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I'm trying to build an Arduino 4WD smart car. so i connected my l298N motor driver module with my v4 shield and used a 4 x 1.5v AA batteries to try and power my 4 motors up. i connected 2 of the motors in parallel so i can use 1 L298N to power it on. initially it worked but then a few minutes later it stopped moving. i thought my connections were bad so i redid all the connections but it didn't work so i changed the battery to 9v. with this the motors worked for a few seconds then stopped but was making noise so i tried powering the motor driver with my Arduino but it didn't come on. I tried powering the motor driver module with my Arduino but the driver module didn't come on.i decided to use my bread board and l293D IC to control my motors it didn't work but the motors were making noise. I changed my motor to one that i removed from a PlayStation controller but nothing still.i did research on the internet and was advised on this tutorial (https://create.arduino.cc/projecthub/maxxlife/arduino-4wd-car-cf5fd0) to not use AA batteries but no explanation why. so i checked other tutorials and saw people using AA to control 1 or 2 motors. Why shouldn't i use AA batteries? does anyone please think they know the solution to my problem? thank you

This is how my kit looks https://www.ebay.com/itm/NEW-4WD-Robot-Smart-Car-Chassis-Kits-car-with-Speed-Encoder-for-Arduino-M26/201561877173?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D777000%26algo%3DABA.MBE%26ao%3D1%26asc%3D36860%26meid%3Dc76077722d4348e88152fa6c7f32c005%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D181329341315

Also should i change my use Li-ion battery 18650 x2 instead of the 6LR61 9v battery i used

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    go back to the begining ... one motor, 4 AA cells, simple sketch that runs the motor in one direction for 1 second, stops motor for one second and repeats – jsotola Sep 24 at 20:14
  • I tried that but it didn't work so i checked the voltage reading of the AA and i got around 5v. i tried my 9v battery but i checked the voltage reading first and it was 7v. the motors worked for a while but now have stopped working i checked the voltage readings and i'm getting 4v – Ayanfe Adekanye Sep 25 at 6:08
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Rule #1 9V batteries a power supply they are NOT. In your case you are looking at small voltages for the motor power. Your choice of a driver is not the best as you will have from 1.2 to 2.4 volts across the L298 depending on the loading. This is directly from the ST data sheet. Try the TB6612FNG instead, taking advantage of the device’s use of MOSFETs. The TB6612 may be a little more expensive, but it will be clearly worth it.

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    Thank you for your answer but i don't really get what you're saying. i know the L298N is not really a good choice but i don't really have an option on what motor driver to use because of where i live. I did some research on the web and i think my problem is the batteries I'm using. i think the 9v and AA batteries cannot supply enough current for the 4 motors but I'm not sure. what do you think? – Ayanfe Adekanye Sep 27 at 19:05
  • I agree. Batteries have a discharge curve which shows how much you can get out of them with a given load. Overloading them causes them to lose capacity. – Gil Oct 1 at 4:41
  • I changed my batteries to 2 18650 li ion batteries and now the driver works well. But can you please explain how i can calculate what battery is best to use. thank you for your help so far – Ayanfe Adekanye Oct 6 at 16:17
  • You are welcome. That I cannot do, I do not know your resources, what the final design is like, how many you are going to make, what the actual load is, what the efficiency of your system etc.. That decision you have to make and rest assured there will always be a better one but there are also a whole bunch that are not as good. You are the design engineer you get to make the choice you will be happy with. – Gil Oct 7 at 19:25
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I give you credit for trying. In your spare time read some materials on basic electronics. I will see if I can help but no guarantee. he motor driver you are using has transistors as the driving element. That indicates the motor power is going through them. Since they are transistors they have a PN junction. When voltage goes through a silicone junction it will drop 0.7volts for each junction. If lightly loaded sometimes less. Note: this loss is expelled as heat. You have two configured as a darlington configuration on each output. This places two junctions in series with each motor lead. That is a total of 4 junctions yielding a drop of 4 * 0.7 = 2.8 Volts. Subtract that from your supply before you start, that is a big hit in low voltage systems. The MOSFET will have a drop of about 0.05Volts on each side leaving you 2.7 more volts to work with. Batteries have power ratings, these are conservative:

Type Cap (mAh)) Drain(mA) - D 13000 200 - C 6000 100 - AA 2400 50 - AAA 1000 10 - N 650 10 - 9 500 15 -

The battery capacity will be better with lower drain currents and shorter with higher drain current. To determine your battery life, divide the capacity by the actual load current to get the hours of life. For example: A circuit that draws 10 ma powered by a 9 volt rectangular battery will operate about 50 hours: 500 mAh /10 mA = 50 hours The cell voltage of alkaline cells steadily drops with usage from 1.54 volts to about 1 volt when discharged. The voltage is near 1.25 volts at the 50% discharge point. Alkaline cells exhibit a slightly increased capacity when warmed and the capacity drops significantly at temperatures below freezing. Mercury and silver oxide batteries have nearly twice the capacity as alkaline batteries of the same size but the current ratings are significantly lower. Alkaline batteries also have good shelf life making them ideal for home-made electronic projects. Rechargeable batteries have less capacity than primary cells Look at it like the batteries are your piggy bank. The more your take out the less you will have. The faster you take it out the quicker you are out of money.

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  • ok thank you. but i still don't really get this.is drain how much current it can produce? if no then. According to the info i found on the internet the dc motors take 100mA at 5v. since 9v batteries have a type cap of 500mAh then shouldn't my motors last at least 5hrs or this is wrong because the drain is 15mA so i should use a type D or C battery. Also if i connect 4 AA in series does this increase the drain. i also connected the 9v battery and 4 AA in series and the motor came on and rotated faster and longer than using 9v alone i know this is part due to the increased voltage – Ayanfe Adekanye Sep 29 at 18:56
  • But does the drain of the batteries also increase to 215mA? Li-ion have a capacity of 2200mAh so if i use 2 for my 4 motors then it should last more than 5hrs (2200/400) so doesn't that mean Li-ion or Lipo is my best bet? – Ayanfe Adekanye Sep 29 at 19:04

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