RichJ53
First Officer
Flight distance : 1837356 ft
United States
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DTK Posted at 2017-9-26 13:49
Since I have been inherited with a troublesome TB48 which has a few weak cells in it. I have individually balanced them a few times but the issue always recurring. It is a pain to open the cover and much more pain to individually balance them. So I have done the harness myself using a cable from another dead TB47. Once it is done, it can be balanced with my Venom Produo charger, very similar to Rich's icharger. Now with the balancing cable, the battery can be left alone and balance charged. Anyone who has these "intelligent" batteries should need one. Down the track, you would need one to do a "real" battery balancing charge. So it will be a good news when Rich is ready for production. At the moment, the advice is to run the battery down to 5% and the circuitry reset the cell charge information and "hope" that the following recharge will balance the cells. It does not work every time, it works probably when the cells with the battery are relatively in comparable strength. With one out of spec weak cell, the balance charging will be faulted.
Discharging to 5% or lower will also kill battery life. Lipo battery should be limited max discharge to around 20%. If you drain your battery down to below 10%, your battery capacity will roughly reduce by 100-120mah. So with a TB47 's capacity of 4500mah, it will not last very long. Even in normal use, every discharge and recharge will cost you about 20-30mah. DJI's claim of useful life about 200 charges is challenged here. After 200 counts, conservatively the capacity of the battery will be down to a couple hundred mah, the flight time is probably a couple of minutes.
DTK
Nice work and yes this is a great way to access the battery for additional maintenance. I sent out a harness to Mark and he will be doing some similar testing. Yes, the batteries are a bit of work to take apart. If you use the right tools from IFixit it can be a lot easier. My Youtube videos were taken with my iPhone and I am not very proud of the quality. Should be posting this anyway just to help get the information out there
Doesn't seem to be much interest from many members. My investment for the required minimum might not work out. Should know very soon
Rich
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