This is a placeholder topic for “Solar Power Manager Module (D), Supports 6V~24V Solar Panel and Type-C Power Adapter, 5V/3A Regulated Output” comments.
Solar Power Manager Module (D), Supports 6V~24V Solar Panel and Type-C Power Adapter, 5V/3A Regulated Output, Optional For Battery Holder (Batteries Are…
Read moreApprox how long would I expect to charge 3x 18650 from cutoff to fully charged, with a 6v 10w panel on a typical sunny day using this solar power manager?
What is the difference between a Type D and a type C
Assuming the panel is running at max capacity with no loses across the manager board you would be looking at ~4.5 - 5 hours to charge 3 18650s with a capacity of 2600mAh.
The C variant of this board is not one that we currently stock, the biggest difference between it and the D variant is that it is closer to a portable phone charger with USB outputs, and can only accept power via a barrel jack.
FYI … Waveshare have a rel 2.0 version of this board, which has updated a few of the chips and added a button which is described as
Function button
Single press: Automatically activate the output when a load is connected
Double press: Enters low-current mode, supporting ultra-low power loads
I have just swapped to this board, and found that this SPM board appears to turn off when my ESP32-S3 went into deep-sleep (ie it didn’t wake up as it should have). A single press of the Function button restarted the ESP32 … but a double press allows the ESP32 to wake from deep_sleep as i intended.
Will the Waveshare SPM work correctly without a battery connected ?
I have previously noted that, while the Solar Panel outputs about 5V during daylight hours, the solar panel only supplies a small current - up to 300mA in direct sunlight. My guess is that UM FeatherS3’s 5V_in is expecting a constant current - ie a USB power adaptor; and that the SPM requires a battery to provide a steady current … so does that mean that I need 2 LiPo batteries ?
OK, in the real world…
Hi Donald
While not knowing anything about this specific device there awesome things that apply to anything.
Firstly for calculations any comparisons convert to Watts
That is 1.5W.
It might be possible that 1.5W is all the load required at the measurement time. If so it will not provide any more. Even if capable of more it will not provide any more than what is needed.
The SPM cannot provide any more power than what is input to it minus conversion losses. In this case if 1.5W is indeed the maximum solar input if you allow for conversion efficiency which could be as bad as 85% you could end up with as low as 1.275W at the SPM output.
Whether this is enough to restart your Feather device depends on that device requirements.
I think you looked into this sort of thing previously have you not?? I thought you had a system sorted.
Cheers Bob
Sorry Robert, you caught me while I was editing my post to make it more meaningful.
I had … and even put it into operation in the greenhouse
… then I decided to add a watering function
… and swapped from a Latching Relay + Solenoid to a latching Solenoid + motor driver (to give +ve and -ve pulses on the same pin)
… and swapped the DFRobot SPM for the Waveshare SPM
… and lastly swapped the ESP32-S3-Devkit-S for an Unexpected Maker Feather S3.
Seems that the more i learn and understand … there is always more to pull my hair out over 
I was more concerned about the 5V-in power flashing on and off at high speed - didn’t think it would be helpful
Hi Donald
Sounds like it would indicate the input voltage dropping or being pulled down in a cyclic manner. Could be worth looking at with an oscilloscope. I think you have one do you not?
Cheers Bob
Hey there, @Donald23173.
Based on the fact that the Waveshare Solar Power Manager (D) expects 6–24 V on its solar input, and relies on its battery to buffer the variable panel output. A nominal 5 V panel is below that range, and without a battery the 5 V output can become unstable. The flashing LEDs you’re seeing are consistent with that, rather than something I’d feed into the FeatherS3 continuously.
If you want to retain the 5 V panel, you will need to use something like DFRobot Sunflower Solar Power Manager 5V which is designed for a 4.5–6 V solar input. Otherwise, use a panel whose loaded operating voltage remains above 6 V with the Waveshare board. An oscilloscope across the manager’s solar input and 5 V output should confirm the start–collapse–restart cycle.
