I'm pondering a Raspberry Pi project, but I need to figure out a few things before I can move forward with it. One is solar power for the Pi. Given I'd like to fit the whole thing in a shoebox sized enclosure when done, some sort of Lithium-Ion or Lithium-Poly battery seems like the solution. However, I then need a solar panel and charge controller.
Searching I found https://www.adafruit.com/products/390 which almost fits the bill, except that I think the batteries shown with it are too low capacity, and so are the solar cells. I don't see a maximum wattage for the controller board.
I'm afraid I need something much larger for the Pi, but not big enough to switch over to more traditional 12v "small solar" systems with like an AGM battery.
Is there any interest in a up-rated kit for the Pi? I'm thinking enough battery to run it for 24-36 hours on battery, and enough solar wattage that should fully charge the batteries in on a typical day and the controller to make it all work. Maybe even output it on a 1000ma capable USB port so a short cable is all that's needed.
USB / DC / Solar Lithium Ion/Polymer charger & high capacity
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capacity
This design will not work with 12V panels, it will ONLY work with 6V. For more details of what the charger can do, please read the datasheet linked from the product page. We have no plans to make a 12V version
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capacity
Ah, missed the data sheet. Looks like the controller you're using is rated for 1.8A, which at 6V means about 10W.
So I'm thinking to "max it out", 3 of the 3.7w "large" 6v panels in parallel on the input would be ok. The Pi would take 750ma of that, so about 1A could go into the battery for ~5-6 hours a day, or 5,000-6,000mAh. A pair of the 6,600 batteries in parallel could provide that with only 50% discharge.
But that means there would only be enough battery to power the Pi for ~8 hours, so 24x7 runtime won't happen.
A board with 2x the capacity would get the job done, I think, if my math is right.
So I'm thinking to "max it out", 3 of the 3.7w "large" 6v panels in parallel on the input would be ok. The Pi would take 750ma of that, so about 1A could go into the battery for ~5-6 hours a day, or 5,000-6,000mAh. A pair of the 6,600 batteries in parallel could provide that with only 50% discharge.
But that means there would only be enough battery to power the Pi for ~8 hours, so 24x7 runtime won't happen.
A board with 2x the capacity would get the job done, I think, if my math is right.
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
Would it be possible to charge the batteries back through the load port on the USB / DC / Solar Lithium Ion/Polymer charger? I want to use a different control board other than the Minty Boost.
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
The load terminals are output only. You cannot connect an input voltage source there.Would it be possible to charge the batteries back through the load port on the USB / DC / Solar Lithium Ion/Polymer charger?
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
I am trying to use the solar power portion of the USB / DC / Solar Lithium Ion/Polymer charger. Is the battery port protected for back feeding? I could tie both circuits to the batteries as long as their are diodes and protection in place.
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
Could you explain a bit more on what it is you are trying to accomplish?
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
Absolutely. I have purchased a Lithium ion charging board which can charge multiple unprotected 3.7V 18650 batteries in parallel. This board has a charging circuit and a load circuit, all are protected for overcharging and overdischarging. This does not support however solar charging, so I am trying to use your USB / DC / Solar Lithium Ion/Polymer charger for the solar charging portion of this project. I don't know that the USB / DC / Solar Lithium Ion/Polymer charger will let me charge the bank of 3.7V 18650 batteries in parallel safely. I don't know if it can distribute the power evenly. Each battery is 5000mAh I plan on using 8x batteries.
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Re: USB / DC / Solar Lithium Ion/Polymer charger & high capa
I don't believe that will work. The load-sharing circuit simply switches between the input source and the battery depending on the demand from the load. You would get pretty much the same results as connecting the solar panel directly to your parallel charger.
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