You'd also want to make sure that the total load of both chargers and everything connected to it doesn't exceed what the power outlet is rated for or what the fuse in the UPS is rated for. Otherwise when power is restored and it tries to pull 3000w or something then something is going to trip out or catch fire.
If you daisy chain battery backups together, you have twice the load running through both units all the time, rather than half the load between them if you were able to distribute the load evenly between the two.
Splitting the load would most likely increase the life span of both units, daisy chaining might lower the life span. I have had battery backups in my server room with 80+% load die within a year, same model with 30% load has been going 3 years strong.
generally ive found only text that doesn't really apply to my situation
in my case, ive purchased 2x "GX1325U" sine wave output 1325VA / 810watt "gaming battery backup" units
all the text ive found only states that stacking will not increase battery backup time because the power from one ups is simulated or stepped and will trip the clean power of the second unit, thus draining both at the same time.
this should not be the case with a "pure sine wave" output unit. as one unit should be electrically indistinguishable from mains power vs the other battery backup
the only other issues commonly addressed are
stacking the units may "overload" them
in my case, I am running 810w units with the loads split between both ups, (desktop on one ups, screen and networking on the second ups)
but my Maximal COMBINED Load never exceeds 310watts just the rather high efficiency gaming computer and a monitor (at non gaming idle, this system + screen only consumes 155W) (in game usage of the desktop is only 310W in worst case loads)
id need to battery operate one ups till it was about half cap, and stick it onto a Kill A Watt reader to get an idea of the CHARGING power draw
if that charging draw + the load of my setup is within 800Watts then in theory the first ups system from the mains shouldn't complain
my main issue is, im only plugging in 2 items. the desktop which idles as low as 95w and games up to about 250w and the screen which is a flush 48w at all times.
my goal is to maximize the runtime on Both of these devices cant really operate one with out the other
yea. im curious as to a graph for this. i know that the SLOWER we drain the battery the MORE efficient the process will be.
so less load will give More time overall the more load on the same unit, the lower amount of TOTAL system output you can get from the same battery cells
my main issue is, ups#1=60w draw ups#2=95-250w draw = uneven runtimes between the screen and the desktop one is getting like up to 5 TIMES the draw as the other if in game and 2 times draw if idling or movie watching
Do you know if these units constantly run the inverter all the time, or switch to inverter when you loose mains power?
If this is the case (which it is with many commercial backups), you will want to count in about 10 to 20 % loss. But even with this loss between both UPSs, you will be fine. These modern DC charging circuits are fairly efficient, so you should not loose much to the charging circuit.
If you have a Kill-a-watt, this would be worth testing. You will probably have no more than 600 watts measured at the wall at load, with the draw from the backups included.
they are line interactive, so they kick within a second of power irregularity into the battery inverted mode. CyberPower GX1325U 1325 VA 810 Watts 10 Outlets UPS http://www.newegg.com/Product/Product.aspx?Item=N82E16842102238 ill give em a test on the kill a watt, suppose the easier way will just be to unplug one for a few minutes lol
ok i am seeing anywhere from 10 to 15- 20 watts At the wall vs whats displayed on the ups this ones @ 20w difference
its also looking like, on the unit that just has the a399u screen, estimate run-times are 70 minutes or so. ill run it down to 50% and then plug that into the killawatt and see the charging draw
You need to include the load of the UPS charging its battery. Its more than likely that the charger is using 10amps or something like that. It will probably say on the back of the UPS. You need to consider the load of both chargers and the load of everything you have connected.
So this sorta kills that other reason. It won't 'overload' the first unit.
It's supposedly pure sine wave. Meant for use with "sensitive" computer equipment that has active PFC. So one unit should not see power from the other as 'dirty or bad' @wendell hows you electrical engineering these days?
Ok, so the last thing I've read, that would stop me. Is this page talking about the voltage/surge resistors
It claims, plugging the ups into a surge protector. Can screw with the electronic signal. And reduce the ability to clean the power.
Wouldn't I WANT the ups in series? Say lightning zaps my home.
Mondo power surge. Fries one unit. The unit does its job. And sacrifices itself to save what's plugged into it. The second unit kicks to battery and I keep on playing.
Have the two plugged to individual wall sockets directly. as suggested by the manufacturer.
Lightning hits. Both units die. And I loose power to my system.
What is all this silliness about "pure sine wave"?!?! All AC power alternates as a sine wave. Lol.
Yes, you can just plug one into the other so that it's like one is charging from the other. However....
it's not super efficient
you cannot pull more load than a single one can handle
the behavior could get weird as they begin to discharge under heavy load.
It would be safe to try it but maybe try with a few 100watt light bulbs first. Try a single, measure the time it takes to discharge. Then, charge it back up and add one. Measure the time again and be careful to observe which one drains first etc. See if anything weird happens. It won't damage them .
I think you will find using two will get you about 1.8x, not quiet double.
you know. tha'd probably be the easiest method i wonder if it would piss off the inverter over the longer duration then again, if it will run over an hour with just the screen. i dont see why it cant run longer..
would adding more sets of batteries in parallel increase the "stress" / heat. of the inverter section ?