06-10-2023, 02:28 PM
Today I measured the lipo available capacity (LAC) on 4 of my lipos:
1. Dualsky 3S 900mah 120C: LAC 87.0
2. Tattu 3S 1050 mah 75C: LAC 79.1
3. Dualsky Ultra 2S 550 mah 50C: LAC 89.6
4. Turnigy Graphene 2S 950 mah 75C: LAC 88.1
Measurements were done on my ToolkitRC M6D charger.
I tried to follow Hopke as closely as possible, including discharging at a constant 2C rate. For the Dualsky 2S, the 2C rate was -1.1A, but for the other 3 lipos the discharge rate was a bit less: For the Turnigy 2S, 84% of the 2C rate, and for both the 3S lipos it was 61.1% of the 2C rate. The reason was the Toolkit charger accepted my request for the 2C rate, but then carried out the discharge at the reduced rate for reasons not explained. My view is this reduction in the discharge rate would have had a minimal impact on the LAC.
If you have seen Hopke's video you know he considers a LAC < 85 as an indication to discard a lipo. However for the Tattu lipo (LAC 79%) I have detected no other sign of anything wrong, it performs well in the plane, the IR is 18 (which is normal/usual ballpark for my 3S lipos, albeit higher than Hopkes 3S), so it may be the case that LAC 85% is too high a standard for smaller 3S lipos.
The Dualsky lipo with the best LAC was Dualsky Ultra 2S 550 mah 50C. Remarkably this has a IR measured during charging of 37, and during discharging of 26. The Dualsky lipos have long been noted by me to have a higher IR than other brands, however I am very satisfied with the performance of the 2S and 3S lipos (but not the Dualsky 3S ECO lipos which I have discarded some time ago).
Measuring LAC is a bit painful, you have to fully charge the lipo, then discharge it, and then storage charge it, all the while keeping an eye on the voltages and IR, and checking for lipo heating. However in my view it makes sufficient sense as an indicator of lipo condition that it may be worth making a schedule to do each lipo at a periodic interval. In future I will do 6 lipos simultaneously.
1. Dualsky 3S 900mah 120C: LAC 87.0
2. Tattu 3S 1050 mah 75C: LAC 79.1
3. Dualsky Ultra 2S 550 mah 50C: LAC 89.6
4. Turnigy Graphene 2S 950 mah 75C: LAC 88.1
Measurements were done on my ToolkitRC M6D charger.
I tried to follow Hopke as closely as possible, including discharging at a constant 2C rate. For the Dualsky 2S, the 2C rate was -1.1A, but for the other 3 lipos the discharge rate was a bit less: For the Turnigy 2S, 84% of the 2C rate, and for both the 3S lipos it was 61.1% of the 2C rate. The reason was the Toolkit charger accepted my request for the 2C rate, but then carried out the discharge at the reduced rate for reasons not explained. My view is this reduction in the discharge rate would have had a minimal impact on the LAC.
If you have seen Hopke's video you know he considers a LAC < 85 as an indication to discard a lipo. However for the Tattu lipo (LAC 79%) I have detected no other sign of anything wrong, it performs well in the plane, the IR is 18 (which is normal/usual ballpark for my 3S lipos, albeit higher than Hopkes 3S), so it may be the case that LAC 85% is too high a standard for smaller 3S lipos.
The Dualsky lipo with the best LAC was Dualsky Ultra 2S 550 mah 50C. Remarkably this has a IR measured during charging of 37, and during discharging of 26. The Dualsky lipos have long been noted by me to have a higher IR than other brands, however I am very satisfied with the performance of the 2S and 3S lipos (but not the Dualsky 3S ECO lipos which I have discarded some time ago).
Measuring LAC is a bit painful, you have to fully charge the lipo, then discharge it, and then storage charge it, all the while keeping an eye on the voltages and IR, and checking for lipo heating. However in my view it makes sufficient sense as an indicator of lipo condition that it may be worth making a schedule to do each lipo at a periodic interval. In future I will do 6 lipos simultaneously.