To UPS or not to UPS?

[DJ Jules]

I've never considered running my kit off a UPS before in the 14 years I've been DJ'ing but, so far this year I have had 6 DJ gigs and the power has cut out at 3 of them :facepalm: Last night I discovered the venues main sockets are fried and don't make a reliable power connection. Unfortunately, I discovered this in the middle of the first dance.

Anyone bother with a UPS? Which bits do you protect?

I have a flight case with laptop, dmx, wireless DMX transmitters, USB hub, Denon controller and wireless mic receivers and I'm thinking that one small UPS ought to be able to run them for a while (the total power draw is probably less than 80w). I did think that switching one of the 12v power supplies for a battery backed supply would be cheaper/lighter/more efficient as it'd keep most of the case alive, and then I remembered the Denon has it's own power supply.

Open to ideas...

Julian

[Excalibur]

On the assumption that some form of lighting remains, although mine would die, if I were using the Maui GO, my laptop and VMS would continue for a while. The idea of an UPS is very appealing nonetheless. I don't have any, but battery uplighters would improve life even more.

[Nakatomi]

Funnily enough Julian I've been looking into buying a UPS recently - not for just any old power cut scenario though... for venues with a limiter!

If you're only looking to keep your playout flightcase 'up' with a total draw of under 100W, a bare bones UPS of around 500VA would keep your stuff juiced up for quite a while. I've tried looking into what the VA ratings actually equate to in terms of run time but all I could find out was that a typical 500VA UPS will be good for long enough for a computer to safely shut down - a couple of minutes or so. If that's with 500VA (500W if the power factor is more or less 1 - it won't be far off) then you could expect it to keep your stuff powered for half an hour at least.

A while back I measured what my rig pulls from the wall (minus hazer) going flat out (RCFs weren't quite hitting their limiter) & it was about 830W all told. To keep that going flat out long enough for venue staff to reset their limiter I think I'd need something like a 1500W UPS - though if I know there's a limiter in the place I'd hardly be pushing my PA much so maybe a 1000VA UPS would do the job. Then again, not only does it need the capacity to keep things running a while - it also has to be able to recharge in time for the next outage. Buying more capacity than you need will help there.

EDIT:

Oh - and be very very careful with venues where power is intermittent, especially when it comes to powering everything back on. Try not to let everything come back on at the same time. A few friends of mine have had kit go faulty because of unreliable power at venues - unexpected unpluggings & all kinds of things. Infact if you don't already have a sequenced power-on regime at your gigs I'd strongly advise you start.

I turn on my playout gear first (laptop, controller etc) then each speaker in turn, then lights, then haze etc. The reasons for this are many but mostly because of what's known as 'inrush current'. What this basically means is when a thing first has power applied to it, internal power supplies can draw a large instantaneous current from the mains for a very brief period. Enough of these at the same time can make the voltage at the socket you're drawing power from dip enough to cause havoc. I've theorised (and as yet haven't proved) that this dip could confuse equipment with auto voltage switching (110 to 240VAC) inputs - hence all the tales of speakers going BANG literally the moment they're plugged in or switched on.

IN THEORY suddenly disconnecting your gear from power while it's going flat out SHOULDN'T harm anything. It's what you do when the power comes back on (even momentarily) that could make the difference between it surviving or not.

Second edit:

Before anybody mentions power conditioners - they're certainly an interesting idea but for my money the jury is still well & truly out on them.

Surge protection offers you only so much grace from nasty mains spikes etc - try to buy a power strip which has an indicator telling you the surge protection devices are still working. The little varistors they use inside can only take so many hits & then they silently fail - leaving you with no protection at all

[Excalibur]

Funnily enough Julian I've been looking into buying a UPS recently - not for just any old power cut scenario though... for venues with a limiter!

The evil in me really fancies watching the faces of the venue when the power goes off, and the Mauis keep singing cheerfully.

Surge protection offers you only so much grace from nasty mains spikes etc - try to buy a power strip which has an indicator telling you the surge protection devices are still working. The little varistors they use inside can only take so many hits & then they silently fail - leaving you with no protection at all

A colleague was devastated to find that the blighters aren't indestructible! The thought of them being almost " single use " was too much for him to bear.

[DJ Jules]

I guess my goals are two fold.... Keep the lights on (I have battery uplighters and I'm often the only light source in the room) and minimise the time for recovery (I think most people understand that when the power goes off, things stop, but it's the minutes where I have to reset the dmx software and wait for the Denon to boot and Windows to recognise again that are the issue).

If I powered my flight case then the sound would go off, but would return as soon as power is restored, but uplighting and the freedom sticks would keep going. Moving heads, stratospheres, etc would obviously all go out.

I don't really want the extra weight of a decent 1kva UPS I do wonder about rethinking the power for the Denon. If I could run that off a 12v rail then I could use a li-ion battery pack instead of a UPS, which would be a substantial saving in weight and size.

Julian

[Nakatomi]

What voltage does the Denon run on? My mc7000 has an awful 4 amp 5 volt plugtop adapter (aka wall wart) which I decided to bypass in my console. I just bought a 5 volt 5 amp power supply & did my own mains wiring inside the console. I'm sure you'd be able to find a suitable converter to adapt 12v to whatever the Denon needs.

[DJ Jules]

What voltage does the Denon run on? My mc7000 has an awful 4 amp 5 volt plugtop adapter (aka wall wart) which I decided to bypass in my console. I just bought a 5 volt 5 amp power supply & did my own mains wiring inside the console. I'm sure you'd be able to find a suitable converter to adapt 12v to whatever the Denon needs.

I think (from memory) that the wall wart is 12v 3A. I'm not 100% sure now why I put it on it's own power supply (I have a 12v 5A power supply in the case running a USB hub, 2x mic receivers, and a Chauvet DiFi transmitter via a voltage regulator). I have a feeling it was because I wasn't sure quite how loaded the supply is at the moment (it used to run the VMS before I switched to Denon, but the VMS could be USB powered). I might have to revisit that and see what the actual load is...

12v Li-Ion packs with 27ah batteries are quite common, but the chargers are rated at 2A on the ones I've seen (despite max output being 6A!) so I'd need to be careful with limits.

Julian

[Excalibur]

(it used to run the VMS before I switched to Denon, but the VMS could be USB powered). I might have to revisit that and see what the actual load is...

The VMS technically isn't USB powered, but if the laptop battery is in good condition, it will actually run from the USB. This can lead to interesting situations, when you find the only thirteen amp socket in the room that doesn't actually have power. The laptop fires up, the VMS loads and plays, but your lights and amps don't work. You then start checking the power to the lights, because obviously, the laptop and VMS have power, don't they, they've lit up?

[rth_discos]

How many plugs are you running this off?

At the very least, the haze should have its own socket, away from the rest of the disco.

You'd be looking at a pretty powerful (and heavy) UPS to provide you with any meaningful power contingency for the load of a disco.

[DJ Jules]

How many plugs are you running this off?

At the very least, the haze should have its own socket, away from the rest of the disco.

You'd be looking at a pretty powerful (and heavy) UPS to provide you with any meaningful power contingency for the load of a disco.

Yup... That's why I'm not thinking about running the whole disco off a UPS, just enough so that the battery dmx lights stay on and when the power comes back on, I'm not waiting for controllers to reboot and having to reset software.

Julian