Odd battery behaviour

SD_DRACULA · 09-11-2021 12:59PM

90% is the DOD.

The force charge value (10%) is actually the amount to charge by not when the battery reaches this SOC it seems.

I think it charges based on voltage and not on SOC, which makes the overdischarge value a bit useless.

I can see that lowest voltage is set to 44v when selecting the puredrive profile which it never got to.

reklamos · 09-11-2021 02:42PM

I think we can be sure that there is no definite answer as it varies between firmware versions and is very poorly documented. I do not think what we are seeing is force charge. I had it before and it actually logs it as a warning message 'ForceCHG-BMS' on the inverter. I have not seen this or any other message during this up and down behavior. What we are seeing is not documented or logs anything, probably some engineering 'feature' that Solis has added for some reason.

graememk · 09-11-2021 03:00PM

I am not sure what protocol the puredrive uses, but a lot of them use the SMA protocol.

SMA CAN protocol.pdf

There is parts of it where the BMS can actually request a charge too, from whereever, but its usually the Grid!.

How deep the rabbit hole do you want to run lol.

SD_DRACULA · 28-11-2021 11:08AM

Still happening and it is p***ing me off now.

Limit set to to 20% and keeps charging itself randomly i.e. wasting power.

Solis support are utterly useless so they won't do a thing.

I explained to them that if I go to the battery settings and just apply them again it stops doing it, in other words something is wrong plain and simple.

Quite obvious the inverter is reading the voltages wrong and panicking:

Was thinking of just setting the force charge to 1% instead of 10% but not sure what effect that might have if the battery has an actual low voltage

Jonathan · 28-11-2021 11:51AM

https://www.boards.ie/discussion/comment/118234647#Comment_118234647

We have same setup (Solis Inverter and PureDrive battery) and I haven't seen this happen. What f/w are you on?

SD_DRACULA · 28-11-2021 02:49PM

340022 and it never did this during the good months.

Also do you have anything hooked up to the AC backup port? I have my network gear connected to it so I assumed it might be this but I seriously doubt it.

Jonathan · 28-11-2021 04:45PM

https://www.boards.ie/discussion/comment/118235404#Comment_118235404

I'm on 350022. No, nothing connected to backup load.. though I might put a repeater up there as WiFi signal poor.

SD_DRACULA · 28-11-2021 06:18PM

Something dodgy going on for sure. I switched off the battery and all the AC backup connected stuff lost power (don't see why this happened as grid was still up, maybe stupid design).

Then turned on the battery and it said battery 0% (after being 20% before being switched off) it charged it to 10% and stopped doing the weird grid charging.

I also removed anything from the AC backup and switched the option off completely, it is pointless since in winter the battery is mostly drained and if a power cut happens it won't power anything anyway. At least I will know if it is related to that if it doesn't happen again.

I asked Solis for a remote FW update and never heard back.

irishchris · 28-11-2021 07:53PM

https://www.boards.ie/discussion/comment/118236187#Comment_118236187

The Solis is DC powered so once battery turned off if there is no solar PV then it will shut down irregardless of grid

SD_DRACULA · 28-11-2021 08:42PM

https://www.boards.ie/discussion/comment/118236723#Comment_118236723

Ok fair enough, that must have been what happened, I assumed if you have AC backup and grid connected it will continue to pull from grid to keep AC backup alive and only revert to solar/battery if they are available.

SD_DRACULA · 29-11-2021 02:17PM

So Solis finally got back to me with this:

yes so the battery management system (inside the batteries) would do estimations of SOC and after long periods of hovering at 20% odd they will be wrong.

Resetting it could help the batteries "find themselves".

Your batteries are not getting much energy at all. I would recommend either shutting them down during winter periods, or applying for a cheaper tariff and fully charging them during that period.

So it looks like my 20% and 48v readings from the readings of the inverter were bogus and the battery needs to be reset every now and again if not getting charged regularly. Shame that I fell for the smart meter scam and can't get day/night anymore

reklamos · 29-11-2021 03:03PM

This is strange, the capacity value is provided by battery through CAN. The inverter should not try to guess it. Maybe check your battery firmware. As @Jonathan has same battery. Try to compare them. My capacity never dropped to 0% when I was having these problems.

Since I have set backup to 30% it never done this. As you are using AC backup, set your soc to 20% and then set backup to 25 - 30%. Just make sure that you allow to charge from grid in backup menu. This way you will have 5-10% in case of power cut and also it will not allow battery to drop low. One thing to note, you may notice that the battery does drop below 30% during dark periods, this is normal. In my case once it drop to 27%, it charges from grid to bring it up to 31%.

SD_DRACULA · 29-11-2021 03:21PM

I cannot see any way to check FW of the battery, maybe some hidden Solis modbus registers?

Only seeing this:

And over discharge/force charge values are wrong also, not what I'm seeing on the Solis setup screen.

I'll leave the AC backup off for a while, see how it behaves.

Jonathan · 29-11-2021 04:15PM

https://www.boards.ie/discussion/comment/118239921#Comment_118239921

I think the difference is that I'm charging on night rate and discharging during the day. This means that the battery is never sitting at low SOC for long periods of time.

reklamos · 29-11-2021 09:29PM

https://www.boards.ie/discussion/comment/118240463#Comment_118240463

Oh yes, completely forgot about that.

https://www.boards.ie/discussion/comment/118240053#Comment_118240053

I do not think you will see firmware on Solis, you should get that from battery itself. At least this is how it is with Pylontech. But it is odd that the values set on inverter are not reflected in the app. As I wrote before you could try to set backup, configure to allow charge from grid and see if it actually works. If it does then you could use it as your safe guard as it seems that FOC do not work for you. The backup could work for you as FOC and SOC in one. It is a simple enough test. Let say your inverter is showing battery as 12% now. You configure your backup as 20% and once applied you should immediately see battery charging to ~20-22% and then stopping.

