Waveshare Solar Power Management Module for 6V~24V Solar Panel Supports Solar Panel/USB Connection Battery Charging Onboard MPPT Set Switch

It's not difficult to find a battery to fit in the main chamber. 3.7v. but it also has a secondary battery connection for a wired 3.7v battery, doubling the life. The options for multiple solar hookups is convenient, and the ability to switch the power intake for solar is convenient. There's indicator LEDs for charging, overcharge warning LEDs, and can outboard into a third battery via USB. The pins are extremely convenient for direct connection to VIN/G on Arduino. Highly recommend.

This unit seems to do it all. Manages the battery, solar panel and the load. I'm using this to operate moisture sensors out at my garden. The solar/battery are powering a Wemos D1 mini microcontroller over the usb connection which then transmits the data to a server. It has all the needed indicators to show the status of the solar and the battery. Although the on-board holder is for a different lithium battery, there is an independent connector that can be used to attach an 18650. In fact, it's pretty simple to remove the holder and replace it with a holder for an 18650. It would be slightly longer than the board, but could be attached using some double sided adhesive, making it self contained. Or, the 18650 can be mounted separately inside the same housing as the Solar Management module and the microcontroller, leaving only the external connections to the sensor and solar panel.

If it had a true 5v/1amp up-converter, it would have been nice. Would not push 5v @ 500mah with a 12v/900mah panel and 12v battery. Maybe a wiring schematic misprint. Still playing with them.

use it for my solar mesh repeater and it has been working great!

I bought this thinking I could use it to solar charge my phone. When it didn’t work, I sent it back for an exchange believing I just got a defective item. Same thing though with the replacement board. The phone draws no current when plugged in to the usb port. After some research, I learned that charging an iPhone is not as simple as just supplying 5 volts to the proper pin on the usb connector. The +data and -data pins must also be supplied with a particular voltage, and this board apparently doesn’t do that. As a battery charger using a solar panel, it’s probably okay. I’ll have to figure out some other use for the 5-volt output. UPDATE: there is no voltage on the D- and D+ data pins of the USB output port of the Waveshare board. Consequently, plugging an iPhone into that port with a charging cable won’t work, no current is drawn. Both data pins need to have a voltage. If both data pins are at +2.0 volts, the iPhone will recognize that and charge at up to 500 mA. If you set the D- pin at 2.7 volts instead of 2.0 volts, I read that you can charge at up to 1 Amp. In the photo, I’ve taken +5 volts and Ground from the terminal pins on the Waveshare board to a small PC board where there is a 3300/2200 ohm voltage divider to generate the +2 volts. The 2-volt line is fed to the data pins of a screw terminal to female usb adapter, along with 5 volts and ground. I’ve inserted a usb tester to show that the iPhone is charging at 0.48 amps. So, it works. This is what you have to do if you want to charge an iPhone using the Waveshare board. Hope this helps someone.

The details (and mfgr documents) are lacking on details of this charger. I'll fill in my observations that the mfgr left out. Notables: - The flexibility is nice, you can use most any voltage of panel with the dip switches on the bottom. - The solar input barrel jack isn't standard 5.5mm. Not sure what it is, but if you plan on using it you will need a male plug to fit. - Max charge rate: 1amp (yes, it is printed on the board). Remember this is charge rate at the battery, not at the panel. For example, if you are for some reason using a 24v panel, the panel would only supply about ~0.125a. (based on 3w) - Max recommended panel: no more than 5-10w. Any larger and the rest of power is wasted by MPPT regulation. - If this is placed in a sealed location, you will have to open it to hit the 'boot' button if it ever turns off. - Can direct solar power to device load. For example, if you have more than 1a incoming, the controller will regulate voltage so that only 1a is supplied to the charge circuit. If you have a device that uses 0.250mah @ 5v, it will down regulate voltage to supply 1a(battery) + 250mah(device). Practical example is this: I have a 10w "12v" solar panel with open circuit voltage is ~20v. That results in the panel voltage when charging w/o load at ~17-18.5v to supply ~2-2.5w of power to the battery. When I have a device connected that takes ~250mah, the controller will push the panel voltage down (voltage depends on battery charge state) to supply ~3.5-4w power to both battery and device. Not all controllers can do this. This minimizes power scrubbing through heat, and is a feature of MPPT chargers. The charge and management circuitry is more advanced, as mentioned above.. but I’m not sure the point and if it's a worthy trade-off for the size of the board or the charge rate. You can find smaller PWM based that can charge up your little lithium IoT battery just as well. Basically, too many 'features' for such a small use-case. With the 1a charge rate, the device(s) you will hook up will need to be low-powered(500mAh or below). The charge rate is prohibitive for a larger battery and device unless you plan on massive reserve power to be slow charged over multiple days. In this case you'd need an even less power hungry device so that you can make up for cloudy days. The Take-Away: While flexibility in panel voltage is nice, the charger is really only good for small IoT devices with the 1a charge rate. Using a higher voltage panel is negated by not being able to use it's strength of higher power output. If they were to up the charge rate to 2a it would have a much wider use case. Multiple devices for example. With 1a, they are competing with other charge boards that are smaller but do the exact same thing in the end. Perhaps it’s possible to change a resistor for a higher charge rate if it's worth your time. But Waveshare should up the charge rate or publish how to do this to differentiate the product. It’s very interesting, and a very complete charge unit, but the completeness is lost w/o being able to use the power to charge or supply something greater than 1a.

versatile solar input; going to put a 250-350mAH 12v pv on it to keep its footprint small; reusing (have to reverse leads on connector) li-ion 2.77Wh icr14500 750mAh 3.7v from just dead just out of warranty Biolite personal solar lights (batteries are ok; charging circuit on all 5 never worked failed all withing 3 months of each other). may desolder battery holder and hotglue the 14500 in place; the connector is correct after reversing leads and plugs into socket on the pc board; first one charged using usb connector; output was ok to recharge other usb devices. Align on board jumpers to make close match to solar input.