Going solar and keeping the conventional geyser.

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
So is anyone who has gone solar still running a conventional geyser? And by running I mean through the solar system and not via Eskom through non-essentials as everyone seems to want to do.

I got quotes for fitting a new solar geyser setup and also some extra work done and it all just seems quite outrageous to me when I have a perfectly working and functional geyser.

So being of the Smart home inclined notion and already having a smart switch in place I don’t see why I couldn’t simply run the geyser when the solar “activates” and set the thermostat a bit higher at 65 instead of the current power saving 55.

I use most of my geyser power during daylight as it stands right now anyway and then a top up at night with the geyser going off completely at 20:00.

I figured I could do this one further and fit a thermal probe to the geyser so that at night it only heats up to say 45-degrees in that way still allowing for a warm enough shower without eating too much power.

It makes more sense to me to throw the money into the solar system as a whole rather than spending it on a new geyser setup when mine is working just fine right now.
 

Koosvanwyk

Senior Member
Joined
Aug 6, 2015
Messages
726
So is anyone who has gone solar still running a conventional geyser? And by running I mean through the solar system and not via Eskom through non-essentials as everyone seems to want to do.

I got quotes for fitting a new solar geyser setup and also some extra work done and it all just seems quite outrageous to me when I have a perfectly working and functional geyser.

So being of the Smart home inclined notion and already having a smart switch in place I don’t see why I couldn’t simply run the geyser when the solar “activates” and set the thermostat a bit higher at 65 instead of the current power saving 55.

I use most of my geyser power during daylight as it stands right now anyway and then a top up at night with the geyser going off completely at 20:00.

I figured I could do this one further and fit a thermal probe to the geyser so that at night it only heats up to say 45-degrees in that way still allowing for a warm enough shower without eating too much power.

It makes more sense to me to throw the money into the solar system as a whole rather than spending it on a new geyser setup when mine is working just fine right now.
I ran my normal element based geyser from solar for about a year (it was a 3.5 kWh element), nothing wrong with your thought process.

I used to heat the water to 65 degrees, starting from 12 noon, using the element and then switched it off at about 4pm. Only issue with this is there is no hot water early morning.

Eventually opted for a heat pump, as opposed to solar geyser, as this (my opinion, there are different thoughts on this) seemed a better option.

With the heat pump we now have hot water (60 degrees) from 10am the morning. Before 10am the water is still at around 40 degrees from the previous day (in summar). All power is supplied by solar and everything is automated using the heat pump control unit.
 

TheChamp

Honorary Master
Joined
Feb 26, 2011
Messages
42,998
If what you were quoted on the solar geyser can get you a decent battery for night time use.
 

maxxis

Expert Member
Joined
Jul 26, 2007
Messages
1,372
For now… I kept my geyser on the non-essential side. Runs for an hour early morning and an hour late afternoon. Uses very little power this way and we have plenty of hot water for two people to shower twice a day.

Next step is a 2kw element and whatever else exists to make it efficient enough to run off my solar.
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
If what you were quoted on the solar geyser can get you a decent battery for night time use.

Yes the plan is to go full solar and inverter and battery and hence why the money would go further to either make the batteries larger or the array bigger with the money.

I’m a big fan of SolarEdge’s inverter and optimiser setup and would love to put a Tesla Powerwall in alongside it but at the end of the day likely won’t justify that.

Other option would be Victron + FreedomWon

Only have the money ready end of February so still a bit of time to go before it happens but was wanting to do the geyser before then.

Sadly it seems we don’t get SolarEdge batteries here, would have loved it to be SolarEdge end to end.
 
Last edited:

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
For now… I kept my geyser on the non-essential side. Runs for an hour early morning and an hour late afternoon. Uses very little power this way and we have plenty of hot water for two people to shower twice a day.

Next step is a 2kw element and whatever else exists to make it efficient enough to run off my solar.

Won’t work for me as it’s a 4 person family.

So usage is 5ish kw in summer and more in winter.
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
I ran my normal element based geyser from solar for about a year (it was a 3.5 kWh element), nothing wrong with your thought process.

I used to heat the water to 65 degrees, starting from 12 noon, using the element and then switched it off at about 4pm. Only issue with this is there is no hot water early morning.

Eventually opted for a heat pump, as opposed to solar geyser, as this (my opinion, there are different thoughts on this) seemed a better option.

With the heat pump we now have hot water (60 degrees) from 10am the morning. Before 10am the water is still at around 40 degrees from the previous day (in summar). All power is supplied by solar and everything is automated using the heat pump control unit.

Yes my quotation is for a thermo dynamic heat pump system which will bring me down to 3 kW or so a day.

Thing is it needs to be installed upright and I need to do quite a bit of work in my garage to facilitate that and on top of that I wanted them to allow a cut over to the old geyser if I ever needed it as well as install a tap to my fridge for me.

