Hi All, so i am about to have a small solar system installed, 5kw SS, 5kwh li bat and 4.8kw pv array. I was hoping that the geyser could be connected to the non essential side and that i would be able to use PV during the day to heat it up a bit before our evening showers and therefore reducing the eskom cost. I also have a pool pump (1.1kw) which i am hoping to run during the day via PV as well, both geyser and pool pump are on smart switches. I now noticed that the geyser has a 4kw element and seeing as I will only have a 5kw inverter, would this expectation be unreasonable? I have measured my base load at various times and its around 400w to 700w. I am very new to all this so any recommendations would be welcome... if this would not be advisable, what other solution(minimal cost) would assist this or should I just resolve myself to the fact that eskom will need to be used twice a day to heat the geyser up. i assume i could replace the element with a 2/3 kw element? what effect would this have on heating my 150l geyser? estimated cost? estimated heating time? 

It would help if you specified what inverter & batteries you are getting.

The pool pump shouldn't create problems, but do you want it on the backed up side of the DB? Doing that means that when the grid is down, the pool pump will run and will draw from batteries. Same with the geyser. If there's no grid, that's going to take a chunk out of that 5kw/h battery.

In my experience, there's a learning period after installation. You figure out what is using how much power and when, how long it takes to charge the battery etc. Then you start "moving" loads around so you do the heavy lifting (so to speak) during the day. So start conservatively (geyser, pool pump, stove not backed up), gather data and see what changes can be made.

Also think about short-lived peaks. If I read your post correctly you only have 5kw of back up power. So your geyser is running - that's 4kw. Then somebody turns on the kettle. Now you're over that 5kw. What's your inverter going to do? Mine would trip and then reboot.

HI @Bobster. thanks for your feedback as always, installing a 5kw sunsynk and 5kwh greenrich up5000 lifepo battery. the pool pump would also be on the non essential side along with the geyser (hope i am getting the terminology correct). Am i correct in assuming that while there is grid power, the system would not trip but just blend eskom and pv when load goes above 5kw? when loadshedding, i will obviously not use the geyser or pool pump. stove is gas so that will not be a problem. What have others done in terms of their geysers? would changing the element be recommended? should i rather just leave the geyser off the inverter completely and let eskom heat up my water? i am obvisouly trying to save as much as possible on eskom costs but with a limited budget, was not able to install a bigger/better inverter/batteries/pv. just looking for ideas to maximize my potential savings.

18 minutes ago, ZCS said:

Hi All, so i am about to have a small solar system installed, 5kw SS, 5kwh li bat and 4.8kw pv array. I was hoping that the geyser could be connected to the non essential side and that i would be able to use PV during the day to heat it up a bit before our evening showers and therefore reducing the eskom cost. I also have a pool pump (1.1kw) which i am hoping to run during the day via PV as well, both geyser and pool pump are on smart switches. I now noticed that the geyser has a 4kw element and seeing as I will only have a 5kw inverter, would this expectation be unreasonable? I have measured my base load at various times and its around 400w to 700w. I am very new to all this so any recommendations would be welcome... if this would not be advisable, what other solution(minimal cost) would assist this or should I just resolve myself to the fact that eskom will need to be used twice a day to heat the geyser up. i assume i could replace the element with a 2/3 kw element? what effect would this have on heating my 150l geyser? estimated cost? estimated heating time? 

You need to change the 4kw geyser element and replace it with a 2kw one. There is the normal 2kw resistive element that you can get from places like builderswarehouse and the geyserwise 2.2Kw PTC element that can be powered by either DC or AC supply. 

The Sunsynk has passthrough up to 35A (i.e. 8kW). You could leave the 4kW element and should be okay, but if it was me I would switch out for a smaller element. Elements cost around R250. 

 

Water heating is linear, so halving the element size will double the required time which, in most circumstances, is not an issue. 

1 minute ago, hoohloc said:

You need to change the 4kw geyser element and replace it with a 2kw one. There is the normal 2kw resistive element that you can get from places like builderswarehouse and the geyserwise 2.2Kw PTC element that can be powered by either DC or AC supply. 

and if you are getting a sunsynk then you don't even need to change that element because your inverter can supply non-essentials with excess PV. Get your installer to just put the Geyser and pool pump on the non-essential and you will save on eskom bill 😀

1 minute ago, Speedster said:

The Sunsynk has passthrough up to 35A (i.e. 8kW). You could leave the 4kW element and should be okay, but if it was me I would switch out for a smaller element. Elements cost around R250. 

 

Water heating is linear, so halving the element size will double the required time which, in most circumstances, is not an issue. 

thanks, this is what i was thinking. just a question... if i leave the 4kw element in for now, would the 5kw sunsynk still run this from pv where possible and if other appliances are switched on at the same time, blend eskom power with the pv or will i be causing issues to the system or possibly trip the inverter? as mentioned i will not want to use the geyser or pump etc while loadshedding so this is only while grid is available... is my understanding our your statement correct in that the 5kw sunsynk can push through 8kw of power while grid is present without issues? what happens in the unlikely event that i go above 8kw? apologies if these questions seem trivial but my knowledge around these things is very limited. 

