I thought I would note some voltage sag figures .. Used 4 batteries
Trustfire Flame 18650
Yezl 18650
Xtar 2200
Ultrafire BRC3600
I discharged at 1A - 500mA and 200mA to see battery voltage sag at various loads ..
Measurements were noted at 15 seconds , 30 seconds and 60 seconds ...
@ 1A the largest amount of battery sag noted was to 3.72v , that's almost half a volt [ 0.46v of sag ]
Brand | Starting Voltage | 1A Discharge |
Trustfire | 4.21 | 3.81v-15sec, 3.78v-30sec, 3.75v-60sec |
Yezl | 4.2 | 3.93v-15sec, 3.9v-30sec, 3.89v-60sec |
BRC 3600 | 4.18 | 3.73v-15sec, 3.72v-30sec, 3.72v-60sec |
Xtar | 4.19 | 3.9v-15sec, 3.9v-30sec, 3.87v-60sec |
Brand | Starting Voltage | 500mA Discharge |
Trustfire | 4.19 | 3.99v-15sec, 3.99v-30sec, 3.96v-60sec |
Yezl | 4.19 | 4.05v-15sec, 4.02v-30sec, 4.02v-60sec |
BRC 3600 | 4.19 | 3.87v-15sec, 3.87v-30sec, 3.87v-60sec |
Xtar | 4.2 | 4.08v-15sec, 4.08v-30sec, 4.06v-60sec |
Brand | Starting Voltage | 200mA Discharge |
Trustfire | 4.19 | 4.11v-15sec, 4.11v-30sec, 4.11v-60sec |
Yezl | 4.2 | 4.16v-15sec, 4.15v-30sec, 4.14v-60sec |
BRC 3600 | 4.19 | 4.11v-15sec, 4.11v-30sec, 4.11v-60sec |
Xtar | 4.19 | 4.14v-15sec, 4.14v-30sec, 4.14v-60sec |
Updated = Going the other way ...
Time to charge the batteries ...
Ive gone with the BRC3600 [ since this is time consuming ]
1A charge rate :
Batt resting Voltage = 3.62v [ after 1A discharge to 3v ]
Put on the charger , and after the charger reached 1A the voltage reading from the charger was 4.06v , if its the battery voltage , then thats a 0.44v increase .
[ There must be some voltage overhead - higher charge voltage than batt voltage , but what is it ? = will have to test for this as time permits ] [ buy data logging MM ]
500mA Charge
Batt resting Voltage = 3.64v [ after 1A discharge to 3v ]
Put on the charger , after charge current reached 500mA , the voltage reading from the charger was some 3.96/7volts , a 0.32v increase
200mA Charge
Batt resting Voltage = 3.66v
Put on the charger , after reaching 200mA , voltage reading was 3.85v , after 60 seconds 3.83v and after 90 seconds 3.82v [ well that was different , voltage actually dropping under charge , one possible reason comes to mind , = the battery had been rested after discharge - takes a long time to charge @ 200mA - so wanted to do most of it while I slept - so it may have initially resisted charging [ more than usual ] , but as the current flowed into the battery the resistance dissipated and the voltage dropped ] = I could be wrong ! [ so related to storing a discharged battery for several hours - Like 10 ]
Charge VS Discharge
1A - Discharge = - 0.46v , Charge = +0.44v
500mA - Discharge = -0.32v , Charge = +0.32v
200mA - Discharge = -0.08v , Charge = +0.16v
Hmmm , interesting .