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Roll my own UPS. Looking for suggestions.

Roll my own UPS. Looking for suggestions.

Roll my own UPS. Looking for suggestions.

(OP)
I had a 600VA APC (American Power Corp) "BACK-UPS" UPS (~$400) that ran my office comp and phone. Worked fine for about five years then it complained about the battery after dropping the load early during a power outage. I bought battery replacements. These were those horking ~20Ahr ones with bolt-on lug connections. I assembled it all and found the UPS was actually screwed up. Dang.

I cast about and found another APC "RS BACK-UPS" that was +800VA (~$750). The thing was narrow like a giant book. To increase the run time to several hours I also picked up a companion, same size/look battery extension unit. The UPS contained 2 of the typical 8Ahr cells and the battery companion unit had 4 more of the 8Ahr batteries in it. Seemed great and actually worked for about 8 years. Along comes a power failure and it jumps into action and keeps things going for 6 hours running my cable router, all the network switches, and hubs, and my cable-router based telephone.

Power comes back and... an hour later we lose everything. Turns out it's fried and just stays on battery always so when power came back it just kept UPSing until the batteries choked.

Now I'm pissed at APC as both of their rather high end UPSs have crapped out on me when they were used in anger. What's the point of a UPS if they check-out during power fail events?

I'm done with APC and their junk.

I'm considering roiling my own using a modified sine or sinewave inverter, about 100Ahr of AGM battery(s), and about a 15A, three or four stage charger to keep the battery charged. This would be an online double conversion UPS capable of something like 800W during a power failure but would only need to be about 350W when infrequently computing and only 50W when just doing it's cable router/phone thing.

Has anyone done this sort of thing? What's your experience been? Recommendations?

Maybe I should try to come up with a transfer relay and run standby?





Keith Cress
kcress - http://www.flaminsystems.com

RE: Roll my own UPS. Looking for suggestions.

Look for an older commercial unit - these were generally built using components which you can obtain and thus the units are repairable. The capacitors will age, and any cells with it will likely be u/s too. The rest is probably salvageable. Over in your part of the world, something like http://www.ebay.co.uk/itm/Clary-Corporation-3000-V... although certainly not at that price!

I acquired an older Chloride unit of about 8kVA a few* years ago when I was in my twenties and kept it going for quite a while with basic repairs. I only got rid of it when I was faced with replacing a lot of batteries and couldn't really justify the expenditure. My source of spares from switchgear tripping batteries dried up (or more accurately was demolished) and my pockets weren't deep enough for a battery that size.

* Less than thirty!

RE: Roll my own UPS. Looking for suggestions.

It appears that in both cases, the UPS did its primary job, then failed to go back to civilian life.

It seems such a simple thing.

My late friend Ermi, the smartest person whom I have ever worked with, analyzed from first principles a parametric oscillator that included both a Coulter(r) aperture and a vacuum tube. I signed, and mostly understood, all 100+ pages of his lab notebooks on the subject.

He also beat on the problem of designing a functional/better power-fail-detect circuit, i.e. UPS brain, for upwards of ten years, and was never satisfied with the results embedded in our products. They mostly worked, passed any test procedure that we could imagine, and occasionally failed, in ways that destroyed any useful evidence.

You are one smart sumbitch, but there are better uses of your time.

Mike Halloran
Pembroke Pines, FL, USA

RE: Roll my own UPS. Looking for suggestions.

My employer has many UPS devices from about 450- 2000VA in service, and used to use APC nearly exclusively; the APC units have been problematic over the years. The most common issues are battery overcharging (the battery shells often swell to the point that they cannot be removed) along with catastrophic failure after a long outage.

About 4 years ago, I started using Tripp Lite units and have been very pleased with them. Here is one https://www.tripplite.com/omnismart-lcd-120v-1500v...
which I have had good results with.

