Hi all

I am new here and really looking for some honest advice.

I have searched some of the other posts regarding inverters which was quite useful.

I am looking for a backup power system for my home to keep the lights on and a few plugs. (Nothing heavy like stove, ovens, geyser)

I was hoping to have my fridge connected as well but various people have said that this is not a good idea as the power draw would be too much.

I was really keen on a generator backup but with the high costs of fuel that idea went out the window quickly.

Are there better brands to look for over others? How best do I size the inverter. I am not looking for solar panels at this stage as my budget may not allow for it.

My budget is in the region of R15k-R20k. Hopefully that is enough.

I have a modest house, but is a 2 storey building with 2 DB's. (Have a 40amp municipal breaker) The one issue with this is if I put the inverter downstairs it won't power anything upstairs and I would think vise versa. This would be an issue which I need to resolve.

I know I will need to engage an electrician but I like to know what is required prior to getting them on site so I pay for only what work is needed.

Would really appreciate any advise you can give me.

Many thanks

Kavesh

 

7 hours ago, Kavesh said:

Hi all

I am new here and really looking for some honest advice.

I have searched some of the other posts regarding inverters which was quite useful.

I am looking for a backup power system for my home to keep the lights on and a few plugs. (Nothing heavy like stove, ovens, geyser)

I was hoping to have my fridge connected as well but various people have said that this is not a good idea as the power draw would be too much.

I was really keen on a generator backup but with the high costs of fuel that idea went out the window quickly.

Are there better brands to look for over others? How best do I size the inverter. I am not looking for solar panels at this stage as my budget may not allow for it.

My budget is in the region of R15k-R20k. Hopefully that is enough.

I have a modest house, but is a 2 storey building with 2 DB's. (Have a 40amp municipal breaker) The one issue with this is if I put the inverter downstairs it won't power anything upstairs and I would think vise versa. This would be an issue which I need to resolve.

I know I will need to engage an electrician but I like to know what is required prior to getting them on site so I pay for only what work is needed.

Would really appreciate any advise you can give me.

Many thanks

Kavesh

 

 

@Kavesh so this is a decision you will have to make , so with that buget of around 20K its tight if you looking at a 5KVA power factor 1 usable say around 4kva , but depending on batteries and load. Example your nominal load essential plugs,lights I'd say average household anything from 700w to a 1000w. You will need either 4 x100amp gel batteries or 3kw lithiumion battery for the load for around 2 hours. That is 2amps for 2hours.Then the question arises with this be enough ,or a year or two maybe requirements change and now you need a 8KW so taking in consideration when deciding on requirements  as sometimes you might getting a bigger inverter now to  cater for later but just some advice in the long run could save cost.

12 hours ago, John2 said:

 

@Kavesh so this is a decision you will have to make , so with that buget of around 20K its tight if you looking at a 5KVA power factor 1 usable say around 4kva , but depending on batteries and load. Example your nominal load essential plugs,lights I'd say average household anything from 700w to a 1000w. You will need either 4 x100amp gel batteries or 3kw lithiumion battery for the load for around 2 hours. That is 2amps for 2hours.Then the question arises with this be enough ,or a year or two maybe requirements change and now you need a 8KW so taking in consideration when deciding on requirements  as sometimes you might getting a bigger inverter now to  cater for later but just some advice in the long run could save cost.

Thanks for the feedback John.

I agree with all your points mentioned. My problem is that what would the average cost of a bigger unit be together with the associated batteries? 

One option that I have debated to death is just get a generator is cheaper and yes the cost of fuel is very high and is still rising, how long will it take me to match the cost of the bigger inverter with my capital outlay on the generator plus batteries? The generator will run just about everything with minimal wiring.

My first choice is definitely the inverter if I can just get it to run what I need, but don't want to be silly and go too small and have regrets later on. This is not an simple decision sadly.

How does one choose an inverter brand?

What I do know thus far that it needs to be pure sine wave and compatible to solar(not that I will be adding solar anytime soon).

All all 3kva inverters the same assuming that is the size I need? Seems that that is not the case.

Please advise, Thanks

 

Hi guys

 

I have done so much research and each day get more overwhelmed with data.

I am now being pushed by my wife to get backup power by month end. 

I was going to get a 3kva Rentech unit that my neighbour has which he seems satisfied with, He has 2 100a gel batteries connected to his essential load (several lights, cameras, wifi, tv, decoder and a few plugs to power laptops and cellphones). He claims it can run for up to 8 hours.

Speaking to my electrician he advised against it as the output on this unit is only 10amps comparted to other 3kva units.

My issue is that i cannot see myself living in this house for more than 5 years and investing heavily in backup power may not be worth my investment.

Please guys in the know, help me make the right decision with regards to a decent inverter and associated battery packs to support it.

