Geyser timer solution for solar

[Lupus]

Cut off is at 60% right now on 1 x 5.12kWh battery. I want some protection for outages.

I'm still monitoring the settings. I have a very basic budget inverter so trying to find that sweet spot.

As long as I can managed to minimum 60% battery at all times I can still use grid for now.

60%?? That is a huge buffer, you're basically wasting 40% of the battery.

 

[denmendez65]

SBU is solar, battery and then utility, what are your cut offs set to?

Yeah but the stupid thing whether its set to SBU or SUB just keeps using the battery. They mind as well get rid of the setting.

 

[denmendez65]

60%?? That is a huge buffer, you're basically wasting 40% of the battery.

Ehem, says the guy that charges the battery when it hits 50% from the grid

 

[cavedog]

60%?? That is a huge buffer, you're basically wasting 40% of the battery.

For this size battery? Do you think so?

 

[Lupus]

Yeah but the stupid thing whether its set to SBU or SUB just keeps using the battery. They mind as well get rid of the setting.

Past 60% if that is the case what are the other settings? Like the cut over voltage and stuff, on my old one if it went below 48v it would cut over to the grid, so it's probably that which is causing an issue.
On the new one there are two settings one for stopping discharge at a certain voltage and then one to actually start charging from grid.

 

[Lupus]

Ehem, says the guy that charges the battery when it hits 50% from the grid

That was once and CP had a scheduled power outage and it looked like it was going to be a miserable day... Turned out it wasn't

 

[cavedog]

For this size battery? Do you think so?

So on the 1st of December we had a massive hailstorm. Damage and all that its in the storm thread. My neighbors have been without electricity since then. I plugged their extension in here at my place so they can at least keep the fridges running.

My concern with Tshwane is the super poor service delivery. Should there be an outage it takes a good few hours for them to fix/attend so I'm thinking that 60% with this entry level battery is a decent buffer.

 

[Lupus]

For this size battery? Do you think so?

Yup, if your demand is low enough it should hold for power outages.

 

[Lupus]

Ok on the inverter what are the following
Shutdown voltage
To Grid battery voltage
Back to battery Voltage

 

[denmendez65]

Past 60% if that is the case what are the other settings? Like the cut over voltage and stuff, on my old one if it went below 48v it would cut over to the grid, so it's probably that which is causing an issue.
On the new one there are two settings one for stopping discharge at a certain voltage and then one to actually start charging from grid.

You get:

SBU, SOL, UTI (I thought there was SUB but there actually isnt).

Low DC cut off voltage or SOC setting

Low DC battery stop discharging when grid available

SBU mode battery stop discharging % when SOC available.

These are the only ones that I see affect the switching to grid.

 

[Lupus]

You get:

SBU, SOL, UTI (I thought there was SUB but there actually isnt).

Low DC cut off voltage or SOC setting

Low DC battery stop discharging when grid available

SBU mode battery stop discharging % when SOC available.

These are the only ones that I see affect the switching to grid.

View attachment 1870345

I had a Mecer Axpert inverter for many a year and it is odd there isn't a SUB there, as the Mecer had SUB

 

[denmendez65]

You get:

SBU, SOL, UTI (I thought there was SUB but there actually isnt).

Low DC cut off voltage or SOC setting

Low DC battery stop discharging when grid available

SBU mode battery stop discharging % when SOC available.

These are the only ones that I see affect the switching to grid.

View attachment 1870345

This all does nothing. It just drains the battery till cut off and switches to grid therafter at night. It doesnt auto switch to grid when solar is gone/mppt is off which is what he had wanted.

 

[Lupus]

This all does nothing. It just drains the battery till cut off and switches to grid therafter at night. It doesnt auto switch to grid when solar is gone/mppt is off which is what he had wanted.

