23-07-2016, 11:23 AM
My experience is mostly with Turnigy lipos 2S and 3S. I always charge at 1C and I have not had the problem described by disoriented of a lipo that is hard to balance. I dont find a need for recharging at 2C or 3C, although I can understand some flyers who recharge at the field might want to do that.
Turnigy now is a dominant player with a range of lipos for each category, 2S, 3S and 4S. To achieve this market position requires good products and a vast amount of testing of lipos, including how many cycles before a pack becomes unusable, and the effect on performance of various recharging regimes, including <1C charging for the first 5 recharges, the effect of 3C recharges etc. If any regime is superior I do not understand why testing data held by Turnigy is not used to issue customers with evidence-based guidelines for recharging. I think the experience of any one flyer might only reflect luck and chance, and people are generally confused or uncertain about the best way to recharge - I certainly am. If the recharging regime makes no difference, users need to know this.
My impression from reading rcgroups on lipos is that avoiding drops in cell charge below 3.7v may keep lipos in better shape. When the aircraft noticeably loses power in the air I find on testing cell voltages on landing that one cell may have fallen to 3.3v or less. To avoid this I am trying the FrSky SP-FLVS - Smart Port Lipo Voltage Sensor which is sold by Aloft Hobbies. I am setting it up on my phantom so I get an audible warning when the cell with the lowest voltage reaches 3.7v.
A typical review of this sensor:
"Much better solution to battery monitoring than an on-board buzzer. With this sensor you have complete voltage level telemetry and can setup multiple audible reporting and alarms from your Taranis for any voltage trigger point(s) and/or battery cell combos you choose."
A second measure is to charge lipos in storage mode after a flying session, immediately on arriving home - this balances all cells and raises the voltage to 3.9v, which means its quicker to balance charge the lipos prior to the next flying session.
I feel the above 2 steps make sense to maintain battery condition, however like breaking in lipos it will remain guesswork until lipo manufacturers release their data on largescale testing over lipo lifetimes, and provide evidence based recharge guidelines. I fear the reason they dont is that they think its better if consumers are kept in the dark; if true this is a sad and stupid policy.
Turnigy now is a dominant player with a range of lipos for each category, 2S, 3S and 4S. To achieve this market position requires good products and a vast amount of testing of lipos, including how many cycles before a pack becomes unusable, and the effect on performance of various recharging regimes, including <1C charging for the first 5 recharges, the effect of 3C recharges etc. If any regime is superior I do not understand why testing data held by Turnigy is not used to issue customers with evidence-based guidelines for recharging. I think the experience of any one flyer might only reflect luck and chance, and people are generally confused or uncertain about the best way to recharge - I certainly am. If the recharging regime makes no difference, users need to know this.
My impression from reading rcgroups on lipos is that avoiding drops in cell charge below 3.7v may keep lipos in better shape. When the aircraft noticeably loses power in the air I find on testing cell voltages on landing that one cell may have fallen to 3.3v or less. To avoid this I am trying the FrSky SP-FLVS - Smart Port Lipo Voltage Sensor which is sold by Aloft Hobbies. I am setting it up on my phantom so I get an audible warning when the cell with the lowest voltage reaches 3.7v.
A typical review of this sensor:
"Much better solution to battery monitoring than an on-board buzzer. With this sensor you have complete voltage level telemetry and can setup multiple audible reporting and alarms from your Taranis for any voltage trigger point(s) and/or battery cell combos you choose."
A second measure is to charge lipos in storage mode after a flying session, immediately on arriving home - this balances all cells and raises the voltage to 3.9v, which means its quicker to balance charge the lipos prior to the next flying session.
I feel the above 2 steps make sense to maintain battery condition, however like breaking in lipos it will remain guesswork until lipo manufacturers release their data on largescale testing over lipo lifetimes, and provide evidence based recharge guidelines. I fear the reason they dont is that they think its better if consumers are kept in the dark; if true this is a sad and stupid policy.