We have already sorted the wiring out between essentials and non essentials. 

Please guys help me ensure I make the correct choice of inverter and battery. (Desperate now)

My 5c worth

1. Inverters are better than generators in some respects. I looked at a getting a so-called silent gennie. They are not silent (they are  a lot quieter), they need a lot of servicing, and you have to keep them fuelled.
2. You need to quantify the load that you intend to back up. Even if it's approximate (1 x 40 ''' TV = some approximate figure, WIFI = some approximate figure etc. Add the approximates up). 
3. I take it from your post that some of what you want to backup is upstairs and some downstairs. So do two quantifying exercises - one for up and one for down.
4. Having done that exercise, review the results and ask yourself which devices you MUST back up.
5. Then, considering your budget, get yourself two decent battery/inverter boxes. You don't say where you live, so it's hard to recommend a dealer. But I have one of these
6. https://www.maidenelectronics.co.za/new-crystal-intellipower-4-2400va-1440w-long-backup-ups-w-2-x-105ahs and it will easily back up TV, couple of lights, wifi, a couple of phone chargers, DSTV decoder through a load shed. It's not big. Once you've done your estimation of the loads you want to back up, then get two, separate such devices, properly sized - one for upstairs, one for down.

You could get them wired in. Some folks do. I run extension leads around the perimeters of whichever room we're backing up.

Notes:

1. Running them with extension leads means you don't need to get them wired in, can move them around and can easily take them with you when you sell up and move.
2. These have sealed lead/acid batteries. Expect to replace every 2 to 3 years. There are options for other types of battery, but they will push the price up.
3. These are good for load shedding. If you are having longer outages then they will run past the 2 hour mark (how long depends on how you load them) but don't bank on half a day or anything like that.
4. They won't save you anything on your electricity bill.
5. They make some noise, because whilst they are charging or inverting (taking the DC battery power and converting to 230 V AC) there will be a fan running
6. They start up automatically and quickly if you leave them plugged in. You won't even see your TV blink.
7. Fridges don't use much when they are running. They can cause a big surge on start up. But if it's a 2 hour load shed they are not going to get very warm in that time. If your inverter doesn't give pure sine wave output, then you shouldn't run anything with a motor off of it.

Ag! @Kavesh I didn't read all your posts before responding. The sort of box I am describing has no solar capabilities. It has a mains input. So maybe not what you want. 

On the plus side you can always sell the boxes later on. Wait until load shedding starts, then the demand and thus the price goes up.

Thanks Bobstar, 

I am based in Pietermaritzburg.  (because its a small town, everything here is expensive)

I have already sorted out my house wiring. All essentials will be wired to a separate DB downstairs in the garage where I plan to mount the inverter. (Thats for both upstairs and downstairs).

The electrician did the load test on the essentials that we want connected and its low, can't remember the number now, but 2amps comes to mind. No fridges will be connected, only my automated garage door if we need to get out. For the test we had all the lights on and in reality we will never have all lights on when on inverter power to preserve the batteries. If I recall my fridge spiked on startup to around 5amps and when the motor is running was 0.8amps. (wired to non essentials)

My neighbour has a lot on during power outages on a 3kva unit with 2 gel batteries of 100a each. He mentioned that it could run easily for 8 hours.

Now I understand that to preserve battery lifespan one should not run the battery below 40% of discharge, something my neighbour is not aware of.

Ideally I would want the inverter to shut down once the battery reaches 40% of discharge. Do all inverters allow this functionality?

I was chatting to a Battery Center salesman and he stated that there is no difference between deep cycle and gel batteries in terms of how long they will last. He mentioned that with the gel batteries you won't get any vapours like you would from the deep cycle. He also mentioned that if you do not run the batteries flat they will tend to last several years. (Are these comments regarding these batteries correct).

At this stage I will have to say that the lithium batteries are outside my budget

 

 

You can look at the Mecer with MPPT. It is a simulated sine inverter and thus not suitable for any AC motor loads like a fridge. Then you can look on the Averge.co.za Web. They offer a 1000 and 1600W pure sine inverter where you can set all the charging and disconnect parameters for the battery. They only list the combo units but phone for details of individual items.

Gel would seem to be a better call if you stick to a 50% discharge. Averge have good priced batteries too but not sure if shipping will make it expensive.

On 2022/04/11 at 2:08 PM, Kavesh said:

only my automated garage door if we need to get out

Does the motor not have battery backup? Otherwise you might find that you eventually end up with no power and no way to get in or out of the garage.

There are actually several all-in-one packages available - battery & inverter in one enclosure, usually on wheels - with a solar input option and pure sine wave output. In your price range too.

Do a little googling.

