Solar inverter for server UPS

[mrzed001]

Hope this is the right topic.
A company popped a question if they can use all-in-one inverters as UPS for they server racks/room (with LFP battery and PV)
For my own little servers I use the MPP MK model as a double conversion UPS
But for big like a rack full with 3U Dell servers ... I have never tried. Theoretically there is no problem (sized properly).
Anybody has any experience in this field?

 

[FilterGuy]

I do not have experience with it, but you want to make sure the inverter states that it provides UPS power. Some inverters will glitch the power during the switchover.... and that would probably take down the servers.

 

[mrzed001]

I do not have experience with it, but you want to make sure the inverter states that it provides UPS power. Some inverters will glitch the power during the switchover.... and that would probably take down the servers.

The MK is a 0ms transfer time unit . I am not afraid of that.
Theoretically I can not find any reason it would not work.
In a smaller scale already working for me.
But never tried in a big scale. So I am cautious. Hate to give bad advice

 

[FilterGuy]

I don't see any issues with it either.

 

[mrzed001]

I don't see any issues with it either.

One little thing is the inrush of the power supplies. That can be a problem, a lot of big capacitors.
My 2 servers (750W PSU) sometimes bring down the 10A 230V breaker if they are connected at the same time. When running they use only 130-130W.
5kW inverter seems to handle them fine.
So in a rack connecting them one-by-one, then starting .... that must work.
I think ....

 

[FilterGuy]

One little thing is the inrush of the power supplies. That can be a problem, a lot of big capacitors.
My 2 servers (750W PSU) sometimes bring down the 10A 230V breaker if they are connected at the same time. When running they use only 130-130W.
5kW inverter seems to handle them fine.
So in a rack connecting them one-by-one, then starting .... that must work.
I think ....

Yes, I can see where that would be a problem. However, That is 'just' part of sizing the inverter to the need. If you do not account for surges when picking the inverter, it will be a problem for *any* application. Note: If you use a low frequency inverter, it will have a much better surge capability.

 

[mrzed001]

Yes, I can see where that would be a problem. However, That is 'just' part of sizing the inverter to the need. If you do not account for surges when picking the inverter, it will be a problem for *any* application. Note: If you use a low frequency inverter, it will have a much better surge capability.

Unfortunately the MPP Solar inverters are all HF if I remember correctly.
But at least cheap. For a price of a Victron Multiplus II 5kW inverter, 3-4 MPP Solar 5kW inverters can be bought.
And the Victron is not double conversion. Neither any other inverter I found until now.

OK I will give the recommendation, but with a warning to start small

 

[robby]

Sol-Ark 5K has 5ms Transfer time. I use the 12K and it does not even cause my computers to blink, even my APC UPS does not pick up and beep when the Sol-Ark Transfers from grid to battery. I am dumping all three of my APC 1500W UPS in my house when the batteries die in them.

BTW before someone says 5ms is an eternity, you should keep in mind that your 60Hz power does a zero crossing every 8.6ms, so 5ms is truly undetectable to equipment.

 

[Bud Martin]

At the old company I used to work, I install AC power sequencer that will power the AC outlets in sequence to reduce the tripping of the breaker when all the power supplies get power at the same time.

 

[mrzed001]

Maybe a pre-charge light bulb?
In the inverter DC side I use 4pcs 12V car lightbulb in serial to precharge inverter capacitors.
A 230V 60-100W old bulb in the AC side (parallel connected with a breaker + a switch for it) could work?
Of course the power sequencer is a good idea

 

[HammaMan]

Hope this is the right topic.
A company popped a question if they can use all-in-one inverters as UPS for they server racks/room (with LFP battery and PV)
For my own little servers I use the MPP MK model as a double conversion UPS
But for big like a rack full with 3U Dell servers ... I have never tried. Theoretically there is no problem (sized properly).
Anybody has any experience in this field?

Yes, they should run 240v there too if not already. I run my computer equipment in my home at 240v --- everything from TVs to computers to phone chargers will work on 90-250v at 47-63hz (assume nothing, read the label). Higher efficiency at the higher voltage. 240v plugs have the 2 narrow prongs rotated 90 degrees.

NEMA 5-15 is the standard US/CA 120v, NEMA 6-15 is the 240v version (for 12ga wire 6-20 plugs can be used, they accept 6-15 as well). Some server PSUs have a switch, most are automatic today though. Label thoroughly if switches are involved.

ATX PSU standard requires at least 16ms hold time. Sub 10ms switching should be fine. Should is the keyword.

 

[K power]

Good day ,

I have a complicated scenario at work , we had a apc ups in the server cabinet powered by few 12 volt battery, it worked fine but the battery died too quickly and was not holding charge for a fille 2 h and we needed it too.
So we install a 5kva inverter with 20 ms change over time supplied by a 100apms lithium battery.The server cabinet draws about 1.8 watts and has two different servers and few other things .
The utility power goes off once every day and for 2 h,
The Fanny thing is :
When the utility power is on the inverter works fine but the second the utility power goes off the inverter trip ( shut off and ) but it will try to start it self but not work

If the we switch of the utility power of manually at the DB board the inverter workers fine with no problem

We even tried to connect a different load 3kW to the inverter when the utility is off , it works fine but as soon s the server cabinet is connected the inverter shutt off,