Well spotted Jane. I bought the Waveshare SPM so that in future I can upgrade to larger solar panel - and forgot that my current panel is below its minimum. 
I’ll go back to the Sunflower SPM 5V with solar panel and connecting 5V Out to the microcontroller board - but I’m not confident that the SPM will operate as expected without its own LiPo battery. I’m afraid I will need 2 LiPo batteries if I want to use the UM FeatherS3’s LiPo connector and battery voltage monitor with a solar panel. Overkill.
But I just came across a forum post on DFRobot which made this click for me. As I understand it, the answer is to connect the Sunflower SPM’s battery connector to the microcontrollers Battery connector. The microcontroller can read the battery voltage, and the SPM will do the solar charging.
Hey there, @Donald23173,
I’m not confident that diagram translates safely to the FeatherS3: the Sunflower header appears to be arranged −, +, +, −, so using the two centre terminals would connect + to + and provide no voltage across the ESP32. I wouldn’t use USB as a workaround either, since that could place the FeatherS3 and Sunflower charger circuits across the same LiPo.
As to whether it would work without the LiPo, I doubt it would.
I have tried inputting a constant current from a Micro-USB and out from the SPM, but I could not even power a microcontroller. From everything I’ve seen with SPMs, they really are expecting the battery to be connected to work as a buffer and regulate voltage.
Hi Donald, Jane
I am currently looking at the diagrams (Fritzing ??) on Core site for the DfRobot device you kinked.
Here is the first copied straight from that page
Now this leads me to believe that your LOAD connection to the green blocks could be incorrect. This is an input for conversion to 5V and an output to suit charging 3.7V cells which ever is appropriate at the time.
This is backed up by the third image
This looks like that once again a device is trying to be used in a manner that it is not designed for.
While we are here it is worth noting the conversion efficiencies
Not the most efficient kid on the block but convenient and looks easy to use so maybe worth the trade off.
Cheers Bob
Donald, Jane. Add on to this scenario:
Having a few more thoughts here.
It is quite possible that your proposed connection to the load to the green terminal block may work. I would need to see a schematic to comment definitely but here are a couple of thoughts.
I assume the green block and JST are connected together in parallel.
While the solar and USB inputs are not suppling charging power the battery will be providing power to the 5V output and in your case the loads it is connected to the green block.
If the solar IN and/or the USB charging IN are powered the JST (and green block) should go into Charging mode and output charging power to the JST and Green block to charge the LiPo cell.
In this situation the voltage at the LiPo (and load) could be up to 4.2V to charge the connected cell. But only at the max current (900mA I think) that this charging system will provide. If the load current and charging current exceed this you will have a problem.
Now I don’t know how well this 4.2V would be tolerated by your load. Might be OK as a fresh cell would be 4.2V for a while. There again it might not.
I am not about to find out either as I am not likely to attempt this configuration at this time so will leave this up to you. I don’t have the parts anyway but will leave you with these thoughts for you to consider. Might give you some ideas.
I am sorry to be so thick, but I don’t have an electronics background, and I don’t understand your arguments.
My objective is the low quiescent current that newer battery-powered ESP devboards are designed for, by utilising the LiPo connector and voltage measurement built into the ESP32 FeatherS3 (or Firebeetle 2, or other) board. This should also reduce parts count and complexity.
Is this better ?
The Sunflower SPM has NO LOAD - all it is doing is charging the LiPo battery … by pushing current out the SPM’s battery connector. Does it matter to the ESP32 whether electrons it receives are coming from the battery or from the SPM ? As long as the voltage & current isn’t higher than a LiPo might supply, I assume not.
I am not trying to operate without any LiPo battery - but my previous attempt using the Sunflower SPM (as in the example Robert quotes) required two batteries.
Robert, what circuitry is between the Sunflower SPM’s “Li Battery IN” terminal block and JST connector ? I assume none. And how does the battery get charged if it is an INPUT only ?
