Hi there,
Pls accept my apologies if this issue has already been addressed on this forum.
Today I witness a strange operating behaviour from my Fox PV system.
Facts when PV strange behaviour happened:
- Cloudy morning;
- Low PV producing aprox 60W;
- PV operating mode=self use;
- Battery SOC was 16%;
- Battery Reserve Capacity set to 20%;
- System Min SOC set to 10%;
- Mode Scheduler disabled;
- No Force Time Charge periods set, charge from grid disabled;
- App FoxCloud v2.1.69 installed on my Android phone;
Since weather report showed the possibility of some clear skies between cloudy and rain showers, I decided to change Battery Reserve Capacity to 30% with the sole idea of profiting from some storage from PV generation when the skies cleared.
Logged into FoxCloud v2 app for changing Battery Reserve Capacity to 30% (battery SOC when I did this change was 16% due to a power outage that had ocurred yesterday).
The moment I did that change, system started charging battery from grid, which I did not expected it to do, considering the setup above (selfuse mode, Mode Scheduler disabled, no Force Time periods set)!
I enclose some screenshots.
What am I missing here?
Any sugestions are more than welcome!
KR,
Pedro
PV system installed:
- Fox inverter H1-3.0-E-G2-WL, version master=1.45, version slave=1.04, version ARM=1.31;
- NGStar EP5 battery, version BMS=1.008;
- AIKO Comet 2N 600W solar panels (x5);
- CHINT smartmeter DDSU666;
- GEYA G2r-63II ATSwitch;
By setting minsoc higher than your battery soc the battery by design will immediately begin a slow maintenance charge from grid as the minimum it is allowed to go has been passed. Minsoc and minsoc on grid should normally be left set at 10%
If you want to charge you battery from solar all you need to do is to set work mode as self use.
If you want to charge you battery from solar all you need to do is to set work mode as self use.
Hi Dave,
Thank you for your reply but I'm not quite grasping what you're trying to say so do accept my apologies.
I've had since day one the system working on self use mode. This setting I've not changed.
I've noticed that system was charging battery from grid when I changed minSOC on grid (Battery Reserve Capacity) from its original 20% to 30%, while battery SOC was indicating 16% (it went down from the original 20% to 16% due to battery feeding my electrical installation during a grid power outage).
When minSOC on grid was set to 20% and battery SOC was 16%, the system was not charging battery from grid.
Never messed with minSOC, which is 10%. I guess this is the lowest value my battery will discharge in case of backup operation due to power grid outage.
Still doesn't make any sense to me...
But thank you anyway for your reply, Dave.
Pedro
Thank you for your reply but I'm not quite grasping what you're trying to say so do accept my apologies.
I've had since day one the system working on self use mode. This setting I've not changed.
I've noticed that system was charging battery from grid when I changed minSOC on grid (Battery Reserve Capacity) from its original 20% to 30%, while battery SOC was indicating 16% (it went down from the original 20% to 16% due to battery feeding my electrical installation during a grid power outage).
When minSOC on grid was set to 20% and battery SOC was 16%, the system was not charging battery from grid.
Never messed with minSOC, which is 10%. I guess this is the lowest value my battery will discharge in case of backup operation due to power grid outage.
Still doesn't make any sense to me...
But thank you anyway for your reply, Dave.
Pedro
Fox are sometimes changing settings in the background from time to time, and this means what worked before... doesn't always work like it used to do before.
Meaning before if you set reserve at 30% it would TRY to reach this if it can, now it actually will PULL grid power to reach this.
This reserve value also means that as long as your system can detect GRID, it will NOT let the system use the battery unless it is above 30% it is meant to reserve battery for loss of grid AFAIK.
Meaning before if you set reserve at 30% it would TRY to reach this if it can, now it actually will PULL grid power to reach this.
This reserve value also means that as long as your system can detect GRID, it will NOT let the system use the battery unless it is above 30% it is meant to reserve battery for loss of grid AFAIK.
Thkx for your reply MaterialBarracuda48!
If what you say is in fact what's currently happening, I guess that should be something to be investigated checked by Fox developers since it's the complete opposite of what one might expect for having set the system's Mode Scheduler as disabled along side with having no Force Time Charge periods and charge from grid disabled as well, IMHO.
