For my first electronics project I needed a 3.7v 3000mah 18650 lithium ion battery to power the whole project. I thought of charging it in parallel using a tp4056 module of amazon and then boosting its output to a required 5V using the mt3608 module. I completed the whole soldering and stuff which is very rough and not polished at all, and plugged in a battery for the first time using the wires (You can see it all on the picture) note that I planned perfectly the wiring and I am perfectly sure that the wiring is perfect. I tested the output voltage going out from the MT3608 and realised it was extremely low(2,7V) even though I had previously set rhe output voltage to be exactly 5v on the module. So i was kind of shocked. I tried with multiple batteries and it did the same. Then I tried to plug in the usb c cable and it got back to normal. Completly normal, it doesnt make any sense. The voltage on each pins got back to the normal standart that I previously thought were goind to be the norm : 4v on B+/B- 4V on OUT+/OUT- 4V on Vin+/Vin- and 5V on Vout. Compared to the previous voltages. The module gave me the right voltage no matter what only after I plugged in at least once the usbc and seem to actually keep the volatge for a long period of time. Like what ? And when I plugged in the usbc again and again it didnt affect any of the previously mentioned measurments.
I don't see any parallel 18650's and that is a GOOD thing as they are prone to catching fire that way if you don't have the proper protections.
The battery pictured appears to be a 14500 800mAh battery.
If you measured voltage while unbder load then that is not unusual. If you want to check the voltage of the battery measure it with no load.
Sorry no the lithium battery is really a 18650 3000mAh battery. Here is the picture. I measured the voltage at the output pins of the mt3608 because I need it to be 5v and that's the problem. I dont eeally know what to do should I just keep the project up by just plugging the usbc once and calling it a day ?
Looks smaller, but a ruler can verify.
Disconnect the battery and measure the battery voltage.
I usually use 2 18650's in series. I also use a pro charger like the SKY RC MC3000 (old) or MC5000 (new, does NA as well)
https://www.skyrc.com/Charger/Cylindrical?from=nav
The battery voltage is 4V not3,7V 3000mAh. The idea of the pro charger is a good idea but here I already invested in the tp4056 chips so I'll stay on that option.
Charger and tp4056 are totally different things. Does the tp4056 have a storage option, discharge, cycle, etc
Ok, good luck.
I wouldn't have the MT3608 connected to the TP4056 while the battery is charging.
I use both of those without trouble, but separately.
The tp4056 doesnt have any storage option I think. It has multiple circuits that assure that there isnt any over charge and over dicharge or short. That's all.
Why ? The Mt3608 is just a step converter turning 4V into 5V. I mean its supposed to provide a steady 5v
Not without minimum current drain, and the TP4056 is not suitable for load-sharing (powering while charging) The chip can not determine when charging should stop while there is a load on the output.
The MT3606 is just a step-up chip and you have an adjustable module.
It can increase the voltage with the input being as low as 1.7v (?? just of the top of my head, check the datasheet for proper minimum input voltage), but it ca never drop the voltage down.
The output voltage can be set while the input voltage can vary, so the makes it ideal for a single LiPo cell (3.7 - 4.2v ) to step up to 5v.
So power your MT3608 with the battery, while not charging. Adjust it till the output reaches 5v, and leave it there.
how did you do that ?
Thank you very much all of what you said is gold. The lowest voltage that the mt3608 can take is 2v. There is an adjustable screw on the blue block in the picture that can determine its output voltage. From what I understand I will have to charge without load on the outputs of the Mt3608 which is doable. Thank you very much. If you understand why the voltage changes if I plug in the usb c or not hit me up.
if that output voltage is set for anything lower than the charging voltage for the LiPo (typically over 4.2v for a battery that is at least half full) then the output voltage will never be lower than that voltage. The output voltage of the MT3608 can not be lower than the input voltage. (regardless of how you adjust the screw) Once you set the output voltage of the MT3608 to 5v, connecting the usb power for charging, will no longer affect that.
Okay thank you very much. I understand everything that was wrong with the actual output. But do I let it be like that ? Do I modify the circuit or do I keep it like that and keeping the 5v indefinitely ?
Try with a load on the output of the MT3608.
Use an LED and 220 ohm resistor.
If it still acts funny then I suspect you have a bad MT3608 board.
Okay, will be trying.
You should not mess with this kind of circuitry if you have no knowledge at all, it is a bit dangerous. Storage is a charger mode just like charge, discharge, cycle.
And what was the MT3608 input voltage?
Also, is it possible that this excerpt from a DW01 datasheet is involved in some way?
If so, it's not a bug, it's a feature. You can test if this is the problem by temporarily connecting the battery negative terminal to OUT- on the TP4056 module, which bypasses the protection circuit.
The voltage going into B+ and B - was 4.0V which is the battery voltage, however the voltage dropped at out+ and out-to approximately 2.3V. How should I connect the battery without having to tear everything down ?
No, I'm asking what the input voltage to the MT3608 was when its output voltage was 2.7V, measured at the MT3608.