Uninterruptible Power Supply?

[AstroRuz]

Hey all

I'm moving to another place soon where the former tenent has told me they've had a few powercuts. 

I'm wondering if anyone uses any Uninterruptible Power Supplys (UPS) for their rigs and if they do, what ones/any recommendations?

Probably would only need backup power for 3 hours or something, 4 at a push I imagine 

Thanks everyone, clear skies

[DaveL59]

not for the rigs as I don't do AP, but indoors I have a few APC SmartUPS units to ride through any blips and outages. Upside they are the sinewave type, downside they aren't double-conversion continuous type tho that hasn't caused any issues during changeover. Being the older (not SMT) type they were cheap to pick up used and usually only need new batteries to get them going again for the next 3-5 years. One of mine is the XL version which can take external batteries, that one has 6x17Ah batteries and can run my comms and desktop for around 2 hours or so.

Runtime however will depend on the load you are driving. You may be better using a larger capacity battery and driving direct at 12v from that rather than wasting Ah on converting from 12v-240v-12v and run a UPS for any mains load you have to run alongside that. Bear in mind too that most UPS aren't exactly weather sealed, so outdoor use would be potentially very dangerous. Being quite heavy (if lead battery type) they aren't exactly a portable solution either.

Also bear in mind that for many UPS's, running on them for extended periods puts a high load on the batteries and that will shorten their lifespan. Some will also not run for extended periods as internal components get hot and the UPS will shut down or fail, most are designed to bridge the gap between mains loss and generator start so only aim for 15-20 mins of supply time. This effect would be increased the higher the load so its best not to run them at capacity, ideally stay below 50% of rated load. The APC units with fan cooling can run longer (as long as the battery is above a capacity threshold), the XL ones being better for this sort of use case.

Edited January 7, 2021 by DaveL59

[AstroRuz]

1 hour ago, DaveL59 said:

not for the rigs as I don't do AP, but indoors I have a few APC SmartUPS units to ride through any blips and outages. Upside they are the sinewave type, downside they aren't double-conversion continuous type tho that hasn't caused any issues during changeover. Being the older (not SMT) type they were cheap to pick up used and usually only need new batteries to get them going again for the next 3-5 years. One of mine is the XL version which can take external batteries, that one has 6x17Ah batteries and can run my comms and desktop for around 2 hours or so.

Runtime however will depend on the load you are driving. You may be better using a larger capacity battery and driving direct at 12v from that rather than wasting Ah on converting from 12v-240v-12v and run a UPS for any mains load you have to run alongside that. Bear in mind too that most UPS aren't exactly weather sealed, so outdoor use would be potentially very dangerous. Being quite heavy (if lead battery type) they aren't exactly a portable solution either.

Also bear in mind that for many UPS's, running on them for extended periods puts a high load on the batteries and that will shorten their lifespan. Some will also not run for extended periods as internal components get hot and the UPS will shut down or fail, most are designed to bridge the gap between mains loss and generator start so only aim for 15-20 mins of supply time. This effect would be increased the higher the load so its best not to run them at capacity, ideally stay below 50% of rated load. The APC units with fan cooling can run longer (as long as the battery is above a capacity threshold), the XL ones being better for this sort of use case.

Hi Dave thanks, that's some solid info.

I wasn't aware UPS were only meant to bridge that gap. I thought they were designed to lift the weight of appliances until mains were restored (to a certain extent). So maybe the leisure battery option would be better as a "UPS" of sorts. Maybe a battery box and a smart charger. I'm thinking I'd have the UPS/backup in the garage and run an extension out to the rig anyway. With a smart charger it wouldn't constantly cook the battery, and leisure batteries are somewhat designed to be charged and discharged simulationusly or regularly  at least. What do you think?

[DaveL59]

The Leisure battery should be a good option and modern smart chargers are good at maintaining them long term, for sure don't cheap out and use a car battery as they aren't good for this sort of use. I have the car hooked up to a C-Tek almost permanently at the moment while it's being used so infrequently just so I know it'll start and run when I do need it.

