An area for discussing the OutBack FLEXnet DC product.
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- My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.
Recently, I have decided to do some calculations on my battery bank based on my Flexnet readings. My bank consists of 32 Trojan T-105RE batteries. 225 amp hour 20 hour discharge rate. Total bank of 900 amp hours (45 amps per hour). Beginning with an FNDC SOC of 100% (calibrated after a full charge and verified by hydrometer several months ago (yes, load was present) I now get the following measurements: The battery capacity figures to 43200 watts at 48 volts. With a load of 11400 watts by the Optics RE, my SOC drops from 100% to 71% over a 5 hour time span (a draw of 47.6 amps at 48 volts per hour). Voltage never goes below 47.9 and is mostly above 48. After load is removed, voltage recovers to 49. By this calculation, my bank capacity is 39310 watts. That too measures out at 819 amps capacity at 48 v instead of 900. And my 24 hour load based on the 5 hours on battery works out to a load of 54720 watts over 24 hours. Taking the math further, my bank has a capacity of 17.24 hours to zero %SOC or 8.6 hours to 50% SOC. So my question is what would be the best way to assure accuracy of the SOC at this point since my load is more than the 20 hour discharge rate. Should I assume that after 30 months of battery use the capacity is really 819 amps and reset my FNDC/Mate 3S to reflect this, or re-calibrate my SOC, change my charge factor, etc. Also it seems to me that since the Mate 3S knows the date and time and the FNDC and shunts provide the power flow info and the user programs in the bank size, Optics RE should easily be able to add an on screen realtime countdown clock timer to any user entered SOC set point(s) as a way to provide users with an easy understanding of how much longer their batteries will power their current load unless receiving a charge somehow. Any ideas on this situation are appreciated.