Post by texag on Dec 8, 2019 16:18:58 GMT -8
Last winter, 80% of the days in February were completely overcast. During this period my 4 solar panel frame (see pic #1) could not keep my 15.6 AH battery charged. I spent much of the month swapping batteries so I could keep the weather station up.
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This year I’m hoping to avoid this by building a large battery and increasing my station’s ability to keep the battery charged through the winter. Last spring I built a large battery (32 18650 cells, 96 AH). Recently I designed and printed an 8 panel frame (see pic #2).
The 8 panel frame uses the 6V 330 ma solar cells and a single Multi Solar Panel Connector Board (https://shop.switchdoc.com/collections/solar/products/multi-solar-panel-connector-board). My design pairs 2 solar cells in parallel to turn the 8-330ma cells into 4-660ma cells. See the back side of the frame (pic #3) to see how it is wired.
Today I measured the VOC and was surprised that the voltage was at ~ 7 volts (see pic #4). I covered the upper half and then the lower half (see pic #5) and the VOC was at 6.6 volts. I did not expect the 2 cells-in-parallel configuration to increase the voltage.
Regardless, even 6.6v is outside the specs of the SunControl board. It seems that I’ll need to install a zener diode to lower the voltage below 6V. I guess I’ve been running my SunControl in an over voltage condition for ~1.5 years with my current 4 panel configuration. I seems like I should have blown out the board.
If anyone is interested, I’ll upload the STLs and CAD files for the 8 panel frame.
Kevin
This year I’m hoping to avoid this by building a large battery and increasing my station’s ability to keep the battery charged through the winter. Last spring I built a large battery (32 18650 cells, 96 AH). Recently I designed and printed an 8 panel frame (see pic #2).
The 8 panel frame uses the 6V 330 ma solar cells and a single Multi Solar Panel Connector Board (https://shop.switchdoc.com/collections/solar/products/multi-solar-panel-connector-board). My design pairs 2 solar cells in parallel to turn the 8-330ma cells into 4-660ma cells. See the back side of the frame (pic #3) to see how it is wired.
Today I measured the VOC and was surprised that the voltage was at ~ 7 volts (see pic #4). I covered the upper half and then the lower half (see pic #5) and the VOC was at 6.6 volts. I did not expect the 2 cells-in-parallel configuration to increase the voltage.
Regardless, even 6.6v is outside the specs of the SunControl board. It seems that I’ll need to install a zener diode to lower the voltage below 6V. I guess I’ve been running my SunControl in an over voltage condition for ~1.5 years with my current 4 panel configuration. I seems like I should have blown out the board.
If anyone is interested, I’ll upload the STLs and CAD files for the 8 panel frame.
Kevin
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