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Solar Solis RHI inverter ignores minimum SOC setting

Discuss Solis RHI inverter ignores minimum SOC setting in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net

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Hi All,
Kit is Solis RHI 3.6k 5G inverter and two LG Chem RESU 6.5k combined with an LG RESU+ box, which is a CAN comms gateway and busbars. I have my SoC clip set at 20% with a grid top-up at 10%. The inverter ignores the 20% limit and regularly drops the batteries to 10%, which halves their life. The Inverter reports this behaviour and does it anyway, which is a costly behaviour.
What is your experience? Do you have a work-around?
Thanks for your time.
Mike
 
Why not phone tech support at Solis? I have had problems with a new Solis 5G inverter and it took 10 minutes to determine the problem was with the unit's firmware and to get Solis to send me an update stick.
 
Why not phone tech support at Solis? I have had problems with a new Solis 5G inverter and it took 10 minutes to determine the problem was with the unit's firmware and to get Solis to send me an update stick.
Good lead @Calson. I emailed because I wanted to send screenshots of settings and SolisCloud graphs. To their credit, they opened a case and stuck with it till resolution. The solution was as they diagnosed but it's not obvious so I'm posting here.

There was a good page on the USService solis site to set up Self Use with charge and discharge but I don't find it now, so I'm posting the pdf,
'Self-use timers Solis online manual'. Contrary to the article, LG RESU max charge and discharge are significantly higher current: my RESU6.5 are rated at +/-100A peak, although I have charge from grid set to 55A for the pair. Also contrary to the article, the inverter is smart enough to limit discharge to house load and not export to grid; mostly. It has the same inductive pickup on the same mains live tail as my bi-directional meter, so it really should be able to export until it sees export to grid then back off: and it gets this right nearly all the time.

Where it had been falling over was exporting from battery > load outside daytime. I have two windows set: 3pm - 6:30pm, Octopus peak import rate; and 9pm - mignight, enough for our stand-alone A/C to take the humidity and temperature down in the bedroom. For both, it would get to 90% SoC then quit on battery and import from grid. You can see this in the SolisCloud graphs Screenshot_20240531-095231_SolisCloud and Screenshot_20240531-095231_SolisCloud.

Solis Service told me this was because I had min SoC set to 90%, so I sent them a picture of Min SoC at set to 20%. We were both right, but the 90% SoC was under the 'Battery Backup' storage mode that was set to disabled/off, as per manual: set only one Storage Mode active.

So this turns out to be the answer: with 'Battery Backup' min SoC set to 20%, I get the peak time discharge and overnight house discharge I'm after, plus the cheap rate charge. Personally, I'd say this is a UI bug: having a setting not even visible in the mode I'm using over-ride the obvious and visible same setting in the Self Use mode.

Pictures Screenshot_20240609-085416_SolisCloud and Screenshot_20240611-212654_SolisCloud.
The set Octopus charge window ~1am - 3:30am can drop to single figures and, just occasionally, go negative to -2p or -3p. I have it set so that if it rains all day or is foggy, I still have battery over the peak import hours.

Hopefully, this helps someone else.
Regards
Mike
 

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Hello , unrelated to your problem , why does the solis app show the load peaking on the graphs when the pv is peaking ? I’d of thought load meant what the house was using .
You are correct: load is house in orange, PV generation is in yellow. If you're set to self-use then the order is PV > Load > Battery > Grid export. If your load exceeds your PV, e.g., washing machine, then the balance comes from the grid import: so load can exceed PV.
 
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