Using only 3 batteries in a 4-battery pack and managing L298 driver

Other Hardware General Electronics
1

Hello !
I am going to participate in a rover competition in the next month.
I am allowed too use only 6 batteries in that competition. Unfortunately, both me and my teammate could only get 4-battery pack holders.
Therefore, we initially considered just using them, but then on realizing that we need the maximum amount of power, we tried looking for a workaround, but we couldnt find a good 6 battery pack holder.
We will be using the battery packs to power the l298 d driver and use 4WD.
The battery packs look some what like this and we have 2 of these:

image
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So, is it possible to place only 3 batteries in each pack and then connect the 2 battery packs together.
Thanks in advance! Do tell me if you need any more information!

2

You need a dummy battery.
Any piece of metal the same length as an AA that will fit and stay put.

You could trying soldering a wire across one of the batery compartments but that plastic melts very easily. Believe me I tried.

Or even a piece of wood covered with a few layers of aluminum foil including the ends

3

Google has lots of options.

Dummy AA battery

Oh, and 6 AA battery holders are commonplace.

1 Like
4

I didn't realize those existed! I'm wondering if the "rules committee" would constantly be concerned about the issue of a dummy battery looking too much like a real one.

5

Given that the OP wants to use 4 motors with a L298D on 6V, I doubt that will be a big concern once they discover how much voltage they'll be losing in the L298D. If those motors are current hungry, they could lose as much as 4.9V, leaving only 1.1V to make it to the motors.

6

Thanks!
Unfortunately, our school bought it for us from the local hardware store, so buying a new one doesnt seem ideal.
also thanks @jim-p i will look into it and just confirm with the organiser's to ensure no issues arise like how @EmilyJane pointed out

7

could you elaborate? I have never used an l293d before so i wasnt aware of this issue, if i were to start a new thread to try and find a workaround, can i invite you to it?

8

Don't start a new topic. Continue here here but maybe add to the topic title

9

First you were using a L298.

Now you say you're using a L293.

Which is it?

In either case, the answer is the same: read the datasheet and look for how much loss there is between the input voltage and output voltage at the test current conditions.

10

Sorry it was a typo it is l298d. I got confused, i apologise thanks for correcting me

11

One second,
I actually have an unlabelled product, looks like this:

image
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Is this l298d or l298n.
I am really sorry for the confusion, forgive me i am still a beginner.

12

If you're going to give up that easily, okay. Good luck with your project.

13

It's a L298 driver and that is fine.

14

TT motors like this?

DC Gearbox Motor - TT Motor with two long wires and yellow body
DC Gearbox Motor - TT Motor with two long wires and yellow body970×728 66.7 KB

15

Make sure you buy the one that act as a short and not the dummy batteries that are real dummies.

16

Not exactly, its slightly different, my teammate currently has these motors currently, i will share their images perhaps a bit later.

17

Is using wood covered with aluminum a practical/effective solution?

18

Sure. Just make sure you wrap several layers and the ends are covered so that it makes contact with the spring and the little contact. I have used a machine screw of the right size with some foam and tape wrapped around it so that it stays in place in the holder..

1 Like
19

Thanks, I will try it out.
Also the rules of the competition specificlly states that only 1.5 v AA batteries need to be used and the rover needs to climb a 30 to 40 degree incline.

20

Cut a peace of metal strip and bend it to c-shape, length of a battery.
You can cut it from some tin can if you don't have anything else in hands.

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1 Like