DIY - Lipo Voltage Monitor (In Flight)

[w_kby]

Tip

Oh, that a easy potential meter to build...thanks for the tip.

By the way, I realise that the battery voltage falls very quickly once it hit 9.5v with the heli at hovering. So infact if the LED only lights up at 9.4V, the battery will be out in matter of seconds. May have to change the resistor value to light up the LED at slightly higher voltage than the 9.4v. Maybe 10V?

Any advise?

U can use 2 or more resistor in series... and then the o/p is tap between that series of resistor to give u voltage divider.... therefore, can create a very very very simple variable voltage supply.

U can use potential/variable resistor to do the job as well.

SH

[w_kby]

UPDATE : Lipo Low voltage warning

This is just an update:

I have found a suitable casing for my Lipo voltage Indicator. It is actually the cover of a blade storage box. Fits perfectly, just need to seal the back. Soldered the 2 wires directly to the battery connector.

The LED works fine and lights up bright when the LIPO voltage drops below 9.5v during flight.

Please refer to the attached photo....

[nizamysf]

hi bro,
i think this is the update for your circuit diagram as the one you are having have problems when operating at high current.
latest diagram

[w_kby]

Hi Nizam,

Thanks alot....didn't realise there was a revised version. Will see if there are big differences....

When will you be coming for FF again?

See ya!

hi bro,
i think this is the update for your circuit diagram as the one you are having have problems when operating at high current.
latest diagram

[zattan22]

help needed.............

i have just done up the volt meter

but the LED lighted up even in 4.8v,9v and 11.1v

it seems that the meter is not working
..................

btw i try turning the 1k trim
but at all volt,,, the LED lighted up

[w_kby]

Hi zattan22,

This is a rather easy DIY and it should work if you have followed all the values and wiring correctly. I suggest you carefully recheck your circuit.

As for me, I did not use the design with the trimmer. Till now it works perfectly.

help needed.............

i have just done up the volt meter

but the LED lighted up even in 4.8v,9v and 11.1v

it seems that the meter is not working
..................

btw i try turning the 1k trim
but at all volt,,, the LED lighted up

[zattan22]

just got the volt meter to re-check the V in adn out of the trimmer

[zattan22]

is urs version 1 or 2????

i tried version 2 but the readings before and after the trimmer is 7.7v and 0.29v
how to get 7v plus and 9v plus as stated in the diagram

if no one can help,,

ii have to convert to the version one without trimmer liao

[w_kby]

Hi zattan22,

I did the simple version 1 without the variable resistor. However, if you do that, you need to ensure that the tolerance of the resistors are very small, else the triggle voltage will not be accurate.

I am not sure what you mean by "the readings before and after the trimmer"??

Based on what I understand, 'detection voltage' is the operating voltage range of the circuit while adjusting the trimmer port from min to max. In other words, if you set the port to min position, its 'detection voltage is 7.7v and with the trimmer at max position, the 'detection voltage is 9.8v. (ie for 3s)

It is not meant to tell you the voltage level before and after the trimmer point.

What I did is to use a few 9 volt batteries with different voltages to test out the functionality of the circuit. If you have a variable DC Power supply, you can input it to the circult and trim the circuit (VR1) till the LED lights up at your prefered voltage level. Based on you 3s circuitry, the range it operate is 7.7v to 9.8v.

and....be happy, this is a hobby

Hope this HelPs

is urs version 1 or 2????

i tried version 2 but the readings before and after the trimmer is 7.7v and 0.29v
how to get 7v plus and 9v plus as stated in the diagram

if no one can help,,

ii have to convert to the version one without trimmer liao

[zattan22]

huh..............

btw the volt meter connect to
the receiver by using y-cable???
or
connect to the batt and the esc???

[w_kby]

I would call it Voltage monitor iso voltmeter to avoid confussion.

You connect the Lipo Voltage Monitor to the battery connector in parallel. Just use a small wire to tap to the battery connector directly (not the battery!)

hOpE thIs HelPs

huh..............

btw the volt meter connect to
the receiver by using y-cable???
or
connect to the batt and the esc???

[khpan2003]

huh..............

btw the volt meter connect to
the receiver by using y-cable???
or
connect to the batt and the esc???

The receiver point => ~5V only...

[zattan22]

i have done up the voltage meter

but can not find the 3.6M ohms resistor

may i know where to but them???

currently, im using 3.9M ohms resistor for R1

but the LED only flackle dimmly.......

Pls help.............thanks

[w_kby]

Hi zattan22,

Did you follow the circuit closely?

From what I see, R1 should be 1k ohm not 3.9M ohm and R3 should be 560 ohm resistors.

If you are using 2s battery, then you select 820 ohm for R2

If you are using 3s battery, then you select 2.2k ohm for R2

If you are using 4s battery, then you select 3.9k ohm for R2

You are using the wrong value for R1. Also, you need select the correct type of LED - Ultra Red LED as different LED has slightly different operating voltage.

You can get any kind of value the resistors at Sim Lim Tower. Many shop at basement also sells them.

hOpE ThiS HelPs

i have done up the voltage meter

but can not find the 3.6M ohms resistor

may i know where to but them???

currently, im using 3.9M ohms resistor for R1

but the LED only flackle dimmly.......

Pls help.............thanks

[zattan22]

sorry....
for the misunderstanding.

im doing the 1st version of volt meter....
it only have 2 resistor...

for the version 2,
i have give up liao

the version 1
has only 2 resistor
1st R1 is 3.6M ohms and R2 is 510K ohms

but i can only manage to get R1 3.9M ohms