is it time to bin it

[dogbiscuit]

i have been closely monitoring the lipos that came with my 2nd hand trex 500. labelled each one and recorded their flight times, charging etc. One of the bunch has the heli wagging is tail and pulsing (ESC ALLERTING OF LOW VOLTAGE) every time you take off. if you land, then take off again, it will then fly for its allocated 5 mins. it also takes more than 2 hours to charge. is it now so close to the end of its life that i should not take the risk of using it, or will they go on for some time like this? so, bin it or kep using it

[Vic.P]

i have been closely monitoring the lipos that came with my 2nd hand trex 500. labelled each one and recorded their flight times, charging etc. One of the bunch has the heli wagging is tail and pulsing (ESC ALLERTING OF LOW VOLTAGE) every time you take off. if you land, then take off again, it will then fly for its allocated 5 mins. it also takes more than 2 hours to charge. is it now so close to the end of its life that i should not take the risk of using it, or will they go on for some time like this? so, bin it or kep using it

Sounds like the pack needs to warm up a bit to allow the voltage to recover so i'd keep going with it the way you are, let it sit on the deck for a while till it stops pulsing and then fly. so long as the pack comes off with the right percentage it shouldn't give out mid flight and cause a forced auto. Once it's puffed i'd bin it. Never know, once the warmer weather arrives it may start behaving itself

[dogbiscuit]

thanks vic. you obviously remember the original posts. i reprogramed the esc and continued with the 2 x 3s packs also for a few tests and again monitored them individually. it turned out that 4 were ok to use, and two that i had bought 2nd hand were the ones getting warm and a bit puffy. one of these has the same issue as the 6s pack above in that it times out on the charger (over 2 hours). i now just use the 4 ok ones, and use the others only for the blade

[cjcj1949]

The older they get the higher the internal resistance gets and it also goes up the colder they get. The higher the resistance the more the volts drop. Warming them up to 30C should get them behaving a bit better.
Its really just the chemical reactions going faster like when you warm things in a testtube or like sugar dissolving in hot tea quicker than cold. The age thing is much like people getting older. Less parts are working so less paths for the current to flow through.


Chris

[dogbiscuit]

ok , thanks, as long as there is no danger of the heli falling from the sky (from the battery and not my flying that is!) then i will cotinue to use it. i to am getting older and begining to slow down so i understand how those old lipos feel in the cold!

[Sqwidge]

This is the reason that I keep hand warmers in my flightbox which heat to a max 50c but are ideal for keeping your lipos warm for a couple mins before you fly on a coldish day.

Nip down to your local camping store and pick a couple up, make sure you get the rechargeable ones, these are liquid with a metal disc in, you snap the disc back and forth and it causes a reaction which turns the liquid to a wax like substance and stays warm for up to 2 hours, to recharge simply put them in water and bring to the boil.