Draigman

It does not require a DC element, it uses the existing element in the geyser. We are a 2 person household and I haven't used ANY Eskom to heat the water in over 4 months. There will be the odd spell when solar PV is poor so I just trigger the control unit to boost the water for one hour.

I went for the Elon 100. Works like a charm, only had to "top up" the geyser om two or three occassions using Eskom in the last 5 months. Now I am looking for a way to route the surplus power from the panels to a small invertor/charger when the water is up to temperature, no point in wasting the spare energy.

Before I went PV solar I installed the Elon 100, PV solar water heating system from Power Optimal. It did not require any changes to be made to my existing 150-liter geyser, only some wiring changes to the element. Inside the house I have a small controller that lets me define how I want to heat my water either via solar or top up the temperature from Eskom, or via an adjustable schedule depending on the time of day. The controller shows you when the water has reached the temperature set on the geyser thermostat. In over 6 months I’ve only had to boost the water temperature on around 10 occasions, for the rest of the time the sun and the panels have done the heating for me. Even on moderately cloudy days the water will heat up.

I understand you wanting to try and charge the batteries from the grid, especially if there is loadshedding due and the PV has not fully charged them. I did manage once to make the grid charge the batteries using the Economy Mode, I charged them for 1 hour so they were 100%. However when I tried to do the same thing yesterday after setting the start/end times, nothing happened. So I'm a little unsure what is going on.

I am on Eskom Rural Pre-Paid. SIngle phase 60Amp. I have a E460 meter witha P180 customer interface. I have 8 x 450 watt panels and 3.7Kw invertor and 7KWh Lithium battery. I have an Elon 100 PV water heating system powered by 3 x 450 watt panels. During the sunning days I am currently producing around 2.6KWh for around 5 hours a day from the panels and on occassions the meter shows me exporting to the grid, which is not supported by Eskom at the moment. However I found this quote on a local solar website and I cannot verify if this is in fact true. "Pre-paid electricity meters do not see the direction of the current, so when the customer has a solar system that at any stage is overproducing the power and start to push back to the grid – the pre-paid meter sees that as a standard electricity usage and bills one for the energy the PV systems produces." If it is then I am being charged for the units my system says is "feeding back to the grid" Does anyone have an knowledge on whether this is true or not?

Has anyone had any experience with this water heating product? https://geysergecko.co.za/

Thanks for you reply Garrie. The reason that I am not thinking of Vacuum tubes is 2 people I know had boiling water blowouts due to excess heating of the water. One of them also had to add and a addition 12 volts pump for some circulation problems. Also we get serious hail storms here in the raining season, I'm talking about tennis balls size hail that punches hold in windows, dented my Landrover 100 body work and dented outside metal tables. Not sure tubes could handle that! I'm not proposing a high capacity solar installation as i've done detailed load calculation for day and night consumption so I don't anticipate having a high degree of surplus PV power for the geyser. The PV direct solar systems I am looking at also claim to perform (at a reduced level) on days that are not FULL sunshine. The Elon system appears to offer the better cost option. https://www.poweroptimal.com/ I'm looking for people who have installed either this system or the geyersise solution to get their opinion.

I'm trying to reduce my Eskom usage. Using solar for the geyser is an obvious starting place. I done a bit of research and my options seem to be between PV solar heating and a Vacuum Tube system. The vacuum tube system seems a bit antiquated with all the new tech on the market. A couple of my friends used this system and they had some bad experiences with the water overheating. I see that there are a couple of players in the PV market, Geyserwise and Power Optimal. Both look good on spec and the only real difference I can see is that Power Optimals Elon system doesn't require any changes to made to the geyser element. Anyone have any advice to point me in the right direction?