as a charging source. The line source starts off as AC, but it has a rectifier to provide DC for charging the batteries.

I've sent you an email with more details.


-- Dealton Lewis (, November 22, 1998.

Please copy me that email. Thanks.

-- Robert A. Cook, P.E. (Kennesaw, GA) (, November 22, 1998.


Raqther than being the 2nd of thousands (or at least tens) and ask for a copy via e-mail, you may as well post it.


-- Chuck a Night Driver (, November 22, 1998.

Well, the reason I went to email is that I drew a diagram, using excel. I'll put the text here, but omit the diagram. And yes, Chuck, I'll send you a copy of the diagram. ------------------------------ When you refer to a 'controller,' what is the function of that device? I am assuming that it switches automatically from line power to inverter power in the event of power failure, and that it provides for charging the batteries when line power comes back. Is this correct? [Alternate energy systems often use a device called a charge controller between solar panels and the batteries in order to provide proper charging taper. Good commercial inverters do the same thing for a generator/line power. You should provide a charge controller, in addition to the solar panels. They're relatively cheap. Browse and for charge controllers. You should have these so that the batterys get a stiff charge to start, with the charge trickling off as battery voltage comes up. They also prevent the panels from draining the batteries at night. The connections would go as follows: a. From solar panels to charge controller -- two lines (+ and - ) b. From charge controller to batteries -- two lines (+ and -) c. From battery bank to inverter -- two lines (+ and -) -- I would also install a fuse in this line (big) d. Inverter/controller -- hooked up per manufacturers original wiring You can do one of several things with the wall plug-in. It's a charger. Although you plug it into the line voltage (ac) somewhere along the way is a converter that rectifies the ac and converts it to dc in order to charge the batteries. You don't want to be charging from two sources at the same time. On the other hand, I wouldn't throw this power source out. If Y2K results in sporadic power outages, it will be good to be able to charge batteries whenever the line voltage is available. What I would do is to put a double pole switch in the system, so that you can use the switch to select either the solar panels or the line voltage in order to charge the batteries. That way, you use what you can get to charge. By using a double pole switch you make sure that you can only connect to one charge source at a time. Hope this helps. Can you use an Excel attachment? I can draw you a diagram if you can DeAlton Lewis..........who spent 38 years as an electrical engineer and who envys you that UPS

-- DeAlton Lewis (, November 22, 1998.

Hi Ed, DeAlton, All,

Ed, I'm kind of curious about the mainframe that had a 1500 watt (volt-amp?) UPS. That's the size I use on my PC.

You might double check the size of the inverter so you get the correct size of wires you use to interconnect the inverter, controller, batteries, etc.


-- Dean T. Miller (, November 23, 1998.

DeAlton, the small backup is only ment to carry an NCR 3430 for one or two hours. Not my decision. I am in a don't throw anything away mode and that is why I now have it. I also have my eyes on a sturdy pallet in the storage area. Might make a good butcher block to put in the barn. Those chickens, rabbits and catfish are going to need somewhere to lay down.


-- Ed Stevens (, November 23, 1998.

I'd like to see which ones wake up if a catfish goes to bed with a chicken....8<)

Guess it depends on the relative size of the catfish, eh?

-- Robert A. Cook, P.E. (Kennesaw, GA) (, November 23, 1998.

<<"...the charge controller, ..... also prevent the panels from draining the batteries at night."<<

A small nit. Commercial solar panels come with a blocking diode built-in, which "prevents the panels from draining the batteries". If the charge controller has an additional blocking diode (just in case it was left off the solar panel?) then all it accomplishes is dropping an ADDITIONAL 0.6 - 0.7 vdc of charging voltage during sunny times, thus dropping the overall efficiency of the system. This info doesn't affect the good tech info supplied above!

- Bill

-- Bill (, November 29, 1998.

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