Monitoring Voltage and Current across Leisure Battery

[mihirshah100]

Hello

I am trying to design a circuit that will enable me to monitor the voltage across a leisure battery. I have attached a schematic below.


The problem I am facing is that I can only monitor the voltage between 9V and 12V

I would like to expand this range to between 6V and 12V.
[This is part of a project I am doing for charging up to 8 phones via a USB port]

I originally got the idea for this part of the project from the link below:
https://www.engineersgarage.com/contribution/voltage-level-display-12v-battery

I have made changes to the op am used and tried to change the values of the LEDs.

Please advice
Thank you in advance

 

[MikeMl]

I assume that Leisure Battery is a Sealed Lead Acid battery (SLA). If you discharge a 12V SLA to lower than ~11.5V, then you have permanently damaged it. Read the maker's data sheet. During charging, the voltage should not exceed 14.4V.

Your voltmeter should indicate the range from 11V to 15V, and you should stop discharging the battery when the voltage drops to ~11.5V.

I hope you are using an efficient Buck Switching Voltage regulator to get from 12V to 5V. If not you are wasting more than half the available battery power.

Since your final load is 5V, I would have started with a 6V SLA. That would have made the voltage conversion process even more efficient.

 

[mihirshah100]

Thank you for your reply

I am using a Gelled electrolyte Battery.
This part of design is aiming to measure the voltage of the battery so it does not become too low.

Here is a brief summary of what I am planning to make.


The input voltage is the voltage from the battery. The 8 different units is the USB ports with an output voltage of 5V so mobile phones can be connected to them to be charged.

What I am trying to do is measure the voltage across the battery so it can let the user know if there is not enough voltage to charge the mobile phones.

 

[mihirshah100]

Thank you for your reply

I am using a Gelled electrolyte Battery.
This part of design is aiming to measure the voltage of the battery so it does not become too low.

Here is a brief summary of what I am planning to make.


The input voltage is the voltage from the battery. The 8 different units is the USB ports with an output voltage of 5V so mobile phones can be connected to them to be charged.

What I am trying to do is measure the voltage across the battery so it can let the user know if there is not enough voltage to charge the mobile phones.

 

[MikeMl]

...I am using a Gelled electrolyte Battery....

Gelled electrolyte Battery = Sealed Lead Acid Battery = SLA = Absorbed Glass Mat Battery = AGM

All my comments above still apply. Do not discharge below 11V, or you will soon be buying a new battery.