Newbie Questions

[Paul881]

I am the very happy owner of a PL8 and have a few questions:

1. Before I changed mode from FMA, cell 4 of my 4S pack was always the highest resistance - usually around 9-20 ohms where the others were at 1-3 ohms.After changing mode to XH/EH, cells 1-3 now measure between 1-2 ohms and cell 4 is at 0.2 to 0.3 ohms. Is this normal?
2. When starting to charge, CCS prompts me to save the graph with a unique name. It also does so at the end of the charge. But when I do give it a unique name and Enter at the prompt, its doesn't save the values! It only does so if I manually choose save and then enter the details to save a bitmap image of the graph. Is this correct - is there any way I can save the tab data?
3. If I parallel charge using my MPA board, will I be able to see all individual Pack Graphs, IR and Cell details in CCS?
4. I currently only charge each cell to 4.05 volts; just under 97% instead of 4.2 volts as I have read that under-charging has a significant impact on the pack life. Is this a myth?
5. I have never pushed the recharging of my LiPos at multiples of the battery capacity; always 1C and no more. Is this playing too safe or is it best practice?

Thanks!

[Gregor99]

Comments inline. Also review this

FAQ - Powerlab Quick Start Guide - Wiring modes, Supply Limits and 1s charging

Originally Posted by Paul881

I am the very happy owner of a PL8 and have a few questions:

1. Before I changed mode from FMA, cell 4 of my 4S pack was always the highest resistance - usually around 9-20 ohms where the others were at 1-3 ohms.After changing mode to XH/EH, cells 1-3 now measure between 1-2 ohms and cell 4 is at 0.2 to 0.3 ohms. Is this normal? Last cell reading high IR is a symptom of using FMA wiring mode when the balance board uses JST-XH wiring pinout.
2. When starting to charge, CCS prompts me to save the graph with a unique name. It also does so at the end of the charge. But when I do give it a unique name and Enter at the prompt, its doesn't save the values! It only does so if I manually choose save and then enter the details to save a bitmap image of the graph. Is this correct - is there any way I can save the tab data? Once the data is saved, in the CCS select "File/Open Graph"
3. If I parallel charge using my MPA board, will I be able to see all individual Pack Graphs, IR and Cell details in CCS? The cells in parallel will be seen as a single cell. If you specified the number of packs in parallel the IR value is average of all cells in parallel. For accurate IR measurements, charge a pack as a single.
4. I currently only charge each cell to 4.05 volts; just under 97% instead of 4.2 volts as I have read that under-charging has a significant impact on the pack life. Is this a myth? Undercharging will extend the life of the pack. The Powerlab includes a long life preset which charges the cells to 4.1v per cell. 4.05v is closer to 85%. Be careful not to over discharge the packs as well. You may need to bump up to 4.1v or 4.15v to get decent flight times without over discharging.
5. I have never pushed the recharging of my LiPos at multiples of the battery capacity; always 1C and no more. Is this playing too safe or is it best practice? Follow the pack manufactures recommended max charge rate and do not exceed that rate. Most modern packs are rated for 5c charge rate if not higher. I find that 3c charging is sufficiently fast even for field charging.

Thanks!

[Paul881]

Originally Posted by Gregor99

Comments inline. Also review this

FAQ - Powerlab Quick Start Guide - Wiring modes, Supply Limits and 1s charging

Many thanks - all noted and understood! However, just one note; cell #4 has a much lower resistance than the others, not higher.

Also, my calculation of percentage charge is 4.05/4.2 = 96.4%. Is this not correct?