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Solar panel to geyser


Jules

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Hi everyone

 

I'm new to the forum and a total amateur when it comes to solar power. I hate Eskom and the ANC with a passion, so I am highly motivated to learn. It seems like this forum is the place to do it. 

To get started I'm keen to do a battery-free installation if possible, sending power from solar panels directly to my geysers. I have three geysers on the property, although they are not all in the same house - one is in a cottage. 

 

I'd be very grateful if someone could give me some advice on the equipment I need and where to buy it from. 

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9 hours ago, ibiza said:

   .

 

11 hours ago, Jules said:

Hi everyone

 

I'm new to the forum and a total amateur when it comes to solar power. I hate Eskom and the ANC with a passion, so I am highly motivated to learn. It seems like this forum is the place to do it. 

To get started I'm keen to do a battery-free installation if possible, sending power from solar panels directly to my geysers. I have three geysers on the property, although they are not all in the same house - one is in a cottage. 

 

I'd be very grateful if someone could give me some advice on the equipment I need and where to buy it from. 

same here

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2 options.

1. get a Smart-Hybrid grid tie inverter that can run off panels only and install around 4500W worth of panels and run your geysers at different times from that. <- Better long term option.

2. get AC/DC elements for the geysers and connect panels to the DC side. <- Probably the cheapest option

 

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6 minutes ago, Johann1982 said:

2 options.

1. get a Smart-Hybrid grid tie inverter that can run off panels only and install around 4500W worth of panels and run your geysers at different times from that. <- Better long term option.

2. get AC/DC elements for the geysers and connect panels to the DC side. <- Probably the cheapest option

 

 

Goodwe hybrid if you want something decent, or go with a infini solar hybrid for something cheaper.

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Allow me to be different again, but I'd put in a Fronius :-)

http://www.sonopsolar.co.za/product/fronius-primo-inverter-5kw-single-phase/

Add another 2kwp of panels, say 8 x 250W modules for a start. It has two MPPT trackers giving you much flexibility to add more modules later.

Why Fronius? Because I cannot imagine why you'd spend the same money on something that isn't IP65. The Fronius will set you back 27.5k. The Goodwe (also IP65 I think?) of the same capacity is over 40k, and a 5KVA Infini is also up there with nowhere near the same protection. The Goodwe and Infini are hybrids of course -- it can take batteries -- while the Fronius is only a GTI, so this isn't an apples for apples comparison, but if you keep that in mind I think you can bring your entry costs down quite a bit.

Then add a separate inverter charger in the future when you get to the battery stage. Since I'm a fan of the blue products, for me that would be a 3KVA Multiplus, but YMMV :-)

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I usually buy from Geyserwise. 900W DC / 1500W AC. You also get an MPPT controller then you use 3x 250W panels per geyser. One of my friends use only the DC/AC element with 2x 250W panels connected in series directly to the element with a 10A Breaker on the positive. It is less efficient, but still delivers around 60 degrees in summer.

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Wiring PV directly to an element will of course be cheaper and more efficient (but then using a good old flat panel or evac tube setup and heating the water directly would be even better for that limited application!), but the reason why I specifically advised a GTI is because you mentioned that there are three geysers and one is in a different building. Using a GTI, you can power all three (perhaps with time switches?) using one solar setup.

My father uses such a setup to pump water on the farm. Time switches turn the pumps on roughly as the power curve rises during the day, thereby getting a kind of self-consumption. In addition, it means he can keep the PV panels at home where security is better (he has three pumps around the house, furthest one is 1km away, single phase with a small motor and appropriately sized cable).

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1 hour ago, plonkster said:

Allow me to be different again, but I'd put in a Fronius :-)

http://www.sonopsolar.co.za/product/fronius-primo-inverter-5kw-single-phase/

Add another 2kwp of panels, say 8 x 250W modules for a start. It has two MPPT trackers giving you much flexibility to add more modules later.

Why Fronius? Because I cannot imagine why you'd spend the same money on something that isn't IP65. The Fronius will set you back 27.5k. The Goodwe (also IP65 I think?) of the same capacity is over 40k, and a 5KVA Infini is also up there with nowhere near the same protection. The Goodwe and Infini are hybrids of course -- it can take batteries -- while the Fronius is only a GTI, so this isn't an apples for apples comparison, but if you keep that in mind I think you can bring your entry costs down quite a bit.

