12 Volt geyser element and PV system

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Nerfiller

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I am looking for anyone that has experience with the PV Water Heating System that use an element that witches between AC/DC and is willing to share their experience. Is it any good? Got bored trying to find info in the threads.
 
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Nerfiller said:
I am looking for anyone that has experience with the PV Water Heating System that use an element that witches between 220v and 12v and is willing to share their experience. Is it any good? Got bored trying to find info in the threads.
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I think you meant AC/DC element, not neccessary 12V. The geyserwise systems do this. It makes sense if you don't have an inverter for your DC solar panels to power the element when the sun is out but if you already have solar/inverter then imho, you don't need this.
 
yup I'm referring to the geyserwise ones, just wanted to get feedback from folk that actually have them.
 
Does not matter. If the element is 2 000 Watt, then the current drawn is going to increase drastically for a drop in voltage. Personally, this is a fire waiting to happen.
 
Geoff.D said:
Does not matter. If the element is 2 000 Watt, then the current drawn is going to increase drastically for a drop in voltage. Personally, this is a fire waiting to happen.
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www.livestainable.co.za

Geyserwise High Irradiation PV Solar Geyser Conversion Kit 150L (Including Panels And Mountings) | LiveStainable

Convert any existing geyser to solar No pipework needed More efficient than conventional solar geysers Modular system design Automatic AC backup SABS Approved
www.livestainable.co.za www.livestainable.co.za
Screen Shot 2021-03-04 at 14.38.22.png
Screen Shot 2021-03-04 at 14.40.17.png
Surely the element will only use whats available ie; 900W DC?
 
wingnut771 said:
www.livestainable.co.za

Geyserwise High Irradiation PV Solar Geyser Conversion Kit 150L (Including Panels And Mountings) | LiveStainable

Convert any existing geyser to solar No pipework needed More efficient than conventional solar geysers Modular system design Automatic AC backup SABS Approved
www.livestainable.co.za www.livestainable.co.za
View attachment 1030910
View attachment 1030914
Surely the element will only use whats available ie; 900W DC?
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Okay I see what you mean. Yes this system will limit the power consumed. But as already posted, it will take longer to heat the water.
 
Geoff.D said:
Okay I see what you mean. Yes this system will limit the power consumed. But as already posted, it will take longer to heat the water.
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I don't think this is an issue as long as you don't have a hair dresser at home.
 
Geoff.D said:
Okay I see what you mean. Yes this system will limit the power consumed. But as already posted, it will take longer to heat the water.
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Okay, doing some research into this reveals the element is in fact TWO separate elements isolated from each other, one used for AC heating and the other for DC heating. Hence the DC PV system does NOT use the same heating element as the AC heating circuit.

Sounds like a very good idea and easy conversion making use of an existing geyser. Makes plenty of sense, and is a self-contained system which to my mind is better than trying to size a backup power system to also cater for water heating.
 
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Would be interesting to hear some experiences.
I tried to work out some figures but let's say your 3 panels give you 600w for 5 hours a day that's 3kw. You will likely lose 1kw per day to heat loss so that only leaves 2kw for heating the tank and only on very sunny days. So there may be some savings electricity wise but I think at least 5 or 6 300w panels will be needed to really get the geyser off eskom power.
 
So the 2kwh available will increase a 150L geyser by 11 degrees per day. My geyser after the off period during the night starts each day at about 43 degrees. A shower only drops the temp by 2 degrees. It can work when there is sun but will still need some grid back up.
 
Sustainable sells exactly what you need
It is a 900 Watt DC element and when there isnt enough solar it uses the 2000W AC element off ESKOM

Im busy saving up for this kit

Geyserwise PV Solar Water Heating Kit For 100L Geyser - Sustainable.co.za

<p style="text-align: left;">To choose the correct components for your PV Water heating system it is important to know the irradiation levels in your area. In case of low irradiation areas more PV panels will be needed to get similar heating performance t
www.sustainable.co.za www.sustainable.co.za
 
Pineapple Smurf said:
Sustainable sells exactly what you need
It is a 900 Watt DC element and when there isnt enough solar it uses the 2000W AC element off ESKOM

Im busy saving up for this kit

Geyserwise PV Solar Water Heating Kit For 100L Geyser - Sustainable.co.za

<p style="text-align: left;">To choose the correct components for your PV Water heating system it is important to know the irradiation levels in your area. In case of low irradiation areas more PV panels will be needed to get similar heating performance t
www.sustainable.co.za www.sustainable.co.za
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900 watt element at what voltage?
900 W @ 12V = 75A.
@ 48V = 19A.
Both scenarios equal lots of panels regardless of the amount of sunlight available.
 
i would think it’s better to plan for your entire home to go off the grid, rather than buy a solar kit for a geyser.

i have 3 solar geysers (2 x 300L [3kw element] and 1 x 150L [GW 2kw element] ) , and they all 3 get the PV power from 9am onwards.

the one junk 300L afrilanga chromagen geyser I had for one of my redundant rooms, is totally fvcked ( 2-3 years ago panel flew off the roof and 3 weeks ago when I had Jaco come fit new panels for me, the geyser tank was leaking), so i‘ll be buying a normal 300L Kwikot soon and trial this system first without any power source, but I will also eventually hook it up to the PV system.
 
Geoff.D said:
900 watt element at what voltage?
900 W @ 12V = 75A.
@ 48V = 19A.
Both scenarios equal lots of panels regardless of the amount of sunlight available.
Click to expand...
I havent done the math myself
I know for a fact that this system is by no means very efficient, but for me it is peace of mind not having water on top of my roof risking a burst pipe and having 100 litres of water in the ceiling.

Ive had so many water scares and problems over the years I am so over it. I want a system with minimum water damage risks and that is why I have chosen to go this PV route :thumbsup:
 
So I have my 200L geyser running off my PV system for the last few weeks. I dropped in a 2kw element to replace the 3kw one that was in there. I then use Home Assistant + NodRed to control when the it comes on. So if there is enough sun the geyser runs until it’s hot then it’s switched off for the day. Fortunately my house only need one heat cycle out of the geyser.
I do have 4kw of usable PV from 9am onwards. So plenty for the geyser plus the house and charge the batteries.
 
Pineapple Smurf said:
I havent done the math myself
I know for a fact that this system is by no means very efficient, but for me it is peace of mind not having water on top of my roof risking a burst pipe and having 100 litres of water in the ceiling.

Ive had so many water scares and problems over the years I am so over it. I want a system with minimum water damage risks and that is why I have chosen to go this PV route :thumbsup:
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The only way to risk water leaks in the roof is to remove geyser from the roof cavity.
It makes no sense to exchange one risk (water leaks) and replace it with another (fire risk from overheated DC cables) in a badly designed PV system used for water heating.
 
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