How to prevent the spark in packs over 5 cells

Have you experiment the spark when you are connecting the battery to de ESC?

 It happens to me using a 6 cell lipo pack (22,2V) and was worried me because it started to degrade the plugs and never is good such phenomena for the components.

 In fact, sparks are caused by the charging of the capacitors included in the ESC, the bigger and better the capacitor, the bigger and powerful the spark will be, and the bigger the chance to ruin the ESC too. Why, because some components are exposed to a huge current every time we connect the pack.

 But there is a simple an inexpensive way to avoid the spark, and is adding some resistors to one of the power cables of the ESC. The idea is to charge the capacitors slowly, and to do so we will put a resistor in middle before plugging the battery directly to de ESC. For a 5 or 6 cells pack a 22ohm 1W resistor is ok, for a 10 or 12 cells pack we will need a 47ohm 1W resistor. But the values are not mandatory, you can use values +/-25% different with the same results.

 I used two 47ohm resistor in parallel for a 6 cells pack (that counts as a half value one, i.e. 22.5ohm) Two resistors have a bigger contact and a more robust installation. First I solder the two resistor together with one lead twisted and the opposite bended. Then I solder the twisted extreme to the positive lead of the ESC in the junction with the plug, letting the another extreme be near the plug end making it easily accessible. I finished the work insulating the components.

 To use the modified ESC you just plug the negative cables, and then you touch for some seconds the resistor extreme with the positive plug of the battery. After this, you just plug the positive cable as usual. The resistor remain  unplugged and have no effect over the working system.

 Good landings

Adrian Muiño


Acerca de Adrián Muiño Ing. Adrián Muiño Educación Ingeniero en Electrónica (UTN, Argentina) Maestría en Dirección de Empresas (EOI, Madrid) Postgrado en Marketing (UCA, Bs. As.) Project Manager Professional, PMP del PMI (USA) Actividad académica (10+ años) Profesor de Postgrado en la Univ. Católica Argentina Instructor en gestión de proyectos Actividad profesional (10+ años) Program and Project Manager (BGH SA, Neoris, Petrobras, Ericsson) Escritor de artículos (PM y aeromodelismo) Beta tester
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