New installation, been in for just over a week, overall we're very happy with it, but I've noticed a weird dip in the logs that seems to happen every 3 hours, for exactly 30m. It's much easier to see overnight with an empty battery, when there's no other activity going on to muddy the waters. It reads as a drop to -0.5kw in output power, with a corresponding increase in charge power and grid consumption. A typical chart looks like this:
-0.5kw dip in output power for 30m every 3hrs
Hi all - hoping someone can help figure out what's going on here.
New installation, been in for just over a week, overall we're very happy with it, but I've noticed a weird dip in the logs that seems to happen every 3 hours, for exactly 30m. It's much easier to see overnight with an empty battery, when there's no other activity going on to muddy the waters. It reads as a drop to -0.5kw in output power, with a corresponding increase in charge power and grid consumption. A typical chart looks like this:
Anyone have any idea what this is all about?
New installation, been in for just over a week, overall we're very happy with it, but I've noticed a weird dip in the logs that seems to happen every 3 hours, for exactly 30m. It's much easier to see overnight with an empty battery, when there's no other activity going on to muddy the waters. It reads as a drop to -0.5kw in output power, with a corresponding increase in charge power and grid consumption. A typical chart looks like this:
Anyone have any idea what this is all about?
H1-6.0-E inverter
Fox Energy Cube 5.8kWh
13 x Evo Super Max Series 455 (5785w)
Fox Energy Cube 5.8kWh
13 x Evo Super Max Series 455 (5785w)
-
Dave Foster
- Posts: 1298
- Joined: Thu Oct 13, 2022 7:21 pm
I think what you are seeing is because the battery is discharged and at minsoc, which is it’s normal behaviour.
The inverter/BMS always takes some power off the batteries to keep it from going into standby, depending on your system this can be anywhere from between 30-100W constant discharge.
When the batteries reach minsoc, the discharge still occurs and what you are seeing is the inverter powering up it’s charger at low power (500W) to maintain your batteries at minsoc - it’s more noticeable at night because during the day it’s taken from your solar generation.
In effect rather than the inverter drawing power from the grid continuously to maintain itself, the batteries provide the power and when at minsoc rather than a steady draw they charge at 500w for a short period, then slowly discharge and repeat until solar starts to charge them (or you charge from grid).
On a normal solar day in summer you would expect the batteries to be full and then run your house overnight so you’d never see this happening. It’s only in winter when you don’t have enough solar to charge the battery during the day that you might expect to see this.
What is your minsoc set to ? - with a 5.8kw battery pack and minsoc at 10% you’ll have around 5.2kw usable which if full would likely get you through the night (assuming you don’t flatten them with cooking dinner). What many people do in winter is to get themselves on a mixed tariff supply such as Octopus GO or Economy 7 - these provide several hours overnight of low tariff energy and you can set the inverter to charge the batteries during this period which gives you the benefit of cheap rate power and starting the day with ‘cheap rate’ charge in your battery.
The inverter/BMS always takes some power off the batteries to keep it from going into standby, depending on your system this can be anywhere from between 30-100W constant discharge.
When the batteries reach minsoc, the discharge still occurs and what you are seeing is the inverter powering up it’s charger at low power (500W) to maintain your batteries at minsoc - it’s more noticeable at night because during the day it’s taken from your solar generation.
In effect rather than the inverter drawing power from the grid continuously to maintain itself, the batteries provide the power and when at minsoc rather than a steady draw they charge at 500w for a short period, then slowly discharge and repeat until solar starts to charge them (or you charge from grid).
On a normal solar day in summer you would expect the batteries to be full and then run your house overnight so you’d never see this happening. It’s only in winter when you don’t have enough solar to charge the battery during the day that you might expect to see this.
What is your minsoc set to ? - with a 5.8kw battery pack and minsoc at 10% you’ll have around 5.2kw usable which if full would likely get you through the night (assuming you don’t flatten them with cooking dinner). What many people do in winter is to get themselves on a mixed tariff supply such as Octopus GO or Economy 7 - these provide several hours overnight of low tariff energy and you can set the inverter to charge the batteries during this period which gives you the benefit of cheap rate power and starting the day with ‘cheap rate’ charge in your battery.
Ah that makes sense Dave, thanks.
We're just in the process of switching to Octopus, and as soon as the switch is complete we're planning on going right onto the Flux tariff, so exactly as you say we'll be charging from the grid at the cheap rate between 0200-0500. I've set 10% minsoc, so my hope is that combined with what solar we do get should be enough to see us through (even allowing for cooking dinner!)
We're just in the process of switching to Octopus, and as soon as the switch is complete we're planning on going right onto the Flux tariff, so exactly as you say we'll be charging from the grid at the cheap rate between 0200-0500. I've set 10% minsoc, so my hope is that combined with what solar we do get should be enough to see us through (even allowing for cooking dinner!)
H1-6.0-E inverter
Fox Energy Cube 5.8kWh
13 x Evo Super Max Series 455 (5785w)
Fox Energy Cube 5.8kWh
13 x Evo Super Max Series 455 (5785w)
Just recently had my inverter upgraded from 1500kW to 2kW - believed it to be undersized. I have been recording the graphs, two of which is attached and noticed I am now getting negative zero load readings - which was not the case before. Can anyone explain what could be causing this.. and is it safe or a problem?
I do appreciate your assistance so thank you in anticipation.
Fox ESS series 2kw
Solar array 2kw
No batteries.
I do appreciate your assistance so thank you in anticipation.
Fox ESS series 2kw
Solar array 2kw
No batteries.
- Attachments
-
-
-
Dave Foster
- Posts: 1298
- Joined: Thu Oct 13, 2022 7:21 pm
It isn’t a problem, it can happen when the load switches quickly such as a kettle turning off, or an induction hob - it can also be a cloud effect when the solar goes from a low output to high output suddenly.
The inverter has to react and is constantly doing the maths between load / export and it’s solar tracker and sometimes because of a small lag in one of the sensors it causes a negative peak - it’s usually for a very small duration (<6 seconds) but if it is caught when the cloud takes it’s 5 minute update it looks to be longer than it really was.
It does seem to get more apparent on the larger the inverter and much worse on the hybrids.
The inverter has to react and is constantly doing the maths between load / export and it’s solar tracker and sometimes because of a small lag in one of the sensors it causes a negative peak - it’s usually for a very small duration (<6 seconds) but if it is caught when the cloud takes it’s 5 minute update it looks to be longer than it really was.
It does seem to get more apparent on the larger the inverter and much worse on the hybrids.
