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Solar Geyser


Thegie

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Good day, 

I am seeking advice on powering up my solar geyser pump and control panel during a power outage. I have a backup system with 5kva inverter, 3,5kw lithium battery and 6 x 300w panels. My solar geyser is connected to eskom and currently runs off a control panel and 220v pump. When there is a power outage for an extended  period (more than a day) I don’t have hot water as the pump can’t circulate.

One of the solutions would be to install a geyser wise control panel, 12v pump with battery and panel.

I want to know is it possible to install a toggle switch in the DB for the geyser breaker, where I could switch between eskom power to battery backup power. 

If this can be done, this will allow the pump and management system to be operational during an extended power outage. 

It is not my intention to heat the geyser via the battery backup, but merely to run the control panel and pump to allow the hot water collected to circulate to the geyser.

Your advice will be greatly appreciated.

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If you just want to run the circulating pump and control panel the cheapest option would be to put those 2 items on to your always on circuit that is covered by your inverter.

What happens most of the time when you get someone to install a solar geyser is that they will just put the pump and controller on the same circuit braker with the geyser. This saves them to have to pay an electrician to come do the wiring to install this under an separate braker (be it existing or new) in your distribution board. It makes the install cheaper which the user would want.
If your municipality use remote control units on your geyser then this will not be ideal as if they want to reduce load your pump and controller will also not get power and not circulate the hot water into your geyser.
 

You will need to change this to run from your inverter instead so that both the control panel and the pump has power.

NOTE: I suggest you look at the specs for your current circulation pump and if the inverter (and your batteries) will handle that. Remember that when a pump turns on it draws more power than when it is running and your circulation pump will switch on many times during the day.

If you are unsure or it will be to much, then rather go for a 12V pump with a small solar panel. Something like this https://ecodepot.co.za/products/geyserwise-max-12v-solar-kit-for-pumped-solar-geyser-includes-max-geyser-controller-kit-12v-brass-circulation-pump-10w-pv-panel-12v-4ah-battery-connecting-cable

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1 hour ago, Thegie said:

 My solar geyser is connected to eskom and currently runs off a control panel and 220v pump. When there is a power outage for an extended  period (more than a day) I don’t have hot water as the pump can’t circulate.

I want to know is it possible to install a toggle switch in the DB for the geyser breaker, where I could switch between eskom power to battery backup power. 

If this can be done, this will allow the pump and management system to be operational during an extended power outage. 

It is not my intention to heat the geyser via the battery backup, but merely to run the control panel and pump to allow the hot water collected to circulate to the geyser.

 

Depending how your backup system is installed (e.g. a separate DB with the essential loads) you could probably just have the control unit and pump moved to the essential load side so no switch in needed. Alternatively a transfer switch of some kind should be an option. Most likely in both cases you will need to get an electrician to run some wire if the pump and controller is wired up as explained by @Louisvdw

Edited by introverter
typo
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3 hours ago, Thegie said:

Good day, 

I am seeking advice on powering up my solar geyser pump and control panel during a power outage. I have a backup system with 5kva inverter, 3,5kw lithium battery and 6 x 300w panels. My solar geyser is connected to eskom and currently runs off a control panel and 220v pump. When there is a power outage for an extended  period (more than a day) I don’t have hot water as the pump can’t circulate.

One of the solutions would be to install a geyser wise control panel, 12v pump with battery and panel.

I want to know is it possible to install a toggle switch in the DB for the geyser breaker, where I could switch between eskom power to battery backup power. 

If this can be done, this will allow the pump and management system to be operational during an extended power outage. 

It is not my intention to heat the geyser via the battery backup, but merely to run the control panel and pump to allow the hot water collected to circulate to the geyser.

Your advice will be greatly appreciated.

Thanks for the response

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You also get solar powered circulation pumps that are pretty cheap. They run of a 10-20W panel and cost a few hundred rand. Like this https://www.sustainable.co.za/its-ts510pv-12v-dc-circulation-pump.html#:~:text=The ITS 12V solar DC,single family solar thermal systems.

Just run it independently of you controller etc in parallel. So if the sun shines it runs, otherwise not. I take it you have no thermosiphon due to the collecter being at the same level or higher than the tank. 

Edited by DeepBass9
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Hi

There is one drawback or caution on a solar circulation pump not connected to a control circuit.

When it very cold <0 degrees and the water in the pipes can freeze. In a solar setup  without control the pump will not circulate if there is no sun. In this case you could damage your pipes. I would be hesitant to do this unless the temp never drops below 3 degrees.

Most modern solar water systems circulate the warm water from the geyser when the temp on the roof is < 3 degrees to combat any damage from freezing the water in the pipes.

For myself personally I would install a 12v solar pump and fit a transformer (220vac to 12vdc about1.5amps) from the existing 220vac input to the input of the pump with a 2amp  diode on the +12v positive  lead. I would also connect the solar panel with a 2amp  diode  on the +12v positive lead. You now have the best of both and you protected against icing up with controller  in the circuit (parallel). You will still have a problem when you are running without  the 220vac controller on very cold times without sunlight.

The controller normally only switches on the pump when there is a delta of 3 degrees or more (higher on the roof) that can set. This is I guess that a solar pump running when the water on the roof is cooler than the geyser will cool the water in the geyser and running the pump less saves electricity.

Edited by Peter Topp
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Quote

When it very cold <0 degrees and the water in the pipes can freeze. In a solar setup  without control the pump will not circulate if there is no sun. In this case you could damage your pipes. I would be hesitant to do this unless the temp never drops below 3 degrees.

If you are using lagged copper pipes this is unlikely to happen, especially if the pump is inside the roof.

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