I installed a 200ltr solar geyser and a 5KVA off grid inverter just as 2019 winter started.

I have looked at my 2018 average winter KWH consumption compared to the same months for 2019 and have more clarity on what I actually saved since my installation. 

I must mention my inverter was not running at full capacity. I lost lots of days during the first two months as I was figuring out and deciding on how to wire and what extras to install as It was my first installation and job in progress, with DB upgrade and even relocating inverter to garage. Than in the beginning my system was manually operated and there were days that I forgot to switch to solar and lost the benefit. But that has now been sorted and operates automatic but I still need to add more solar panels for maximum PV Watts benefit but that as the budget allows.

I also wasted lots of eskom electricity with my geyser because while I replaced my DB my solar geyser was connected straight without a controller, so for a couple of days I would have the occasional boiling water running down my roof day and night as the geyser could not switch off.(That was not very clever🧐).

You can see on my attached note my geyser seem to be the definite savings winner, The geyser was R15k the smallest layout cost but with the biggest benefit of about R766 per month. My inverter installation has saved me only about R145 per month for R35K layout. (But It does give me the luxury of power when eskom load-shed or have there possible future blackout 🤭)

I hope this can help someone that is thinking to go solar and don’t know what to expect, Also keep in mind this is a clone Axpert inverter installed by myself in the cheapest possible way.

5 minutes ago, Gerrie said:

I installed a 200ltr solar geyser and a 5KVA off grid inverter just as 2019 winter started.

I have looked at my 2018 average winter KWH consumption compared to the same months for 2019 and have more clarity on what I actually saved since my installation. 

I must mention my inverter was not running at full capacity. I lost lots of days during the first two months as I was figuring out and deciding on how to wire and what extras to install as It was my first installation and job in progress, with DB upgrade and even relocating inverter to garage. Than in the beginning my system was manually operated and there were days that I forgot to switch to solar and lost the benefit. But that has now been sorted and operates automatic but I still need to add more solar panels for maximum PV Watts benefit but that as the budget allows.

I also wasted lots of eskom electricity with my geyser because while I replaced my DB my solar geyser was connected straight without a controller, so for a couple of days I would have the occasional boiling water running down my roof day and night as the geyser could not switch off.(That was not very clever🧐).

You can see on my attached note my geyser seem to be the definite savings winner, The geyser was R15k the smallest layout cost but with the biggest benefit of about R766 per month. My inverter installation has saved me only about R145 per month for R35K layout. (But It does give me the luxury of power when eskom load-shed or have there possible future blackout 🤭)

I hope this can help someone that is thinking to go solar and don’t know what to expect, Also keep in mind this is a clone Axpert inverter installed by myself in the cheapest possible way.

5KVA Axpert clone with 4 x 320W panels and 48V 120Ah gel batteries

Very nice! More than halved your bill, with some backup for load shedding all for R50K. Money well spent. The saving will only increase in the future.

Quote

You can see on my attached note my geyser seem to be the definite savings winner, The geyser was R15k the smallest layout cost but with the biggest benefit of about R766 per month. My inverter installation has saved me only about R145 per month for R35K layout. 

I will refer people to these figures when they try to make the case for heating their geyser with PV and spending hundreds of thousands to do so! Your geyser use was 38% of your total bill. 40% of total usage being the geyser is usually used as a rule of thumb.

Edited August 16, 20196 yr by DeepBass9

41 minutes ago, DeepBass9 said:

Very nice! More than halved your bill, with some backup for load shedding all for R50K. Money well spent. The saving will only increase in the future.

I will refer people to these figures when they try to make the case for heating their geyser with PV and spending hundreds of thousands to do so! Your geyser use was 38% of your total bill. 40% of total usage being the geyser is usually used as a rule of thumb.

sorry to clarify, do you mean that is a good or bad thing to heat the geyser with PV (and here are you referring to a seperate system or through your regular solar installation?

 

//some context - i am wondering if it is worth connecting my geyser to my solar installation since i have so much unused potential during the day or if i should get a seperate solar geyser to replace the existing etc.

It is an expensive thing to do. What Gerrie has above is a nice case study. He is saving about 400kWh per month with a R15000 solar geyser. To produce 400kWH from PV you will need at least a 3000W solar array, which will be entirely dedicated to heating your geyser.

