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Basic UPS system


daniemare
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Hi. 
I am trying to understand what a basic Pure Sine Wave based UPS system will cost. (Inverter plus battery)

I can conveniently source prices of inverters and batteries online, but the wiring and installation requirements and costs are not that easily understood by a noob like me without getting formal quotes.
 

Requirements:

- Wired into DB board

- Specific circuits already identified which do no exceed 1500W when all is turned on at the same time. No items have high inrush current when turned on

- Required time 2 hours

- Recharge time 4 hours

So What:

I am actually considering a solar grid tied system. But I just cannot justify the expense from a payback point of view. So my thinking is, as I am comfortable to invest in a basic UPS, I will deduct the above and see where my ROI ends up. If it does not make sense, I revert to the basic UPS option

Thanks for the input

Danie

 

 

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49 minutes ago, daniemare said:

I am actually considering a solar grid tied system. But I just cannot justify the expense from a payback point of view. So my thinking is, as I am comfortable to invest in a basic UPS, I will deduct the above and see where my ROI ends up. If it does not make sense, I revert to the basic UPS option

Show us your calcs so we can add a comment or 2..

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Base UPS system

Victron 12/1200/10 R11000

Omnipower 240Ah R7000

Install and other 25% assumption (hence my question)

Total R22,500

Solar System

Victron Multiplus II 3000 GX R20,000

MPPT Bluesolar 150/30 R4,500

Pylontech US2000 R15,000

Solar Panels (6x300W) R12,000

Install and other 25% assumption (hence my question)

R65,000

Difference

R42,500

 

The Calc

I use 588kWh per month of which I assume 14 is during sunlight hours per day (averaged over year - Stellenbosch)

Now if I self consume 60% of that or +-250kWh at my marginal municipal tariff of R1.90 for that bracket I save R475 per month of electricity costs

If I use my bond rate of 9% as my cost of capital, and I assume an Eskom increase of 12% per year I work out a return adjusted payback period of 8 years.


Now I do not even think my solar option of R65k is realistic any more the more quotes I get. So the payback is starting to look even worse.

Maybe I was just unrealistic about what these things cost.

But thanks for the input

 

 

 

 

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It is difficult to motivate solar financially. Even more so when you're slaving away 12 hours or more per day. And you will have 64 cloudy and rainy days every year - just plan your solar maintenance for then ..

Its rather like buying a car - difficult to motivate the purchasing price when you're a male (but boy we're good at supplying reasons why we must buy a certain model lol).

Unless you do it when you're young and you'll be living in the same house till you die, payback is not going to happen.

Its all about convenience and security and looking after your family.

And when Eskom goes on stop off course.

 

Edited by Johandup
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1 hour ago, Richard Mackay said:

Is there no FIT in Stellenbosch?

If so you could increase the number of panels and get something back from the utility..

FIT is a joke. At R250 odd meter reading, which is 25% of my consumption bill, its as if they do not want you to feed in. 
 

58 minutes ago, Johandup said:

Unless you do it when you're young and you'll be living in the same house till you die, payback is not going to happen.

Its all about convenience and security and looking after your family.

And when Eskom goes on stop off course.

 

Thanks Johan. Starting to realise that. Just funny how every solar website touts savings as this big motivation factor. 
 

 

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Personally I am not at a fan of the Axpert units, but as a UPS they are quite good, I think @Gnome bought a 5kVA Axpert King just to use as a UPS, he also removed his MPPT charger.

You could perhaps get something like the 3kVA Axpert King R8.5K+- and then a Pylon UP2500 R16K+- 

The big advantage of that Axpert is that it has a 60A charger, which is much bigger than the 25A one found in the 24/1200 Multi, or you could pony up for the 1600VA Multi and then you would have a 40A charger.

Being on team blue I would just add the little extra and get a 1600VA Multi :)

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1 hour ago, daniemare said:

FIT is a joke. ... which is 25% of my consumption bill,

Don't forget that a FIT is only meant to compensate you for your energy generated. Generation is generally about 25% of a retail bill. The rest is transmission, maintenance, losses, etc. What you generate has to go over Eskom poles and wires, even if it typically only goes down the street before being consumed.

