Forced Charge charging beyond cut off

[jbeearr]

Hello,

Last night I charged my battery up for the first time.

I use Mode scheduler and set:

00:30-07:30
Forced Charge
Charging cut-off SOC: 80%
Charging Power from Grid 10500.W (default)
Charging from Grid: enabled

(It is on self-use the rest of the time)

I can see that System MaxSOC is 100%

When I woke up, it had charged to 100% and not 80%.

I wanted to do this as I won't be able to sell to the grid for a month or so, so I wanted to allow for solar generation to go to the battery.

What am I doing wrong?

I have only just set up my battery and are new here. I did try my best to find this answer in the forum so apologies if I missed an answer elsewhere.

Thanks!

John

[MaterialBarracuda48]

Probably in the first instance, you should turn off any charging, and let the Sun charge the battery each day for free.
Once your export MPAN is setup, I would then setup overnight charging.

Mop up the free energy whilst you cannot export, do some energy intensive tasks while you have the Sunshine; hot dishwasher load/washing machine/hot water cylinder and so on.


The 80% SoC value being ignored is nothing new, some firmware bugs exist, with regards to that behavior.

[jbeearr]

Ah okay. Good to know it's a bug and I wasn't just being stupid!

Thanks for the advice. Yes, looking forward to being able to export!

Thanks!

[MaterialBarracuda48]

If your future plans are for max solar export, then you will need to program an overnight charge and then have system run in 'Feed-in' mode going forward.

PV -> Load -> Export -> Battery if export limit is breached.

Example, you have 6kW of PV being made
A 1kW Load
Export limit 4kW

This would mean 6kW of solar would lose 1kW to house load, leaving 5kW.
Then 4kW goes to grid and your pocket.
1kW then goes to battery (or is clipped if battery is full)


This is how I run my system, and you may also need a little room in your battery to mop up the overspill if your export limit is not that high.

[evilbunny]

Charging cut-off SOC: 80%

Did you set that in the schedule or in the global section?

[jbeearr]

That is in the schedule. I don't want that in the global setting because I want to allow the possibility of the solar power to charge above 80%.

Essentially I want a 'top up to this percentage overnight on the cheap rate to get me through the day without using peak rate'

I am in the UK so definitely not enough solar power at this time of year.

[jbeearr]

If your future plans are for max solar export, then you will need to program an overnight charge and then have system run in 'Feed-in' mode going forward.

PV -> Load -> Export -> Battery if export limit is breached.

Example, you have 6kW of PV being made
A 1kW Load
Export limit 4kW

This would mean 6kW of solar would lose 1kW to house load, leaving 5kW.
Then 4kW goes to grid and your pocket.
1kW then goes to battery (or is clipped if battery is full)


This is how I run my system, and you may also need a little room in your battery to mop up the overspill if your export limit is not that high.

Thanks! That's really useful for when I get it up and running. Especially in the summer too

[evilbunny]

That is in the schedule. I don't want that in the global setting because I want to allow the possibility of the solar power to charge above 80%.

That setting only effects grid charging, but overnight the inverter should have been limited by that unless it mis-guessed the SoC from battery voltage or Fox made another change that broke things.

I just checked and there is 2 SoC settings when force charging, maxSoC and force charge cut off SoC.

I am in the UK so definitely not enough solar power at this time of year.

We don't have enough panels for self sufficiency in winter either.

[EcoByte]

I managed to set a Force charge cut off using the web interface rather than the app. It allowed me to limit both Max SOC and FCSOC to 80% and this worked for me...until I used the app to make other changes and then it reverted to 100% Too many bugs in the mobile app at present.

[MaterialBarracuda48]

I managed to set a Force charge cut off using the web interface rather than the app. It allowed me to limit both Max SOC and FCSOC to 80% and this worked for me...until I used the app to make other changes and then it reverted to 100% Too many bugs in the mobile app at present.

I just made a post about the alternative methods a moment ago!

The App I find from the past stores settings and loves to push these each time it gets opened. Months ago my son was using iPhone version and I am on the Android version, I worked out each time he opened his, it screwed up the scheduler, I was getting random events like charging from grid at peak times as he opened app at work.


Link for OP and anyone else that follows the thread.
viewtopic.php?p=14637#p14637

[jbeearr]

This is all really helpful. Thank you.

So do you think that changing Max SOC. to 80% just in the 00:30 - 06:00 slot here will work as I intended (in photo below).

