UPS requirements

[C@sparis]

Morning

Perhaps somebody could assist - Need to know which UPS would be sufficient for running my router for the allocated 2.5hour load shedding time periods. No idea how to work these things out, specs as follow:

I have an Asus RT88U router
AC Input : 110V~240V(50~60Hz)
DC Output : 19 V with max. 2.37 A current

Been looking at this one: takealot.com
Just not sure if it would suffice??

Many thanks

 

[Launch]

It's hard to tell from just the 2000VA figure. See it could provide you with say 2000VA but they don't indicate for how long. It really depends on the battery capacity and the efficiency of the inverter in the UPS.

Many of the reviewers claim running their routers for several hours. One even mentions running he's whole gaming PC for around 20-30 minutes. I reckon it can handle your 45W router just fine.

Have you considered instead building your own UPS by buying a deep cell battery and inverter ?

 

[C@sparis]

Tx Launch

Yes I have considered the option you mention, however doing it right allowing for sufficient battery power and relative hardware prices in excess of 15K, add installation, and last the DB board installation . for 15 - 20k you will be limited to a few items in the house being at during load-shedding though.
it will hurt the budget - BUT.....
it's in the pipeline, considering the future of electricity in SA it would certainly be beneficial going semi off the grid, solar, etc....

 

[Jero814]

The DC output of your router power supply isn't the actual consumption of the unit - its the rated power the power supply can provide. To work that out u multiply the voltage y the current to get the max power ie 19Vx2.37A = 45W.

BUT that ISN'T the power draw of you router. Doing a quick google on the RT88U gave me this so i would assume actual power usage to be in the range of 14-21W.

Quick google shows the specs of the UPS you linked has 2x 12V 9Ah batteries. That means it can provide 2x12x9 = 216W of power. As it is 60% efficient you would have about 130W available. SLA batteries shouldnt be drawn below 60% in general so it leaves u with 130x40% = 52W. So, 52W (safely usable) / 21W (router) =2.5 - so yes it should easily meet your needs.

I have a RCT 850V UPS that powers my router for 2.5 hours with no probs. My router only uses 4-6W however measured at the wall. There is however 1 annoyance with both the Mecer and RCT (Rectron made product) and that is that they both have an auto switch off after 2 hours regardless of settings/ battery life remaining etc - annoying as hell but you can just switch the unit off and back on and it will power itself for another 2 hour stint. Its done for safety reasons and cant bloody well be switched off

Regarding UPS's / inverters I wrote a post about it explaining abit about them here. Should give you some idea of what u looking at when you look at an inverter or ups specs.

 

[Caliph]

Quick google shows the specs of the UPS you linked has 2x 12V 9Ah batteries. That means it can provide 2x12x9 = 216W of power. As it is 60% efficient you would have about 130W available. SLA batteries shouldnt be drawn below 60% in general so it leaves u with 130x40% = 52W. So, 52W (safely usable) / 21W (router) =2.5 - so yes it should easily meet your needs.

This calculation is wrong.

 

[LanLord]

Hi.

I have this product;

Takealot

When it was new it was able to keep the fibre equipment and router running for over 2 1/2 hours. After a year the batteries started failing though.

Regards

 

[Thanatos]

Looking for an ups for just my router.

Would one of these be sufficient?

takealot.com or takealot.com

 

[el3venth]

Quick google shows the specs of the UPS you linked has 2x 12V 9Ah batteries. That means it can provide 2x12x9 = 216W of power. As it is 60% efficient you would have about 130W available. SLA batteries shouldnt be drawn below 60% in general so it leaves u with 130x40% = 52W. So, 52W (safely usable) / 21W (router) =2.5 - so yes it should easily meet your needs.

Your calcs are wrong. You are missing the hour component.

So 2 x 12V x 9Ah = 216 VAh or rather 216 Wh.
At 60% efficiency, give you 0.6 x 216 Wh = 130Wh.
You cannot adjust the depth of discharge. But lets assume and stick to your 0.6%.
So 52Wh. Then 52Wh / 21W = 2.5h or 2.5 hours.

So calcs kind of right, symbols wrong. Also making some assumptions regarding DoD. My old lecturer at 'varsity would give you a fat zero. He was an ass. He was always preaching symbols symbols.

Also, keep in mind some UPS have automatic triggers. I know for a fact that the previous Mecer UPS I had shut down after 10mins. Regardless of battery capacity. I hooked up 2400Wh of batteries and it still died after 10mins.

You might be better off getting a DC-DC converter, a big battery and a battery charger.

 

[VandaL]

So I have a mecer 2000va ups running our voip phones and a wifi extender, been using it a few years now. It appears the batteries are finally tired, usually lasts around 5hrs(a few times our area has had no power for 24hrs), but now it's giving its death beep around 1hr 30mins into loadshedding.

Was wondering if there are better batteries like Lithium etc that would replace the current ones and all fit nicely inside that little housing.

Also would like to mod it with a more silent fan, and if possible mod my 2400va mecer inverter with a better fan?

 

[Off-The-Chart]

So I have a mecer 2000va ups running our voip phones and a wifi extender, been using it a few years now. It appears the batteries are finally tired, usually lasts around 5hrs(a few times our area has had no power for 24hrs), but now it's giving its death beep around 1hr 30mins into loadshedding.

Was wondering if there are better batteries like Lithium etc that would replace the current ones and all fit nicely inside that little housing.

Also would like to mod it with a more silent fan, and if possible mod my 2400va mecer inverter with a better fan?

a 2000va should take something like 7.2ah or 8ah batteries

someone shared that he got some Lithium 8ah batteries and I think I checked and they had the same dimensions as a 7.2ah (give or take a few mm)

however 2 issue: 1) price and 2) have no idea how a normal UPS charger would work with LIthium batteries and if they are compatible off the bat

@eleventh @PJtheKILL3R could you guys comment how Lithium batteries would work with your regular home UPS?

as for talking about the fans.... I went and changed my online UPS fan for a more silent one, however now my UPS has a constant "fan error" because it somehow detects it's not the correct fan

I am thinking in my case, it has to do with power draw as the new fans are much lower amperage

so, depending on how your system has it's fan connected, you shouldn't have a problem changing it, but just take something like my case into account

I actually wanted to try and see if I could do a mod where I power a fan directly via the UPS' AC input that it gets from the wall, however that would require some sort of mod for 220v to 12v

 

[el3venth]

Assuming a 48V system:
The biggest issue with Lithium is that it works in the 48-53.2V range (give or take, depending on the subcategory of Li-tech etc.)
Lead acid is typically in the range 43-63V (give or take depending if it is flooded/sealed/gel etc.).

The charging cycle has to be able to be programmable to be compatible with the Li-battery.
Secondly, some Li-battery manufacturers require their batteries to be able to communicate with the inverter for warranty purposes.