Then add a separate inverter charger in the future when you get to the battery stage. Since I'm a fan of the blue products, for me that would be a 3KVA Multiplus, but YMMV :-)

 

Or you could go for a Microcare 3kw GTI and use their Grid-limiter so you don't get into trouble with the municipality. Give or take R23k.

http://www.sustainable.co.za/microcare-3kw-single-phase-grid-tie-inverter.html

http://www.sustainable.co.za/microcare-grid-tie-limiter.html

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4 minutes ago, plonkster said:

Agreed. But there is something reassuring about buying an inverter from people who build welding machines... you know, stuff designed to take the smoke out of large pieces of iron :-)

 

True! ABB, SMA, SolarEdge, Delta and Victron all make wonderful products.

At the end of the day, you need to base your decision on product availability and support. There is no point in buying an ABB inverter and the installer/supplier is 500km away.

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11 minutes ago, plonkster said:

Wiring PV directly to an element will of course be cheaper and more efficient (but then using a good old flat panel or evac tube setup and heating the water directly would be even better for that limited application!),

I'm against installing a common solar geyser. My better half complains when she gets burned when the water temp is too high. I know it's law to have one of those temparature control valves in solar geysers, but then I complain that the temp is too low! I want a geyser with a thermostat! 

 

An inverter seems like an awfully large expense for this application. But if it gives me the option to add batteries and more panels, then maybe I'd consider it. 

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As long as the inverter won't be used for just heating your geysers then it will be a good option. I am currently testing a 3kw smart-grid hybrid inverter that has no problem running my geyser for an hour between 12 and 1pm. It also runs everything else in my house except for stove and oven, which is gas. Even without batteries it cuts my usage from 30kwh per day down to 12kwh/day. I get around 16 to 18kwh/d from my panels.

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20 minutes ago, Jules said:

I'm against installing a common solar geyser. My better half complains when she gets burned when the water temp is too high. I know it's law to have one of those temparature control valves in solar geysers, but then I complain that the temp is too low! I want a geyser with a thermostat! 

Go with a prefeed system. I converted my thermosiphon system to a prefeed in 2013. Because I already had a tempering valve installed that simply remained behind. This means I actually mix the very hot water in the outer tank (on the roof) down to a lower temperature before it enters the inner tank (inside the roof). This means a small loss in efficiency of course, it means my electrical geyser still spends a tiny bit of electricity keeping the water hot (standing loss) which I could possibly eliminate if I fed it with very hot water.

But, since the tempering valve is adjustable, I suspect you can set it so you feed the internal unit with water at 65 Celsius, and then set the thermostat to 55. Since it will take around 10 hours to drop from 65 to 55 at the normal standing loss rate, and because 65 isn't so hot that anyone should burn as long as they know how to work the mixer in the shower, I'd think that will get you the best of both worlds: Free hot water, properly regulated by a thermostat.

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  • 2 weeks later...
On 12/14/2016 at 11:30 AM, Johann1982 said:

I usually buy from Geyserwise. 900W DC / 1500W AC. You also get an MPPT controller then you use 3x 250W panels per geyser. One of my friends use only the DC/AC element with 2x 250W panels connected in series directly to the element with a 10A Breaker on the positive. It is less efficient, but still delivers around 60 degrees in summer.

Has he tried it with 3x 250W panels? For the same price as the MPPT he could add another panel if needed. The element should handle the extra load, otherwise connect to the 2000W side. 

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  • 4 years later...
On 2016/12/13 at 5:45 PM, Jules said:

Hi everyone

 

I'm new to the forum and a total amateur when it comes to solar power. I hate Eskom and the ANC with a passion, so I am highly motivated to learn. It seems like this forum is the place to do it. 

To get started I'm keen to do a battery-free installation if possible, sending power from solar panels directly to my geysers. I have three geysers on the property, although they are not all in the same house - one is in a cottage. 

 

I'd be very grateful if someone could give me some advice on the equipment I need and where to buy it from. 

Hi Jules
Did you come right with connecting your PV panels to your geyser? Would love to chat to you a bit more. Feel free to drop me a mail: [email protected]
I'll gladly discuss the solution I found during lockdown 2020. Cheap, DIY and very effective

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