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Compaq R3000h UPS

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New Member
Anybody familiar with the R3000h ups I believe it is a re-badged APC unit with a reasonable output and management software.
I have a couple of these which I was looking to see if it would be possible to strip down and add GTI circuitry to it possibly where the battery bank would have been.
The bulk of the construction already having been done i.e the main inverter - if it would be possible this would make a nice rackmount unit suitable for small wind turbines.
They can be picked up fairly cheaply I bought 2 for 40GBP - there is also USA and UK variants so could be a good project for all of us as an alternative to the fully blown GTI project.
Spec link - **broken link removed**
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Most Helpful Member
I have been playing with modifying UPS circuits to do exactly what you are trying to do.
I am coming to the conclusion that with a few circuit modifications the basic H-bridge can be used along with the main power transformer without any problems except the heatsinks are not big enough on the ones I have been looking at. They run hot after a few minutes! :(
But unfortunatly the power transformers are often 15 minute duty cycle rated at full output on almost everyone I have taken apart that uses a fixed size or internal battery.
The actual power transformer continuous VA ratings are more like 1/3 or 1/2 the maximum rating. :(
This does give them an excellent overload capacity though. But do to the limited run time design I think thats where part of the heatsink problem comes from as well. ;)

I do have a large Sola 2500 VA rated unit that ran off an external battery pack that does have a full 2500 VA continuous duty rated tranformer and big fan cooled heat sinks. But it is the only one like that I have found so far. However, it also ran off a 60 volt battery system so the transformer will only work with a system voltage of 60 volts or higher.

If there was a way to get into the actual program software that the UPS control systems run on I think it could very well be possible to reprogram them for full GTI operation with only a few added circuit components and minor modifications.
I know they already have most of the feedback and monitoring components on the boards, Its just a matter of finding out how to rework or modify them to serve a slightly different purpose. :)

But that is only a theory it may very well not even be possible. I just dont know.

By design they are about 90% of the way to being GTI capable. ;)

What I have found as far as physical modification to the power side is they need the reverse blocking diode on DC the input, the correct size H-bridge filter capacitor, Larger heat sinks, and a correct size power factor correction capacitor on the output. :)

The rest is just a matter of a control system retrofit or possible program rework, In thoery.

If any one has any ideas or knows how to hack the programs on the better UPS units please post it! :)


New Member
Thanks for the reply tcmtech - yes these are 3000va and very heavy construction also were a few thousand dollars when new.
I do not think they run as high as 60V input but will be stripping one down maybe over the weekend and will check on the battery input.
I did use these on a bank of servers and they would run for about 40 mins - not to sure on the actual load - should have measured it :-(
If anybody else is familiar with this model any info would be appreciated as I am sure they would make a great GTI unit after a suitable sized H-bridge etc as suggested.


Most Helpful Member
Heres an actual specs write up. You may be a bit disapointed!

The HP R3000 UPS is a high power-density solution, designed for customers who want to provide power protection in space constrained rack enterprise environments. This leading edge Uninterruptible Power System, R3000, features the industry's first 2U, rackmount design offering up to 2700 watts of true power - unprecedented power density! The R3000 uses a unique transformer-less technology, where high performance Digital Signal Processor (DSP) controllers replace bulky transformers. Through this advanced technology, the R3000 offers several benefits including increased power efficiency and smaller foot-print with less weight. In addition, the HP R3000 UPS has the capability to be connected to optional Extended Runtime Module (ERM). Key Features

•Increased power density with up to 3000VA / 2700 Watts of power packed in just 2U rack space
•Greater system uptime with support for Extended Runtime Module (ERM)
•Easy configuration through enhanced front panel display
•Support for HP Option Cards that extend the power management capabilities of the UPS
•More efficient voltage regulation with revolutionary technology
•Hot-Swappable Battery and Electronics Modules
•120 Volt Input
•NEMA L5-30P (30 Amp TwistLock Plug)
•3000 VA
•2700 Watts
•6 x NEMA 5-15R Receptacles (Standard 120V 3-prong North American sockets)
•1 x NEMA L5-30R Receptacle (30Amp TwistLock socket)

Batteries & Runtime
•Full Load 5 minutes
•Half Load 12 minutes
•Voltage Wave Form Sine wave
•Battery Type Maintenance-free, sealed, valve-regulated lead acid (VRLA)
•Extended Batteries One ERM with two battery strings
•Recharge Time <3 hours to 80% usable capacity; <24 hours for complete recharge

Battery Pack I found listed for it uses 16 X 6volt 12Ah = 96 volts!

Bummer! All the way around! Bummer! :(


New Member
Thanks for the info - Yeah what a bummer :(
Mine are the older type and are the 3U units and hopefully will have transformers - will get to have a look over the weekend and let you know.
Thanks for your input.
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