6 minutes ago, hoohloc said:

and if you are getting a sunsynk then you don't even need to change that element because your inverter can supply non-essentials with excess PV. Get your installer to just put the Geyser and pool pump on the non-essential and you will save on eskom bill 😀

brilliant! thanks @hoohloc

8 minutes ago, ZCS said:

What have others done in terms of their geysers? would changing the element be recommended? should i rather just leave the geyser off the inverter completely and let eskom heat up my water?

I have two geysers. One is the guest geyser. This is mostly kept off, and I downgraded the element to 1Kw. The main geyser is heated by a heat pump, and I get away with running that on the backed up side. In any case the heat pump uses less power for less time to heat the water.

Because of the heatpump, I can usually run the guest geyser in the afternoon and it will take a couple of hours to heat up. But something has to give on overcast days. 

 

8 minutes ago, ZCS said:

i am obvisouly trying to save as much as possible on eskom costs but with a limited budget, was not able to install a bigger/better inverter/batteries/pv. just looking for ideas to maximize my potential savings.

Well, this depends on your consumption and WHEN you consume. IMO you're a bit light on batteries, but if your usage is low then it may suffice. But as I said, start conservatively and look to get through load sheds, then start stretching your muscles.

1 minute ago, Bobster. said:

I have two geysers. One is the guest geyser. This is mostly kept off, and I downgraded the element to 1Kw. The main geyser is heated by a heat pump, and I get away with running that on the backed up side. In any case the heat pump uses less power for less time to heat the water.

Because of the heatpump, I can usually run the guest geyser in the afternoon and it will take a couple of hours to heat up. But something has to give on overcast days. 

 

Well, this depends on your consumption and WHEN you consume. IMO you're a bit light on batteries, but if your usage is low then it may suffice. But as I said, start conservatively and look to get through load sheds, then start stretching your muscles.

thanks @Bobster. i am also concerned that i am a bit light on battery power but the budget doesnt allow me to do more right now. for now i am hoping to at least negate loadshedding and save some cash on the monthly eishkom bills. will be trying to move most of the loads like ironing, dishwasher, pool, washing machine etc to the day but will need to figure out the timing of such so as not to have too much running at the same time. the biggest draw will probably be the geyser and pool pump during the day so hoping to schedule one after the other using cbi astute timer on each. 

 

Separate question and unrelated to this topic... seeing as I am light on batteries, is it possible to easily change the settings (or have various pre programmed modes) for periods of loadshedding. effectively, when eskom announce loadshedding, I want to save my battery for outages, when no loadshedding, i want to maximize the use of my battery and therefore cost savings...

I wouldnt worry about the 4kw geyser at all . The amount of time that it will be on and overlapping with other loads will be minimal and maybe cost an extra few rand a day at most . I have been running with a 4kw /200liter geyser for over a year and it works great as it heats the water up quickly. When you put loads on the non essential side you dont need to worry about much . Here is a graph of my usage a few days ago ,grid only supplied about 300watts above the 5kw load.

 

9 minutes ago, Nexuss said:

I wouldnt worry about the 4kw geyser at all . The amount of time that it will be on and overlapping with other loads will be minimal and maybe cost an extra few rand a day at most . I have been running with a 4kw /200liter geyser for over a year and it works great as it heats the water up quickly. When you put loads on the non essential side you dont need to worry about much . Here is a graph of my usage a few days ago ,grid only supplied about 300watts above the 5kw load.

 

great. thanks for the info bud. will definitely ask the installers to put the pool and geyser on the non essential side and then hope for the best

while on the topic of geysers, is anyone able to explain what this geyserwise is that i keep reading about on the forums? what are the pros and cons of installing this? currently using a cbi astute smart switch to programmes my geyser to switch on/off at certain times, is this the same as geyserwise or are there additional benefits?

The Geyserwise has a temp probe that inserts into your existing geyser element,you can then set at what times you want whatever temps . At the moment i set mine to come on at 12pm and heat up to 65. In the Morning there is also a slot where it heats for an hour but only up to 50 degrees. This has saved me loads of money especially now in the past 3 months.Edit* you can see in my graph where the geyser comes on briefly at 6am.

Edited August 11, 20223 yr by Nexuss

Thanks @Nexuss. i assume this is controlled remotely via app? what does it cost to purchase and install if you dont mind me asking? i assume this would then replace my cbi astute timer?

33 minutes ago, ZCS said:

Thanks @Nexuss. i assume this is controlled remotely via app? what does it cost to purchase and install if you dont mind me asking? i assume this would then replace my cbi astute timer?

No unfortunately no remote control , only a rather basic controller box to set temps and times. I paid around R1,000+-  and did the install myself.