As for the third image…
The solar panel is connected to the Sunflower SPM and charging it’s LiPo - which is converted to 5V and passed to the ESP32 to charge it’s LiPo - which is used by the ESP32. This seems excessive conversion inefficiencies and unnecessary expense.
Robert I am still open to your suggestion of what is the right device to connect a solar panel safely to the 5V input of an ESP32 to charge the battery.
Hi Donald
Donald, far from it. Actually full marks for getting so far.
Not arguments
I am sorry I am not familiar with these boards (or many others might add) and don’t have time to research at the moment.
But if the 2 “Battery” connectors on the SPM are indeed connected in parallel then your revised sketch
is electrically the same as your original in the previous post with the battery connected to the JST and the ESP32 connected to the terminal block.
As I said in the “add on” to my previous post that set up may well work if the ESP32 can indeed be POWERED via the battery connection. You will have to try it as I don’t have the bits.
I would expect a direct parallel connection so if this is the case your assumption of “none” would be correct. Without a schematic or actual device I have no certain idea.
I would assume It is only an input in the absence of an external charging voltage from Solar or USB or other. and the 5V output is generated from the battery. When these voltages are present this point becomes a controlled charging source.
I THINK as in the absence of a device or schematic I would not guarantee this to be correct.
I think our wires could be crossed here. The “3rd image” I referred to is on the Core product page for the Sunflower Device. There are 3 images stacked in a group which I copied in my previous post.
It is not. It looks to be shown as being POWERED from the battery connected to the JST connector.
Regarding your last image:
You now seem to be going in circles.
The Solar when present charges the battery and supplies regulated 5V to the load (ESP32) which in turn charges its own battery.
Solar disappears so battery now generates regulated 5V to load which in turn continues charging its own battery.
When Solar battery depletes regulated 5V disappears and ESP32 is now powered by its own battery
Questions:
What exactly is that new device that you have introduced at the bottom left of the image. I just love (I don’t think) unknown new things just popping up in the middle of a problem. I can’t read any info here as it is too small.
What is needed to power the ESP?? 5V, Battery or both. That is is the primary power 5V with the battery being a UPS type of back up or both needed. I gather from your posts the ESP is capable of charging this battery and monitoring it. In which car there is some duplication going on.
Cheers Bob
Hi Donald
Eureka !!!
Have found a schematic for the DfRobot Sunflower device.
Have got some tree pruning to do tomorrow but will have a good look at it first chance I get.
At first glance I don’t think it advisable to connect the “Solar” battery and ESP32 to the same point. I think you will lose the built in battery protection if you do this.
Can you post a link or something for the ESP32 details or the Core SKU number as I might be able to come up with something definite if I can find a schematic or some sort of description of how this section works
Cheers Bob
Hi Donald
Regarding use of the DfRobot Sunflower management device linked by Jane
Be very careful here. I would suggest you carefully look at the product Wiki available via the Core product page or here
The schematic is available via a link in the Wiki or here
I suggest you DO NOT connect anything to the BATT input except a single 3.7V LiPo cell. in other words DO NOT connect the ESP32 device to the BATT input as you show in posts 9 and 13.
The reason is the Sunflower has a battery protection arrangement fitted which connects the batt negative to ground. In the event of the battery subject to a destructive condition (low volts, high volts etc) this connection is broken which will isolate the battery. This condition remains until the reset button is pressed or a fully charged battery is fitted. Much like the individual protection fitted to some cells. Pressing the reset button momentarily connects negative battery to ground and resets the protection chip.
This can be seen in the relevant part of the schematic.
Reference your second schematic (Fritzing ?) in Post 13.
I still don’t know what that device is at bottom left. I don’t think it can be connected for the reasons above. Depends what it is I suppose.
Using 2 LiPos actually gives 2 levels of UPS.
When the Solar loses input the 5V from Sunflower output is maintained until the battery voltages drops to 2.4V and the protection isolates it. The battery connected to the ESP then maintains operation of the ESP until it too depletes to a predetermined point.
This is how I think it should work anyway.