10 hours ago, Bobster said:

Does the motor not have battery backup? Otherwise you might find that you eventually end up with no power and no way to get in or out of the garage.

No battery backup on the garage door, its an old digidor motor

I can get the Rentech 3kva inverter for R7 000, have option for deep cycle batteries at R2 100 or Gel batteries for R3 250 each.

Electrician is not too happy with this saying that max output on this unit which is a 2400w is 10amps. Apparently this cannot have a second inverter added to it in parallel.

Mercer 5kva from sustainable.co.za for R10 048, then will need 4 batteries. (if I decide to go with this bigger setup). 

 

What do you guys think? 

 

Edited April 13, 20224 yr by Kavesh

10 hours ago, Kavesh said:

I can get the Rentech 3kva inverter for R7 000, have option for deep cycle batteries at R2 100 or Gel batteries for R3 250 each.

Electrician is not too happy with this saying that max output on this unit which is a 2400w is 10amps. Apparently this cannot have a second inverter added to it in parallel.

Mercer 5kva from sustainable.co.za for R10 048, then will need 4 batteries. (if I decide to go with this bigger setup). 

 

What do you guys think? 

 

Ask your sparkie why is a 10A unit too small if your need for back up circuits is only 2A??

Do you need the 22A 5000W unit. Or am I missing something.....

1 hour ago, Scorp007 said:

Ask your sparkie why is a 10A unit too small if your need for back up circuits is only 2A??

Do you need the 22A 5000W unit. Or am I missing something.....

He says if I decide to add more circuits to the inverter the 10amps will not be enough, say we decide to add a fridge at a later stage with more batteries. He also says this unit cannot be run in parallel with a second inverter which will add costs should we need to expand our backup

33 minutes ago, Kavesh said:

He says if I decide to add more circuits to the inverter the 10amps will not be enough, say we decide to add a fridge at a later stage with more batteries. He also says this unit cannot be run in parallel with a second inverter which will add costs should we need to expand our backup

I take your point if you expand at a later stage. I can just say if you are not going to run 2 or more heating items at a time and it is for LS you can easily cope.  It will easily run 4 fridges but not a aircon and microwave.

Yes a 5kw does provide using more big users at the same time and life carries on as usual. We all add items as we go as it works so well.

If you look closely there are a few 3kw units that can be bought that will parallel. Just nog the clone and bargains.

 

Edited April 14, 20224 yr by Scorp007

Can you suggest brands that would be preferred? 

So still very undecided on inverter choice!

I am considering the option of getting a lithium battery which would allow me to run for longer periods without damaging it. However, if i go this route then I would like to see some ROI. Is it possible to to set an inverter to run at a specific time everyday, to run some selected circuits (yes that may mean getting a 5kva inverter) so like at a certain time of day or night there is a dual system powering the house, some from the inverter and some from the grid? Is this a pipe dream? 

If not then I will just stick with a hybrid 3kva with gel batteries.

Bundupower has a 3kva Growatt at R7k, there gel batteries are R2.7k each and about R15.3k for a 2.4kw lithium battery 

Opinions please guys

24 minutes ago, Kavesh said:

So still very undecided on inverter choice!

I am considering the option of getting a lithium battery which would allow me to run for longer periods without damaging it. However, if i go this route then I would like to see some ROI. Is it possible to to set an inverter to run at a specific time everyday, to run some selected circuits (yes that may mean getting a 5kva inverter) so like at a certain time of day or night there is a dual system powering the house, some from the inverter and some from the grid? Is this a pipe dream? 

If not then I will just stick with a hybrid 3kva with gel batteries.

Bundupower has a 3kva Growatt at R7k, there gel batteries are R2.7k each and about R15.3k for a 2.4kw lithium battery 

Opinions please guys

yes, Axpert can do that 

16 minutes ago, ibiza said:

yes, Axpert can do that 

Thanks for the reply.

This thread reminds me of my solar journey.

I started with a small Ryobi Inverter generator which I'm glad broke down and I got a refund.

I considered a small inverter with a lithium battery to work as a UPS but I also wanted ROI. Once you start thinking about ROI you might as well go all in. Now I have a 5kw SunSynk, 5.1KwH lithium and solar panels and don't regret the decision, in fact it's one of the best financial decisions I have made.

You must decide what the target is: ONLY  a load shed convenience?

or an electricity investment?

If only load shed issue then you need not bother with more than a few electronics and lights. 400 watt max draw (TV, x2 PC's, few LED lights, maybe your garage door pushes it up a bit )  But you do NOT bother about a system that can pump out 3000 watts and will sit idle through every single load shed. I have been through this journey.  

