Connecting Different Watt Solar Panels
We recently received the following question from one of our users: Is it ok to connect a 100 watt and a 45 watt solar panel together ??? and what is the best way to do this to charge a battery bank the quickest?
In order to answer the question properly we reached out to a few of our engineering friends around the country and came up with the following: The answer is maybe...
If you just connect a solar panel to a battery, when there is light, the battery charges. But at night the solar panel looks like a resistor and will slightly discharge the battery. Completely discharging it over time.
So they usually put a diode between the panel and the battery. This diode does lose about 5 percent of the power (.5 volt drop, so more with a 6 volt system, less in a 24 volt) .5/6 about 15 percent 5/24 about 2 percent.
If the panels are the same voltage, and they both contain a diode to prevent reverse current, then yes you can.
A diode allows current to flow in only one direction. Much like a hydraulic check valve, or those gates at 6 flags that let the people move in only one direction :)
In short, must be the same voltage. Matched voltage even better. Both panels within a few hundreds of a volt. Both must have a diode, or both not have a diode and some kind of external power control to protect the battery.
Properly done, yes you can parallel the panels for more current.
In order to answer the question properly we reached out to a few of our engineering friends around the country and came up with the following: The answer is maybe...
If you just connect a solar panel to a battery, when there is light, the battery charges. But at night the solar panel looks like a resistor and will slightly discharge the battery. Completely discharging it over time.
So they usually put a diode between the panel and the battery. This diode does lose about 5 percent of the power (.5 volt drop, so more with a 6 volt system, less in a 24 volt) .5/6 about 15 percent 5/24 about 2 percent.
If the panels are the same voltage, and they both contain a diode to prevent reverse current, then yes you can.
A diode allows current to flow in only one direction. Much like a hydraulic check valve, or those gates at 6 flags that let the people move in only one direction :)
In short, must be the same voltage. Matched voltage even better. Both panels within a few hundreds of a volt. Both must have a diode, or both not have a diode and some kind of external power control to protect the battery.
Properly done, yes you can parallel the panels for more current.
DIY Solar Pool Heater
This morning one of our readers sent us a little do it yourself tip for heating a swimming pool based on what one of her friends is doing. The full comment follows: "Not a question, but a little info: Knowing how hot the water gets in a garden hose, a friend with a swimming pool bought a bunch, I do not know how much, of black garden hose. She spread it out in big curls on top of a nearby flat roofed building. She then fixed up a small recirculating pump, ran the water to the swimming pool to warm...Headlines:
Solar Resources
State Programs
Leave a comment