We finally want to pull the trigger & go Solar

[Lupus]

Even if only 5 of them bath, and only bath every other day, that's still equivalent to 250-300 L of hot water per day on average, which is about 10 kWh per day in winter. Or in terms of toast that's about 67 toastings.



Correct, that's it's selling point. EDIT: Geysertech may be easier to source. The downside is you generally need one more panel to get equivalent energy production, so it might be swings and roundabouts.

So what you're saying is, replace the element with a heat pump and shower instead of bath ;-)

 

[Lupus]

We've had our system for a year now and have saved north of 60k on prepaid. We buy R1000 worth of power on the first of the month and we usually have some units left. We run everything off solar including the geysers and the stove

Why do you want to go with Deye inverters and Dyness batteries? We saved a lot of money by going with Luxpower inverters and Revov 2nd life batteries.

I top up with R400 just to keep the connection fee and I get 55.5 units

 

[Tomtomtom]

So what you're saying is, replace the element with a heat pump and shower instead of bath ;-)

Even switching to showering won't generate the savings of a Geysertech/Geyserwise MPPT system. It is about the only cheaper option though.

 

[Lupus]

Even switching to showering won't generate the savings of a Geysertech/Geyserwise MPPT system. It is about the only cheaper option though.

So instead of just adding the geyser to an 8kw inverter with solar panels and just turn it off manually, they must add another solar controller and possible panels? Otherwise why would you add a solar controller if you're not going to add panels? Or they could get a sonoff for R360, be able to monitor their usage and control it?

 

[biena]

Yes I updated the link to Geysertech's unit which is also cheaper.

Not really previous link was 4kw element this one is 3kw
need the 4kw version to really compare and it is R 5k

I would add some DC fuses also.

Really do wish that they would add a solar DC out that you could plug into a Inverter.
logic as follows
sun shining geyser under temp, use solar panels to heat
sun shining geyser over temp, divert solar panel output to inverter.
no sun use only grid

Feels like a waste to have 3-4 panels taking up roofspace that is at times not going to generate anything since geyser is up to temp.

 

[Tomtomtom]

So instead of just adding the geyser to an 8kw inverter with solar panels and just turn it off manually, they must add another solar controller and possible panels? Otherwise why would you add a solar controller if you're not going to add panels? Or they could get a sonoff for R360, be able to monitor their usage and control it?

"Just" adding a geyser to an 8 kW inverter is the crazy part imo. Why do you have 3 or 4 kW of inverter capacity powering a simple resistive element that can be driven directly from the PV via an MPPT? Think of a geyser as basically a battery.

A Geysertech/Geyserwise plus its panels and balance of system is about R 10-12k. That gives a 2-3 year payback. As I mentioned, that was enough for us, we're down to less than 6 units/day of grid consumption and no more investment makes sense at this point absent regular outages.

But there's no reason you can't have both. And you save inverter headroom by putting the geyser on its own MPPT. Maybe you don't need 8 kW any more.

 

[Lupus]

"Just" adding a geyser to an 8 kW inverter is the crazy part imo. Why do you have 3 or 4 kW of inverter capacity powering a simple resistive element that can be driven directly from the PV via an MPPT?

A Geysertech/Geyserwise plus its panels and balance of system is about R 10-12k. That gives a 2-3 year payback. As I mentioned, that was enough for us, we're down to less than 6 units/day of grid consumption and no more investment makes sense at this point absent regular outages.

But there's no reason you can't have both. And you save inverter headroom by putting the geyser on its own MPPT. Maybe you don't need 8 kW any more.

How is that the crazy part? You're wanting to add 12k more to the install + more roof space for a geyser? Proper management and running during the day will work fine, a 5 min shower instead of a bath, turning the temp down on the geyser as well can save some power.
Quite a few posters here run their geysers on their inverters. I just went one step further and replaced the element with a heat pump.

 

[Tomtomtom]

Not really previous link was 4kw element this one is 3kw
need the 4kw version to really compare and it is R 5k

I would add some DC fuses also.

Really do wish that they would add a solar DC out that you could plug into a Inverter.
logic as follows
sun shining geyser under temp, use solar panels to heat
sun shining geyser over temp, divert solar panel output to inverter.
no sun use only grid

Feels like a waste to have 3-4 panels taking up roofspace that is at times not going to generate anything since geyser is up to temp.

If roof space is at a premium go with Geyserwise. That's 2 panels.

I agree it would be nice to have a pass-through option but the waste is not bad especially over a full year. Only a few months of the year do we have some excess kWh each day. And that comes with the territory with PV.

You can also set the geyser temperature higher to get effectively more storage out of it.

 

[BLG]

yeah from monitoring via the SMart Life App it looks like our geyser is pulling around 3800 watts, would need a 4Kw solar controller but that looks like a real feasible option ROI as you say would be pretty quick on that

 

[Tomtomtom]

How is that the crazy part? You're wanting to add 12k more to the install + more roof space for a geyser? Proper management and running during the day will work fine, a 5 min shower instead of a bath, turning the temp down on the geyser as well can save some power.
Quite a few posters here run their geysers on their inverters. I just went one step further and replaced the element with a heat pump.

From an electrical engineering standpoint it's just a very sad thing to do, although I agree if you are committed to a single big install then sure, overprovision the inverter and put the geyser on it.

But it's not going to be a big saving. For one thing if the only reason you're going for 8 kW is to accommodate the geyser, then the R 5k extra MPPT pays for itself if you get a smaller inverter. If you needed 8 kW anyway well now you don't have to worry about losing half that whenever your geyser turns on.

