UPS battery backup question

[Reef Pilot]

Originally Posted by Coasting

I have no issue spending $150 on a backup.
•1325 VA/810 W capacity
•Half/full 10 minute / 2 minute runtime

Part of my brain wants to say that a 5w power head would use 5w an hour, so a 810w UPS should power a single 5w powerhead for days.... But obviously that's not how it works lol.

No, that's not quite how it works... haha. It goes by the battery capacity not the UPS output power capacity. With this UPS, it will give 10 min running at 400 watts (1/2 power), so at 10 watts should give 400 min or 6+ hours.

But if you don't have a desktop, agree that this is overkill and paying for additional capabilities you don't need. Also note, that surge protection is not UPS power backup.

What you really need is a battery inverter power pack like these. I have two that I use at our lake cabin with solar power and take them home for the winter to back up my tanks during an outage. They have much higher battery capacity (more like a car battery) and can run my tank pumps for a day or more (have had to do that in the past).
http://www.canadiantire.ca/en/pdp/mo...l#.VoBDrVKLDak

I bought mine (older versions) about 10 years ago (and they are still good) during fall clearance time for less than a 100 bucks (way cheaper than this one).

And a cheaper alternative might be to get a booster pack (on sale now) and just leave it plugged in (auto trickle charge) all the time.
http://www.canadiantire.ca/en/pdp/mo...l#.VoBFDVKLDak
And use it with this inverter.
http://www.canadiantire.ca/en/pdp/ca...l#.VoBFmVKLDak
Should be able to find these cheaper elsewhere, too.

[Coasting]

Honestly could care less about power backup for the computers. If my laptops going to die and I'm going to loose what I'm working on, it will do it and have a melt down when the power still works.

We have one of those power booster pack thingers you linked there haha.
But I just want something small enough that it wont get in the way with the minimal space we have beside the couch and tank (where everything is plugged in) that will automatically keep running the powerhead when nobody is home. Then when they get home they plug it into the battery pack car charger thinger....

I figured the UPS would work perfectly, could mount it to the wall or side of the stand or something. But clearly I know nothing so..... lol

[Reef Pilot]

Does your booster pack have a cig lighter type plug? If so, then all you need is the inverter to plug into that. Just leave your booster pack plugged into the wall all the time (should have an auto trickle charger adapter) and your tank pump plugged into the inverter. That should give you all the run time you need for just a small pump.

Yeah, might be a little unsightly, but it is the size of the battery that gives you the capacity (run time) that you need. Small might be nice, but they won't last very long. Not sure what your set up looks like, but maybe you can hide it a bit, out of the way?

Yes, a real UPS looks nicer, but the size you need would still be quite obtrusive. And overkill, like we said before.

[Coasting]

Its my mothers house not mine that's half the problem
I know she liked how yours was all set up and hidden in the kitchen and downstairs :P

It has normal outlets in it, i wouldn't need an inverter. Its what we bring up stairs and start plugging stuff into when the power does go out. I don't really want something that size up stairs by the tank, there really isn't a huge amount of space.




Old photo but that's what I'm working with. Space between the couch on the left and the side of the tank. All my powerbars are crammed down there, the couch is a bit closer now.

I'm only asking for enough run time out of a ups to get it through a typical work day until the power head can be plugged into the big ugly battery pack/car charger thing or we can put a battery air pump in.

[Reef Pilot]

OK, well, sounds like you already have what I was suggesting. Looking at your pic to the left, isn't there room behind/beside the couch? They aren't that big?? Mine is 9" wide and 14" long (just measured it). Just pull out the couch a bit. And/or maybe put something else there in front to hide it further.

[mike31154]

There are pros & cons to UPS as backup for something like a powerhead. As ReefPilot mentioned already, the key to run time of your powerhead is the ampere hour (a/h) capacity of the battery in the UPS, which typically is not that great, since the primary design is to keep a computer running long enough for you to shut it down without losing data. The math isn't that difficult, it's Ohm's Law in conjunction with the a/h rating of the battery in the UPS. The variable that's a bit obscure in all this is the Hour (h) and that's why you need to now the a/h rating of the battery in the unit you intend to use. Most of them do provide charts listing typical loads & how long you can expect them to last. In your case an ideal set up would be a 100 watt UPS with 40 a/h battery. You don't need a high power (1,000 watt) UPS to run a 5 watt load, but you do need a big honkin' a/h battery so that you can run those puny 5 watts for a very long time. Sadly, most UPS units are not built that way. Note that the 'a' in a/h is amps or I(current) as used in Ohm's Law.

P(watts) = E(voltage) x I(current in amperes). You already know the powerhead uses 5 watts, so you need to calculate the current (I) it draws at it's nominal operating voltage (E). Transpose the formula & plug in the numbers I=P/E. Once you have that number use it in conjunction with the a/h rating of the UPS battery(or any deep discharge battery) & you will have an approximate run time for your 5 watt powerhead. Most reasonable sized UPS units should handle a 5 watt load for a few hours at least. Keep in mind that as any battery ages, it's original a/h rating will decline, even if it's not used. In some cases battery life is actually shortened if it's not given a deep discharge from time to time.

Personally I'm not a fan of these residential consumer grade UPS units. I've never owned one but my Dad did & it failed after a couple of years. I dismantled it to see what was up & found the battery bulging at the sides. It could have burst or started a fire IMO. Some of these units have next to no ventilation & that's why they use these sealed batteries. I think they are time bombs. I see that some of them now offer replacement batteries so the unit is not trash once the battery fails, as it ultimately will. That's great, but I doubt that the average consumer keeps an eye on these things & essentially run them 'til they quit. They are plugged in 24/7 & even though the chargers are pretty smart these days, constant charge cycles eventually cause the electrolyte to evaporate & since you can't top them up, they overheat & fail.

The alternative is of course to use a good old deep discharge wet lead acid battery that you can keep an eye on & maintain. Might be what's in those Can Tire boost units. The issue now becomes proper ventilation of the hydrogen gas produced during charging. Probably not that big an issue if there's only one battery & it's a reasonable size.

[GrantB]

Hey also be aware that unless they have changed recently the normal computer UPS's won't run an AC pump very well. I have tested this on large AC pumps which would not turn over at all and also on tiny powerheads which would run but no where near full power. I did buy a true sine wave UPS that worked great (other than very limited capacity) but they are way more money.

I ended up going with an auto transfer switch, True sine wave inverter, charger and sealed AGM battery so there's no venting of hydrogen gas. More money but you can run everything for hours and if one part goes your not replacing the whole thing.