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3 hours ago, PJJ said:

 

You could perhaps get something like the 3kVA Axpert King R8.5K+- and then a Pylon UP2500 R16K

Being on team blue I would just add the little extra and get a 1600VA Multi :)

Thanks PJ. But I am still unclear about the wiring and installation costs. The inverter and battery part is easy enough to get pricing, but the rest is unclear

and what is the advantages of the UP 2500 over the US2000/3000 in this UPS application?

3 hours ago, Coulomb said:

Don't forget that a FIT is only meant to compensate you for your energy generated. Generation is generally about 25% of a retail bill. The rest is transmission, maintenance, losses, etc. What you generate has to go over Eskom poles and wires, even if it typically only goes down the street before being consumed.

I do not mind the low selling price, I do care about the fixed fee which I currently do not pay on prepaid, so for my calcs it is incremental

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40 minutes ago, daniemare said:

But I am still unclear about the wiring and installation costs. The inverter and battery part is easy enough to get pricing, but the rest is unclear

I also don't really have a barometer as to how much a UPS only install would cost, but probably not a lot, from a additional hardware point:

You would need battery fuses and a disconnect the size would depend on which inverter you go with, lets be safe and add R800 for that.

The Pylon Cable pack is R350, So that should be your battery cable sorted.

Then there would be additional AC components needed which I also don't know at what cost.

40 minutes ago, daniemare said:

and what is the advantages of the UP 2500 over the US2000/3000 in this UPS application?

No advantage really, in fact its actually a bit gutted in the sense that it doesn't have a CAN interface, so you just run it till the BMS turns it off.

The only reason why I suggested it is because its the only 24V Pylon available, it also has around 400Wh more nominal energy than the US2000

Edited by PJJ
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6 hours ago, Johandup said:

It is difficult to motivate solar financially. Even more so when you're slaving away 12 hours or more per day. And you will have 64 cloudy and rainy days every year - just plan your solar maintenance for then ..

Its rather like buying a car - difficult to motivate the purchasing price when you're a male (but boy we're good at supplying reasons why we must buy a certain model lol).

Unless you do it when you're young and you'll be living in the same house till you die, payback is not going to happen.

Its all about convenience and security and looking after your family.

And when Eskom goes on stop off course.

 

When I got my system, initial calculations suggested a 9 to 10 year payback. Which is not the whole truth because round about then I'd be having to replace batteries. But I think that as the price of power climbs (and it will) we get into a window where one can see an eventual payback (whether that would beat what the money would have done in a savings acct is another matter). But as @Johandup says there is the soft value too. What is it worth to have uninterrupted power, to know that you are not going to lose the contents of your freezer (as has happened to us twice because of long municipal cuts)? These things are harder to put a value to, but they are worth something.

5 hours ago, daniemare said:

FIT is a joke. At R250 odd meter reading, which is 25% of my consumption bill, its as if they do not want you to feed in. 

Yep! Same in Joburg. I'd have to convert from pre-paid to FIT, which means a flat fee every month, a special meter (at my expense) and then they pay you something like 45c per kw/h. There's no way I can justify it. If it was just putting the system into export mode I'd take the dribble of income, but with the extra costs I can't make it pay. As you say, it's almost like they are discouraging it.

I think this is to be expected. Any utility will see solar systems as a loss of revenue. Why then should they reward you for depriving them of income they need to maintain their system? I have a solution for me, but I may be part of a bigger problem.

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1 hour ago, Bobster said:

they pay you something like 45c per kw/h.

The payback principle in first world cities is to serve as credit where they supply the power when the sun goes down. I.e. they are the batteries and you only have a string inverter. This balance then goes against your night time power consumption. 

The muni does not read meters now. Why on earth would they do it if it is going to cost them money. 

If there's one thing we all need to agree on is they are NOT trustworthy. 

And not one SA city is actually a first world city. Whatever their pretences..... 

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On 2020/02/07 at 6:34 PM, daniemare said:

I am actually considering a solar grid tied system. But I just cannot justify the expense from a payback point of view.

Hi Daniemare, Your usage is not much and the payback will be longer if you don’t use much power. I also use about 588kwh / month in summer time. If you still use a electrical geyser than there is hope for a faster payback when converting to solar, but if you already have a solar geyser your payback will be much longer.

Most of my savings that I make per month (+-R1000/month) comes from my solar evacuated  tube geyser and that saving per month actually pay’s for my PV solar installation. My geyser was the only motivation that made it worth going solar, otherwise it would be purely like Johandup  said it’s convenience and security.