As I sit here typing my entire house is drawing 435 watts and I have three fridges, two computers lights wifi tv and dstv electric fence desk lamp etc etc all running right now. If there is a load shed at this instant I will not notice. I can remove the fridges from the circuit and will still not notice - a fridge lasts 2 hours without power.  IOW - the convenience factor is FULLY repeat FULLY met with 400 watts and a battery that provides maybe 800 Wh useable energy.

HOWEVER, if you want to add hairdryers and kettles and heaters, then 5000 watt is NOT ENOUGH.  

So you catapult from a simple relatively cheap system that does everything you ordinarily need into the stratosphere - ie into the INVESTMENT scenario.

The investment decision.

This is a VERY viable option. BUT BUT BUT!!!  you need quality equipment and your house needs to be wired so that every photon is used all the time. IE Victron or comparable; Canadian Solar panels or comparable, LIfePo4 Blue Nova (at least) preferably Pylontech. I know all this. Personally. Very well. 

The wrong decision.

That was me. I fell in between the two options. That resulted in a system that provides 3000 watts but because it was not set up properly it NEVER worked to capacity. Not nearly. Exactly because I had the load shed problem in the back of my mind (cheap) but the investment decision in front of me (tempting me to go cheap) I did not budget for quality and ended up with a system that looks on paper like a 3000 watt system but in fact was fake.  First the batteries required to be balanced and that excercise cost so much I could have rather purchased a LifePo to begin with. Then next , the Axpert (within 18 months) lost its solar charging function. So it was now only an expensive load shed solution with well balanced batteries mind you. But the Axpert had more in store for me - some or other setting problem and I burnt out FOUR 180 amp LEAD ACID Omni's.

At that point I had neither an investment nor a load shed solution. 

It was a total and completely irrecoverable loss.  Whatever ROI I will harvest from the sun in future can never undo the loss.

In fact I nearly had a divorce.

 

Quality LiFePo's CANNOT destroy themselves.  They balance themselves. They last 10 years plus. Victron and proper wiring allocate your usage between the load shed solution and the investment solution and WILL NOT burn out and uses every photon.  You can start small and EXPAND. You can connect a further Victron or add panels later. You can fully solve the load shed problem at the same time and over 10 years you have a return on investment. You see the installer at installation and never again.

You will NEVER divorce.

 

 Or just do the load shed solution - but AGAIN - use quality equipment. These trolleys with batteries sell with low quality batteries, often no more than 18 months use, are so heavy that you need a front ranker to move them, make an incredible noise, are not pure sine wave, tempt you with a 1000 or even 2000 watt rating (a completely unnecessary expense - see above)  and are thus overpriced.

I know this. I have TWO. (the interim and yet further loss making solution after the Axpert but before the Victron)

 

Maybe someone can work out a QUALITY load shed solution that provides 500 watts draw, has a LifePo that provides 800Wh, is silent and long lasting.

Anyone??

 

 

Very easy to design a system with reserve and a 3kw inverter to cover 800wh a day. The silent one has to choose right. My portable 12V inverter only has a fan over 300W. Quite a joy to run 2 fridges at night silently. Even adding an electric blanket at setting 2 in silence.

Hi Kavesh, 

I agree 100% with @Clivevan 

ROI, if it is just for load shedding avoidance, is going to be very long as it will just be saving a bit of generator petrol when there is load shedding. 

If you purchase a decent solar system then there will be a significant return on the money you are spending in saving on your monthly power bill.  You can easily reduce your electricity bill by 50-60% as well as giving you power during load shedding.

When I worked out my ROI, if I factor in the cost of running the generator, it worked out to less than 5 years and a lot less hassle than running a generator. 

You want to buy an inverter that is large enough to run your house during the day from solar and a battery large enough to run the house when there is no solar for 3hrs. 

I would definitely suggest getting something capable of running your geyser as well as that is a large consumer of power. 

A Sunsynk 5kw and 5kw of battery is sufficient for the average house along with as many panels as you can afford. 

You could install just the inverter and a battery in the short term if your funds are limited.

Thank you all for the valuable advice given, really appreciate it.

You have helped me with staying away from the cheaper inverters which I have to admit is very tempting.

I do not want to over invest at this time as mentioned at the beginning of this thread is that I am not sure how long I will be in this house, I'd say 5 years max, maybe less.  I guess if I wanted I could uninstall my inverter take it along to the next house easily. The solar panels may be another story I think.

How many panels would one need to power a 200l geyser? I have already decided to reduce this to 150l once its sell by date arrives and insurance covers that cost.

I would look at the 5kva system if maybe 1 or 2 panels can run my geyser and other appliances during the day. With the cooler weather I only power my geyser for 2 hours and in summer for an hour, so will continue to do the same, the rest of the time I guess solar could feed back to power my needs, if I understand how these things work.

OK who are the recommended suppliers who offer decent service I should be looking at?