mrd

Hi everybody! Greetings from Croatia... This is my first post on this forum. I've been reading you for a long time, and most of my solar issues over the years are being resolved by reading your experiences and advices. Thank you all for that & for your persistent enthusiasm. I'm completely off grid for 12 years now. Currently, I've three pip5048MK ( firm. 71.90, 2.40), (2 paralleled, one currently not connected). I've 5kWp solar panels on the roof, and additional 6 kWp in garage waiting to be installed. Besides this, I've recently replaced my AGM battery bank, with 6 pylontech US3000C batteries. For me everything works fine, I've crimped the cable as per instructions I read here on the forum. I've communication going between my 5048MK and pylontech batteries, but I'm worried with high voltage settings for program 26=53.2 V, and program 27=53.2V with program 5 = PYL. So I've changed the this to USE on both of my inverters, and set program 26=52.5V, program 27=51.8V, as Coulomb suggested in one of the threads. I personally think that the most troublesome setting in PYL profile is program 27=53.2 V, to keep such a high voltage throughout the day is insane, and will definitely prove to be detrimental to batteries over the time. I do not have ICC or any other monitoring devices such as Victron BMV 7xx. Anyhow, I wanted to repeat question from wolfandy;" Do the MPPT and the Pylon BMS need any kind of direct communication? Or does the MPPT change between bulk, float, etc purely based on the voltage that it reads?" Why? Because if it is purely voltage based decision, than since I'm off grid I really do not care about wrongly displayed SOC on my Voltronic devices, and overnight I never really discharge more than 20% of my batteries, and hopefully(?) they will over time update their firmware and change (or to enable user to change) value for program 26, and 27. But there is another solution to this. If there are some other benefits, that I do not see now, to have Voltronic BMS to Pylontech BMS direct communication, I can install third 5048MK unit, not have it connected with PV, set program 5=PYL and establish BMS to BMS communication. On two other units, that have PV connection, I would set program 5=USE, with program 26=52.5V, program 27=51.8V. In this layout, I have a BMS to BMS communication, inverters are in parallel, and they exchange information about SOC and other stuff that inverter with PYL setting is getting from Pylontech BMS, and I do not risk overcharging the batteries, since inverter with PYL setting do not have any PV connected to it. Only drawback of this solution is self consumption of the unit that is not connected to PV (and initial investment , but I already have it, and there is investment anyhow for monitoring device, on a plus side you have a spare inverter, and less strain on each inverter). To minimize self consumption , during winter nights, I can just turn it off (or even turn off two of the 5048MK units), and leave single inverter running. In the morning, as soon as light is bright enough, inverter with PV connected will work as charger automatically, and I would have to turn on manually the inverter without PV(but with BMS to BMS communication). I've put this idea to test, and it works as described above. What do you think? Is it crazy, or does it make sense?