Odd battery behaviour

SD_DRACULA · 19-10-2021 8:55pm #1

This is the second time I am seeing my inverter charging the battery to 20%, let's it go down down to 10%, charges it back to 20%, and so on, from the grid and without me telling it/setting it to that.

The min charge is set to 10%

Anyone else came across this and any idea how to stop it? I feel like it is putting needless tress on the battery.

SD_DRACULA · 19-10-2021 8:59pm

Inverter is a solis rhi-6k-48es-5g on FW 340022 and the battery is a 5kw puredrive DC

MAULBROOK · 19-10-2021 8:59pm

Its probably forced charging, I dont know how to change it. Give Darrell a call he should be able to sort it in seconds

jkforde · 19-10-2021 9:18pm

if you get it sorted could you update us for future reference!, I've got the same inverter.

have you tried a full system shutdown and restart?

SD_DRACULA · 19-10-2021 9:25pm

Both overdischarge soc and force charge at 10%, he doesn't know why, he said he'd get Solis to update it.

Thought it's doing it maybe because of the stuff I am running directly from the socket connected to the inverter but that makes no sense since it didn't do it until now.

I'll bump up the overdischarge SOC to 12% that might do it for now but shouldn't have to

SD_DRACULA · 19-10-2021 9:26pm

https://www.boards.ie/discussion/comment/118044879#Comment_118044879

Avoiding that since I got my network gear hooked up to the inverter directly and it's a royal pain to reboot everything.

jkforde · 19-10-2021 9:51pm

send your inverter & logger SN to euservice@solisinverters.com, they're very responsive (Radosław is good).

they'll log in and check, and may even update the firmware for you

SD_DRACULA · 19-10-2021 9:52pm

Set the overdischarge to 12% and it stopped doing it

I'll get onto Solis for that FW update too

reklamos · 20-10-2021 4:21pm

I have this with my inverter also. Firmware upgrade did not sort it out. What I did notice that it only happened during autumn/winter and seems to be happening in the mornings. It has never happened in summer. The inverter would force charge battery a bit and then discharge and would keep on doing that for a while and then would stop. The other way to stop it is to reboot inverter or the battery. I do not have an answer why this happens but it is battery related. It has happened at the end of September this year. I've pulled the graphs and one thing that does stand out is that the cell temperature has dropped to 17-18C . It seems like inverter is exercising the battery to raise the temperature but 17C is not low temperature. I am waiting for it to happen again but the temps are staying above 20.

You can see charge spikes start happening at 6am and then there is discharge and it keep repeating it.

SD_DRACULA · 20-10-2021 4:48pm

I'm not seeing the battery temp but the attic ambient temp was just above 20 degrees so in no way too low temp.

Stopped doing it as soon as I bumped the overdischarge to 12%.

I wonder if it somehow discharged to just under 10% and then it forced charged but then again why do it a few times.

reklamos · 20-10-2021 5:02pm

When I had this first time I also bumped the the values up but it did not stop it from happening again. The ambient room temp is also at 20 and you can see from the graph that some cells from other batteries are reading 20-21 degrees. That one battery is always reading lower temps compared to other two even though they are on top of each other. I would say the temp probes are not accurate. I am just waiting for temps to drop again but we've been blessed with unusually warm weather. There is no harm to talk to support but the last time I reported this, it went nowhere. Since I have logging now I just need more data. :)

SD_DRACULA · 20-10-2021 5:23pm

And it was also draining it with more than the house load at the time.

For example house load was maybe 500w and it was draining at over 1kw but then as soon as I bumped it up it went down to the real load value.

reklamos · 20-10-2021 5:26pm

Yes, exactly same behavior it was force discharging and dumping into grid or in my case into water diverter.

SD_DRACULA · 20-10-2021 5:36pm

Let's post here if we find anything, we have different batteries so that rules that out, must be the Solis

reklamos · 20-10-2021 5:49pm

Sure will do. Maybe need to pull more data from Solis. Not only that our batteries are different but also inverters. I see your one is 5G and mine is not and also we are on different firmware versions.

SD_DRACULA · 21-10-2021 9:37am

Come to think of it I think originally the overdischarge was set at 15% and then I set it to 10% myself.

SD_DRACULA · 05-11-2021 1:02pm

Started happening again and Solis support are getting thick with their replies:

Your system is setup exactly to do what its doing. Please contact your installer if you have further questions.

reklamos · 05-11-2021 1:05pm

Mine have not done it so far. I had no luck with support couple years ago also.

Mickeroo · 05-11-2021 3:21pm

I noticed mine doing that last winter during colder weather, I think it's to protect the battery. No idea if it can be turned off.

Does anyone know if there's a way to stop it going below 20% to begin with?

SD_DRACULA · 05-11-2021 4:43pm

Did it about 4 times today already

@Mickeroo you would go to the battery settings and change the overdischarge to 20% and hope for the best, inverter seems to be ignoring the force charge of 10% and charges at 12% anyway.