Trying to get avoid any exporting to the grid while only paying for night rate until I can get paid for export. i.e charge just enough overnight so that the battery only just gets to 100% in the middle of the day from solar, to give as much as possible in the evening.

[MaterialBarracuda48]

How big in kWh is your battery?
How much PV do you have in terms of kWp?
Do you have a G98 or G99, if latter, what is your export limit?

As for charging to 80% on a Sunny day you are going to be sending a lot to the grid, so you are going to start looking at Solar forecast websites potentially, or winging it by looking at forecast for the next day

Example, it is going to be Sunny, so you can cancel the charge or set 40% or some such for now.

[jbeearr]

How big in kWh is your battery?
How much PV do you have in terms of kWp?
Do you have a G98 or G99, if latter, what is your export limit?

As for charging to 80% on a Sunny day you are going to be sending a lot to the grid, so you are going to start looking at Solar forecast websites potentially, or winging it by looking at forecast for the next day

Example, it is going to be Sunny, so you can cancel the charge or set 40% or some such for now.

10 kWh battery and inverter rated to 5 kWh - it is an EVO 10-5-H
11 solar panels rated to 450W (so I think 4.95 kWp?)

I will explain a bit more my situation.

eg.
Yesterday I generated 4kWh solar (it was very cloudy all day and will be for the coming days)
House used about 15 kWh
Battery started at 6am at 100%, discharged for breakfast, went back up a bit as the solar kicked in (peaking at 93% at 10:30am, and then fell to 10% in the evening (using a little of grid at peak).
This was pretty much best possible for yesterday I reckon. All electricity was either solar or night cheap rate.

But on a sunnier day, I would want to start with less charge in the battery so the battery never hits 100% during the day (or it is so sunny such that I don't charge overnight and then can export)

Which is why I want to be able to control the charge for now while there is very little sun and I don't have an export tariff.

Does that make sense?

[MaterialBarracuda48]

I understand what you are trying to achieve right now, before you export goes live.
Hardest part is guessing how much charge to put in each night for now.

Two things you can really do at this point.
1. Stick inverter into 'Feed-in' mode and keep your charge overnight running to 100% SoC.
You will export energy, but you can try to use as much as possible in meantime.

2. Check the forecast for the following day, and each night adjust the charging times (if it keeps ignoring SoC values)
So rather than 00:30 to 06:00 you could shorten the charging time window down to say 1hr only or 90mins etc.

Best to choose what you wish, and find easier.

[jbeearr]

Yep, that is a good idea!

Thanks again for the advice!

[MaterialBarracuda48]

11 solar panels rated to 450W (so I think 4.95 kWp?)

Yes you have that correct, do you have a G98 or G99 certificate yet?
Trying to work out your Export value, G98 should be 3.68kW, G99 can be whatever they wish!

[EcoByte]

This is all really helpful. Thank you.

So do you think that changing Max SOC. to 80% just in the 00:30 - 06:00 slot here will work as I intended (in photo below).

Trying to get avoid any exporting to the grid while only paying for night rate until I can get paid for export. i.e charge just enough overnight so that the battery only just gets to 100% in the middle of the day from solar, to give as much as possible in the evening.

firefox_6JQkFOmAuq.png

If that doesn't work, try changing Max SOC to 80% as well. I think I had to change both in the Force Charge schedule, but I can't remember now

[evilbunny]

so you are going to start looking at Solar forecast websites potentially

That'd be my advice, although things can change within 30mins at times so fresh forecasts/data is a must.

I'm checking both https://solcast.com.au and https://forecast.solar but Solcast seems more accurate most of the time for me.

When working out the azimuths, both sites differ and is very confusing.

[jbeearr]

I managed to set a Force charge cut off using the web interface rather than the app. It allowed me to limit both Max SOC and FCSOC to 80% and this worked for me...until I used the app to make other changes and then it reverted to 100% Too many bugs in the mobile app at present.

Update - this worked!

In mode scheduler on the web interface I changed, just in the night time schedule , both cut off and max SOC to a lower percentage and it only charged to that overnight.

App doesn't even say anything about the maxSOC just for that part of the schedule and the System maxSOac is still 100%

Yes, just started looking at Solcast.

Waiting for the export details from the installer, but that will be simpler as at least if the battery does get to 100% I will actually get some money for it.