UPS: Only battery supported outputs (no surge suppression only) and printer?

[BonzaiDuck]

I should try and make the long story short.

A certain established battery reseller also offers a wide variety of "refurbished" UPSes, and I decided to go that route, ordering one of them. They made a shipping mistake; charged me for the one; and sent me two. I was happy to inform them of their error so they could take corrective action for the future, and offered to send back the second unit if they would send adhesive shipping labels pre-paid. But since shipping charges are $57 each way, I'm pretty sure that I'll end up keeping the second unit. Both of them were the same APC SMT1000 model. So -- lucky me. I got two for half the price of one. The link below shows the brand-new unit offered at the Egg:

APC SMT1000
Some UPSes offer three-prong output ports which are merely surge-suppressed as opposed to those behind the battery. These units apparently don't have "surge-suppression-only" ports.

Usually, you get the advisory in the install and operation guides to avoid connecting a printer to the UPS (unless it has surge-suppression-only ports).

Because of limited wall-sockets, I'm toying with the idea of connecting a printer anyway. The printer's maximum power draw is ~300W, and idle draw is 8W. Under the less-likely scenario that a power outage will cause the unit to switch when as much as 500W are being drawn from the UPS, shutdown would still occur within 3 minutes.

Should I or shouldn't I -- use the SMT1000 to power the printer in addition to the PC and minor peripherals? What do you think? Comments?

 

[Charlie22911]

I'm assuming from your stated power draw that it is a laser printer. They draw so much because they have a heater element in them that "melts" the toner to the paper.

As long has your total load is within APC specifications I don't see why it wouldn't be fine. However the product page for that UPS mentions it has a switchable outlet group. I'm not sure what this means, but it may be possible to configure them to go offline when a switchover occurs.

 

[XavierMace]

You sure about that max power draw? That's pretty low for a laser printer. A common practice, at least in the past, was the printer would list it's power draw when printing, which did not cover the initial spike of the fuser warm up.

 

[Red Squirrel]

Printers have a very high initial power draw. In fact I would not be surprised if it's more than even 15 amps, just that it's not for long enough to trip the breaker. Any printer I've used causes the lights to dim quite a lot when it first kicks on. That initial "bang" sound when it first starts is quite disruptive power wise. That's all the motors engaging at the same time, I guess and it's a highly inductive load. At my parents house for some reason it's always been problematic as even the computer being on UPS sometimes reboots or locks up. It's like if the brownout is so short that the UPS does not pick it up on time and then trips to battery only to trip back to AC immediately, and the computer ends up eating the brunt of it. Some better UPSes will stay on battery for like 5-10 seconds so there's less switching around back and forth during brown outs, but that's not exactly a feature that they advertise so it will be hit and miss when you buy a UPS. I find APCs are bad for that, while Trip Lites are better, but that's from a rather limited sample so I can't really vouch for one over the other.

I would definitely not plug a printer in the battery side of a UPS. In fact I avoid plugging it even in the surge side, and will plug it into a separate outlet. Idealy on a different circuit.

At my house my printer does not seem to cause any issues with my UPSes though and it's all on the same circuit, but I have seen it cause issues in other houses. I don't know if it has to do with how long the runs are, or if they are not tight enough at the breaker or what but my parents' always had issues. I told them to turn off the power bar to the computer before they print something. This forces the computer to go on UPS power gracefully, and it won't see the brownout when the printer turns on. Once the printer is running and actively printing then they can switch back the power bar. Would be interesting to put a scope when on their UPS when the printer turns on. I need to bring it in one day and test that.