@Mickeroo do you have anything running off the AC backup, seems to happen to us folk which do

Mickeroo · 05-11-2021 6:47pm

https://www.boards.ie/discussion/comment/118123811#Comment_118123811

Nothing running off backup for me though it always shows it as consuming a few watts on the logger for some reason (110w at the mo).

I haven't had the forced charge happen yet though a very strange thing happened yesterday where my total consumption (since system install) doubled on the portal and my consumotion for the day was way more than what it actually was, It also no longer shows the battery percent in the little graphic (but the graph still has it). On the inverter itself everything looked fine so I guess it was an issue with the logger or something on ginlong's end.

All the total figures on the right are double what they were the day before (eg Total consumption is now 12MWh+ when in fact it was only 6MWh+ before):

reklamos · 05-11-2021 7:07pm

As I have not experienced it for a while and normally by this time of the year I would have had this multiple times, I think I have theory.

After reading/watching multiple articles/videos about LiFePO4 batteries I decided to bump my minimum SOC to 30% during dark period as we do not get enough sunlight to get it charged 100% anyway. According to the info that I've seen it is preferred to not leave batteries at minimum SOC for long periods of time. So I thought 30% is going to be a sweet spot. Now since this change I have not seen this charge/discharge behavior that I had last 2 winters. It is still a theory and will see how long it will hold. I will reduce SOC back to normal in spring. I'll let you decide if you want to try it. :)

SD_DRACULA · 06-11-2021 2:15pm

You could be right. I bumped it up to 15% and it stopped doing it straight away.

Was also chatting to the installer and he said to have grid charging turned on - this part doesn't make sense since surely this is part of the reason it pulls from the grid

Look at the battery voltage, the 4 spikes is when it bumped itself up to 22%, then went down to 12% and so on.

However WTF did it go down to 48v? I think the 12% SOC was total BS and went down past it, after the spikes stopped is after I changed overdischarge to 15% and it stayed at around 50v

I am guessing voltage/SOC don't quite line up and it knows the voltage is too low so it pulls from grid, maybe?

I think you're spot on with leaving a higher SOC in winter too

Mickeroo · 06-11-2021 3:03pm

Do you have a pic of where you can set the minimum SOC? Was up at the inverter yesterday and couldn't find it. I'd say I must have an older version of the software on there as I didn't see any settings for charging from the grid either.

reklamos · 06-11-2021 3:23pm

My understanding is that charge from grid is required for FOC otherwise inverter will not charge the battery when it dips below FOC.

SOC is calculated using Coulomb method and not Voltage method as voltage fluctuates greatly during charge/discharge and would be unreliable.

I have looked at battery voltage in my setup and it does dip below 48V during normal operations when there is a surge in power required from battery but it does recover. Looking at the stats now I did noticed that the last 2 times this happened the voltage dropped close to but not below 48V. When all is ok the voltage is ~49V. Since I have raised SOC to 30% the voltage is ~49.5V. As I wrote before this only happens during Autumn/Winter and my only logical explanation is that this is temperature related. Dip in temperature lowers battery voltage by ~0.5V close to 48V and that is enough for inverter to go into panic mode.

SD_DRACULA · 06-11-2021 8:01pm

https://www.boards.ie/discussion/comment/118127539#Comment_118127539

I think it is when you go to battery storage select, you select Self use, and maybe when you click into that you can set the values there. You're better off looking up the manual as they differ a lot.

https://www.boards.ie/discussion/comment/118127702#Comment_118127702

For me it is hovering at 50v with SOC 15% for today, 13-15c temp attic temp.

reklamos · 06-11-2021 8:17pm

https://www.boards.ie/discussion/comment/118127539#Comment_118127539

got to advanced settings>storage energy set>Battery select. Select your battery then as you apply seeting you will get options for SOC and FOC

reklamos · 06-11-2021 8:27pm

https://www.boards.ie/discussion/comment/118128841#Comment_118128841

I think Solis is over cautious. I have looked at my battery information and discharge voltage can go as low as 45V. The battery shutsdown only if it drops 44.5V. The settings on Solis is showing battery undervoltage is 46V but it has never dropped that low. Also when Solis starts this charge/discharge cycle it does not log any warning or errors.

SD_DRACULA · 08-11-2021 9:10pm

Did it again just now twice so definitely something wrong with the inverter I think (software I'd say)

So I had the overdischarge set to 15%, it bumped it from the grid to 25% then back to 15% twice.

Then I went to the inverter and clicked 15% overdischarge again, saved and it stopped doing it.

It did think the SOC went to 1% which is BS, as the voltage went no lower than 47.1v so the calculation must be way off and then it charged from grid to "10%" and voltage 51.5

Something to do with wrong voltage/SOC

SD_DRACULA · 08-11-2021 10:04pm

If battery not charged for long time but got charged to 70% today from PV....

reklamos · 09-11-2021 12:46pm

Interesting. Yuor inverter bumps it up by 10%, mine only bumps it by 1% then force discharges then does it again.

Thankfully it is still has not done it since I've raised ti to 30%. Before it would do that at least once a week. What is is DOD for pure drive batteries? I could not find that info on their page.

Odd battery behaviour

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