You can't do that on the Axpert clones, you can sort of do that with others like my Luxpower

 

[denmendez65]

You can't do that on the Axpert clones, you can sort of do that with others like my Luxpower

The only way i can see is if he gets an electrician to install a timer. A 30A capable one would be decent. Then he can use UTI. Leaves grid off during the day and at night the timer tuns mains on again to the inverter. You do miss out on the overload passthrough option though during the day.

 

[leon.davibe]

You get a relay that is powered by eskom and the geyser live is connected via this relay

So the moment eskom dies the relay opens and geyser can't work

Some relays have a switch you can slide , permanently on/off /auto so you can overide if needed

 

[cavedog]

You get a relay that is powered by eskom and the geyser live is connected via this relay

So the moment eskom dies the relay opens and geyser can't work

Some relays have a switch you can slide , permanently on/off /auto so you can overide if needed

I was thinking of this. Just thought if I can get a proper smart timer with this build in as a feature would be handy.

 

[cavedog]

You get:

SBU, SOL, UTI (I thought there was SUB but there actually isnt).

Low DC cut off voltage or SOC setting

Low DC battery stop discharging when grid available

SBU mode battery stop discharging % when SOC available.

These are the only ones that I see affect the switching to grid.

View attachment 1870345

I think I figured out why its still draining the battery.

It will only switch to grid when solar is unavailable. At 6pm its not generating anything but its not unavailable because it doesn't switch the mppt controller off yet. Mine only goes off like at 19:40 or so.

If I switch the solar dc breaker off. It immediately switched to grid in the SUB mode. As soon I switch the breaks back on the very little light there is is enough to trick the inverter to switch the mppt back on and it drains the battery to stabalize the load. It still pulls from grid but mostly from battery probably at 60& bat and 40% grid.

This also means because I have my solar priority set to CSO and battery charging at LBU that when eventually the MPPT controller gets switched off battery drained to 50 - 60% depending on my loads at the time.

Now program 20 is preventing grid charging unless I set the cut of voltage higher to make sure battery SOC is at around 80 - 90% because its waiting for the morning solar to charge the battery.

If I leave it like that it leaves me at risk when there is a power outage during the night so I let it grid charge the battery to 80 SOC at 5A just to be safe.

 

[Lupus]

I think I figured out why its still draining the battery.

It will only switch to grid when solar is unavailable. At 6pm its not generating anything but its not unavailable because it doesn't switch the mppt controller off yet. Mine only goes off like at 19:40 or so.

If I switch the solar dc breaker off. It immediately switched to grid in the SUB mode. As soon I switch the breaks back on the very little light there is is enough to trick the inverter to switch the mppt back on and it drains the battery to stabalize the load. It still pulls from grid but mostly from battery probably at 60& bat and 40% grid.

This also means because I have my solar priority set to CSO and battery charging at LBU that when eventually the MPPT controller gets switched off battery drained to 50 - 60% depending on my loads at the time.

Now program 20 is preventing grid charging unless I set the cut of voltage higher to make sure battery SOC is at around 80 - 90% because its waiting for the morning solar to charge the battery.

If I leave it like that it leaves me at risk when there is a power outage during the night so I let it grid charge the battery to 80 SOC at 5A just to be safe.

Change CSO to SNU, this will blend grid and solar when there isn't enough sun. Also charging at 5A on a 48v or 24v system? As that would be 240 or 120w so not a lot at all.

 

[denmendez65]

Change CSO to SNU, this will blend grid and solar when there isn't enough sun. Also charging at 5A on a 48v or 24v system? As that would be 240 or 120w so not a lot at all.

Remember the charging current is the sum of both pv and grid. He has to set the grid one low. Bulk should be from PV. If he wants to stick to 20A then 5A and 15A from PV would do the trick.

 

[Lupus]

Remember the charging current is the sum of both pv and grid. He has to set the grid one low. Bulk should be from PV. If he wants to stick to 20A then 5A and 15A from PV would do the trick.

Oooh right, but at night he can change that. But also don't remember the axpert being that dump as I had my solar at 60a and my grid at 30a and it handled it perfectly with blending what it needed where needing it.