"Accidentally" buying very expensive 220 volt inverter at auction?

softdown

 Unison SU10KPM Battery Backup, 208/240V

Bought an auction 220 volt UPS (uninterrupted power supply) mostly for the batteries. But there are no batteries. They were removed. 

Also thought I could maybe run 220 volt compressor for a couple minutes when the old 220 volt diesel genset doesn’t start in cold weather. 

The second case seems to have once held ~ twenty 12 volt 7 aH batteries - guessing here. Smallish connecting cables still present. 

The first case is VERY heavy and filled with expensive looking electronics and a BIG transformer. 

I am wondering what range of DC voltage the inverter box needs to create 220 AC volts? Can’t seem to find anything useable but this is out of my league. Not an electronics guy.

Left at handymans shop. This gives us a more likely shot at getting it functional. 

Anybody have a clue?

Found a PDF "manual download" but have found the vast majority to be scam malware that just try to download more malware. While appearing legit. 

Found a fairly similar used unit on ebay for ~ $5500. Wow. 


Unison SU10KPM Battery Backup, 208/240V

Marc Kurth

Well, twenty 12v, 7a batteries would be 1,680 watt hours of total storage capacity, so about half of one of your 8Ds. Not a lot of capacity, but there might be something in one of them to justify the $17.50.

softdown

Marc Kurth said:

Well, twenty 12v, 7a batteries would be 1,680 watt hours of total storage capacity, so about half of one of your 8Ds. Not a lot of capacity, but there might be something in one of them to justify the $17.50.

How did you know top bid was $17.50???

Going to measure, I think 12 aH or even 15 aH may fit. No reason batteries could not be stacked sideways - that I know of.

Shoot - I don’t see a reason to confine oneself to the storage space inside of the second cabinet. They are designed to be daisy chained as well. But very expensive to do so. 

My biggest question is serial vs parallel wiring. How many DC volts for the inverter? Could be 12 or 24 or 36 or 48 or 60 etc. Could well be 240 DC volts. Though the inverter had an awfully lot of electronics to be a simple DC to AC converter. I should have taken pictures. Will try to remember. 

NANOcontrol

Form follows function.  Look inside for the input capacitor voltage.  Or take an ohm reading from one positive lead to another.  That should give you a clue of the serial parallel connections.

softdown

NANOcontrol said:

Form follows function.  Look inside for the input capacitor voltage.  Or take an ohm reading from one positive lead to another.  That should give you a clue of the serial parallel connections.

How does one take an ohm reading with zero batteries/power?

Input capacitor voltage seems a great idea!

BB.

I think he was suggesting to "Ohm out" the positive wiring... But if all the batteries are removed, it may be difficult to figure out the exact wiring paths/battery bus voltage... If they are just short battery to battery cables, that could be a clue of series connections. Have 9x positive "jumpers", then should be 10x 12 volt batteries (if 12 volt) and a 120 Volt battery bus.

Looking at input filter capacitor voltage ratings, would give you an idea of the working voltage--I.e., a 48 volt battery bus may have 72 volt capacitors... A 300 volt battery bus would have 400 VDC or so rated capacitors, etc.

Realistically--Try to scrap out the copper. A friend was saying "random" metal scrap was $0.05 a lbs or $100 a ton in our area... Copper would be a lot more, but may need to take the transformer apart to get the "copper" scrap price (somewhere around $3-4 a lb for "bright" copper?).

This appears to the the manual (front controls appear to be the same layout as yours) ... Labeled as Tripp-Lite (bought/private labeled Unison?)... A 240 VDC nominal battery bank:

https://www.manualslib.es/manual/544925/Tripp-Lite-Smartonline-Su6K.html?page=17#manual

-Bill

softdown

Appears to be very little copper. Why not use it as a UPS if a deal could be found on the batteries? 

BBs link shows ~ 110/208/240 volt availability from inverter. Wonder how that works. 

Good link on my laptop. Just downloads more apps on my smartphone. Weird. 

Marc Kurth

softdown said:

Appears to be very little copper. Why not use it as a UPS if a deal could be found on the batteries? 

BBs link shows ~ 110/208/240 volt availability from inverter. Wonder how that works. 

Good link on my laptop. Just downloads more apps on my smartphone. Weird. 

It would appear that with 40 brand new batteries in place, it is rated for 10 minutes of operation at full load and 31 minutes at half load. Even extrapolating that out at lower loads, it just doesn't seem worth the effort when you recognize the danger level when dealing with higher voltage DC. I do understand the desire to reuse stuff, but I strongly feel that the high DC input voltage spells walk away.

This is coming from a guy who has worked on a lot of large AC systems running 480/3/60 and ground mount commercial solar systems with some scary level combiner box voltages. I am not inherently afraid of power, but I would not do it.

Marc

softdown

Could use 20 12aH or 15aH batteries. The 2nd case is just a battery holder.

Yes - not worthwhile unless a great deal can be found at auction or something. 

Bills link shows it also offers 120 ac volts. I need that almost once a year - or so. Eight freezers and fridges etc. 

JRHill

@softdown : you bring up some really interesting things.