Discharge graphs for OptiPower 2150mAh 3S 35C ?

[Bronek]

Setting up my "batter low" warning. Currently it is 3.5V under load for "other" 40C batteries I have, which according to vendor graphs (for that particular brand) correspondes to roughly 3.55V without load and 75% used up.

I would like to see similar graphs for OptiPower to see whether my 3.5V under load is suitable or not.

For battery monitoring under load I use Quantum Low Voltage Buzzer Alarm. It's monitoring all cells individually, that's why voltage not in "normal" 3S range ~11V.

[Guest]

THis rather depends on the load? If you consider the average 3D pilot pulls less than 10C (on 2150 3S pack this could be slightly higher say 14C) then at 75% our pack under is above 10.5V. At 20C discharge the pack is at 87% used capacity when it hits approximately 10.5V (3.5v/cell) and actualy makes 38C comfortably but we rate it a 35C. Does this help?

Andy

[Bronek]

THis rather depends on the load? If you consider the average 3D pilot pulls less than 10C (on 2150 3S pack this could be slightly higher say 14C) then at 75% our pack under is above 10.5V. At 20C discharge the pack is at 87% used capacity when it hits approximately 10.5V (3.5v/cell) and actualy makes 38C comfortably but we rate it a 35C. Does this help?

Andy

Yes this is helpful, thank you. Since I'm only learning basic stuff I probably don't pull more than 5C. Recently changed battery warning (under this load) from 3.5V to 3.6V and this seems to be appropriate setting, leaving 15% - 20% in the battery.

[cjcj1949]

3.7V is a better setting for good batteries if you want them to last. I would aim for less than 75% as a rule. Going for 3.7V gives you shorter flights but you do have plenty of time to land. Sometimes it's useful to have a minute in reserve. I think there is a fine line between 3.6 and 3.7. I use 3.6 at the moment as I need that for my older batteries.

[Bronek]

with my "learner style" I can land seconds after the warning , so 3.6V (under light load) it is for me, for now.

[cjcj1949]

I'm not being critical in any way, but it will be interesting to see how many flights you get. Assuming you run to the warning. You are going beyond the 80% but in a very controlled way.

[Bronek]

Right now I'm charging my batteries for storage (won't fly during vacations - not enough baggage space ) and the moment I started the charge, PowerLab 6 showed they are on 19% . So not bad I think (yes, I run to the warning).

EDIT: with no load (other than the meter, obviously) and after 3.6V alarm, all cells are normally in the range 3.68V -3.72V .