Fixing the Charge Circuit of the Batteries of the DC Motor

[Astonished]

Hi friends of electronics

What you see in the video and pictures attached is the circuit for charging the batteries of a DC motor.

The problem is that this circuit cannot charge the batteries (3 1800mAH NiMH batteries) any more. When the circuit was OK, its green LEDs lit up one at a time to show that the batteries have charged more. But now that the circuit is flawed, LEDs light up as you see in the video and at the same time successive beeps are heard.

Please help me fix this circuit.

(the datasheet of the IC: https://pdf.datasheet.live/28f5a65a/...461V-10SU.html)

[stj]

the charging looks like it's just current limiting and the chip does the leds.
if the cell capacity is low they will charge faster - very fast if they are killed.

are they a common size like AA or AAA?
if they are then go to ikea for some 1900 or 2400mAH re-badged eneloops
dont use Lidl batteries - they have poor lifespan

if you put a voltmeter across the cells you can watch the voltage as they charge too - to see if they reach 1.45v

[sam_sam_sam]

Where is the video link and where is the picture of the board front and back of it

If this is controlled by a micro controller it going to be very difficult to troubleshoot this device because you would have to know how each pin of the device works

But you could use a single cell li-ion BMS board would be easier to work with that is used for cell external battery packs

1.25 charges up to 1.4 to 1.5 volts. ( 1.4 X 3 = 4.2 ) this might make the NIMH battery pack not 100% charged but if you used a 4.35 volt version of these BMS boards would get you a little closer to being fully charged which would be 1.45 X 3 = 4.35

They do make HIMH BMS boards but they are hard to find but they are available you just have to do a Google search

[Astonished]

Where is the video link and where is the picture of the board front and back of it

If this is controlled by a micro controller it going to be very difficult to troubleshoot this device because you would have to know how each pin of the device works

But you could use a single cell li-ion BMS board would be easier to work with that is used for cell external battery packs

1.25 charges up to 1.4 to 1.5 volts. ( 1.4 X 3 = 4.2 ) this might make the NIMH battery pack not 100% charged but if you used a 4.35 volt version of these BMS boards would get you a little closer to being fully charged which would be 1.45 X 3 = 4.35

They do make HIMH BMS boards but they are hard to find but they are available you just have to do a Google search

I had attached all the files but they dissappeared. Again here are the attachments:



You said: "you would have to know how each pin of the device works". Can not the datasheet of the Attiny 461V-10SU (linked in the first post) help you?

[stj]

it looks like the batteries are done.

[Astonished]

it looks like the batteries are done.

Why and how does it look like the batteries are done?

[stj]

the charging looks like it's just current limiting and the chip does the leds.
if the cell capacity is low they will charge faster - very fast if they are killed.

are they a common size like AA or AAA?
if they are then go to ikea for some 1900 or 2400mAH re-badged eneloops
dont use Lidl batteries - they have poor lifespan

if you put a voltmeter across the cells you can watch the voltage as they charge too - to see if they reach 1.45v

[Astonished]

the charging looks like it's just current limiting and the chip does the leds.
if the cell capacity is low they will charge faster - very fast if they are killed.

are they a common size like AA or AAA?
if they are then go to ikea for some 1900 or 2400mAH re-badged eneloops
dont use Lidl batteries - they have poor lifespan

if you put a voltmeter across the cells you can watch the voltage as they charge too - to see if they reach 1.45v

Bravo stj!
You hit the mark: The bad battery was the culprit.
(The battery is 3 1800mAH AA NiMH cells connected in series. I fetched 3 other AA cells and connected them in series: the problem went away. Thank you very much indeed.)

1. Can you explain the differences between "re-badged eneloops" and "Lidl batteries"?

2. The DC motor in this device cannot operate while the battery is not connected to the circuit but the charger is connected. Can you show me a way to operate the DC motor while the battery is not connected to the circuit but the charger is connected?

[stj]

eneloops are made by panasonic and are the best NiMH batteries you can buy.
some companies sell them with their own name on for a better price.
https://eneloop101.com/
Lidl batteries look cheap but they are crap.

[Astonished]

eneloops are made by panasonic and are the best NiMH batteries you can buy.
some companies sell them with their own name on for a better price.
https://eneloop101.com/
Lidl batteries look cheap but they are crap.

The DC motor in this device cannot operate while the battery is not connected to the circuit but the charger is connected. Can you suggest a modification to the circuit for enabling the operation of the DC motor while the battery is not connected to the circuit but the charger is connected?

[stj]

no, because i cant see the circuit to know what it's doing.
it is probably done so you dont destroy the charger by drawing too much current.
but it could also be so you dont damage the motor with the higher voltage used to charge the cells

[sam_sam_sam]

The battery is 3 1800mAH AA NiMH cells connected in series. I fetched 3 other AA cells and connected them in series: the problem went away

The DC motor in this device cannot operate while the battery is not connected to the circuit but the charger is connected. Can you suggest a modification to the circuit for enabling the operation of the DC motor while the battery is not connected to the circuit but the charger is connected?

To answer your question no because of what I have explained below *******

*******(This is completely normal and is not an issue these chargers do not have enough current to run the motor and it probably has a cut off circuit to prevent you from doing both at the same time*****

Plus you might destroy the micro controller by trying to run both at the same time because of voltage spikes from the motor and the power supply

I am not surprised by the fact that you had to replace the battery cells so the micro controller controls the charging function interesting but I am surprised that the micro controller controls the charging function

The video confirms my suspicions about weather or not the microcontroller controls the battery charger plus does it have a speed control on this device or is a fixed speed

[Astonished]

the charging looks like it's just current limiting and the chip does the leds.
if the cell capacity is low they will charge faster - very fast if they are killed.

are they a common size like AA or AAA?
if they are then go to ikea for some 1900 or 2400mAH re-badged eneloops
dont use Lidl batteries - they have poor lifespan

if you put a voltmeter across the cells you can watch the voltage as they charge too - to see if they reach 1.45v

I have another circuit (let's call it Circuit No. 2) similar to the circuit I introduced in the posts 1 and 3 (let's call it Circuit No.1), but with some differences for example it has 2 ICs.

Unlike the Circuit No. 1, replacing a good battery did not solve the following problems of the Circuit No. 2.

When the Circuit No. 2 was OK, its green LEDs lit up one at a time to show that the battery has charged more. But now that the circuit is flawed, LEDs light up as you see in the video: just the intensity of their light increases and decreases. When the light is more intensive, the voltage applied to the battery becomes 5.9, when the light is weaker, the voltage applied to the battery suddenly becomes 4.8 and decreases to 4.3; again the voltage becomes 5.9 and after a couple of seconds becomes 4.8 and decreases to 4.3, and so on and on. (In Circuit No. 1 which now works well, the voltage applied to the battery changes very very rapidly between 4.3 and 5.3 volts so that the digits on the voltmeter are hardly readable).

What is wrong with Circuit No. 2?

[Astonished]

ٰThe video file which I had attached to the previous post is not there any more. I do not know why.
I attach it again in this post.

By the way, let me point to another problem of the Circuit No. 2: It is unable to run on battery alone (it only runs when the charger is plugged).