frivan

Lithium batteries have cells balanced by the BMS. If charge settings are according to the battery requirement, leave equalization.

No. Your solar can only do 110A. Lower charging rates is good for your batteries. Do you have a generator?

I started with the thermometer on the element side but it only shows when the element is on: Going to try the output side of the gryser now.

Unfortunately from an asset price point of view, tech prices come down. I would start with the current price and linearly depreciate over the life of the equipment...10 years.

My solar system has an IRR around 23%. I added a second battery which has an IRR of about 18%. However, winter in Cape Town is not the period when the equipment performs. Any IRR above inflation is good but the higher the IRR, the more pain for Eskom. A solar panel can theoretically give 200% IRR. This father's day, spoil someone you love with the gift that keeps giving: a PV panel.

If you held at wrench to my head, I would set the inverter not communicating with the batteries to only charge to about 90% of SOC based on voltage.

Then don't parallel the batteries. Manage batteries and solar panels according to the connected loads.

Typically inverters that are paralleled manage operation and charging with communication between the inverters. The battery comms goes to the master inverter, the slave inverters get instructions from the master.

Ok, leave the Solis but only run the generator at night... elegant.

If you add a changeover switch (and disconnect the Solis), why isn't it a long term solution?

You could install a Sonoff temperature controller and set it both on time and temperature to cover most hot water generation.

The ZigBee switching works fine but turns out I have a normal bridge and I need a Pro bridge to show the "geyser temperature" remotely. The temperature probe on the end plate is not as effective as with an internal pocket. The wife wasn't happy when her second bath for the day ran cold.

A cheap system could set their 0% where others call it 20%. But then you would see poor energy per weight figures. Sungrow is a reputable player in the grid scale environment, I would buy their equipment.

Seems like Eskom will join us: Eskom breaks ground on R1.2-billion Lethabo solar plant https://techcentral.co.za/eskom-breaks-ground-on-r1-2-billion-lethabo-solar-plant/281908/ However, this could kill people at home if Eskom doesn't obtain permission from consumers!

Once you invest in solar, you want to maximise use of the solar system under normal conditions: use it for the geyser, cooking, etc. I like induction plates because they are very responsive. When the grid is out, you want to minimise draining batteries and then gas heating comes in handy. I use a Cadac cylinder if needed. I doubt if gas heating beats electrical heating on a price basis.

15 to 20 kWh per day is not much energy. I estimate you will be energy independant on sunny days with an 8kW inverter and 13kWh of batteries. Redundancy is a function of your essential loads and how long the sun doesn't shine.

I am using the R3 to switch the old 20A relay. The Geyserwise main unit would probably be installed at the geyser. But running a small wire for the display is not so bad. Financially the Geyserwise and Geyserwala is not better than my solution, specifically because I had some of the components already.

I am a big proponent of Geyserwise. But I have two issues where I am staying now: it is a rental property with a concrete roof. This makes installing Geyserwise problematic. There is an old geyser control box where I could fit a WiFi temperature controller (Sonoff geyser controller). However, getting WiFi on the roof will be a bit of a mission. I have a Sonoff ZigBee bridge that could communicate onto the roof. I have a ZigBee R3 that can switch the geyser's relay. I just need to buy a temperature sensor with a probe and a remote display. Then I should have all the functionality of a Geyserwise and more...right?

I would use the generator just to charge the battery. You could get a dedicated charger, a chargeverter or rectify the generator output onto a MPPT (unconventional). All of these would probably work better with a traditional alternator.

When did the battery charge to 100% before this? SOC calculations do go out after a few cycles. It could also be that one of the cells require balancing.

Looks like the Multiplus 2 and S6 can do what you want. It seems unconventional to have a composite three phase setup control a single three phase inverter. Why not replace the Multiplus inverters with the S6? While on generator, you won't be able to phase shift.

I don't think the Neutral In is needed, but check if earth leakages trip without it.

My proposal doesn't create a NE bond if Eskom is present at all.. But doesn't the inverter blend solar in phase with Eskom? Then it may still work.

Why can't you utilise the Eskom supply to operate a relay/NEB?

Option C. Build an off grid system as large as you want. You can use change over switches or chargers from the existing supply and it should still be seen as off grid.