While I do believe the plumber is taking the piss and I could fight it down it just had me question if the entire expense is worth it.
 
Last edited:

CranialBlaze

Expert Member
Joined
Jan 24, 2008
Messages
3,662
I’m in the process of installing solar and they geyser is going on it, the entire house is.

5KW inverter with 2x 100ah batteries and 10x 540w panels. Friends got the same system, house like 3x the size of mine, 2x geyser and 2x ac units, entire thing runs off the 5KW.

I do plan and adding a few more smart plugs in just to balance the logic to prevent too many items on at once, but there is no good reason to keep they geyser on with Eskom unless you are incapable of preventing it from going on with the washing machine, AC, kettle and over all at once.

Geyser itself is already on a smart switch so it goes on when I leave the gym, start a run, finish a ride or at 5pm daily, and powering off 1min after it reaches peak temp, whatever that is, with periodic check in place to cater for loadshedding so that if the power of off the geyser is turned on within 15 minutes of it coming back on.

That same logic will be expanded to a few other, I’ll have to do some testing and see what combos are bad, but an example would be if washing machine running, wait till done before turning geyser on.

Sure if you get a small inverter then it’s unwise to keep it on, but I’ve had 3 solar installers and 2 electricians confirm there is no good reason to keep it off the solar, just be cognizant of what combinations are a terrible idea, which smart plugs accident proof that.

So geyser, coffee machine, washing machine, air fryer, AC and oven would go into a managed cycle.

If you really worried get an 8kw, but that’s almost double the price of the 5
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
I’m in the process of installing solar and they geyser is going on it, the entire house is.

5KW inverter with 2x 100ah batteries and 10x 540w panels. Friends got the same system, house like 3x the size of mine, 2x geyser and 2x ac units, entire thing runs off the 5KW.

I do plan and adding a few more smart plugs in just to balance the logic to prevent too many items on at once, but there is no good reason to keep they geyser on with Eskom unless you are incapable of preventing it from going on with the washing machine, AC, kettle and over all at once.

Geyser itself is already on a smart switch so it goes on when I leave the gym, start a run, finish a ride or at 5pm daily, and powering off 1min after it reaches peak temp, whatever that is, with periodic check in place to cater for loadshedding so that if the power of off the geyser is turned on within 15 minutes of it coming back on.

That same logic will be expanded to a few other, I’ll have to do some testing and see what combos are bad, but an example would be if washing machine running, wait till done before turning geyser on.

Sure if you get a small inverter then it’s unwise to keep it on, but I’ve had 3 solar installers and 2 electricians confirm there is no good reason to keep it off the solar, just be cognizant of what combinations are a terrible idea, which smart plugs accident proof that.

So geyser, coffee machine, washing machine, air fryer, AC and oven would go into a managed cycle.

If you really worried get an 8kw, but that’s almost double the price of the 5

Yeah same here everything is smarted already and as such I figured I should leverage that.

My coffee machine actually uses very little and my stove is induction so no worries there. Similarly the washing machine is actually very light.

Only ever use one aircon at a time so that shouldn’t be a drama and rarely put the oven and aircon on together because that doesn’t make sense.

But yes part of the reason I was leaning towards maybe going Powerwall after all is that it can handle the higher peaks and then a smaller inverter for the solar side of things would be just fine.

Actually want to inquire again why we don’t have the Powerwall + Solar Inverter here as I would love that simplicity but then I can’t go SolarEdge.
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
@CranialBlaze

Out of interest do you have a cut over to put the geyser back on Eskom should you need to?

Or because it’s all handled by the solar setup does it simply fail over automatically.

If you do have a cut over how does that work with a smart switch mounted in the DB board. My brain can’t brain that right now.
 

Moby Grape

Honorary Master
Joined
Jul 18, 2008
Messages
54,721
@CranialBlaze

Out of interest do you have a cut over to put the geyser back on Eskom should you need to?

Or because it’s all handled by the solar setup does it simply fail over automatically.

If you do have a cut over how does that work with a smart switch mounted in the DB board. My brain can’t brain that right now.
As I understand it you can have a combined AC and DC element in the Geyser and compensate with Eskom at night.


BTW which Freedom Won batteries are you getting? eTowers seem a bit scarce at the mo with new stock coming in at the end of the month only. I grabbed a 10/8 tower and 5kw SunSynk inverter. The Victron is a very nice unit but pricier since it's modular. The SunSynk is integrated so not repairable / upgradeable at a modular level... but the same 5yr warranty. I just decided at the price I can add another 5 later rather than buy the Victron.
 

TheChamp

Honorary Master
Joined
Feb 26, 2011
Messages
42,998
I’m in the process of installing solar and they geyser is going on it, the entire house is.

5KW inverter with 2x 100ah batteries and 10x 540w panels. Friends got the same system, house like 3x the size of mine, 2x geyser and 2x ac units, entire thing runs off the 5KW.

