Okay so i got the esp8266 Wemos d1 r1 board that I used to make a 2WD car controlled by an app on my phone. I'm using an l298N motor driver to drive the two generic BO motors. The issue is that I'm using 2 9v batteries, one to power the L298N and one to power the Wemos. Both are straight out of the box, new batteries. The setup worked fine for hardly 3 minutes before the motors started slowing down and sometimes even refused to turn. Also he led on the driver gets dimmed wherever I give the command for it to move.
So I went through similar posts on this forum and figured it would be the batteries supplying not enough current and dying out quickly. I checked the voltage and current of the batteries using my multimeter and got 7.6V and about 0.5 amps. So my question is, can i use a 2 or three 3.7V 2000 mAh rechargeable Li ion batteries to power the driver and motors consistently and continue using the 9v to power the Wemos. Im a newbie at this so any help is greatly appreciated.
Please use schematics to comunicate.
Please read rhe datasheet for the driver. It tells the minimum voltage for the motors.
9 volt battery? Hope it's 6x AA.
Forget 9V batteries. They are great for the smoke detectors in your house, but not much else.
Please post a link to the li-ion battery so we can check it will be safe and suitable, or what else you need to make it safe and suitable.
The safest type of battery pack for you to use would be 4xAA or 4xC NiMh rechargeable cells in a holder.
Lithium rechargeable batteries are more dangerous, if you don't know how to use them correctly. They can explode and start fires. But they can be used safely if you know how. They also need special chargers.
Li-po battery packs are relatively safe because they normally have a tiny circuit board inside which protects the pack from over-discharging and dangerously high output currents and short-circuits.
Li-ion batteries such as 18650 size sometimes have similar circuits built in but most do not, so you will need to add those extra circuits yourself.
Whichever type you choose, they should be able to run the Wemos and the motors together.
However, you should replace the L298 driver. It's an old and inefficient design and will "drop" around 2~3V, leaving very little for for motors.
I suggest you read some of the posts on this forum, several times a week the L298 and 0V batteries comes up. The recommendation consistently is not to use either for the above stated reasons.
It should work ok, but it has a very low capacity for 18650 size. The ones I have are about double that. They are LG brand. You can get even higher capacity, over 3,000mAH.
You may also see 18650 size that claim to have very high capacity, but they are fake/scam and their true capacity is a small fraction of what they claim. My advice (learned the hard way): only buy a high capacity 18650 with a well known brand like Sony, LG, Panasonic etc.
Yes, that is good. But you must permanently wire it into your circuit so that it can protect the battery when it is in use, not only when it is charging.
The battery you have ordered has no built-in protection circuit, so you must have one in the circuit when the battery is used. The charging board you have ordered also contains a protection circuit.
If you want to keep that charging board only for charging, you can additionally buy a small protection board. I have used this type and they work well (sorry for the bad quality image)
I hope the 1200mAh ones will last atleast an average amount of time. As for the charging module usage, should i have the batteries in parallel or series connected to the module? If it were without the charging module, i would've probably used three of it in series to get 3.7*3 Volts to power the Driver.
Have you tested your motors yet with 3.7V from a li-ion battery? You may find they run well. So far, you have only tested them with L298 and 9V battery, which is not a good test because the L298 will drop a large voltage, and the 9V battery will drop even more volts when you try to draw a large current.
i will need atleast 3.7*2=7.4V to drive the motors and a third battery maybe to account for the drop across the L298N, so three batteries in series should work fine, but then would connecting all three in series to the charging module be fine?
No, it would not work. That charging module can only charge single batteries.
If you use 3 batteries in series you will need either a protection module for each battery or maybe a protection circuit designed for "3s" which means 3 batteries in series.
It would be better to replace the l298, then only 2 batteries would be needed, and less energy would be wasted.
So, I ordered 2 more TP4056 charging modules, one for each battery, and in the meantime, i hooked up one battery to the module, and when i check the voltage across the out+ and out- terminals, its about 4 Volts although the battery is rated 3.7 V. Also, when i check the current across the battery terminals directly, it reads about 11 amps and when i do the same across out+ and out- terminals, i barely get 0.1 amps. Is this normal?
Edit: I plugged in the TP4056 via micro usb and now i get 4 amps output across out+ and out-. Wait, so does this mean i will have to have the charging module hooked up via micro usb while its powering my 2wd motors?
You are short-circuiting the battery, which will damage it. Do not do that!
The protection module is probably doing its job and protecting the battery against you short-circuiting it.
The protection module protects the battery, not the USB. You may be damaging whatever is supplying the current. If it was a pc/laptop, the automatic protection in the pc/laptop would probably disconnect the USB device and give a warning message. Do not do that either!
That's normal. A fully charged li-ion battery is around 4.0~4.2V and fully discharged it is about 2.8~3.0V. 3.7V is simply the "typical" voltage when it's not fully charged or discharged. All batteries behave in a similar way, it's because of their chemistry. The voltage changes with the % of charge. That is how devices like smartphones can measure how much charge is remaining in the battery.
So I was trying to make a 2WD project using a wemos d1 r1 and L298N driver and I required a power supply good enough to power the whole thing. So based on recommendations I got here, I got a couple of 18650 batteries (3.7V, 1200mAh) and a TP4056 module to charge the battery. I was also made aware that I should use a protection circuit for the 18650 battery, which could be given by the TP4056 module. So i hook up the battery to the bat+ and bat- terminals and my load (power to the L298N) to the out+ and out- terminals of the TP module. The issue is that the TP module only gives output across the out terminals if i plug in the micro usb charger on its other end ;i.e.; it doesnt give an output from the out+ and out- terminals if the microusb is not powering it, despite having an 18650 connected. Is there any solution to this problem or will I need some other form of protective circuit?
I do not think you will be happy when you get it assembled. If the motors actually move I would be surprised. The antique L298N is a bipolar part with darling transistor outputs. The motor is powered by two pairs of darlington transistors which will drop about 3V. That will be dissipated as heat. I recommend you get a MOSFET bridge driver.
