Digiwit Posted August 5, 2019 Share Posted August 5, 2019 Hi All, I am new to this forum, and just installed a solar system at home. Its running well, but I am not 100% sure if I have configured the system correctly, specifically with regard to charging current. The system consists of the following: 18 x 370w Mono panels, 3 x (48v) Axpert MKS 5K in parallel , 16 x 100aH Gel's The panels are wired 2 in series, and 3 strings on each Axpert I currently charge the batteries from Solar Only, and most of the time I manage to get through the night with a back to grid voltage of 48v. My main concern in the charging current, I have seen the system charging on Solar at 75A, is this OK, for the batteries I have? Limited battery spec below. Also should Gel Batteries be Equalized from time to time? Are the Equalization settings below correct? If anyone notices issues with the existing setup any advice would be greatly appreciated. Many thanks! Quote Link to comment Share on other sites More sharing options...
Coulomb Posted August 5, 2019 Share Posted August 5, 2019 (edited) 6 hours ago, Digiwit said: My main concern in the charging current, I have seen the system charging on Solar at 75A, is this OK, for the batteries I have? Your batteries seem to be rated for a maximum charge current of 0.25C. You have 4 strings of 4 12 V modules, so your battery is 400 Ah. So 0.25C would be 100 A. So 75 A is within that. However, 0.25C is considered rather high; most suggest 0.15C (that would be 60 A). So from that perspective, it's a bit high. Also, 4 strings are very hard to get the current to share equally, so I would not go as high as 100 A total. Your settings are presently 50 A per inverter; that means a total of 150 A (if your PV was capable of it; it can supply well over 130 A). I suggest that you drop that to 30 A per inverter. Perhaps even 30 on one or two, and 20 A on the other(s) (for a total maximum charge current of 80 or 70 amps). Towards summer as the angle of your panels approaches the ideal, your panels will probably put out more than the 75 A you are seeing now. Quote Also should Gel Batteries be Equalized from time to time? No, not the way flooded cells should be equalised. However, you have selected an equalising voltage of 57 V (14.25 V per 12 V module), which is well within your battery's limits, especially in winter. I'm no lead acid expert, but I believe that your settings for equalisation would be fine. Edited August 5, 2019 by Coulomb 60 A per inverter → 50 A per inverter. Quote Link to comment Share on other sites More sharing options...
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