UPS Capacity & USB Cable

[SauRoN]

Anyone here in the UPS game?

Some silly questions maybe...

1. Am I correct in understanding that the VA rating has absolutely no bearing on the size of the battery and that it's really just the peak support power the device can handle upon switch over? Basically if I'm only going to connect 250W to the thing would it be stupid to buy a bigger UPS since I'm not going to get any more time out of it really?

2. Is there anything special about the USB cable? I need to do about 10m and there aren't a whole lot of those around. APC make it sound like theirs is somehow special but I call bullshit on that.

Thanks!

 

[Ninja_Theory]

Subbed. I also want to know about #1.

My understanding is the same as yours but that you need a little fat on the peak load, based on your estimated usage. So for my use case - a 950w load - I was recommended to buy a 2kva (1200w) pure sine inverter. Then 4x105ah batteries to give me around 4 hours. Batteries buy you the time you need to be up.

 

[SauRoN]

Subbed. I also want to know about #1.

My understanding is the same as yours but that you need a little fat on the peak load, based on your estimated usage. So for my use case - a 950w load - I was recommended to buy a 2kva (1200w) pure sine inverter. Then 4x105ah batteries to give me around 4 hours. Batteries buy you the time you need to be up.

Not really so worried about time being up as that would cost money in there here and now...but I am keeping my options open to units that support external battery expansion like the APC ones.

Partly why I'm asking the question as I can get an APC for much lower VA or for the same money an EATON with much higher VA...but no battery expansion option.

Which is why I question the USB as I need my UnRAID server to shutdown cleanly as a priority, then after that I would think my Router and AP should stay alive for a pretty long time on the UPS battery as they are super low power.

My gate/alarm/garage all have their own batteries so my smart switches will keep on working and I won't be locked out of the house.

 

[Ninja_Theory]

Ah will wait for the UPS experts. I’m keen to see the light here as well.

I see plenty inverters seem to be rated at 10ms switch over. That’s like half a cycle, so at 50 or 60 cycles per second, I would think that will be just fine for the switchover, even in your case.. but stand to be corrected ofc.

About adding batteries, you need to consider your use case and if it will be needed (which knowing you, you’ve already done). For me, I had to decide between an inverter that can take up to 4 batteries or one that can take up to 6 batteries. Edit: Made me see how long I’d need to run my peak load for.

Your peak load is relatively small. I’m not sure how long you’d want to run it for, that should give you an indication of max batteries you will need so you can make the right call on the inverter.

 

[SauRoN]

Ah will wait for the UPS experts. I’m keen to see the light here as well.

I see plenty inverters seem to be rated at 10ms switch over. That’s like half a cycle, so at 50 or 60 cycles per second, I would think that will be just fine for the switchover, even in your case.. but stand to be corrected ofc.

About adding batteries, you need to consider your use case and if it will be needed (which knowing you, you’ve already done). For me, I had to decide between an inverter that can take up to 4 batteries or one that can take up to 6 batteries. Edit: Made me see how long I’d need to run my peak load for.

Your peak load is relatively small. I’m not sure how long you’d want to run it for, that should give you an indication of max batteries you will need so you can make the right call on the inverter.

Yeah the battery expansion is just kind of a future proofing optional extra.

Since this is going in the garage I've seen a few DIY hacks where you can basically hook up them up in series as required. In my case though a single full size battery would make it 400minutes or so of run time which would get through any load shedding arrangement.

 

[Phence]

Yo, from my past experience my last Smart UPS from APC used a special type A to B USB cable. Meaning the pinout was different but the connectors looked the same.

I ended up testing all the cables I had and eventually labelling the actual APC cable partially not to loose it but also to make it look professional lol.

Btw my old APC only liked the APC USB cable. There pinout on the internet if you want to make your own or see how it's different.

Sent from my ONEPLUS A6003 using Tapatalk

 

[SauRoN]

Yo, from my past experience my last Smart UPS from APC used a special type A to B USB cable. Meaning the pinout was different but the connectors looked the same.

I ended up testing all the cables I had and eventually labelling the actual APC cable partially not to loose it but also to make it look professional lol.

Btw my old APC only liked the APC USB cable. There pinout on the internet if you want to make your own or see how it's different.

Sent from my ONEPLUS A6003 using Tapatalk

Maybe that’s enough reason right there to simply buy the Eaton.

Emailed them earlier today to see if there is a major difference in on board battery capacity so that might swing it.

Why oh why they put the USB port on the front I don’t know.


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[Off-The-Chart]

Anyone here in the UPS game?

Some silly questions maybe...

1. Am I correct in understanding that the VA rating has absolutely no bearing on the size of the battery and that it's really just the peak support power the device can handle upon switch over? Basically if I'm only going to connect 250W to the thing would it be stupid to buy a bigger UPS since I'm not going to get any more time out of it really?

2. Is there anything special about the USB cable? I need to do about 10m and there aren't a whole lot of those around. APC make it sound like theirs is somehow special but I call bullshit on that.

Thanks!

1. ok, hope I am understanding question correctly. yeah, VA is basically size of load more than size of battery. this is the kind of situation where I think you would be better suited to buy one of those inverter setups so that you can manually add your own batteries for extended runtime when/if needed. the only thing that I am unsure about has to do with the size of the UPS in relation to charging time of the batteries. I know with my old RCT 2000VA, someone on here did a mod on his where he added larger batteries and that in turn meant an increase in charging time.

2. trying to think why I said what I did........

maybe @MSI1104 could chime in

 

[SauRoN]

2. well with the APC units the USB cable helps you install the software that helps you with auto shutdown and monitoring. I think it just comes down to what kind of software your UPS comes with and if having it connected via USB adds some kind of feature such as the above mentioned.

maybe @MSI1104 could chime in

Heh? There would be no way for the PC to know what is happening with the UPS without having the USB permanently connected.

