I have a roof top solar geyser, its always off. We only turn it on during winter once or twice a day. Gas cooking only and we don't use the oven at all. washing machine is used during the day. Pool pump is turned on when I have enough sun.It depends a lot on your solar forecast and usecase. Schedule your batteries to use PV to recharge as much as possible, then look at your historical usage to determine what SOC you need at what time of day. You may need to play around with geyser timers, adjusting when you cook/do washing/bath etc accordingly.
This is what my settings look like for reference:
Battery shutdown: 20%
Battery restart: 40%
Low battery: 30%
Grid Charge: Enabled for 20:00 - 00:00 and 00:00 - 06:30 to maintain minimum levels.
Time / battery:
00:00 - 06:30 | 30%
06:30 - 11:00 | 60%
11:00 - 13:00 | 100%
13:00 - 17:00 | 80%
17:00 - 20:00 | 60%
20:00 - 00:00 | 40%
That being said I am busy revamping my schedule entirely, as I want it to only charge from the grid if absolutely necessary and also if there is an upcoming LS slot where I will need to run on batteries when there is no incoming PV.
Basically this is what the logic will be(and it is a WIP):
If no sun and ~60min prior to a LS slot and battery SOC is below 40%, charge battery to 70% and turn off the geyser.
If sun present (>1500w) and SOC is below 50% and ~60min prior to a LS slot, turn off the geyser
If sun present (>1500w) and SOC is above 80% and ~60min prior to a LS slot, turn on the geyser if current time is after 09:30
If there is a LS slot happening between 18:00 and 08:00, turn off geyser and set SOC to 100% even if charging from grid is required.
I also have a button in HA that I can klap to max out the SOC and override the above rules if I see we are entering a LS slot that I somehow missed, or anticipate heavy usage and need the battery to be full for this reason.
Usage is pretty much for lighting, cameras, network and computers. Hence the standby usage of almost 500Watts average throughout the day.
last month we haven't used any eskom power except the 20 watts the inverter uses to keep the line active... so around a unit per day.
My worry is with the days getting shorter now, I might run out of battery in the morning at around say 5 or 6am and with no solar or eskom I would be without power.