If you have some spare power during the day, you may as well dump it into your geyser, but it will be much more cost effective to get a solar geyser as they are cheaper and more efficient.

Nice analysis. Thanks.

This reinforces the point that the quickest, cheapest saving is a solar geyser.

My old electrical geyser was only about two years old so I decided to keep it, just drained the water and switched it off for future backup. 

So in the future I will test run it, shut off the solar geyser for a month and switch on the old electrical geyser. 

But this will cost me about R766 + new increased tariff and I’m not sure If I can afford that yet. That money can rather go towards another solar panel.😁😁

So when I am again board 

2 hours ago, DeepBass9 said:

It is an expensive thing to do. What Gerrie has above is a nice case study. He is saving about 400kWh per month with a R15000 solar geyser. To produce 400kWH from PV you will need at least a 3000W solar array, which will be entirely dedicated to heating your geyser.

If you have some spare power during the day, you may as well dump it into your geyser, but it will be much more cost effective to get a solar geyser as they are cheaper and more efficient.

Yeah i currently have a 2.4kw array that mostly sits idle for half the day and we barely use hot water as it is, like sometimes i shower at home like 2-3 times a week (shower at gym etc) thus why i am pondering on this route.

3 hours ago, DeepBass9 said:

He is saving about 400kWh per month with a R15000 solar geyser. To produce 400kWH from PV you will need at least a 3000W solar array, which will be entirely dedicated to heating your geyser.

Here is my take. Yes, you are right. Even more so with a low pressure system.

The path I walked.
9 years ago I installed a +-R32k EV tube system - my cost was +-R24k. Made that back within +-24-28 months just on geyser savings with lifestyle changes.
This year it needed replacement. Insurance claim.
I KNEW every cent I spend on a water heating system would not be recouped. That only works the 1st time. No ways you are going to recoup that cost again the 2nd round.

So I have a 2.4kw inverter and 2 x 2kw geyser elements on 2 timers. I heat each geysers on a set time for 2 hours each per day.

To do that all I needed to do was add 4 x 350 panels as a 3.5kw array for in Cape Town in Winter it can power a 2kw element with the average loads of 500w continuous with ease AND recharge the batteries, all in a days work.

So there are other peaks in between ... so what? Grid tied sure DOES spoil one. 😁

56 minutes ago, Dex_ said:

2.4kw array that mostly sits idle for half the day

So put a 2kw geyser element in the geyser, get a Geyserwise timer (the cheap one) and set it to heat the geyser at optimal solar times.

14 hours ago, Gerrie said:

I must mention my inverter was not running at full capacity. 

My inverter is running at full capacity most of the time, the array most definitely.

Savings, before the last increases, we dropped, based on spent before to spending now, about +-R1200 per month (and it is increasing the closer summer is getting) from before grid tied to after grid tied (no feeding back to the grid). I simply schedule the high end loads daytime like geysers, dishwasher, dryer etc to run at optimal solar times so that I can use the 3.5kw array as best I can.

This is on non-optimal solar the last two days, max PV is about +-2.8kw AND I took off the grid +-500w from 12am-7am.
Batteries are charged 100% by 5pm each day.
As I said, have not seen consistently over 3kw yet ... rain and farmers see. 

 

For most people wanting to save on their electricity bill, a solar geyser is a cheap and easy win and a 40% reduction in your bill should be expected (plus having much more hot water than you had before).

Once you have installed a whole solar system, the marginal cost of adding a few more panels to help with the geyser is also fairly easy to justify, but that is only if you have already have a large sunk cost on the rest of the equipment.

3 hours ago, The Terrible Triplett said:

This is on non-optimal solar the last two days, max PV is about +-2.8kw AND I took off the grid +-500w from 12am-7am.
Batteries are charged 100% by 5pm each day.
As I said, have not seen consistently over 3kw yet ... rain and farmers see. 

 

Here is my last few days and i am also running two geysers on timers (manual).

Initially when i purchased my solar i had no intention on running the geysers off solar, but i tried it and it seems to be going great. I can do with one more pylontech though

Now, the thing here is, going over to solar made us work smarter. I used to use close to 50kw a day ... now we am doing around 21kw a day. My bill was around R3.5k per month, and is now MAX R500p/m that includes a R90 connection fee.

When it comes to saving on your monthly bill, the best way to do it is to save on electricity usage.

