Solar Panel Design
Can a 5w Solar Panel directly charge an 18v 1.5 amp NiCd Black and Decker Firestorm battery?
I have a small solar panel which I use to keep a 12V truck battery topped off. It has the following specs (in bright sun).
24Voc
5 watts
350mAmps @ 15V
The actual wall charger for the 18V battery NiCd Firestorm says it produces 21.75Vdc @ 210mAmps
The panel was designed to trickle charge 12V car batteries. What would happen if I connected this solar panel directly to the 18V battery? Could I damage either my solar panel or the NiCd battery? What about the blocking diode, would they work at 18V? Does my panel even have the ability to charge an 18V battery?
You can connect the panel and it may charge the 18V battery sometimes. You should have a multimeter to measure the current in series, so you know what is happening. However the solar panel will get hotter due to being in the sun, and this reduces its voltage, so it will probably not charge once the panel is hot. They normally come up to 50C or 60C depending where you live - that is very hot to the touch. Make sure it is well ventilated. However I don't expect it will work very well at all. It is meant to charge a 12V battery, and can only charge the 18V battery under certain conditions, like when the battery is low and the panel is cold. Don't worry about diodes, they only reduce the already starving for voltage situation you will have.