Hello,
i would like to power Wemos D1 mini with solar panel and two 18650 batteries. I was thinking to wire two TP4056 parallel (each charge their own battery) and with OUT pins powering Wemos. I'm also attaching diagram for better understanding. Would this wiring be OK ?
This is for my hobby project (weather station:), and since I'm more in SW development I would really appreciate for any advice from you HW gurus.. 
Thank you in advance!
Regards,
Matko
Hello,
Have you considered you are trying to power 29.6W with a solar cell rated at 2W, and I'm certain your gonna have losses in your circuits. I'm not sure if this is possible with this solar cell, but I don't have much experience with them.
I think that chip does one charge cycle only, then cuts out(*) until it is power cycled - its a phone
charger chip, not a solar panel charger chip.
It wouldn't work well in overcast conditions, its assumes the supply can provide full charge
current.
A dedicated chip that knows about the behaviour of PV panels would likely be much more
satisfactory.
And you definitely can't just parallel outputs from two such devices, they will probably get
completely confused as each one switches in and out of trickle mode...
(*) I think it will trickle-charge only once the charge cycle is only, which isn't useful for this application.
Thank you for your answer!
What dedicated chip would you advice instead of this two TP4056 ?
For reference for my wiring, i was having this project:
The place to search for components is at electronics stockists websites and major semiconductor manufacturers websites - they want to sell the parts, so they provide tools to find them...
Hello mat_ko,
In all honesty I do think that all the replies you have gotten sofar have not been very helpful.
I have been taught that it is sometimes very helpful to look at you problem very modular, and I think in this day and age were single purpose PCB have become so cheap this would be an ideal way to solve your problem. The end solution is that you want a solar powered voltage supply for you Wemos D1 mini, so you want 3.3V. Have a look at this, and scroll down to see the specs and look at the pics they posted.
This chip can be provided by either one or two 18650 batteries in parallel (not in series, because the max voltage input of the chip is 6.0V, I don't know why you need two batteries, but i'm assuming your doing this for power reasons. It is perfectly acceptable to put 2 18650 batteries in parallel, as described here.
Have a look at this, if you can agree with what we have achieved sofar then we only need to add a charger PCB for your batteries and the solar panels. If there is something you don't agree with or don't like on what I suggested so far, then please let me know
With regards,
Mike
So assuming the Wemos is asleep and in low current mode, what is the quiescent current consumption of the module you recommended ?
Mike, thank you for your answer! I really appreciate and i'm grateful for any advice or direction...
I'm fresh in arduino development and i really like to do something useful. I already have wemos with sensors, but since it's located near house i would like to move it somewhere on open space, so I need alternative power supply. I found similar projects with TP4056 (but they used only one battery) so this was my reference for thinking further. Since i was not sure about my wiring I asked here. Wemos D1 mini can be connected to 5V (5v pin), so there is no need to convert back to 3.3V.
The only reason for two batteries is because winters here can be really foggy so some times there is no sun for a week or two. So i put two of them to ensure enough power in such conditions. Or one would be enough? Wemos is reading from sensor every 5 minutes and then goes to sleep mode.
If I would take this chip u recommended, i still need charger. Could I use TP4056 as charger anyway ? Or some kind of solar regulation would be more appropriate (like this for example: https://www.aliexpress.com/item/Cool-Solar-Controller-10A-Solar-Regulator-12V-24V-LCD-Display-USB-5V-Solar-Panel-Charge-Regulator/32716946371.html )
I'm really open to any advice, so thank you again in advance!
Regards,
Matko
MarkT:
I think that chip does one charge cycle only, then cuts out(*) until it is power cycled - its a phone
charger chip, not a solar panel charger chip.
Correct.
Once a battery is fully charged you need to cycle the incoming power for the charger to start again.
srnet:
Correct.Once a battery is fully charged you need to cycle the incoming power for the charger to start again.
I'm sorry, I don't understand totally, does this means that it will charge battery only first time? What means 'cycle incoming power' ?
Thank you!
mat_ko:
What means 'cycle incoming power' ?
Removing the incoming power input to the charger.
Can you please explain this a little bit more?
If it's used as phone charger for example, when battery is full, and I don't disconnect incoming power, it will start recharging again when phone battery voltage drops.. (i'm assuming phone chargers behave like this)?
mat_ko, hello again.
I don't know why some here keep saying that you tp4056 isn't suited for this job and claim its a phone charger. When looking at the datasheet of the tp4056 it is clearly mentioned that its suited for automatic recharge and even better it has 2.9V Trickle charge threshold. It is also clearly mentioned that it is used for allot more things then charging phones. In short I do believe your choice for this product was a very good choice, you can even use this to charge two 18650 in parallel, or, if you think the sun will not play along, use two in series and use two solar panels. For being able to generate the max 1000mA the tp4056 can deliver, and witch I would recommend you will need a 5V 5W solar panel, do the math. This would be for two batteries in parallel. If you decide to go for the batteries in series I would go for 5V 2.5W or, since you prob have them use your 2W one's.
For the disbelievers of the tp4056 here is the datasheet.
good luck with your project mat_ko
Thank you Mike !
I will take more powerful solar panel 5V 5W and give it a try...
Regards,
Matko
You are welcome Matko,
I have just ordered 10 tp4056 boards myself. I would say if you want, keep me informed of your project, if you have the time.
Good luck,
Mike
For sure, I will!
It would be a pleasure to consult with someone more experienced, just to be sure that I wont burn something
Regards,
Matko
Hi Matko,
I am planning to build something similar.
Do you have any experience to share?
Did the circuit work? Or did it release the well know "magic smoke"?
You could save me a lot of concerns by telling me it worked.
Regards
Frederik
srnet:
Removing the incoming power input to the charger.
srnet:
Correct.Once a battery is fully charged you need to cycle the incoming power for the charger to start again.
Sun goes down, power is cycled.