... and those red bars does not make an appearance if i do not game until 2am

 

 

Edited August 16, 20196 yr by stoic

You guys can say what you want. There is no way using PV to heat water is ever the most efficient value for money 🙂

With one exception: If you use a heat pump. Heat pumps have COPs of 3 or even 4 (you get 3 times the heat of the electricity you put in). If the PV module is 15% efficient, that means you're effectively about 45%-60% efficient in getting heat into the water. Solar water heaters do 60% to 70%.

A decent solar water heater has a lifetime of over 30 years. My parents have a Siemens for example (indirect system, Namibia gets frost). It's been there since I went to high school, and it's only been opened once to clean it.

The one I have on my roof is an X-stream tank. I'm told these fibreglass tanks rarely make it past a decade, though I don't see any signs of bad wear yet (it's 8 years old now). So I too will possibly have a failure in the coming years, and when that happens... I'm putting in another one, a better quality one.

On 2019/08/16 at 12:32 PM, Dex_ said:

i am wondering if it is worth connecting my geyser to my solar installation since i have so much unused potential during the day or if i should get a seperate solar geyser to replace the existing

In my opinion I would say it is probably worth connecting your geyser to your solar geyser to minimise waste capacity.

But I do not know what additional strain such a geyser can put on a idling inverter, I would think the lighter a inverter have to work the longer life span you will get from it no matter what make it is. I might be completely wrong but it might be something to consider when you want to get good life out of your expensive equipment.

1 hour ago, Gerrie said:

In my opinion I would say it is probably worth connecting your geyser to your solar geyser to minimise waste capacity.

But I do not know what additional strain such a geyser can put on a idling inverter, I would think the lighter a inverter have to work the longer life span you will get from it no matter what make it is. I might be completely wrong but it might be something to consider when you want to get good life out of your expensive equipment.

this is a good point, would be interesting to get some knowledgeable perspectives on this?

2 hours ago, Gerrie said:

... when you want to get good life out of your expensive equipment.

I agree with you but then I wonder, like batteries, one can molly coddle them and they fail, or use them and they fail.

So what is different on a inverter? If say it has a 5 year warranty, then used it ... that is my thinking at present.

4 hours ago, plonkster said:

You guys can say what you want. There is no way using PV to heat water is ever the most efficient value for money 🙂

Agree 100%. EV tubes are THE most efficient way of heating a geyser. 

BUT, if you have the spare, use it.

20 hours ago, stoic said:

... and those red bars does not make an appearance if i do not game until 2am

And you have no qualms doing that I presume, with that blerrie good graph!

Stoic, what have you got installed?

4 hours ago, The Terrible Triplett said:

And you have no qualms doing that I presume, with that blerrie good graph!

Stoic, what have you got installed?

Well i purchased 3 Victron MPII's as i was running 3-phase, but i subsequently change the house over to single phase and i run those MPIIs in parallel now, so i  know they can take the strain.

I have:

18x275 Canadian Solar panels

250/100 Victron solar charger

3x Victron Multiplus II

3x Pylontech US2000B

Its by no means the biggest  , but I have to admit though, both myself and my wife is at home, so max loads are during the day and we have a gas oven and stove. 

Oh, and my panels are fixed at 32degrees North. this way i have the same output winter and summer. We like know what we have to play with, rather than getting a surprise in either winter or summer, so the output on the panels are not optimal.

...the entire system by the way was installed with Plonkster's patience, I messaged the poor guy constantly, so thanx once again @plonkster

9 hours ago, plonkster said:

You guys can say what you want. There is no way using PV to heat water is ever the most efficient value for money

Yeah, 100% if you gonna buy solar to heat water. I just realised I ain't using all of the solar's capacity, so i decided to give it a go. .... the money was already spent

And with both my geysers on the entire load on the inverters is around 5kw (it includes other things like pc's and tvs), but i ONLY do that on a day when i get around 4.5kw from the panels, and from what i understand those three inverters are more than capable of delivering it, but it rarely happens though.

 

 

On 2019/08/16 at 7:00 PM, stoic said:

i had no intention on running the geysers off solar, but i tried it and it seems to be going great.

At least your still giving Eskom something hopefully that still cover the CEO’s cuppa tea.😁

25 minutes ago, Pietpower said:

How does it work for you?
What is the adaptation from normal electrical geyser?
Do you have enough hot water in the mornings?