 

[VirtualLarry]

Printers have a very high initial power draw. In fact I would not be surprised if it's more than even 15 amps, just that it's not for long enough to trip the breaker. Any printer I've used causes the lights to dim quite a lot when it first kicks on. That initial "bang" sound when it first starts is quite disruptive power wise. That's all the motors engaging at the same time, I guess and it's a highly inductive load. At my parents house for some reason it's always been problematic as even the computer being on UPS sometimes reboots or locks up. It's like if the brownout is so short that the UPS does not pick it up on time and then trips to battery only to trip back to AC immediately, and the computer ends up eating the brunt of it. Some better UPSes will stay on battery for like 5-10 seconds so there's less switching around back and forth during brown outs, but that's not exactly a feature that they advertise so it will be hit and miss when you buy a UPS. I find APCs are bad for that, while Trip Lites are better, but that's from a rather limited sample so I can't really vouch for one over the other.

I would definitely not plug a printer in the battery side of a UPS. In fact I avoid plugging it even in the surge side, and will plug it into a separate outlet. Idealy on a different circuit.

At my house my printer does not seem to cause any issues with my UPSes though and it's all on the same circuit, but I have seen it cause issues in other houses. I don't know if it has to do with how long the runs are, or if they are not tight enough at the breaker or what but my parents' always had issues. I told them to turn off the power bar to the computer before they print something. This forces the computer to go on UPS power gracefully, and it won't see the brownout when the printer turns on. Once the printer is running and actively printing then they can switch back the power bar. Would be interesting to put a scope when on their UPS when the printer turns on. I need to bring it in one day and test that.

Parent's PC probably has a newer, APFC PSU, and you're still using an older design stepped-sine-wave UPS, rather than a "pure sine" UPS. That's probably your problem right there.

 

[Red Squirrel]

Pretty much all SOHO UPSes are "stepped sine" which is more like a square wave. I've never seen a pure sine one sold at a normal retail store. (people like my parents arn't likely to order stuff online) I wish they were more common though, as yeah it can be an issue with some loads. I ordered a pure sine inverter online for my camping solar pack so I can charge stuff without worrying about whether or not the charger would like the square wave. You pay a lot more though, like 2-3 times the price.

I eventually want to look at designing my own pure sine inverters as they are very expensive otherwise. My ideal UPS would be a DC-DC converter -> battery -> inverter. That way there is no delay when power goes out, i the load is always running on inverter. They do make UPSes like this (dual conversion) but they are harder to find and much more expensive.

 

[VirtualLarry]

Pretty much all SOHO UPSes are "stepped sine" which is more like a square wave. I've never seen a pure sine one sold at a normal retail store. (people like my parents arn't likely to order stuff online) I wish they were more common though, as yeah it can be an issue with some loads. I ordered a pure sine inverter online for my camping solar pack so I can charge stuff without worrying about whether or not the charger would like the square wave. You pay a lot more though, like 2-3 times the price.

I eventually want to look at designing my own pure sine inverters as they are very expensive otherwise. My ideal UPS would be a DC-DC converter -> battery -> inverter. That way there is no delay when power goes out, i the load is always running on inverter. They do make UPSes like this (dual conversion) but they are harder to find and much more expensive.

APC just introduced their consumer "Pure Sine Wave" UPSs last year, and CyberPower has been making them for some time now. (Look for PFCLCD models.)

 

[Red Squirrel]

APC just introduced their consumer "Pure Sine Wave" UPSs last year, and CyberPower has been making them for some time now. (Look for PFCLCD models.)

Good to know, maybe these are finally going to start being more mainstream. Not even sure why they bother with square wave, BOM wise it's not that much more expensive to go pure sine. Still need a H bridge either way to generate the AC. Need a bit more smarts to generate the sine wave with PWM and then smooth it out, but it's basically just a SMPS at the end of the day.

 

[thecoolnessrune]

DO NOT connect a Laser printer to a UPS unless your UPS is a facility sized unit. The Inrush current of a Laser Printer is massive (Over 20 Amps at 120V). Your UPS isn't even qualified for more than 6 Amps. Even off battery, the wiring in the AVR and Surge Suppression systems is not to spec to repeatedly tolerate that sort of current, and if your voltage sags and you swap to battery you're absolutely going to fry out your Inverter.

It's just a bad idea. There's plenty of ways to get out of outlet limitations. Connecting your printer to a UPS is not a good way of dealing with it.