You could finish up going in circles a bit. I don’t know if the battery protection will reset when Solar power reappears, it might if the initial charging voltage is high enough but if not the button would have to be pressed or a full battery connected. Either one would be pretty inconvenient. I just don’t know and to find out some deeper research into the protection IC data sheet might be requires.
An added bit of trivia. If you look at the Solar charging section of the schematic you will see that when USB power is connected this takes priority and isolates the Solar panel.
Cheers Bob
Found an English Data sheet for this protection IC. DW06
http://www.pingjingsemi.com/UploadFile/pdf/DW06.pdf
Bob, Bob, Bob … I think you’ve got it the wrong way around. I’m not looking for problems. I am looking for a solution.
Anyway, my DFRobot Firebeetle 2 ESP32-C6 devboard has arrived, so I am even now doing yet another change to my greenhouse project.
The major advantage is that the Firebeetle 2 board has the MPPT built into the board - so the 5V solar panel and LiPo both connect directly to the Firebeetle - removing the need to keep a Solar Power Manager board in the mix, and thus simplifying the system.
My main concern is that the ESP32-C6 doesn’t have as much memory, or as fast a processor, so I may have to forego some of the functionality. We shall see.
BTW, the “new device” in the bottom left corner is an INA3221, which measures 3 channels of voltage and current, and communicates to a microcontroller through i2c … because I do not want my microcontroller dying without warning because a battery was depleted.
@Jane FYI, I have had the battery connectors wired as per my post of 7th August (that’s 9 days now), and it seems to be operating well … except that the UM FeatherS3’s voltage measurement seems to max out at 3.65v. I still have the INA3221 and a voltage display connected, so was able to see that the Sunflower 5V SPM did still charge the battery up to 4.15V. Possibly that is a quirk of the ESPHome ADC software. I let the battery run down, and once the battery voltage came below 3.65V they all tracked together down to 2.7V
Your current stock of UM FeatherS3 is the [D] series which uses a MAX17048G+10T to measure battery, so shouldn’t be a problem.
Hi Donald
I think we are getting confused here.
“Solution” to what. I would think that a “solution” is what is requires to resolve a “Problem”. I think maybe the “Problem” is a terminology one.
So far I for one am not quite sure what your ultimate goal is. I surmise hat you want to operate this ESP32 device from a Solar charged battery. Then you produced a Fritzing diagram asking would this be OK to connect the ESP in this manner.
I replied I thought this was not a good idea, then went on to explain why. Namely connecting the ESP to the battery in this manner would effectively bypass the battery protection.
You have just explained to Jane how this configuration did actually work. This is probably true but the re will be no battery protection in this case. I have thought about this some more and the protection could be restored if you connected the ESP negative connection to GROUND instead of BATT NEG. This would probably restore voltage reading tracking. The slight discrepancies could be the voltage difference between BATT negative and Ground. Due to the small Mosfet voltage drop connecting BATT negative to Ground.
That “new” thing I referred to is as you say a batter voltage monitor. Connecting as shown will bypass the battery protection and to prevent this the negative input should be connected to Ground for the same reason.
Of course if you wish to disregard the battery protection please disregard all of above.
If you connect to this battery what would you do with the 5V output ?? You have not revealed what the SPM 5V output load would be up to now. Just the ESP32 or some more.
Your latest acquisition of a new model ESP32 looks to be the goods. As you say all the Solar/USB charging arrangement and battery monitoring is on board. All clean and tidy and as you say you get rid of all the external bits except the Solar panel. This will have to be big enough to replenish the battery remembering the sun “moves” at 15º per hour so restricting useful output to something like 4 or 5 hours. Unless you are tracking the sun but that is another can of worms I don’t think you want to open.
Let us all know how this new device goes. Complete with you final diagrams.
Cheers Bob
Hey there, @Donald23173,
Well, colour me surprised. I’m glad to hear the setup is operating ok, even with the voltage measurement issues.
Good to hear the Sunflower arrangement has also been running reliably in practice. Let us know how it progresses.
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