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S9V11F5S6CMA working until connected to TP4056

I want to use the S9V11F5S6CMA to take Voltage of around 4 V-10 V from my Solarpanel in and give out 5V to power the TP-4056 to charge li-ion batteries. It works when it’s not connected to the two TP-4056s that are connected in parallel (work correctly via USB and worked a number of times by just pressing VOUT and VIN of the Regulator against + and - of the TP4056s). However, usually the Voltage drops to a stable 0.88V and stays there until I try to solder something on VOUT and suddenly it’s back to 5V (Perhaps the heat causes some kind of refresh?). I have no idea what I’m doing and I don’t want to damage the regulator… I hope somebody can help me

What I forgot to mention: The Input voltage measured on the regulator is also at just around 2.33 V when it gives out 0.88 V. It should instead be at least around 4-5 V.


Since the input voltage to the regulator is dropping, it sounds like your solar panel is probably not able to produce enough power for your charger and batteries. From some documentation I found online for the TP-4056 module, a source with at least 1A available is recommended. Have you tried powering the regulator with a different source like a battery or power supply? Could you send pictures of your setup that show all connections including the solder joints?


Hi Claire, I read that the max. input current of the TP4056 is 1A and my Solarpanel also produces up to 1A, when I put it under a bright day lamp, so I don’t think that’s the problem. At times it did work already when I connect VOUT and GND of the regulator with the TP4056. In shade with bad lighting conditions, the blue light of the TP4056 flickered and turned blue in good lighting. But as I said I wasn’t able to get it working soldered because VOUT switches from 5V to 0.88V( also under the lamp), that’s probably why the lights of the TP4056 don’t light up at all. I will try a different power source and send you images of the setup in a few hours!

I tried supplying 5V from an Arduino Uno to the regulator- you were right, everything worked! So-the TP4056s apparently works correctly (tried disconnecting it from the regulator, didn’t matter) and the problem seems to be that the solarpanel doesn’t give out a high enough voltage(around 2.3V), hence the 0.88V output.That’s why I desoldered it and measured again - around 6V. When connect to the regulator the voltage drops.
Image of TP4056 when Arduino Uno is connected to the regulator:

images of setup:

image of solar panel when (dis)-connect from the regulator:

Do you have an idea what may be the cause of my problem?

The voltage from your solar panel dropping when you connect it to the regulator is a strong indication that it is not producing enough power for your load as Claire suspected, and it seems like you established that in your last post (given that it worked when you powered it from a different source). Is that the problem you are referring to, or are you asking about something else now?

By the way, it looks like a lot of the wire in your setup is bare, unprotected wire and there is a high chance that something will short and cause some kind of damage to your system (if it hasn’t already). I highly recommend reworking your setup with insulated wire.


Hi Brandon, I just think it’s weird that it worked already (even in shade), so the power there didn’t seem to be a problem. With low power the indication light just flickered a little. If I put it under a bright light at other times, it doesn’t react at all (Voltage too low). So I don’t think the low power supply of the solar panels is the problem (Why would it work in worse conditions?). My question is: how can I make it reliable? Do you think a larger solar panel would solve my problem? I am still in doubts about that. Thank you for your premonition about the wires, I used them just for this prototype and was very cautious. Greetings, Philipp

It sounds like your system is working intermittently, so there could be a combination of issues and confounding factors. For example, the chargers will likely draw more power with fully discharged batteries than almost full ones, and the level of sunlight will affect the output voltage of the panel, which will affect the power conversion and efficiency of the regulator. At 1A the losses in your wires might also be significant, and this sounds like the unpredictable behavior you might get with a flaky connection. It sounds like you have done some of this already, but I recommend testing each piece of the setup in isolation and then adding them together one at a time to pinpoint where the issue is.