Battery Backup UPS 650

I have the battery backup's, a 750 & a 650 made by APC. I believe one gives me 1 hour and the other 75 minutes of reserve power. Their model numbers are BACK-UPS-ES 750 & 650.

Our power here went out last Thursday. We have cable and a generator that I am using to power the house and this computer at this moment.

Well, the first night having not yet bought a generator, I plugged a 25 watt light into the UPS. I calculated 650 / 25 should give me 26 hours of light. Well I got maybe 3 hours before the UPS started constantly beeping and I had to switch over to flashlights. I believe the other UPS also gave about the same.

Could someone help me in what I figured wrong in my calculations.

Right now, I have the computer plugged into the UPS. It beeps 4 times every 30 seconds indicating noise in the line. The generator is gived 120 volts at 63 Hz. Is their any danger to the computer/monitor, etc. using a generator to power the device?

Everything you ever wanted to know

http://www.apcc.com/products/runtime_for_extendedruntime.cfm?upsfamily=21

Mark , that is like saying $10 will buy me a meal , yes at McD's it may , but it won't get you through the front door of a decent restaurant . One hour backup driving what , or should I say Watt ?


What on earth are you doing to the genny ?
Now , the UPS is telling you that things aren't well in the State of Denmark , do YOU think it would be a good idea to power equipment that is not tolerant to spikes and transients into a supply that maybe producing spikes and transients ?

Mark , if you throw a pin at me , i'll be sure to duck , maybe you have the grenade in your mouth.

Sorry to be a bit naughty Mark , but I think this one is on a plate for you .

Please remember that UPS's are rated on 2 things , the load that can be driven , and the capacity of the backup battery available to drive it . For example , you may have a 0.5 kVA UPS , but with a 24V 1000AH battery to power it .

The numbers like 650 or 750 indicate the total instantaneous load that the UPS can drive. Suppose your load is two PCs. If one of your PC power supplies is 400W and the other is 300W, the combined load (300 + 400 = 700) wcould exceed the 650, but not the 750 rating (assuming the p/s are actually maxing out, not always true).

The instantaneous load has no relationship to the capacity of the batteries used for back-up. There are desktop UPS supplies with small batteries and industrial supplies with battery packs that need to be moved with a forklift. Since most UPS use lead acid batteries, the weight of the battery is somewhat of an indicator as to how much chemical energy.

The spec sheets of UPS give amp/hour ratings and either a table or a calculation for figuring out how long the batteries will last for a given load.

Dan