Hi All

I have a Kodak OG5.48 (Axpert King) inverter with 2 x Pylontech US3000 batteries and 8 x 460W panels.

My 200lt electric geyser burst and I am now considering various alternative options.

My setup can handle a 2KW geyser element off the PV after the batteries are charged at around 11am - so the most cost effective solution I can think of is to get 2 x 150 liter geysers with the first fitted with a 2KW element and connected to the inverter, switch it on only when batteries are full and have it feed the (hopefully) warm water into geyser no 2 which is on the grid permanently.

This way the grid element is used as a backup and hopefully the thermostat will rarely switch on since I'm feeding it hot water, but I still have hot water on cloudy days and when having guests.

 

Any thoughts?

That sounds like a plan, I think it will work.  Mine is similar and also in series.

- Two geysers both hot and in series you can probably only heat once a day (not that it matters much with grid on 2nd geyser)
- My 200l lose about 2kWh per day with no water draw. Newer 150l geysers maybe 1.5kWh each or 3kWh total. (including pipes)
- Thus without water usage your grid consumption will still be 1.5kWh per day.
- Maybe set first geyser to say 65C and second one to 60C to minimise grid power usage.
- 3kW element will also work and draw from batteries, then allow enough time to top up batteries again.
- You will most likely use 8-10kWh per day to heat the first geyser so maybe not enough juice from 8 panel to fully heat the geyser.

I have a cheap flat plate collector on the first 150l geyser and heat the second 200l geyser from PV.
- Geyser, flat plate, pump and installation was about R10k
- Use no grid power to heat water.
- PV load is average 4kWh per day now. (down from about 10kWh)
- sometimes run out of battery capacity when cloudy days (set to 35% min) since I have to use PV 

Thanks, I'm going to give it a go and see. I will definitely set the temperatures as you suggest, so let's see how that works, and I'll post some results once I've been running a few days.