Li - Ion Battery Level Indicator

Are you looking for a simple circuit to measure your Lithium Ion single cell charging and discharging level? Here is one chip circuit, powered up from the same Lithium Ion battery you want to measure.

This circuit is design to measure 3.7V rechargeable batteries level.

4.2V - 100%; 4V - 80%; 3.8V - 60%; 3.6V - 40%; 3.4V - 20%

LED1 - RED; LED2 - YELLOW; LED3 - YELLOW; LED4 - GREEN; LED5 - GREEN

D1 is used to protect a circuit from the battery being placed wrong way. You can use 1N4007 or something similar.

When this circuit was simulated on LTSpice, I used R1 value 18k, however, after this circuit was soldered on a printBoard, this value was to high, so i had to change it to 15k. It might be because of inaccuracy of the other resistor values.

LM339 datasheet: http://www.onsemi.com/pub_link/Collateral/LM339-D...

The circuit for 12V battery level indicator was found on http://www.electroschematics.com/6868/12v-battery...

but with the changes was made to measure 3.7V batteries.

4 People Made This Project!

Recommendations

  • Build a Tool Contest

    Build a Tool Contest
  • Remix Contest

    Remix Contest
  • Epilog X Contest

    Epilog X Contest

24 Discussions

0
None
jchristakis

2 years ago

is there any way i can regulate the margins of voltage that the leds are working? meaning, when i put it on a simulator, it works for voltages 3.7V to 4V. is there any formula to calculate the R1 and R2 or any other resistors needed for a lower margin 2V to 4.8V?

3 replies
0
None
jchristakisjchristakis

Reply 2 years ago

nevermind my previous comment. i m so nab i totally missed to consider kirchoff's laws.... i am designing the pcb now . message me anyone for a copy if you want it.

0
None
acidkiddjchristakis

Reply 2 years ago

Please sendme the PCB design Thank you

info@digico.in

0
None
ChochoR

1 year ago

I have a 3s3p battery pack 18650 and i have a voltage meter as well. If i understood correctly the instructions, it should be like this:


20% 40% 60% 80% 100%

10,2V 10,8V 11,4V 12V 12,6V

(3*3.4) (3*3.6) (3*3.8) (3*4) (3*4.2)

Am I Correct?


0
None
LenarOX

1 year ago

I think this doesn't work without a zener diode because the battery voltage changes and the reference voltage too

1 reply
0
None
gsmhackLenarOX

Reply 1 year ago

yep, thats what I think, too... Aaaaand, yes, the original 12V version used a zener... This circuit is useless.. :(

0
None
rahuldj

2 years ago

Hi , This is very useful, can you please send PCB design and schematic at rahul.jinralkar@gmail.com? Or post it here itself

0
None
leodemon

2 years ago

need a circuit which shows battery level during charging, for charging purpose consider a simple nokia lion bat charger which produce around 5 V

0
None
gaurav_23

2 years ago

Will it work for li-ion battery pack in 4S?

0
None
kamhagh

2 years ago

Don't resistors only limit current? And doesnt the - on the comparators change as battety voltage drops?

Anyway to get more accurate readings to my arduino? I want to be able to tell percantage

0
None
Vitor HugoC

2 years ago

PCB Please :)
vitorhchavesc@gmail.com

0
None
SubhodipM

2 years ago

hello....can i use it in 7.4v circuit?? if not...then any suggestions.... NEED HELP..

0
None
FatihF2

2 years ago

hi i try it in Proteus program and its working but when its 3,7 v its all led are on but they are dim and when giving more then 3,7 v until 4,2 its just all leds is on and just giving more brightness. why is that

0
None
DejfM

2 years ago

Hi, can you pls send me schamatic? dejfmastejn@gmail.com thank you very much

0
None
MoezT

3 years ago

can you send me pcb secheme ,lllmoez@yahoo.fr ,i release the circuit in

BREADBOARD

but wan't work

0
None
FahmiN4

3 years ago

Could I get the PCB Scheme? Send to my email : fahminlb33@gmail.com

0
None
RaulE3

3 years ago on Introduction

Hello, this apply the same way for batteries Li-Po. Thank's

0
None
amiir

3 years ago on Introduction

can u please upgrade this circuit for 6V battery?