SD_DRACULA · 29-11-2021 09:54PM

Ok I enabled this, and set it to 20%

And it started charging, from 12%.

Question is, when it gets charged by PV to over 20%, will it send power to the house until it gets to 20% or it will save all for AC backup?

Ac backup is disabled now, so it should not go below 20% in theory

reklamos · 30-11-2021 08:29AM

20% is your bottom line it will allow to use 20-100% for house load. Once the battery discharges to 20% it should stop and keep it at that. The battery will lose charge over time even when there is nothing connected to it depending on room temperature. But that should be within 1% in 24hours. If it losing more than something is not right. As I wrote, inverter will allow to drop charge bellow 20% but in my case once it dropped by 3%, it started topping it from grid.

SD_DRACULA · 30-11-2021 10:14AM

Thanks for the suggestion, will keep an eye on it but I suspect it won't make a difference if what Solis said is true, if it starts to drift due to a low charge for an extended period and the only way to bring it back is to power cycle the battery.

That would indicate a crappy BMS inside the battery in my opinion.

reklamos · 30-11-2021 11:04AM

https://www.boards.ie/discussion/comment/118243482#Comment_118243482

It would be interesting to connect directly to the battery, log the data and see what it is doing. This could give better insight and maybe it is issue with BMS or comms between in battery and inverter. Unfortunately I can not help much here as I do not have puredrive. On pylons I do have rs485 and rs232 and have logging and see everything. The concerning thing is that battery goes to 0% as you noticed after powering it off/on. But even if inverter is not reporting properly the battery itself should shutdown before going that low independent of inverter.

SD_DRACULA · 30-11-2021 11:37AM

Basically the battery readings of the inverter are still a "mistery" according to Solis - which should not be the case

I don't think it was actually 0 anyway, if the voltage was to be trusted it got as low as 47.9 and the lowest limit is 44v for that battery according to the settings on the inverter when you select puredrive form the list - but yes it would be nice to be able to monitor the real battery values directly via rs485 or similar.

I asked them a while back how can the SOH go to 97% in less than 6 months and got an answer like that's still experimental/not an accurate science/it's an estimate and similar non-sense.

reklamos · 30-11-2021 01:25PM

Think what they have here is a half baked product. They have not figured out the whole protocol yet for batteries and just guesstimate. The battery profiles on Solis are a bit hit and miss, my original in old version was ok. But in new version the Min/Max voltage values were way too low/high.

SOH should be coming from battery BMS and not inverter. In pylons each battery would provide the SOH to master in the pack and then the master would provide SOH to inverter.

Deagol · 03-12-2021 10:46AM

I had a different issue with Solis and Puredrive battery. System would randomly start jumping between grid changing and discharging (i.e, was using grid to charge battery over and above what was available from PV).

Darrell spent a lot of time chasing it and eventually Solis set my battery to 'other' and manual settings. If you want a copy of the settings to try and see if it helps your issue?

SD_DRACULA · 05-12-2021 10:20AM

Sure paste them here, might help someone in the future as well.

graememk · 05-12-2021 01:16PM

https://www.boards.ie/discussion/comment/118261512#Comment_118261512

When in the other setting, How does the SOC behave?

S' · 05-12-2021 03:57PM

Does this look right? Exporting 1.5kW. Is there a max limit when charging the battery? I’d rather send power to Eddi than back to grid.

solis hybrid with pure drive battery

THE ALM · 05-12-2021 04:38PM

https://www.boards.ie/discussion/comment/118272235#Comment_118272235

Should be charging the battery before sending to the grid, you have plenty of excess.

Have the same setup and battery was charged by 12ish then it switched to the Eddi for over an hour. Unfortunately have the car with me today so have sent over 6kWh back to the grid 😪 😪😪 I'll be setting up a heater or something for the next time so that the excess will be used.

S' · 05-12-2021 05:49PM

Thought that. What firmware version are you on? I’m on 35. Checked settings and they look ok from what I can see.

Jonathan · 05-12-2021 06:50PM

https://www.boards.ie/discussion/comment/118272771#Comment_118272771

Behaviour should be as @THE ALM described. I have the same inverter and battery and haven't seen this before either. I'm also on F/W v35.

If it happens again, check the Solis app to see what Battery Charging Current Limit the BMS is reporting. Puredrives are capable of 100A charge/discharge, but might throttle that back if cold.

S' · 05-12-2021 07:48PM

Thanks, charging current limit looks set to 20A. Is it ok/possible to change this via the inverter settings?

Jonathan · 05-12-2021 09:01PM

https://www.boards.ie/discussion/comment/118273520#Comment_118273520

Yeah, you can change this via Advanced settings, Energy set, Battery select (might be slightly different, recalling from memory). What is the ambient temperature of the room in which your battery is located? LiFePo4 batteries cannot charge below 0°C.

Edit: Just to note that I have set charge/discharge limits here, but the BMS seems to override them.

Odd battery behaviour

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