Edited August 11, 20223 yr by Nexuss

6 hours ago, ZCS said:

Thanks @Nexuss. i assume this is controlled remotely via app? what does it cost to purchase and install if you dont mind me asking? i assume this would then replace my cbi astute timer?

You can still retain your Astute to allow you to change times the geyser will be on. Also you can use it to ensure battery is charged if one suddenly gets LS. This can be used with the Geyser wise and provides the remote control of at least when geyser is on.

Some good input. With your PV and the times the 4kw element is on and you only get like 4kw from PV your other loads will be powered from grid. I will change the element to 3kw not to increase heating time much but run the standing load from PV even if the 4kw will only be on for short periods. Any bit not from grid is a plus in your favour.

Edited August 11, 20223 yr by Scorp007

45 minutes ago, Scorp007 said:

With your PV and the times the 4kw element is on and you only get like 4kw from PV your other loads will be powered from grid. I will change the element to 3kw not to increase heating time much but run the standing load from PV even if the 4kw will only be on for short periods. Any bit not from grid is a plus in your favour.

With his size PV array and battery he should be able to supply 5kw of load power say 3kwish from PV and 2kw from battery, so only the bit over 5kw will be from the grid ,then after the geyser was on the battery will just continue to charge up. Hence why i say there is no need to change the element. People who are using 2kw elements are usually running the geyser on essential side. Going through the hassle of replacing the element from 4kw to 3kw just to be at 1kw less doesn't really make sense to me.

food for thought. thanks guys.

I am also using a 5kW Sunsynk. I have 2 x 150l geysers each with a 3kW element on the non-critical side. They are connected is series. The bottom geyser receives the cold water, its outlet then feeds the top geyser inlet. The top geyser then feeds the house. Only one geyser is powered at a time.

Geyser controls

 

Geyser temps for the past few days:

Hi, if you choose a Sunsynk inverter there is a great way to save on your geyser power by utilising the AUX as an output. When the batteries are 100% SOC the AUX switches on and heats the geyser until 96% SOC (a selection). Of course one needs a RCD to protect anyone getting electrocuted at the geyser. If there is a cloudy day it is a simple ticking of the Aux under settings to force the Grid to heat the geyser. This is useful on both cloudy days and when one has a house full of guests using hot water. My electrical account for usage varies between R24.00 to R75.00. The R75.00 was during 4 days of massive rain and flooding in KZN with visitors in the house. (This is usage and has to include a basic charge of R294.00)

10 x 390W JA East West configuration

8KV Sunsynk Inverter

2x5.5KV Hubble batteries

1 hour ago, TonyH said:

Hi, if you choose a Sunsynk inverter there is a great way to save on your geyser power by utilising the AUX as an output. When the batteries are 100% SOC the AUX switches on and heats the geyser until 96% SOC (a selection). Of course one needs a RCD to protect anyone getting electrocuted at the geyser. If there is a cloudy day it is a simple ticking of the Aux under settings to force the Grid to heat the geyser. This is useful on both cloudy days and when one has a house full of guests using hot water. My electrical account for usage varies between R24.00 to R75.00. The R75.00 was during 4 days of massive rain and flooding in KZN with visitors in the house. (This is usage and has to include a basic charge of R294.00)

10 x 390W JA East West configuration

8KV Sunsynk Inverter

2x5.5KV Hubble batteries

Have you tested the AUX functionality and does it work 100% as described? Because I recall @Tariq tied it and it didn't work. Even Sunsynk support couldn't help him.

50 minutes ago, PowerUser said:

Have you tested the AUX functionality and does it work 100% as described? Because I recall @Tariq tied it and it didn't work. Even Sunsynk support couldn't help him.

sorry for the noob question but is the aux side the same as the 'non essential'? my plan is to have my oven, geyser and pool pump connected to the non essential side in order to not use battery when loadshedding. everything else to be connected to essential backup side of the inverter. 

35 minutes ago, ZCS said:

sorry for the noob question but is the aux side the same as the 'non essential'? my plan is to have my oven, geyser and pool pump connected to the non essential side in order to not use battery when loadshedding. everything else to be connected to essential backup side of the inverter. 

Not exactly the same thing. The non-essential side is better for loads that are too large to run through the inverter, or from the available battery. Typically the oven and geyser. When Eskom goes off, these devices are also off.

The AUX-load or smart-load will pass through the inverter, and it's good for loads that are but nice to have on solar if it's available, but not essential. It depends on how you program it, but if  your batteries are mostly full above a set point, and if you've got enough spare solar capacity during the day, then this load switches to run from solar/battery. Else it's off, or running from grid. To use possibly for the geyser, or possibly the pool pump.

Just the theory. I don't use mine.

1 hour ago, PowerUser said:

Have you tested the AUX functionality and does it work 100% as described? Because I recall @Tariq tied it and it didn't work. Even Sunsynk support couldn't help him.

Yes I heat up my geyser exclusively on the AUX output. I have setup the Aux as an output. When the battery is 100% SOC the AUX switches on and at 96% SOC it switches off.