How to Make Any Home Appliance Into a Solar Electric Hybrid

Step 7: Preset the Potentiometers

Before assembling the circuit, it is a good idea to preset the potentiometers. This will prevent a lot of troubleshooting later. As indicated in the pictures, the values of the potentiometers should be set to the following:

Basic Control Circuit Design
Potentiometer connected to pin 2: 8600Ω between wiper and the positive rail, and 1400Ω between wiper and the negative rail.
Potentiometer connected to pin 6: 7200Ω between wiper and the positive rail, and 2800Ω between wiper and the negative rail.

Optional Charge Controller
Potentiometer connected to pin 2: 8700Ω between wiper and the positive rail, and 1300Ω between wiper and the negative rail.
Potentiometer connected to pin 6: 7500Ω between wiper and the positive rail, and 2500Ω between wiper and the negative rail.

These will not be the final calibrated values. These are just convenient starting locations to get you in the ball park. The final settings will depend on the specific battery that you are using and its recommended operating range. When making the final adjustments, it is helpful to use a power supply with an adjustable voltage regulator such as a LM317T (Radio Shack #276-1778). See the following step for an example. If you don't have access to an adjustable power supply it will take a bit of time tweaking the values and checking it with a multimeter while the system is in operation.

(A larger version of the images can be viewed by clicking on the image once to zoom in. Clicking on the image a second time takes you to the image page where you can select "ORIGINAL" for a much larger version)