V
Although my batteries are Rolls and you do need to check with the manufacturers with regard to the charge settings for your specific battery make here is my operating method with the SI off-grid. Experience gained with progressive combinations of - generator only, generator/PV and generator/PV/wind. This is a 24v system but the principles should be the same.
Float setting - 2.26
Boost setting - 2.55
Full charge and Equalisation setting - 2.55
The SI will usually Boost charge around every 24 hours for 1.5 hours. The SI trigger for this is either nominal throughput or SOC below 70%. SOC at the end of Boost is entirely dependent on starting SOC. When PV and/or Wind is in excess of demand the periods between Boost increase correspondingly. I imagine every system will behave a bit differently according to the attached generation and usage - we effectively use ours as a buffer most of the time.
Yes, this is how the Boost seems to work for me too. Only the frequency is different but consistent with the SOC you are talking about.
I have used the SI Full and Equalisation defaults of 5 and 10 hours every 14 and 180 days (and some variations on those defaults) but now operate both of these charges manually as required. Although the defaults worked fine I find that it is more convenient (and efficient) to activate these charges for periods of excess renewable generation manually - something auto cycles can not be guaranteed to achieve. Currently I rarely use Full charge and usually activate an Equalisation every 4-6 weeks. I did find that it is beneficial to have summer and winter settings if using auto activation with shorter cycle periods during the winter mainly to compensate for the reduced capacity of the battteries with temperature change.
My version of the SI doesn't give me an option to manually do the full or boost charges, only the EQ. But the SI asked for the Boost two days ago and I knew it would be sunny today so I waited and it worked well. I could do the same with the full charge and give it some generator time in the evening to get the starting SOC higher.
When the SI is not in Boost, Full or Equalisation mode it is obviously in Float. The voltage setting I use is as high as I can get it to operate before gassing starts.
Once my PV was in I did similar - I increased the float to 2.33 per cell and found that the batteries were gassing every day. I decreased it back to 2.25 which was recommended by Paul Byrne who supplied my batteries and by SMA. Just for info, Paul is not the installer, nor is he anything to do with the problems I had of incorrect settings. He has been fantastic and hugely helpful. A knowledgable person who has no problem saying 'I don't know' if he doesn't know the answer.
I think that the various terminologies used for battery charging can be a little misleading. Essentially SMA Boost, Full and Equalisation are all combined, sequential Bulk and Absorption phases just with different triggers and durations. I have heard Boost charge referred to as "passive equalisation".
Understood. Thanks. Except for the phrase Passive Equalisation

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The SI SOC number is a complex mixture of voltage and throughput calculation and at least the SOE also needs to be referenced if using it as a benchmark when assessing the charging performance.
Sorry to be so naive, but SOE? I know about SOC and SOH, but E? Is that equalisation?
My batteries are now well into their fourth year and showing no obvious signs of reduced performance although there must be some. I trust the general SI charging regime but it does need to be set up for each specific system.
Do you do the SG measurements on them or Multimeter, or both?
Thank you so much for all of this detail.
V.