The geyser Is a high pressure 200l ltr with evacuated tubes. Its tubes fit directly into the geyser with no pump or electricity required. But it has a 2KW element for backup. 

My old electrical geyser was a 150 ltr and when I decided to go solar I read somewhere on this forum that it’s better to upsize a little when going solar to ensure you have enough hot water. So I went for a 200 ltr and it is working great for a family of four.

It has a Very cheap R450 solar controller to see water temp and to set 7 day timer and temp requirements. I have set mine to come on only if water drops below 33 Degrees and that basically never happened only on occasions when the wife fills the corner spa bath, but even so the rest of the boys can still shower. It has a bypass function that I press only when the spa bath was used. This is for winter so I still need to see what its going to do in summer. The geyser is very well insulated and water is more than sufficient the next morning, the max I saw it drop was about 4 degrees and that was with very cold weather about a month back. 

My water goes up to about 80 degrees after showers in evening it shows about 44degrees but that is still sufficient for morning shower.

The controller is on top at DB. on picture

 

1 hour ago, Pietpower said:

What is the adaptation from normal electrical geyser?

I left the old geyser as is. Only thing I had to to is fit two extra 1/2inch valves one inlet and one outlet to shut of water.

The new geyser piping is in parallel over this old system with its own inlet and outlet valves. So you can shut any of the two geysers. I did not want to modify my old geyser to solar as lot of plumbers recommend, as I was skeptical about solar and thought I can quicly switch back if I have to.

I also fitted a additional new pressure regulator before both geysers as the old ones position was not good for the solar geyser connection so I just left the old p/r in the system to avoid too many pipe work. This all was purchased for just under R15K and i installed myself.

33 minutes ago, Pietpower said:

A question on your calcs.

The R1086 / month was just the saving year on year on prepaid power that I would normally buy.

What I done is installed a small KW hour meter at my inverter output to measure my solar usage. This comes to 75 KWH/month and this is basically an extra bonus, so based on what Eskom would of charged me for this = R145 at their R1.94/KWH Rate. 

I added this R145 to my actual monthly R1086 saving.= R1231 

When I add more pv panels to my system I should be able to increase the R145 bonus generation and might at the same time reduce my monthly prepaid buy.

I run completely of grid from 8H00 to 17H00 set on sonoff timer and if my batteries are still full at night I sometimes use batteries to get extra little kwh out of the system.

1 hour ago, Pietpower said:

Why do you only get 2.5kWh per day while you have a 5kVA inverter?

I have a 5KVA inverter with only 4 x 320Watt = 1280Watt total panels. It actually works perfect for the load I have and the batteries 4 x 120 AH are normally fully charged at 5H00 when my system switch back to grid. My budget did not allow for more panels at the time and the plan was to buy at least one panel per month but the system was running so fine that I tend to forgot to add panels. I do need this extra capacity for the dishwasher though as that eats into my batteries.

There’s no one really at home during the day. My usage during the day is fridge, cctv, alarm, electric fence and son’s computer/ playstation after school maybe bit of microwave and kettle and small led lights that i never switch off . This is only about 2.5 kwh according to my kwh meter. I have a gas hob with electric oven (oven seldom used)

hope this all makes sense🙂

5 hours ago, Pietpower said:

One thing not taken into account is that you will require 250-300L of electrical geyser to store enough energy during the day

One thing I noticed with the solar geyser was on cloudy days I were worried that my water would not be warm enough by the afternoon when I got home, to my surprise the water was actually a few degrees warmer than normal. 

It seems the clouds had a positive effect on the heating, I don't know if PV panels will have the same effect. I think with heavy overcast weather there will be a different story than elements need to do the job.

Other factors to consider I would say is repair cost when things do go wrong.

1. Cost of labour 

2. Need for specialists or local plumber/electrician

3. Insurance premium cost and repair turnaround time as this can be days/week when insurance is involved?

4. Do this system add value to your property or is it a luxury?

It seems like flipping a coin here can cost you some money if not thought through properly.

1 minute ago, Gerrie said:

It seems the clouds had a positive effect on the heating, I don't know if PV panels will have the same effect. I think with heavy overcast weather there will be a different story than elements need to do the job.

EV tubes absorb the UV and does give you a little bit of heating even when it is overcast.