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Ironman

Victron UPS for small office (8 PCs, server, network)

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We needed a UPS for a small office (about 8 PC's, server and network hardware) to be able to continue working through loadshedding (4-6 hours at a time).

We are renting our office and did not want a permanent setup.

 

Requirements:

- Ultimate long term reliability - high quality brand

- Expected lifetime: about 15 years for inverter and 7-10 years for batteries (expecting much more regular loadshedding while eskom repairs its infrastructure)

- Backup system that works for many years without maintenance

- Standalone system ( rack on wheels)

- Ready to be moved to a new office if we have to move, OR be re-purposed into a solar home ESS system (just add MPPT and panels)

 

If we bought an off the rack 3KVA UPS system with 6000 WH runtime, we could probably get it for about R20k.  But I have a long history with cheap UPS systems - they never make it to 2 years - then you have to replace the batteries - at huge cost, labour - weekend time etc.  At about 4 or 5 years the inverter's cheap capacitors start sweating and it becomes very unreliable - almost worse than not having a UPS. Not one lasts over 6 years - and in the process, the PC's that you are supposed to protect are subjected to many power spikes and failures due to the unreliable UPS.

 

So we went this route - about 4X more expensive but we know it will last, and protect the sensitive equipment properly for many years:

- Victron Multiplus 3000

- Victron Venus controller

- 2 X Pylontech US3000 batteries

- 19" computer rack on wheels

- Small DB with input breaker, earth leakage on output, and two circuits on output.

- DC Fuses, cables and building the rig (took about 5 hours).

 

 

@Jaco de Jongh built this rig for me:

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The Venus controller reads the battery State of Charge from the BMS of the pylontech batteries. So the system gets an accurate battery state of charge, and thus will ensure a much longer discharge time. You can also build your own controller with a raspberry and Venus image. 
The system will work without the venus, but the MPII will then try to judge the battery charge level by just reading the battery voltage.  There are many tales of broken expectations when systems are set up like that - under load, the voltage drop in the batteries and cables cause the MPII to under-estimate the battery level badly, eventually switching off due to low battery voltage, while the batteries still contain a good charge. 
@plonkster - feel free to elaborate or correct me if I am wrong here.

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2 minutes ago, Ironman said:

The system will work without the venus, but the MPII will then try to judge the battery charge level by just reading the battery voltage.

That's not true. The Multiplus does its own SOC by counting the amp hours going through its inverter/charger. In an AC-tied system this is sufficient and you can get away without any additional stuff.

In a DC-tied system, the Venus device will periodically tell the Multiplus: "Hey, there is also these extra amps coming from the solar chargers!", and the Multi will then add that to whatever its own charger is doing and so the SOC can still be computed. This is assuming there is no battery monitor in the system at all.

But if there is a battery monitor (eg, part of the BMS, as is the case with the Pylontechs), then the SOC of the battery overwrites the one of the Multi. The Multi still does its own (so should you lose the BMS connection, it still keeps track of things), but because it periodically gets a more accurate one from the BMS, that is effectively the one that is used.

The Multi never uses voltage to estimate SOC.

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11 hours ago, Jaco de Jongh said:

Almost, there is a few devices that can be used to give you access to VRM, the Venus being one of them.. 

Well, if you roll your own, you're still using either the Venus firmware (which is Linux+OpenEmbedded), or you're using the Raspberry Pi packages... so I'd say "No Venus no VRM" is about accurate.

Also, the one very nice upshot of the software name is that I frequently have a Bananarama song stuck in my head... NOT 🙂

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2 hours ago, plonkster said:

Also, the one very nice upshot of the software name is that I frequently have a Bananarama song stuck in my head... NOT 🙂

Well, if you're my age, more Stockley Sisters than Bananarama.

I was barely a few months old when the original was released by the Dutch band Shocking Blue. Which is all quite ironic because of the Victron/blue/Netherlands/electricity link. 😉

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1 hour ago, VisN said:

Well, if you're my age, more Stockley Sisters than Bananarama.

What!? You mean the Bananarama version isn't the original!? My whole childhood is ruined now... 😛

I've actually had quite a few such cases. The first version of Baker street I heard, was the Undercover (British band) cover of the song, and I initially preferred it to the Gerry Rafferty version, and later learned to love both. Similarly with "Never let her slip away", I got the Undercover version first, and only discovered THIS YEAR that the original is from Andrew Gold (1978). I prefer the 1978 version in this case. I will always love you by Whitney Houston? First version I heard was the one by Tears 'N Joy. First time I heard Nirvana's Smells like Teen Spirit... was the Weird Al Yankovic parody. And so on and so forth...

But then I discovered this backport of Gotye's 2011 hit... and the 80s kid in me prefers it.

Edited by plonkster

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On 2020/01/26 at 12:11 PM, plonkster said:

I've actually had quite a few such cases

I ruined my wife's day once when I informed her that Celine Dion: All By Myself  Is actually from Eric Carmen.

 

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25 minutes ago, PJJ said:

Eric Carmen

Eric Carmen only had one song and it was "Hungry eyes". No... no... I don't want to hear that I am wrong. He had only this one song! Just like there was only one Matrix movie.

matrix-4-5.png.4d537dc7786d17a1a03db0dc223efdbf.png

Edited by plonkster

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Quick on. The changeover between mains and battery. Quick enough the the computers don't mind? I've got a server on very fussy PFC power supply and it wont even sustain a turnover on a cheap UPS. 

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