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1 hour ago, Gerrie said:

/ month in summer time. If you still use a electrical geyser ...

Have a heat pump. Very happy with that. In the western cape, with kids using water in the evening, and the adults in the morning, I cannot be happier or recommend it more. 
 

I actually use about 550kWh per month, but buy up to the limit of the 3rd tier of Stellenbosch’s tiered pricing. The accumulated energy is then used in Jan and Feb for the aircons at night, essentially using the prepaid system as a battery. 

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On 2020/02/08 at 3:08 PM, Bobster said:

matter

 

On 2020/02/08 at 3:08 PM, Bobster said:

When I got my system, initial calculations suggested a 9 to 10 year payback. Which is not the whole truth because round about then I'd be having to replace batteries. But I think that as the price of power climbs (and it will) we get into a window where one can see an eventual payback (whether that would beat what the money would have done in a savings acct is another matter). But as @Johandup says there is the soft value too. What is it worth to have uninterrupted power, to know that you are not going to lose the contents of your freezer (as has happened to us twice because of long municipal cuts)? These things are harder to put a value to, but they are worth something.

What Bobster said is so true and one thing not to forget is the fact that most of us on this forum live in S.A. These problems we are seeing is probably just the beginning of what lies ahead. It’s also a matter of trying to be pro-active now and not to be sorry later. It is difficult to justify the purchase of expensive solar system, but the positives still outnumber the negatives.

If you invest say R50k on a system, it’s not money gone down the drain, that system could still have a value of at least say 50% or more after ROI. By the time ROI occurs that systems will cost more than double it is now. So the sooner you start the more you will benefit. Battery replacement will have to be done at some stage, but that you need to make provision for. It’s like replacing an old car.

Positives to consider.

1. Solar gives you piece of mind, your fridges and deep freezers won’t easily defrost. (You can now buy that hind quarter without worries)

2. You can use that air-con during the day without worrying what the bill will be like.

3. If lights are left on during the day there is no worry of extra payment on bills.

4. Hot water is not a problem during Eskom load shedding anymore.

5. Alarms, cctv, gate motors will not bail on you with flat batteries.

6. Eskom yearly increase will not have a big effect on your pocket.

7. When the neighbours phone you if your power is on and you have to tell them you don’t know, that’s when you realize how lucky you are.😊

 

 

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53 minutes ago, Gerrie said:

Positives to consider.

Just today, I again mentioned this thing called opportunity cost.

Opportunity cost is money you lose because you lost the opportunity to invest it elsewhere. For example, if I buy a car (which typically devalues at 10% a year) instead of investing the money into some interest bearing vehicle (which could gain 10% per year), my opportunity cost might be 20% of the present value of the vehicle.

This sort of argument works well in countries with good public transport. There is a real opportunity not to have a car, and skipping that opportunity has a cost.

In South Africa, there are far fewer such opportunities. Well, of course you could take the bus, the taxi, the train... but almost everyone buys a car because frankly they cannot live without it. In short: the opportunity doesn't exist. If the opportunity does not exist, there is no cost to consider. The only question is how badly you want it 🙂

 

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4 hours ago, Gerrie said:

replacement will have to be done at some stage

And that's why you go for the best warranties. 

There's a huge difference between a one year and a five year warranty. 

Apart from the lack of confidence a manufacturer has in the quality of his own product. 

The only way we as consumers can make them see the light is by not buying their products. 

Nobody will buy a car with a poor reputation. But we don't even think twice before buying an inverter with many reported problems... 

Why?? 

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4 hours ago, plonkster said:

if I buy a car

Which we only use for a very short period of time per day / week / year. 

Compare the cost of any car against the cost of a decent solar system (which can save you money) which you use 24/7.

My highly financially qualified daughter and son in law only buy cheap second hand cars. And in hindsight I must admit they might be right with this approach. 

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9 hours ago, Gerrie said:

When the neighbours phone you if your power is on and you have to tell them you don’t know, that’s when you realize how lucky you are.😊

Happened to us last night. Our suburb was one of those hit with a 6+ hour outage due to a failed overhead line in Randburg. First thing I knew about was when the street whatsapp group lit up. I'm like "oh, I'd better go check the inverter". Power came back on about 22:25 and again I didn't notice anything. 

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