I do plan and adding a few more smart plugs in just to balance the logic to prevent too many items on at once, but there is no good reason to keep they geyser on with Eskom unless you are incapable of preventing it from going on with the washing machine, AC, kettle and over all at once.

Geyser itself is already on a smart switch so it goes on when I leave the gym, start a run, finish a ride or at 5pm daily, and powering off 1min after it reaches peak temp, whatever that is, with periodic check in place to cater for loadshedding so that if the power of off the geyser is turned on within 15 minutes of it coming back on.

That same logic will be expanded to a few other, I’ll have to do some testing and see what combos are bad, but an example would be if washing machine running, wait till done before turning geyser on.

Sure if you get a small inverter then it’s unwise to keep it on, but I’ve had 3 solar installers and 2 electricians confirm there is no good reason to keep it off the solar, just be cognizant of what combinations are a terrible idea, which smart plugs accident proof that.

So geyser, coffee machine, washing machine, air fryer, AC and oven would go into a managed cycle.

If you really worried get an 8kw, but that’s almost double the price of the 5
That's a lot of watts to draw from a 5kW inverter, it must involve a lot of juggling.
 

The Trutherizer

Executive Member
Joined
May 20, 2010
Messages
5,228
A solar water geyser is not expensive. And you can feed it into your existing geyser. You'd just need to get something to up the pressure again from the solar geyser to the normal one.
Probably cheaper than getting the extra solar..battery..bigger inverter (?) you'd need to run it completely off your installation.

Or so I hear. Still finding out stuff myself.
 

Moby Grape

Honorary Master
Joined
Jul 18, 2008
Messages
54,721
A solar water geyser is not expensive. And you can feed it into your existing geyser. You'd just need to get something to up the pressure again from the solar geyser to the normal one.
Probably cheaper than getting the extra solar..battery..bigger inverter (?) you'd need to run it completely off your installation.

Or so I hear. Still finding out stuff myself.
No inverter, you replace the element with a DC element and provide 3 dedicated panels to run it.
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
41,536
A solar water geyser is not expensive. And you can feed it into your existing geyser. You'd just need to get something to up the pressure again from the solar geyser to the normal one.
Probably cheaper than getting the extra solar..battery..bigger inverter (?) you'd need to run it completely off your installation.

Or so I hear. Still finding out stuff myself.

That doesn’t work at night.

The thermodynamic does.
 

Snyper564

Honorary Master
Joined
Oct 1, 2008
Messages
10,221
I apologize for not reading everything I am currently running an evac system but with my 3kw elements in for top up.

I have my entire house including oven induction stove and geyser all on essential. Goal of our system was to be off grid as much as possible and still have everything run "as normal"

It works no problem when I need to ramp it on days the evac isnt enough.

My 2c if you going full solar DO NOT go evac/collection tube etc. Take that money and add it to your system.

Also go the 8kw sunsynk route then you never ever have to think about whether you should turn something on or off.

Dinner - stove and induction stove

1642193396926.png

Geyser on

1642193501753.png
 

Snyper564

Honorary Master
Joined
Oct 1, 2008
Messages
10,221
PV to heat water is horribly inefficient.

A vacuum tube solar geyser will keep plenty hot overnight.
You are correct horribly inefficient BUT taking that 15-20K and putting in 4-6 additional panels and generating 2-3kw an hour is better.

Thats why I said if you going full solar DONT touch evac but if you going SOLAR boost your system. If you just want geysers sorted thats a good route but not if you going the solar route.

So do you want hot water only or 3kwX6hours -> 18 extra KW a day?

1642194643349.png

I speak from experience I would in a heart beat put the money I spent on my evac system and add that to my solar system.

In my case I had 2 geysers (30k to retrofit) I could have added 8-10 more panels
 
Last edited:

CranialBlaze

Expert Member
Joined
Jan 24, 2008
Messages
3,662
@CranialBlaze

Out of interest do you have a cut over to put the geyser back on Eskom should you need to?

Or because it’s all handled by the solar setup does it simply fail over automatically.

If you do have a cut over how does that work with a smart switch mounted in the DB board. My brain can’t brain that right now.

Smart switch is before the isolator, not on the DB, won’t interfere with the failover.
 

CranialBlaze

Expert Member
Joined
Jan 24, 2008
Messages
3,662
That's a lot of watts to draw from a 5kW inverter, it must involve a lot of juggling.

How much of that does anyone every run all at once, smarts will be fore just in case but in all likelihood they’ll almost never trigger.

Geysers is the main one and it’s never on when other things are needed, the only possible crossover is the 5pm on a hot day where the AC will probably be on, but my geysers seldom running for more than a combined 40mm.

Even then, the AC will be long past peak draw so it’s also likely to not matter.
 
Top