Stupid question maybe,about a UPS

Shadow250 · Post by **Shadow250** » Tue Jun 22, 2004 9:41 am

i have a tripplite 750 va UPS backup. what i wonder about it is will it damage a laptop if it is using the inverter? what ie been told is inverters do not convert to true ac but mimic it some how? what makes me wonder is we usually get at least one bad t-storm that kills the power for a day or two and i cant run my big comp off the ups for more the 30 mins but at 7% load it would run a laptop for much longer than the internal batt if converted power is not harmful. i think it would not be a problem since the big comp runs on it fine but the laptop could be more sensitive.

Karchiveur · Post by **Karchiveur** » Tue Jun 22, 2004 4:14 pm

but the lappy can run off a battery anyways?
I can't see it being much different... on UPS

wvjohn · Post by **wvjohn** » Tue Jun 22, 2004 5:07 pm

hurricane last year i ran my lappy off an inverter hooked to a car battery with no apparent issues

Pugsley · Post by **Pugsley** » Tue Jun 22, 2004 7:26 pm

Older inverters (1950-1975ish) Are bad because they dont make a sine wave AC they make a square wave AC. Newer inverters are all sine wave just like whats comming out of the wall.

Post by **FlyingPenguin** » Tue Jun 22, 2004 7:30 pm

Any modern UPS will work just fine.

However, assuming your laptop battery is in good condition, it'll last a LOT longer than the UPS. Most laptops run 2 - 3 hours on a battery. Some (like mine) run for 4 hours.

Shadow250 · Post by **Shadow250** » Tue Jun 22, 2004 10:00 pm

testing it with fah. uptime so far on ups 4hrs 28 mins. ups still at 73% total capacity. 10 bux says it goes another 4 hours.... i guess my battery's not a spring chicken after the 5 charges the book said to give it it only lasts about 2 hours. but i found a place where i can get another one cheap. 25$ new the place is going out of business i got them to hold me 2 batts.

canton_kid · Post by **canton_kid** » Wed Jun 23, 2004 10:22 pm

I been runing lots of stuff off a UPS here. I have lousy power company!

I took an old APC 800RT UPS, batteries were shot and wired as 24vdc, connected 2 deep cycle 12vdc 115 amp hr batteries for a total 115amp hrs at 24vdc and all is well! Mostly I kept the cordless phone, 100 watt light, digital clock, and a couple other small items connected permanantly on it.

I did some testing with heavier loads also, vacume cleaner, large fans and all work fine. I think this is a 600watt inverter, probably modified sine wave. Looking at the LARGE transformers inside I would say it's an older type. This UPS will also startup when the power is out. Very nice feature, they all are suppose to kick into battery backup mode if the power goes out, but many do not turn on cold if the power AC power is out of if they are not plugged in.
Many of the larger ones can be turned on and ran off the batteries even if they are not plugged into AC, I have tested this one that way for hours with a heavy load and the deep cycles.

Runs transformers for cordless devices fine, and wouldn't a lap top basically be a rechargeable cordless type device when ran with the wall adapter? My cordless phone has been used when the power was out and running off the deep cycles and UPS. Nice thing about cordless phones, the handset works fine with a charged battery when the power goes out, but the phone is dead because the base shuts off! No more random disconnected calls here just because the power goes off 20-30 seconds

Shadow250 · Post by **Shadow250** » Wed Jun 23, 2004 11:50 pm

man, your power company does suck with it goin out like that, here he usually get eithier a t storm or ice storm that kills it for awhile. my ups is only a year old and has 2 6v 20ah batts in series for 12v its runs just the laptop for 9 hrs much longer than the 36 watt battery thats like 1.5 ah i think. i tried a car batt on it but it got way too hot trying to charge it back up. i guess 9 hrs computing time is enough........NOT!

canton_kid · Post by **canton_kid** » Fri Jun 25, 2004 2:50 am

Yep power company here is crap!
I am building some windmills and other projects to make my own power, got busy with stuff and haven't done much for awhile. Most the stuff is sitting here, just no time to put it together.

That's why I was testing out the UPS on deep cycles to begin with. Eventually I plan to have enough batteries to run the house for a few days. I already bought a 5k inverter and I have about 1,000 amp hrs of batteries, maybe alot more, I have some I don't know how good they are I haven't counted.

That's one of the reasons for testing the UPS. If yours got hot while charging the batteries you could probably put a diode in the hot line so 12v only flows to the UPS and then it willl not charge the battieries. But, then you have to charge the batteries somehow like with an automotive battery charger.
Would be a pain, but if you keep the battery charged you have several hours of power at least when the grid goes down.

What actually got hot? The UPS or the batteries? If it was the battery then maybe the UPS was over charging it, not regulating to the correct level.

Walleye · Post by **Walleye** » Fri Jun 25, 2004 3:29 am

Originally posted by Pugsley
Older inverters (1950-1975ish) Are bad because they dont make a sine wave AC they make a square wave AC. Newer inverters are all sine wave just like whats comming out of the wall.

that is by no means true.

all inverters will provide a pulse, they cant put out a true sine wave. some have a stepped sine wave, but those are Mucho dollars. most people buy a normal inverter, which puts out a modefied sine wave, with a lull period between ups and downs to simulate a sine wave. but it's not a sine wave.

electronics run a little inefficiently off this, but they still run.

The_Frapster · Post by **The_Frapster** » Fri Jun 25, 2004 5:07 pm

Heh, plug a digital clock into a new convertor and see what happens

canton_kid · Post by **canton_kid** » Sun Jul 11, 2004 12:03 am

Not sure what you mean,

plug a digital clock into a new convertor and see what happens

Mine runs just fine, cheapo 200watt UPS and if you remember many of my other comments about our crappy power company here you know it is running on the batteries and inverter at times.

Post by **FlyingPenguin** » Sun Jul 11, 2004 9:29 am

Some (not all) AC powered digital clocks work by using the 60 cycle pulse on the power line and using that as the clock.

Not very common anymore except in cheap clocks. ANy clock with a battery backup will have an internal crystal and won't use the line freqency.

The_Frapster · Post by **The_Frapster** » Sun Jul 11, 2004 11:21 am

Thanks FP, that is what I was referring to.

canton_kid · Post by **canton_kid** » Mon Jul 12, 2004 8:09 am

Yea all of mine have battery back up built in for those little 9 volt transitor batteries, though I never install the batteries. The power company was killing to many of my batteries with outages and the cost of batteries was eating me up

Probably cheaper for me to just buy the UPS and for get it

The battieres don't seem to last too long in those digital alarm clock radios even for just keeping time.