Another worth consideration if you can find it is the (discontinued) Best Power 610 unit, they are very reliable in my experience. We have several in service for 15+ years with no more than battery replacement.

RE: Roll my own UPS. Looking for suggestions.

Concur with Wayne.. if you can find a good used Best Power UPS.. preferably one with the configuration option for external batteries. Various FERRUPS models were designed to be operated from multiples of 12volts e.g. battery strings of 12, 24, 48 volts, typically automotive sized 70AH batteries.

Next I would look for the smaller Eaton Powerware units..

The small 7AH 12 batteries used in many UPS systems don't have the lifecycle of the larger 12 volt batteries.

RE: Roll my own UPS. Looking for suggestions.

(OP)
Thanks for the input folks.
I hear you Mike! But, instead of watching the idiot-box this is often my entertainment.


Those Best Power inverters do look pretty nice but WOW they're pricey, even as older used units.
Kinda seems like Eaton may have swallowed up Best Power.

I once used a Tripplite in an emergency and it flamed out on me so I'm not too keen on them.

This looks interesting:
xantrex 1000W

It has a built-in 20A 3-stage charger(AGM, GEL and flooded) AND a transfer switch! Just add batteries and it's a robust UPS!

In an extended blackout I could drag it out to a car to make it an inverter generator capable of running one refrigerator a light or two, and a laptop.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Roll my own UPS. Looking for suggestions.

Victron inverters are popular with marine smallcraft owners, a bit of digging should get you some unbiased opinion from users.

As a general observation, I prefer the units which use relatively few large-capacity cells in series (12V / 24V / 36V / 48V) because you have reduced probability of one bad cell taking out a full battery string. That's the great weakness of the UPS designs which use a large number of small cells in series: put enough VRLA batteries together in one place and you'll have bad cells.

RE: Roll my own UPS. Looking for suggestions.

If you do not require double conversion, the Xantrex unit looks like a way to do the job.

RE: Roll my own UPS. Looking for suggestions.

Not to sound like a shil, but I've had good results from Xantrex and using one of their stand-alone inverters for my back-up battery power has been 100% effective.

I've had some of the APC units, but saw no evidence of multi-stage charging or battery status monitoring, which are essential to ensuring that the unit will work when the next power outage comes.
APC dispenses with things that add no resale value or would overwhelm the consumer with information.

STF

RE: Roll my own UPS. Looking for suggestions.

(OP)
Scotty; those Victrons look nice but 230Volty.

I also agree with your cell-in-a-string failure synopsis. That actually occurred in my erstwhile APC RS UPS which was a 24V input unit with three paralleled blocks of two batteries in series. One had a shorted cell that got four other batteries to drain into it.

Because of the aforementioned car gambit and the fact that I'm looking for 1000W or less I want this inverter to be the more flexible 12V input.

During a recent 50hr power outage my Mother-in-law was subjected to, brought to us by California drought annihilating weather, I used an 800W StatPower 12V inverter to run her refrigerator and laptop for 8hrs. Rolled her car out of the garage and clamped the inverter to her battery. I left her car idle for 8hrs with just a big extension cord running under the garage door. Her Camry was the quietest generator I've not heard in a long time. It used 2 needles worth of fuel in that time, I'm guessing 2~3 gallons.

Spar thanks for the Xantrex inverter experience data.

APC.. don't get me started. They turn over their designs about once a year and have dozens of models. If you look at their support pages they list HUNDREDS of models! That's how you make a really bulletproof design - completely replace all your products every year. Instead they should refine their products fixing what millions of user-hours show them are weaknesses. Nope. They have so many models the one I have they don't even admit to having made yet they have ones that look identical. APC acts like Nike shoes with model churn.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Roll my own UPS. Looking for suggestions.

I have used several APC small UPS over the years and until last year they have worked fine. (ie 8 years or more). I had issues with the most recent APC unit and had to send it back. I like the PowerChute software that comes with (most) APC UPS units.
I also inherited a Liebert (Emerson) unit 2 years ago and it is been no problem, but the software interface is not as good as the APC package.
I usually replace the entire UPS when the battery expires.

