SKU: DFR05595 5V solar charger

I am looking to maintain a 5V supply for an arduino project 24 x 7. I see this device use a 3.7v battery. Does this mean the output will drops to 3.7v at night ?


Hey Robert,

Welcome to the forum, thanks for posting :partying_face:

Was that DFR05595 that you’re referring to? Typically with an appropriate breakout to regulate the voltage (with LiPos to 5V this is often a DC-DC boost converter) even though the LiPos voltage out fluctuates between around 4.2V and ~3.6V depending on the manufacturer, capacity, and present charge the voltage headed to your board will remain relatively constant.

I’d suggest taking a look at Tims tutorial for setting up a Solar Powered Raspberry Pi, you can use essentially the same principles in your own project to power an Arduino instead (which typically can even accept a wider and higher input voltage on the Vin than a Pi):


Assume you are refering to a DRF0559 Sunflower: Solar Power Manager 5V.
No, the output will not drop until the battery is discharged.

I have one of these and it works good to charge battery when connected to a solar panel and when the sun goes down continues to provide 5V output until the battery is discharged. You need to decide on the battery capacity and the solar panel to allow your circuit to work all the time. Consideration also to how much capacity the Sunflower has to charge the battery and still provide enough current to run the circuit.



Yes, that was the device and a very interesting tutorial. Would love to give it a go just hard to justify $240 for the panels when the project is just a weather station !!


Out of curiosity what solar panel are you using ?


An important point is the DRF0559 Sunflower: Solar Power Manager 5V can only be used with 6V max solar panels.

Its bigger brother will work with standard solar panels which output 21V or so, unloaded. DFR0535 Sunflower: Solar Power Manager 9V/12V/18V Also have this unit. Note: the 9V/12V/18V in the title refers to the solar panel voltage not the output voltage. The DFR0535 provides 3 outputs, 3.3V, 5V & 12V. It is more expensive but it would be my choice for a fixed weather station.

I have this device connected to a 20W solar panel from Jaycar mounted on my house roof. At $59.95 its pretty expensive, but it is the highest power the DRF0535 can handle. Depending on your requirements the 10W or 5W may be ok.

Ok; with the DRF0559 I used a 2W Solar Panel 80X180 (Seeed Studio) SKU: SS313070003. These type of panels deteriorate over time because of the material used even if not in the sun. The 20W panel has a guaranteed 20 year life before it falls below 80% output.

The setup with the DRF0559 and Seeed panel is mainly used as a portable setup to charge a phone or other device when there’s no mains power available. Like camping, etc. The whole setup can easily fit in a backpack. But at 2Ws it can take a long time to charge anything.