Need help about 1S lipos

[Maxx]

Allo everybody !
I have six 1S 150mah 25c for my UMX radian . When trying to fly , the batteries give the three cutoff warning after only 15 seconds ...
I charged them all at 4.2 before I left . When back home and checked all 6 lipos and they're at 4.2 or 4.1... So still charged.
The first time I charged them was at 1 amp. now I charge at .3 amp . So the batteries are dead or the charger is at fault or the glider ???
I also have a small charger that came with the radian ,I put any battery on it to check if they're fully charged but they never stops charging ... even after 3 hours , the red light is still on. Is it possible that charging them at 1amp killed them ?
Lost my two last no-wind days because of that .

Please help me find what's the problem .

 

[randyrls]

I suspect you are seeing voltage sag under load. I use 1S 280 or 300 mah batteries in my UMX radian and Night Vapor. Indoors during winter.... Hope this helps.

 

[Maxx]

voltage sag under load

What's that ?

 

[randyrls]

Maxx; When you draw current from the battery, the voltage on the battery terminals goes down. I believe this is related to the internal resistance of the battery, but this may be wrong. Under rated mah (capacity) makes this worse. I have the same problem with my Inductrix (tiny drone). On a larger model, if you draw too much current from the battery, the voltage can go low enough that the receiver and servos will shut down momentarily.

 

[quorneng]

Maxx
Charging a 150 mAh battery at 1 A will do it no good at all.
For a reasonable battery life they should be charged at 1c. That's a charge rate equal to their capacity, 150 mA in your case.
You were charging them at 7 times that rate which will have damaged their internal structure so they now can neither accept and deliver much charge but will still show 4.2V indicating that what little they have is fully charged.
You will have to replace all those batteries. Remember only charge them at 150 mA using a suitable LiPo charger that will cut off the charge at exactly 4.2 V. If it go on after that it will also damage the LiPo.

 

[PsyBorg]

What revision connector is used? I remember when whoops first came out the connectors on both the batteries and the quads were crap. They did not transfer current well enough and these same symptoms occurred. You may have to change the connector on the plane and buy batteries with the better connectors.

 

[Maxx]

Maxx
Charging a 150 mAh battery at 1 A will do it no good at all.
For a reasonable battery life they should be charged at 1c. That's a charge rate equal to their capacity, 150 mA in your case.
You were charging them at 7 times that rate which will have damaged their internal structure so they now can neither accept and deliver much charge but will still show 4.2V indicating that what little they have is fully charged.
You will have to replace all those batteries. Remember only charge them at 150 mA using a suitable LiPo charger that will cut off the charge at exactly 4.2 V. If it go on after that it will also damage the LiPo.

Thank you ! I need to understand how to calculate how to set the the changer . 1C is equivalent to what amps for a 150mah ?
What's the formula to calculate this ?

 

[Maxx]

Maxx
Charging a 150 mAh battery at 1 A will do it no good at all.
For a reasonable battery life they should be charged at 1c. That's a charge rate equal to their capacity, 150 mA in your case.
You were charging them at 7 times that rate which will have damaged their internal structure so they now can neither accept and deliver much charge but will still show 4.2V indicating that what little they have is fully charged.
You will have to replace all those batteries. Remember only charge them at 150 mA using a suitable LiPo charger that will cut off the charge at exactly 4.2 V. If it go on after that it will also damage the LiPo.

OK I get it , 1C for a 150mah I would charge at 0.15 Amps ... Now I understand ... I was wayyyy too high at 1Amp .
Thanks man !

 

[quorneng]

Maxx
The one in 1C denotes the discharge rate a battery could achieve to empty in 1 hour. So a 150 mAh could (in theory) deliver 150 mA for 1 hour.
A 1C charge rate for a 150 mAh battery is the same - 150 mA.

So for LiPo technology the capacity of the battery in mAh is the recommended charge rate in mA . Simples!

Your charger may not be able to set such a charge figure. Mine can only do steps of 100 mA so its either 100 mA or 200 mA. You can have 200 mA for a faster charge and be a bit harder on the battery or 100 mA and simply wait a bit longer!

Note other battery chemistries will have different charge rates.

 

[PsyBorg]

The clue here is NOT the charge process guys.. its how the batteries are coming down after flight. If they are coming down showing full charge then no big amount current was drawn. The plane flew so there had to be something taken out.

That leaves several conditions. First the current sensor in the plane is bad OR it is set wayyy to high. I don't believe that can be changed and is hard coded. If it were a quad I would say take a look at the voltage and mah warnings set in the FC.

That leaves the most obvious issue the connector problem which is common on 1s powered RC gear. The last part of the video pertains more to fixed wing where there is single esc higher current draws.

 

[Maxx]

The clue here is NOT the charge process guys.. its how the batteries are coming down after flight. If they are coming down showing full charge then no big amount current was drawn. The plane flew so there had to be something taken out.

That leaves several conditions. First the current sensor in the plane is bad OR it is set wayyy to high. I don't believe that can be changed and is hard coded. If it were a quad I would say take a look at the voltage and mah warnings set in the FC.

That leaves the most obvious issue the connector problem which is common on 1s powered RC gear. The last part of the video pertains more to fixed wing where there is single esc higher current draws.

Thank you for the link , I like that dude .

 

[PsyBorg]

Thank you for the link , I like that dude .

Yeah Bardwell has a TON of great information on his site if you can get past the begging bowl fast enough to see it. For future reference Painless360 is another go to for all things RC. between the two there is very little rc aviation wise not covered.