As for UPS, I don't have a generator so they run to bridge until power is back or software or I intervene. They use the 17Ah lead batteries that you'll find in many as well as the powerbanks. What tends to happen under load is the plates get hot and buckle and then a fairly rapid decline in lifespan and runtime follows. Some UPS will often not be charging/maintaining at the right voltage, again shortening battery life. I've adjusted these APC's so they sit just at the bottom of the battery manufacturer recommended float voltage and 3 years on these batteries do still seem to be holding up fine. I've seen some where batteries are indicated as failing after just 2 years, which makes things expensive, esp where I'd currently be replacing 12 batteries in a service cycle here at home.

[Skipper Billy]

We too suffer from power cuts - its a pain!!!

I took a slightly different route - everything in the observatory is powered by a 12volt 150 ah leisure battery - enough to run my rig for at least 2 full nights. This is kept charged by a smart charger that is just left on all the time.

The other benefit is that the battery supplies nice smooth clean power.

 

[kirkster501]

9 minutes ago, Skipper Billy said:

We too suffer from power cuts - its a pain!!!

I took a slightly different route - everything in the observatory is powered by a 12volt 150 ah leisure battery - enough to run my rig for at least 2 full nights. This is kept charged by a smart charger that is just left on all the time.

The other benefit is that the battery supplies nice smooth clean power.

 

^^^As an ex sparky this is 100% the best way to do it.  I do this too for the rig and gear.  I have the PC on a UPS in case of a ten second or so glitch to keep the guiding, mount sync and subs going.

When I do DSO imaging that is; which lately, is never due to the weather.

[AstroRuz]

Right I might go leisure battery and smart charger then. Like I said it's just as backup and I'd be using an ASI air or a laptop anyway so that should be fine also. Hopefully it's good for an EQ6-R Pro. Those things are notorious for wanting a nice clean supply. 

 

Any recommendations for battery and charger then?

 

Thanks

[pete_l]

53 minutes ago, AstroRuz said:

I wasn't aware UPS were only meant to bridge that gap. I thought they were designed to lift the weight of appliances until mains were restored (to a certain extent).

Yes. Many of them like to give that impression.

Living in "the country" (past the point where Google Maps gives out) and having mains power from overhead cables, we tend to have quite a few outages. Most are only for a few seconds or a few minutes and the UPS that keeps my computers alive can handle that. But anything past 10-15 minutes is getting decidedly dodgy.
Recently I put a mains power monitor on the output of the UPS - which is rated at 450 Watts. It shows that the computers and other bits'n'bobs use about 120 Watts. At perfect efficiency, that would require a 10 Amp draw from the bitsy little 7Ah SLA battery in the UPS. Even when it was new, that would be quite an ask.

Edited January 7, 2021 by pete_l

[DaveS]

I have a basic Schneider APC 1400 UPS in the obsy, but it's main function is so that the Talon roof automation can park the 'scope, close the roof and safely shut down in the event of a power cut. It's kept the PC going through several cuts, but during Storm Bella we had several during the night (I counted 4 before I went to sleep) and in the morning the PC had shut down, so the cumulative time must have been beyond its capacity, It runs the PC, a 5 port switch and the security camera. The power monitor said 165 mins run time, but that might be optimistic.

It also puts out a fair bit of RF noise.

[Skipper Billy]

I quite enjoy the power cuts now - my rig keeps on bimbling away and the few house lights in the area are out!

Almost any of these will do the job https://www.tayna.co.uk/leisure-batteries/

Add one of these and you are good to go https://www.amazon.co.uk/CTEK-MXS-5-0-Reconditions-Motorcycle/dp/B00FC42HAA

 

 

[DaveL59]

yeah know that feeling, had more power outages since moving to Kent than I did in Essex, a couple that were >45 mins. I was the only house that had light PC and TV during those and in fact during the day I didn't even notice one for 10 mins when I thought hey, why is the fan still running on the UPS? Oh, I see 😄 

I have geared them tho to be able to keep the work area and TV going for > 1 hour and the CCTV NVR for approx 30 mins.

Edited January 7, 2021 by DaveL59

[DaveS]

Those are decidedly un-cheap! Not sure I would want to pay in excess of £650 for a battery.

[DaveS]

What are "outages" do you mean power cuts?

[DaveL59]

Just now, DaveS said:

What are "outages" do you mean power cuts?

yep, that's them 🙂