I think my battery is OK, but just want to check.

[aamacgregor]

So, I have an e-sky 11.1V 1800mAh 20C Li-Po, but I haven't used it for about 4 years. I was quite sure I tried to discharge it to roughly around 50%, but probably discharged it a little further. Today I decided to check the voltage across the three cells.

The charge connector has black, yellow, blue and red wires. The voltages are as follows:

black->yellow: 3.81
black->blue: 7.62
black->red: 11.43

I originally assumed that the charge connector would be connected to the cells in parallel such that black would be connected to the negative terminal of all three cells, yellow would be connected to the positive of cell 1, blue to the positive of cell 2, and red to the positive of cell 3; however the results clearly show that I was wrong.

Based on the above readings it is clear that black is connected to the negative of cell 1, yellow is connected to the positive of cell 1 and the negative of cell 2, blue is connected to the positive of cell 2 and the negative of cell 3 and red is connected to the positive of cell 3. Thus, the above results show the all three cells have a voltage of 3.81:

cell 1 voltage = black->yellow = 3.81
cell 2 voltage = black->blue - black->yellow = 3.81
cell 3 voltage = black->red - black->blue = 3.81

My conclusion is that a voltage of 3.81 volts per cell is OK, and therefore I can recharge the battery and use it.

Anyway, I just wanted to check. Comments welcome. :-)

[cjcj1949]

From your readings your battery is ok. It is unlikely that it is much use after 4 years I'm afraid. Your capacity will have decreased and the voltage drop for a given current will have increased. If you have a flight at all it will probably be quite short. Lipos have improved a lot in the last 4 years and are cheaper.

[aamacgregor]

Thanks for your input cjcj1949. I'll give it a try, but I expect you are right, I'll probably end up buying a new lipo... I'll probably go for a higher capacity, higher output one so that I can use it with my planned helium upgrade towards the end of the year.

[paulsouthport]

What heli is it for? And remember, you can never have too many batteries!

[aamacgregor]

At the moment it is for an esky belt cp but I would like to upgrade to a gaui x5 or something later on this year.

[cjcj1949]

Phoenix is a good upgrade. The only thing you can buy guaranteed to save you money.

[aamacgregor]

Sorry for not responding sooner, I've been away from the forum. I got Phoenix a couple of weeks ago, I've found it pretty good. I can now hover in all orientations, figure 8 in both directions, land random engine failures (most of the time), land auto rotations (those starting inverted too) and do a little 3D, but not accurately. It's all good fun. :-)