Thought of sharing the schematics of a voltage regulator/charge controller I have fitted to my trimaran.
The point is to regulate the voltage output from my Tohatsu OB going to the battery as well as to dissipate any excess current and/or voltage spikes that might try to overcharge the battery after it is fully charged.
The dissipation is done by means of a 12V/55W lamp that is fed throught a transistor which "opens" when the voltage reaches about 14V DC.
It has been working very well for me for quite a while now and so I thought of sharing it. Hope it is of any use to someone.
Here is the schematic
Before use there´s a calibration procedure THAT MUST BE ACOMPLISHED and which goes as follows:
1- Remove all the loads (dissipation lamps and/or lead acid battery)
2- Apply 14Vdc at the input
3- Measure voltage between TP1 and ground
4- Adjust R3 untill there´s a sudden voltage rise
And that´s it. You can now connect the dissipation loads and connect the circuit.
-It is supposed that the output of your generator is allready rectified to DC. Most outboard manufacturers provide simple plug-and-play rectifier kits;
-Q2 must be installed in a dissipator with adequate dimensions;
-The lamp wil light and, consequently,WILL HEAT UP. Please make sure it is well away from anything sensitive to heat and in a suitably ventilated place. In my installation the lamp is on the outside of the assembly box;
-This circuit is designed for a generator with a maximum of 55W output (small outboard motors, solar panels etc). For higher power operation simply add as many Q2/L1 pairs as necessary until the desired capacity is achieved.