Car Large capacitor charge controllers

Posted on Jun 27, 2012

One-farad capacitors require some care. It`s a common knowledge that they must be pre-charged with a current-limiting resistor before plugging in. It is less common knowledge that those fifty-dollar `smart cap controllers` are in fact very simple devices, two dollars for parts and labor. Here`s a basic cap switch that will connect capacitor to ground only when it`s charged to within 0.4-0.7V from battery voltage (otherwise, it`s charging through a 22 Ohm resistor, which can be a low-power 12V lightbulb, too).

Car Large capacitor charge controllers
Click here to download the full size of the above Circuit.

Note that when the circuit is open, and a high current draw starts dicharging the capacitor, T1 (N-MOS with low channel resistance - IRF1010, IRFP054, IRF048, P60N06 etc) is actually conducting in reverse direction (as in syncronous rectifiers: S->D no

Leave Comment

characters left:

New Circuits



Popular Circuits

Simple LF converter
Programming Cable for Kenwood
raspberry pi thermostat hookups
Capacitive liquid level sensor circuit
PT7M6101 Ultra Low Voltage Detectors
High PoE made easy
high power regulator
interfacing ultrasonic distance sensor ascii pic microcontroller
Technical Proposal for Subcutaneous Transmitter
SN754410 Dual Motor Control Circuit
7809 Pin and
Poor Mans DDS Board
XTR115 116 Basic circuit diagram connection