Connect more Solar Panels to the SLA Power Board

Q: We need more (battery) power after expanding the Data Logger with a few sensors. Is it possible to use the original SLA power board in conjunction with the SLA board and two (or more) Solar panels instead of replacing the Solar Panel for a bigger one?

A: yes, it can be done. Use a power diode on each panel to connect it to the SLA board as shown in Fig. 2.

Fig. 1 Original lay-out: SLA board ”IN” is connected to the Solar Cell, “BATTERY” to the battery. The SLA board is regulating and protecting the 12V output power, Solar Cell and Battery. The white “OUT” terminal is delivering regulated 3.6V power for the Data Logger and Sensor.

Board Lay-out:

1. Solar Cell Input. (Use a 36 cell Solar Panel).
2. Main Fuse. (Fast acting, 2A).
3. Charge Indicator. (Green).
4. Unregulated “BATTERY” output and monitor pin. (Green).
5. 3.6V output terminal (White). Regulated power to the Data Logger.
6. Battery Fuse (4A, fast acting).
7. Battery “IN” terminal.
8. Battery full indicator. (Orange).

Fig. 2 Upgraded Lay-out. After extending  the Data Logger with more sensors, the power need has increased. When using an extra Solar Panel, it can electrically mounted in parallel. To prevent the panels are feeding each other, each panel (also the originally mounted) needs a power diode in series to the “+” input on the SLA board. Use similar type of Solar panels only. The SLA board is regulating and protecting the 12V output power, Solar Cells and Battery. The white “OUT” terminal is delivering regulated 3.6V power for the Data Logger and Sensor.

Board Lay-out:

1. Solar Cell Input. (Use a 36 cell Solar Panel).
2. Main Fuse. (Fast acting, 2A).
3. Charge Indicator. (Green).
4. Unregulated “BATTERY” output and monitor pin. (Green).
5. 3.6V output terminal (White). Regulated power to the Data Logger.
6. Battery Fuse (4A, fast acting).
7. Battery “IN” terminal.
8. Battery full indicator. (Orange).
9. Power Diodes. Use one on each Solar Panel. Use a type that matches the Solar panel like:

• 100 Volt. (Solar Panel open voltage).
• 5 Amp. (Solar panel maximum current).