[SOLVED] LM3914 interface to microcontroller

[shahbaz.ele]

Dear all
I am using LM3914 as battery Level indicator for 48Volts battery.
The problem is that I need to send this battery level on remote location (through lane or RS232 etc).
I want to interface LM3914 with microcontroller for the purpose.
Any suggestions ?

 

[Aussie Susan]

1) ADC (being careful to scale the voltage to the ADC)
2) Send via comms link - your choice of protocols
3) DAC to the LM3914 (setting the reference accordingly)
Susan

 

[KlausST]

Hi,

When using a microcontroller I don't see any need for the LM3914 at all.

Follow Susan's recommendation.
Even LED control can be done by the microcontroller ... if you still want LEDs.

Btw: Voltage is no good indicator for battery status. Current, temperature, aging, charge status influence the voltage in a wide range.

What do you want to achieve?
There are dedicated battery monitoring ICs (including coulomb counter).

Klaus

 

[Audioguru]

If you use a resistors voltage-divider to make the 10th LED of the LM3914 light when the battery is 48.0V then the 9th LED will light when the battery is 43.2V that is probably too low. The 8th LED will light when the battery is 38.4V. The 7th LED will light at 33.6V.
If you add a voltage to pin 4 then you can have a reduced range of voltages as shown in its datasheet.

 

[shahbaz.ele]

Btw: Voltage is no good indicator for battery status. Current, temperature, aging, charge status influence the voltage in a wide range.
There are dedicated battery monitoring ICs (including coulomb counter).
Klaus

I want to use a battery in my Robot,
want an indication at remote PC on wireless to monitor battery health.
Can you recommend "dedicated battery monitoring ICs"

 

[KlausST]

Hi,

How could I (or we) recommend an IC or a solution?
What information do we have? 48V battery. That's it.
No chemistry, no current, no capacity, no features, no accuracy, no interface, no timing....no price, no volume, no package informations...

Farnell lists more than 1000 ICs in the category "battery management".
About 250 ICs for "fuel gauge" and "monitoring".

No one of us knows
* what you need
* all the datasheet details of the available ICs

Thus distributors as well as IC manufacturers help you to find the "best" IC for you....and every one.
They provide online selection guides. Professionals use them. They are for free, so hobbyists may use them, too.

I think there is no better and no faster way for you to find what you need.
And in case you find 50 "suitable" ICs: lucky you, don't be afraid, just choose the one out of mood, maybe the one with lowest cost.

Read datasheets. Every IC manufacturer provides additional informations like application notes, design notes, calculators, design examples, evaluation boards, software... All for you, all information usually for free.
Search the internet for information from those IC users. Sometimes they talk about problems and experienc, show their hardware design, show their software..

Just a couple of decades ago when I started to design electronics there was no internet.
Can you imagine what huge benefit the internet gives? So use it.

Klaus

 

[BradtheRad]

It's chancey to use the simplest method, namely to carry battery voltage directly over a wire to your remote station.
Suppose you make a voltage-to-frequency converter?
Or, voltage to pulse width converter?

The range of voltage is likely 40V (depleted battery) to 60V (charging). It should be possible to make an oscillator respond to this range by changing frequency or pulse width.
Then send this signal over a wire, to be interpreted by your microcontroller.
Or if wirelessly then have it modulate the rf carrier.

 

[Easy peasy]

Good ideas above, you could also convert from 40V to 60V to a 4 - 20mA loop ( industrial standard ) and then re-convert from 4-20mA at the other end ( chips avaliable ) to drive the led bar graph display ...

 

[shahbaz.ele]

Can anyone suggest some IC or module used to translate battery charge status into digital data.
I am using Li-ON 48 VDC battery.

 

[KlausST]

Hi,

re read post #6.

is none of the 250 parts listed at Farnell suitable? If 200 are suitable, then be happy. Just pick one.
We can´t choose one for you, because you hide informations. Already written in post#6.

It´s like recommending shoes for you without knowing what size you need.

Klaus

 

[danadakk]

Arduino over uart would accomplish all this -

LED Bar Graph | Arduino Documentation

Learn how to make an LED bar graph - a series of LEDs in a line.

www.arduino.cc

https://create.arduino.cc/projecthub/ingo-lohs/10-segment-led-bar-graph-7e6212

And many more on web.


Regards, Dana.