|See 'Schematic' link above for larger image .pdf file|
And here are some 3D renderings:
The module is approx 3x4" (actually, 80mm x 100mm), utilized 100v FETs and caps (I am suggesting keeping solar panel voltage below 85v), and can support up to 25A battery current. These give it the following range of charging support per module:
- 12v battery: 345W capacity
- 24v battery: 690W
- 32/36v battery: 1,000W
- 48v battery: 1,380W
The costed BOM come to $73.30 + price of PCBs, which could be found for under $10 using overseas supplier. I expect parts to arrive some time in December and will start assembling one unit then, and when I return to Viking Star will be able to start playing with trial runs on our solar panels as well as start developing the more advanced firmware.
For those interested there is a LTSPICE model of the buck converter using in this design under the CAD resource tab above - kind of fun to play with.