35 replies to this topic

[Craig3426]

Thanks Cawdor and Donna for the fast replies.
Decided against the UPS idea when I realised i'm running:
3x Fluval 404
1x Eheim 2215
2x Eheim Pro3 2075
They add up real quick, next time i'll have to say no to myself when I see a new canister filter at my LFS.
Hope my plan holds up.

[Neakit]

buy cheap genny and you only have to run the filters.

[convict paul]

ive seen power boards with back up batteries, how long do u think they would last?

[Kieran]

Not long. If you can get some stats from the packet on the powerboard, we could give you some time estimates.

[convict paul]

i dont have any sorry, but i saw one in dick smith it was a huge block with a power boards built in.

[golden_dase]

Was it the Powerware series Paul? For about $129? If so, then they're the 500va/700va versions... enough to power air-pumps etc. for hours..

[tranced]

couldnt you take the strainer off your filter intake, feed an airline through and into the filter... then the bubbles would theoretically rise up through the bio media and exit via the outlet??

obviously this depends on the make/model, but the eheim classic would have no worries with this...

[werdna]

Craig, it all depends on the load.. Canisters range in wattages, eg: Eheim 2217 is about 25watts (I think!) so a 700va UPS would probably run it for 1.5 - 2 hours.

I think that is incorrect Kev


VA rating is the same as watts which is power flow per hour.
So to work out how long it will last for you add up all the wattages for all your equipment and divide the UPS rating by that no
In your example it is 700va / 25

So it would run for about 28 hours (In a perfect world with no loss.....)

Thats what I was taught anyway....

Cheers

Andrew

[Kieran]

Also, you should really try not to deep-discharge any kind of battery too much. You can end up with thousands less cycles than if you only discharged to, say 50%.

EDIT: Also I assume a UPS has some sort of moified sine wave inverter built in, which I really can't see being more than about 85% efficient, which would have to be factored in too.

[golden_dase]

I think that is incorrect Kev


VA rating is the same as watts which is power flow per hour.
So to work out how long it will last for you add up all the wattages for all your equipment and divide the UPS rating by that no
In your example it is 700va / 25

So it would run for about 28 hours (In a perfect world with no loss.....)

Thats what I was taught anyway....

Cheers

Andrew

I think you're right, Andrew..
Maths isn't my strong-point (hated it in school).

[ado]

watts which is power flow per hour.

To quote Brian from half-baked "It's more complex than that!"

The wattage isn't flow of power per hour. It's the amount of energy the appliance consumes.

I don't have time to go into now, but have a look at the wikipedia page for Wattage and for Volt-amps...they are (suprisingly!) good for a brief explanation.

They give the specs in VA because it doesn't directly translate to Watts (due to power factor) but it looks a lot higher

Bit like amplifiers and other electrical appliances which give the power ratting in peak-peak wattage, which looks really nice on the box, but is actually pretty meaningless in reality

cheers
ado

[MrOrange]

VA = Watts only in DC, for AC it is more complex.

700va UPS will run a 25W AC load for around 2 hours.

[werdna]

I realised after posting that that was wrong, mainly cos the battery generally used is a 12v 7ah sla. So it supplies 84w, so even in a perfect world with no loss it can only supply 25w for a little over 3 hours.

My bad!

On a side note ratings such as 700va and 2000w pmpo really annoy me!
Why cant ups's say the 1hr power rating like batteries. Grrr
And stereo systems just say rms?
Stupid imaginary useless confusing ratings.

[convict paul]

Was it the Powerware series Paul? For about $129? If so, then they're the 500va/700va versions... enough to power air-pumps etc. for hours..

yeah kev thats the one

[ado]

They annoy me too mate. But I think it all comes down to marketing...
There is an old saying that some is up pretty well...Merda taurorum animas conturbit

Mass produced stereos and amplifiers are some of the worst. Giving ratings in peak power so that together with the flashing leds and fancy design speaker fronts some poor unsuspecting consumer is conned into thinking he is getting something spectacular and happy to pay top dollar.

[Witters]

I hadn't considered the effects on an aquarium from a long power cut until reading this thread. I like that people have a back up plan, or are looking for one. I wondered what the LFS' do in these situations. As i would say a lot of the time power cuts happen with out notice and after hours. Maybe one of them could give an insight on there procedure, if one at all.

Ryan