English

DIY electrosmog free solar controllers

After the first simple 2-point controllers with relays (on/off), the pulsed shunt mosfet regulators have prevailed now already for many years. They feed the battery at the end of the charging only with small chopped pulses (50-100Hz) of the charging current, in order to keep it always at the maximum charge-end voltage. Like this the battery is fully loaded as quickly and as effectively as possible.

Disadvantage- The strong electromagnetic fields are also distributed via the whole cable systems and often you can hear interferences in audio devices witch are connected on the same supply network. Also the strong electrostatic fields disturb then with strong interference fields and frequencies that are very similar to the 230V mains.

My Tip: With a very simple device you can make low frequency fields hearable. Connect a insulated coil, like a guitar pick up without the magnets, with a small guitar amplifier.

If you want a eletrosmog free solar controller, you will not really have much choice than to build one yourself! Because untill now we cant buy such a thing anywhere.

The here described solar controller uses the latest MOSFET shunt technique but with very slow switching frequencies of about 20 seconds witch makes it electrosmog free. The only drawback with it is that the last 5% of the battery capacity is only recharged quite slowly. A small loss but it should be worth for our health.

This circuit is designed for easy reproduction. It is very energy efficient and consumes only 0.01Watt in stand by. The circuit is also very sensitive to moisture and dirt and should therefore be in a box.
Reaching the maximum voltage of about 14 volts the transistor T1 switches through.
Via a timing element (T2 and the 470uF capacitor) the gate (G1) of mosfet 1 is controlled. This stops the charging for about 25 sec. During this time the green LED is on.
The right part of the circuit controlles the gate (G2) of the consumer mosfet by T3 to T5 (all NPN eg BC 547). The red LED and the 47 Ω resistor creates a hysteresis of about 0.5 volts. The cutoff should be set to 11.5 volts. T5 only turns around the signal for the mosfet. The thick 2200μF capacitor smooths interference in the circuit.

(click on the picture to enlarge)

A strong Schottki diode (MBR 2045) prevents back flow during the night from the battery into the solar panel and allows using the shunt principle (short circuit). The mosfets (eg IRF 1405) controlles the battery from overcharging and regulates the consumers, which must be further protected by a fuse.

The mosfets and the Schottli diode must be protected with a sufficiently large heat sink from overheating. The MBR 2545 Schottki diode can tolerate up to 30 A from the solar panels. The mosfet IRF 1405 can stand also 30A with good cooling.
Use big connector blocks and short cables with end terminals and at least 2.5 mm ².
For the cables to the control board you can use very thin cables.
I wish you a lot of fun rebuilding it.
For further questions please contact me at: solarmichel@hotmail.com