"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

RE: Roll my own UPS. Looking for suggestions.

Aren't Xantrex and APC now owned by the same company?

There are a few other similar units to the Xantrex around, Alpha Technologies' Outback Power is one of them, and they're becoming more common as the crossover into energy storage and solar becomes more prevalent. Some of them are big enough now to be able to be permanently connected to your house as a backup.

EDMS Australia

RE: Roll my own UPS. Looking for suggestions.

Schneider bought APC to complement their own larger UPS range and to gain a market-leading brand name. Merlin-Gerin had some good designs at the heavy end of the market but their smaller ones never really broke through in the IT mass-market sector where APC is king.

I didn't know they also had Xantrex - last I heard Xantrex had hooked up with Elgar, Power Ten and Sorenson resulting in one company having an unhealthy dominance of the large PSU market with only Agilent and far-eastern junk to compete against them.


Keith - pretty sure there are 115V variants of the Victrons although I have never seen one. Whether any made it across the water I'm not sure. I'm also far from clear whether Victron is any relative of Invertomatic-Victron (IMV), a respected Swiss UPS manufacturer which was swallowed up by GE a few years ago and re-branded.

RE: Roll my own UPS. Looking for suggestions.

We have a little experience with UPSs here at work (many more outages in our area than a typical suburb). Most workstations in the engineering group have little 500w APC units under the desks, and mostly these work. We have had one go south a few years back, exactly as you describe, smoked.

FWIW, we build a machine with a "failsafe" option, wherein we incorporate an OTS UPS (made by SOLA) to keep the controller alive long enough to put the machine into a user specified safe condition. We have one wired to our shop test unit, which gets power cycled a lot, and so far it has held up well. These are quasi industrial devices...though we buy them from DigiKey I think.

At home I use an IPS, powered by a little 6 hp Honda; burns about 7 gallons in 24 hours of running at the load we put on it, depending on weather (it runs the blower in our forced air heating system). IPS because it takes me about 15 minutes to fart around getting it working. Which reminds me, I need to put a reminder on my phone to rebuild the carby this summer, it was pretty balky starting this last time around.

RE: Roll my own UPS. Looking for suggestions.

Btrue, the carby will be happier if you feed it ethanol-free gasoline, which is available in many areas as a premium grade with a premium price.

Mike Halloran
Pembroke Pines, FL, USA

RE: Roll my own UPS. Looking for suggestions.

Where I worked we pulled them and replaced at 5 years.
Honestly for as little as the middle of the road ones cost expecting 8-10 years out of one is unrealistic.
We also tested them every quarter.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Roll my own UPS. Looking for suggestions.

Mike, ever had any luck with additives? I'll have to ask around and see who sells the good stuff.

RE: Roll my own UPS. Looking for suggestions.

Btrue, I have tried a bunch of additives over the years.
The only one that ever worked at all is Marvel Mystery Oil.
On early EFI cars, subject to 'varnish' deposits,
it feels like a valve job, in ten miles.

Okay, absent proof, I use Sta-Bil in stored gasoline.
... or replace the gas,
when it smells sweet and not sharp,
and mix the old gas with what's in the car.

Mike Halloran
Pembroke Pines, FL, USA

RE: Roll my own UPS. Looking for suggestions.

I have been using SeaFoam in my generator and mowers when I store them. It has been working for me.
I try to start me generator every 4-6 weeks. But the mowers sit for 5 mo and they start easily.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Roll my own UPS. Looking for suggestions.

I have found the ethanol slowly deteriorates whatever rubber hosing is in the system... which eventually gunks up needles, ports, etc. It's possibly easier to replace the rubber crap once, then you don't care what kind of gas you put in it.

Dan - Owner
http://www.Hi-TecDesigns.com

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