Just got a call from a relative, it would seem as though i am supposed to be an electrical expert ...

Anyhow, they have an office...

• 5 PC's 2
• 2x Toshiba Studio 2000AC (larg office printer)

They are in need of a UPS to run this during load shedding. Which is usually 2-4 hours, but today it is 8hrs (don't ask me  why).

Does anyone here maybe know of anything?

 

Edited March 6, 20197 yr by stoic

2 hours ago, stoic said:

Does anyone here maybe know of anything?

5kva Axpert. 🙂 

FWIW, laser printers are not light on power consumption.

Axpert ... and then a some batteries?

I suppose Lead acid will be fine for right now. 

8 minutes ago, stoic said:

Axpert ... and then a some batteries?

Agree with that, Keyword: Load-shedding for hours on end.

Although 1000's of differences, UPS look for high yield, for a very short period, Eg just enough time to shutdown servers and or other equipment.

Many batteries like CSB etc are advertised for a 15 min rating, mainly used in UPS environments.

Edited March 6, 20197 yr by Riaanh

You'd probably be looking at 10KWh of usable battery storage required to keep that lot going for 8 hours.

That is not small. If you go for some form of lead acid battery in the typical vehicle form factor which store roughly 1KWh per 100A/H battery and you plan on not more than a 50% discharge cycle (more is not good for lead acid) you would need 20KWh or some 20 of these batteries.
If you go the Lithium route which is probably preferable you can get away with a 10KWh bank - maybe only just (plan for 80% discharge max), say 14KWh to be safe. Say around 100 grand for the batteries ?

A good small diesel generator is perhaps a much better option here. A small 5KW or better 10KW will do this much cheaper for now and is perhaps a better investment for load shedding purposes. Then you just need the usual small UPS units to bridge the gap between grid failure and generator startup. Advantage of this is that you can keep the coffee machine going as well...

Our office block invested in a 400KW beast. It still conks out due to overload after 45 minutes as everybody insists on keeping their big aircons running...

Its almost cheaper to send the staff home for the load shedding period  

Stoic rather spend a R1.5k now and get an energy meter installed something like this would be more than sufficient for what you need:

 

https://www.builders.co.za/Electrical/Inverters-%26-Solar-Energy/Solar-Accessories/Efergy-Energy-Meter-E2/p/000000000000492466?gclid=CjwKCAiA_P3jBRAqEiwAZyWWaJLmYhsgdzT5b2X-OFlbUEi1L-x2PSK9ifJZ6CrotOAjnBaGg6j1BhoC50YQAvD_BwE

 

After a week or two send us the trends from the meter. Then we will be able to more accurately predict how many battery capacity is required. 

If just for UPS (without Solar attached - but can add Solar later...):

I have to recommend the Mecer 1400 that come complete with 2 batteries,  or better systems for your specific environment and request - Damn, even Makro supply.

My office ignored my suggestions of a proper system with solar for 8 laptops, 1 server, telephone system, router and 1 printer that would have run them about 20k min (without solar) and decided to just go for a Mecer solution powering 1 laptop, no printer, telephone system  and router. Paid R8.3k from Makro and a few extension leads on top. I have to admit that that the unit performs well - With that small load, we easily get 6+ hours.

That said, it is not a decent install and although very impressed with the capabilities of the Mecer unit, it is still a UPS setup, so batteries are key. Decent quality and size batteries can make even a "crappy" invertor seem good and perform decently.

That solution is definately not "top of the range" not is it the "best build" but it seems like it will cope with the needs requested in your post (although my suggestion is to only use 1 printer attached and advise them very carefully that it will be for emergency use only... Any printing will kill the available power).

Now I wait for people to beat me up on the forum for recommending such a basic solution

As an aside, I have assisted some acquaintances with an Oxygen generating unit that was on a Mecer 1400 with some decent 105Ah boat batteries - Lady can't survive without added Oxygen for more than 15 min - That unit has survived through many Eskom debacles and is still going strong after 3 years. I think they only have had to use Oxygen tanks once in that time.

As a UPS unit/invertor they are very impressive, but they will not solve all your problems unless you understand the uses.

Edited March 6, 20197 yr by KLEVA
Added oxygen stuff