So it’s not about installing the software at all, it’s about communicating with the software.

Without the USB no auto shutdown is possible.




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[Off-The-Chart]

lol, edited that "wtf" part

but what does APS 'claim' on theirs?

is it just what Phence mentioned that makes theirs 'special'?

 

[AinsleyHarriott]

Why not get a small generator?

 

[SauRoN]

lol, edited that "wtf" part

but what does APS 'claim' on theirs?

is it just what Phence mentioned that makes theirs 'special'?

Yeah it’s very wishy washy on APC’s direct claims but APC daemon (the Linux software) claimed various pin outs which is why I had to ask.


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[SauRoN]

Why not get a small generator?

I don’t need it to stay on in perpetuity

Also that would involve a lot more expense and noise and fuel etc.

If anything I would go completely solar in the future and off fossil fuel all together.


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[pXius]

Almost all PC UPS' run 2x 9ah batteries unless you go server rack-mount style where you really pay for the form factor.
So your first assumption is correct.

You could hack up an existing UPS and and replace those 9ah batteries with something bigger (many youtube tutorials) but the quality of the charger and protection circuitry for discharge/overcharge protection ect are all unknowns as they are not advertised. That's important because something like a 120ah deep cycle battery will run you R2.5k easy, of which you'll need 2. So having a shitty UPS degrade your batteries is imo not worth the risk.

The third option if you need capacity would be an inverter + deepcycle battery combination. Buying a hybrid inverter already sets you up to go solar if you're serious about that step.


As for the USB cable, longer just means more isolation to protect against signal degradation. Some cheapo chinese cables might have connection issues at longer lengths. If you run into issues, an active USB2 cable should sort you out. So no, nothing fancy about their cable aside from being properly isolated.

Edit: If the USB pinout is really different, that'll obviously be an issue. Seems like a lot of shlep for something large manufacturers can just buy for a few cents though.

 

[ThatGuy_ZA]

1. Yes but lower VA rated UPS's tend to have smaller batteries and chargers which means you could run into trouble if you hook a 100ah battery up to a 650va UPS. It's always surprised me that there aren't more lower output wattage UPS's (EG 300w) with support for bigger batteries (100 - 200ah)

2. Some of the older APC USB cables had an RJ45 style connector on one end but apart from that it's just a normal cable. 10m is quite long for USB so you'll want to get a good quality one.

 

[SauRoN]

Almost all PC UPS' run 2x 9ah batteries unless you go server rack-mount style where you really pay for the form factor.
So your first assumption is correct.

So far I've found the vast majority have one single 7.2 Ah battery.

But that's why I emailed Eaton because looking at weight and dimensions it appears their larger units (1100VA and up) should have two batteries or one much larger one but nowhere do any of them get specific on this stuff.

You could hack up an existing UPS and and replace those 9ah batteries with something bigger (many youtube tutorials) but the quality of the charger and protection circuitry for discharge/overcharge protection ect are all unknowns as they are not advertised. That's important because something like a 120ah deep cycle battery will run you R2.5k easy, of which you'll need 2. So having a shitty UPS degrade your batteries is imo not worth the risk.

Yeah this is why the APC's seemed like a good option with their battery expansion supported without a hack job, but then you dig deeper and it's near impossible to find that battery expansion for the lower end models.

The third option if you need capacity would be an inverter + deepcycle battery combination. Buying a hybrid inverter already sets you up to go solar if you're serious about that step.

Yeah I saw the Ellies inverter + battery trolley setup but it's a bit rich for my blood and which is why I looked at potentially rather going smaller and "ups only" if the capacity doesn't mean much for my use case.

As for the USB cable, longer just means more isolation to protect against signal degradation. Some cheapo chinese cables might have connection issues at longer lengths. If you run into issues, an active USB2 cable should sort you out. So no, nothing fancy about their cable aside from being properly isolated.

Edit: If the USB pinout is really different, that'll obviously be an issue. Seems like a lot of shlep for something large manufacturers can just buy for a few cents though.

Yeah the murmurs about APC cable pin outs being different are pushing me towards the Eaton which seems more "open" or just not documented at all.

Also less money for larger batteries...I hope.

 

[SauRoN]

2. Some of the older APC USB cables had an RJ45 style connector on one end but apart from that it's just a normal cable. 10m is quite long for USB so you'll want to get a good quality one.

Aaah that starts to make a bit more sense now as it did seem simply unnecessary to create a special USB cable when it's a known standard.

I'll be buying a brand name 10m cable and hoping it does the job. Will make a plan to measure a bit more accurately maybe I can get away with less.

It's from the garage through roof into the next room over and close to the ceiling so 5m may just do it. Maybe I'll make the effort and run a 5m piece of string up to see.

 

[ThatGuy_ZA]

Aaah that starts to make a bit more sense now as it did seem simply unnecessary to create a special USB cable when it's a known standard.

I'll be buying a brand name 10m cable and hoping it does the job. Will make a plan to measure a bit more accurately maybe I can get away with less.

It's from the garage through roof into the next room over and close to the ceiling so 5m may just do it. Maybe I'll make the effort and run a 5m piece of string up to see.

Why don't you get a rpi or snother SBC to run NUT to monitor the UPS? You could plug it in with a shorter cable and leave it with the UPS.

 

[SauRoN]

Why don't you get a rpi or snother SBC to run NUT to monitor the UPS? You could plug it in with a shorter cable and leave it with the UPS.

Ag just too many extra things to manage.

I have an Unraid server with the functionality built-in so running a cable seems pretty simple and straight forward.

I did consider some move to make it "wireless" with a ESP8266 based board but like I say it's just more complexity.

Once the cable is in, it's in and doesn't require anything more.