crashalot

I burned up a speed control in flight today and it had a strange effect on one of my batteries. I lost power from the main leads that go to the speed control but when I check the individual cells there is still 3.75V there.

I am using 2 x 3cell 3700mah 25C batteries in paralel for 22V total output.
only one of the batteries was affected,but it shut down all power from the lipos.....

Any ideas what is going on here? can I get the power leads connected up again??

No - the plane didn't crash - I have a seperate power system for receiver and flight surfaces !! Thank goodness...... was able to dead stick in

CHELLIE

you will have to open the battery up, you may have burned up a safety tab fuse that connects all the lipo cells together, or a battery lead that attaches to the lipos burnt off. some times you can repair a lipo and sometimes you cant, the tabs are fused on and the metal looks like aluminum so you cant solder it. anyway lipos are cheap Take care and have fun, Chellie

slipstick

I think you mean 2 x 3S batteries in SERIES not parallel. In series any break in connection anywhere in the series chain will lose all the power.

It's quite possible that one power lead has simply come disconnected but as Chelly says it may not be that easy to put it back together....depends on the battery and how it was originally constructed.

Steve

crashalot

Thank you Chellie and Slipstick - I opened up the lipo and the + wire had disconnected - a careful resoldering has solved the problem and the battery is ready to fly again.

Slipstick, you are so right, the 2 3 cells are connected in *series* and it is apparent that my spelling is not too great either..........

Now all I have to do is figure out what caused the speed control to expire in mid flight . I was only cruising at 1/3 throttle.

Thanks again - very helpfull....

Craig

CHELLIE

Hi Craig put a wattmeter on it, that will tell the story, use a ESC thats 25% bigger than what you have now, also check to see that you have pleanty of air flow through the Fusalage to cool the electronics, also check the motor to make sure that its not shorted out, all 3 wires should have the same ohm reading, and none of the wires should show any reading when a wire and the test lead is touched to the motor body, Take care and have fun, Chellie

BTW Glad you were able to repair your lipo

http://www.wattflyer.com/forums/showthread.php?t=35216