 

[BonzaiDuck]

Thanks, all. I was drawn away from this thread temporarily, but the situation involves using my server for some print-server duty with an old HP 1200 LaserJet. The availability of sockets can be resolved easily, so I don't really need to plug it into the UPS. And I think I was looking at the specs for the wrong laser printer. I would bet that the peak wattage draw from the HP 1200 is more than 300W.

I can let the printer set for a while as I set things up. I just put in an order for three battery kits for a BX1200, an SMC1500 and an SMT1000 -- the UPS I mentioned. I need to check for tracking information. The shipping on batteries kills you. The total bill is around $158.

The SMT1000's are warrantied-refurbished, and came with new batteries. I didn't know you had to disconnect the batteries to prevent them from slowly discharging of the unit isn't plugged in. So the other day, the SMT1000 started beeping from a self test and a red LED signaled "Replace batteries." But that's OK, because I purchased one of those SMT1000 units, and they sent me two. I offered to return it if they paid shipping, and so -- it's mine as they abjured doing that.

I've almost got more UPSes than I can use. Almost, anyway . . . I surely want to avoid ordering batteries more frequently than a periodic refresh after a few years, or when the diagnostics indicate it. The battery recycling is a Saturday-morning PITA for the trip out to the recycling center . . .

 

[thecoolnessrune]

Those basic APC Pure Sine Wave units (SMT, SUA, etc etc) have really poor float charge circuits that tend to drive too high and burn out the batteries. But if you got battery packs for all 3 for only $158, then you're doing well. I'd just keep them in budget mind for the years following.

 

[Red Squirrel]

I've noticed too that some UPSes seem to overcharge the batteries. They also don't seem to detect if there is a bad or shorted cell, so what happens is all the other cells get too much voltage and it ends up killing the whole battery real good. Makes it leak and overheat etc.

 

[bigboxes]

I think you can wait until the power is restored to use your printer. Is it really mission critical that you be able to print during a blackout?

 

[BonzaiDuck]

Those basic APC Pure Sine Wave units (SMT, SUA, etc etc) have really poor float charge circuits that tend to drive too high and burn out the batteries. But if you got battery packs for all 3 for only $158, then you're doing well. I'd just keep them in budget mind for the years following.

I remember at one time I merely discarded the entire UPS, until I discovered the difference between APC-direct batteries and those offered at RefurbUPS.com. I usually get about three years out of a battery kit. I really hadn't noticed an unusually short life for battery kits on units you mention, but I'll remember your thoughts.

I've noticed too that some UPSes seem to overcharge the batteries. They also don't seem to detect if there is a bad or shorted cell, so what happens is all the other cells get too much voltage and it ends up killing the whole battery real good. Makes it leak and overheat etc.

Again -- the answer I gave to thecoolnessrune.

I think you can wait until the power is restored to use your printer. Is it really mission critical that you be able to print during a blackout?

We brought Moms' Sandy Bridge downstairs when we had to relocate Moms for safety -- two falls and a hip replacement last year. Her old HP 1200 LaserJet was still up in her computer room, where I relocated the new, replacement server that I finished building with the 2012 R2 E OS installation recently. We had always used that HP on the LAN, from elsewhere in the house.

But the more I think of it, I have an available wall-socket that I'd overlooked previously. A printer that old, we can afford to give it no more than a power-strip surge-suppressor. But it seems like a good idea to make the 2012 server function as print-server as well -- at least part-time.

The battery kits arrived yesterday, and I intend to take my time with the hands-on work. The units are of course clumsy and heavy, because all of those batteries are clumsy and heavy. I'll probably work on one per week.

Someone else posted a thread here recently asking for a UPS recommendation, and I'm now going to volunteer a link to the ReFurbUPS web-site. They sell tons of new and refurbed UPS units, and so far my refurb acquisitions seem stellar. [I ordered one SMT-1000's; they shipped me two by mistake; I offered to return one if they paid shipping, but it's apparently mine now! It was a shipping error, so nobody should hold their breath hoping for the same lucky mistake.]