There are advantages to going incrementally, but the main one is the one that's tricky to explain unless you've seen it: the economics can change once you've taken care of the first 30-40% of consumption.

 

[Dimpie (JIGSAW)]

This thread feels "DeJaVu"

 

[SauRoNZA]

ok i think I just pinpointed one of the culprits haha - our kids live on toast, everything must get toasted, from peanut butter to marmite to chocolate spread, you name it - i just checked using one of those power meter plugs that thing pulls 1921 watts! So besides the 6 cups of coffee (each) we make ourselves a day on our 1500 watt coffee machine, we have some serious contenders in the kitchen alone....

Nah none of those are even worth a mention.

It does 1921 watts for all of 5 minutes so not even 160W an hour.

 

[SauRoNZA]

Here we go again! Power over 5 minutes is still 1900 W. You want to build in the time factor. That leaves energy, 150 Wh. Equivalent to a 150 W appliance running for 1 hour.

OP needs to do the energy audit everyone is suggesting. But we can already predict the biggest consumer is going to be the geysers. Especially since baths were mentioned. A 150 L bath costs on the order of 5000 Wh = 5 kWh = 5 units.

Between the 3 kids and 3 adults and two geysers I'm guessing about 15 kWh a day is going to water heating.

And just to put it out there again, running a geyser off solar does not require an inverter or batteries. Just one of these.

Which is crazy when you consider that’s minimum R50 a day just to wash yourself…before the water.

 

[SauRoNZA]

From an electrical engineering standpoint it's just a very sad thing to do, although I agree if you are committed to a single big install then sure, overprovision the inverter and put the geyser on it.

But it's not going to be a big saving. For one thing if the only reason you're going for 8 kW is to accommodate the geyser, then the R 5k extra MPPT pays for itself if you get a smaller inverter. If you needed 8 kW anyway well now you don't have to worry about losing half that whenever your geyser turns on.

There are advantages to going incrementally, but the main one is the one that's tricky to explain unless you've seen it: the economics can change once you've taken care of the first 30-40% of consumption.

To me it just doesn’t make sense to replace something that is working just fine to offset a cast very far into the future.

If mine dies or starts dying, then I wouldn’t replace it with a conventional option and look towards solar options or heat pumps but until then it doesn’t make much sense.

 

[Magnum]

That last bit is Defy induction hob making hamburgers....Bugger gas.,

 

[BLG]

This makes no sense whatsoever because 1 you will be paying to charge those batteries.

Two the most expensive installation IS the solar panels so to add more later is going to cost you a fortune.

You do AS MUCH SOLAR AS YOU CAN up front and rather leave the battery/ies as an upgrade.

Where's the logic in buying a 8kW inverter and then feeding it 2kW from solar?

View attachment 1905526

That should just about max out each MPPT per string...can probably do 9 on each string but then you are over the inverter limit anyway and it will trim off the excess but it certainly won't hurt.

So I know I am harping on this for a bit but I really want to bite the bullet and do the Solar thing, what if we went this route, and they configure / wire it so that it is "battery ready" but usable in the day, & we purchase the battery/ies at a later stage? That way we have the foundation for a decent system and would afford the hardware and install (potentially)

 

[SauRoNZA]

So I know I am harping on this for a bit but I really want to bite the bullet and do the Solar thing, what if we went this route, and they configure / wire it so that it is "battery ready" but usable in the day, & we purchase the battery/ies at a later stage? That way we have the foundation for a decent system and would afford the hardware and install (potentially)

View attachment 1905976

It’s winter now…it’s going to be pretty useless until at least end of August.

Just save your money until then and do it all at once.

You’ll be sad and disappointed about it not performing as expected etc etc, rather install in spring and ride the waves through summer.

Stick the money in your home loan and let it sit.

 

[B-1]

.

So I know I am harping on this for a bit but I really want to bite the bullet and do the Solar thing, what if we went this route, and they configure / wire it so that it is "battery ready" but usable in the day, & we purchase the battery/ies at a later stage? That way we have the foundation for a decent system and would afford the hardware and install (potentially)

View attachment 1905976

Ive never seen it done that way so not sure how it will perform practically but in theory it is a good idea.
Get the expensive install out the way, start saving on daytime electricity use and then just add batteries at a later stage with minimal install cost(you can do that yourself if you are technical)

I guess one thing to do is find an installer willing to do it that way and signing off on the system. Also make sure they install the battery cable and disconnect/fuse so the batteries just need to be hooked up.

 

[B-1]

It’s winter now…it’s going to be pretty useless until at least end of August.

Just save your money until then and do it all at once.

You’ll be sad and disappointed about it not performing as expected etc etc, rather install in spring and ride the waves through summer.

Stick the money in your home loan and let it sit.

What are you even talking about? PV generation in JHB is great in winter.

 

[Lupus]

So I know I am harping on this for a bit but I really want to bite the bullet and do the Solar thing, what if we went this route, and they configure / wire it so that it is "battery ready" but usable in the day, & we purchase the battery/ies at a later stage? That way we have the foundation for a decent system and would afford the hardware and install (potentially)

View attachment 1905976

Or get a smaller system with batteries and start upgrading once you're saving. Do you need a Deyes 8kw inverter? Do you need 16 solar panels right now?
6kw inverter 8195

Luxpower Solar Inverter SNA6000 Offgrid WPV(with CT) 6000w 48v+ Wifi D

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300ah 15kwh battery

Luxpowertek Li-15e-15kWh LV Lithium battery 51.2V

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Plus those panels you can put down 8 for now.
This would total 44792 and start bringing in the savings you want, eventually add on when you can. At least this will get you started.