I don't want my PV system to auto charge my battery from grid unless I enable that option...
Every more so when I try to get the most from my solar production by choosing self use mode ...
Hey, but thank you for your input!
KR
Pedro
If what you say is in fact what's currently happening, I guess that should be something to be investigated checked by Fox developers since it's the complete opposite of what one might expect for having set the system's Mode Scheduler as disabled along side with having no Force Time Charge periods and charge from grid disabled as well, IMHO.
I don't want my PV system to auto charge my battery from grid unless I enable that option...
Every more so when I try to get the most from my solar production by choosing self use mode ...
Hey, but thank you for your input!
KR
Pedro
If you raise your battery reserver higher than SoC it will ALWAYS (i.e. in every generation of Fox inverters from the beginning) take power from grid if there is not enough PV (it's not a bug, it is by design).
If you are in interested in the detailed mechanics of it the BMS will do a maintenance charge at 5A DC to get the batteries above battery reserve, so to get the power it will charge at you have to multiply your battery volts by 5A.
MinSoC is the minimum setting you want your battery to go to, the manufacturer recommends this to be 10%
MinSoC on grid (now called Battery Reserve) is only set differently to minSoC if you have an EPS installed and need to reserve some power should the grid fail - the difference between this and minSoC is your ‘reserve’.
You normally only change these settings if you are trying to stop the battery discharge below a certain level and not go below it (hence the reason why the system charges it from grid if you set a higher level, think of it like a bucket that must maintain a level of water) - if there is adequate PV it would use that instead, if not it will be grid.
MaxSoC is usually used where you want to limit the maximum amount of charge that goes into the batteries - if you set a force charge with your MaxSoC set to 30% it will only charge to 30% either from grid or PV if available.
If your minSoC is set to 20% and your battery SoC is dropping to 16%, that suggests your batteries are not properly balanced and the batteries are passively balancing. This is because the SoC figure reported by the BMS is actually a virtual number and is calculated from the battery cell voltages but there are dozens of cells in the battery (hence the balance required).
With LFP batteries the cell voltage change is very flat for the majority of the discharge and falls rapidly at 10% and increases rapidly at >96% - this is when the BMS re-validates it’s estimate. The recommendation for battery balancing is that you do a 100% charge at least once a month, and this will correct your SoC accuracy.
If you are in interested in the detailed mechanics of it the BMS will do a maintenance charge at 5A DC to get the batteries above battery reserve, so to get the power it will charge at you have to multiply your battery volts by 5A.
MinSoC is the minimum setting you want your battery to go to, the manufacturer recommends this to be 10%
MinSoC on grid (now called Battery Reserve) is only set differently to minSoC if you have an EPS installed and need to reserve some power should the grid fail - the difference between this and minSoC is your ‘reserve’.
You normally only change these settings if you are trying to stop the battery discharge below a certain level and not go below it (hence the reason why the system charges it from grid if you set a higher level, think of it like a bucket that must maintain a level of water) - if there is adequate PV it would use that instead, if not it will be grid.
MaxSoC is usually used where you want to limit the maximum amount of charge that goes into the batteries - if you set a force charge with your MaxSoC set to 30% it will only charge to 30% either from grid or PV if available.
If your minSoC is set to 20% and your battery SoC is dropping to 16%, that suggests your batteries are not properly balanced and the batteries are passively balancing. This is because the SoC figure reported by the BMS is actually a virtual number and is calculated from the battery cell voltages but there are dozens of cells in the battery (hence the balance required).
With LFP batteries the cell voltage change is very flat for the majority of the discharge and falls rapidly at 10% and increases rapidly at >96% - this is when the BMS re-validates it’s estimate. The recommendation for battery balancing is that you do a 100% charge at least once a month, and this will correct your SoC accuracy.
Hi Dave,
Thank you very much for your explanation.
If that's how all Fox inverter work there's nothing more left to me than accept that fact as it is.
Again, I appreciate you taking time to answer me!
KR,
Pedro
Thank you very much for your explanation.
If that's how all Fox inverter work there's nothing more left to me than accept that fact as it is.
Again, I appreciate you taking time to answer me!
KR,
Pedro