I don't own a six figure Digatron like EnerSys does so my test station had to suffice for the best accuracy I could attain.


My test station includes:


*Power Supply for Charging - Mastech 3050EX

*MPPT Controller / 80W Solar Panel - Rogue MPPT /Siemens Panel

*Victron BMV-602 - Ah/Coulomb Counter

*Multiple loads for discharging including constant current pure DC and inverted DC>AC

*PentaMetric Multi-Input Ah/Coulomb Counter & Computer Interface

*Fluke DVM


TEST METHODOLOGY:


#1 Determine actual 20 hour capacity for each of the batteries tested through 20 hour capacity testing. Both used and new batteries were tested. New batteries DO NOT deliver full rated capacity, until fully broken in, so as-is condition / 20 hour Ah capacity had to be determined.


#2 Program two Ah counters with the new 20 hour capacity and run load tests side by side with the SGBMU.


#3 Test SGBMU for accuracy during charging & discharging events, including solar, inverter loads and pure DC loads. Batteries were determined full when charge current fell to less than .5% of Ah capacity at target absorption voltage. (absorption charging voltages varied by battery type).


#4 Control room temperature to 75F to remove the temperature equations from the test calculations. (77F was just too damn hot)


#5 Re-test batteries for physical Ah capacity at the end of testing to note if changes were noted or the batteries declined in capacity during testing. Two batteries actually increased Ah capacity by approx 4% (new batteries not yet "broken in") and the rest were under 1% changes or well within my range of error resolution to even calculate.


#6 All batteries were equalized and serviced BEFORE being put into testing.


NOTE: This testing took approximately four months to complete. This is not quick or easy work if you want to get accuracy as close as you can for the equipment you have on hand. It was a real eye opener as to how inaccurate traditional Ah counters can be, in regards to SOC, if a new 20 hour rate is not established on a fairly regular basis.